--- /dev/null
+From c69dc5230c9d9e40b853f6ee7cd81afa0f2437d7 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:01 +0200
+Subject: ARM: cpu: Switch to arch_cpu_finalize_init()
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit ee31bb0524a2e7c99b03f50249a411cc1eaa411f upstream
+
+check_bugs() is about to be phased out. Switch over to the new
+arch_cpu_finalize_init() implementation.
+
+No functional change.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20230613224545.078124882@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/arm/Kconfig | 1 +
+ arch/arm/include/asm/bugs.h | 4 ----
+ arch/arm/kernel/bugs.c | 3 ++-
+ 3 files changed, 3 insertions(+), 5 deletions(-)
+
+--- a/arch/arm/Kconfig
++++ b/arch/arm/Kconfig
+@@ -5,6 +5,7 @@ config ARM
+ select ARCH_32BIT_OFF_T
+ select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE if HAVE_KRETPROBES && FRAME_POINTER && !ARM_UNWIND
+ select ARCH_HAS_BINFMT_FLAT
++ select ARCH_HAS_CPU_FINALIZE_INIT if MMU
+ select ARCH_HAS_CURRENT_STACK_POINTER
+ select ARCH_HAS_DEBUG_VIRTUAL if MMU
+ select ARCH_HAS_DMA_WRITE_COMBINE if !ARM_DMA_MEM_BUFFERABLE
+--- a/arch/arm/include/asm/bugs.h
++++ b/arch/arm/include/asm/bugs.h
+@@ -1,7 +1,5 @@
+ /* SPDX-License-Identifier: GPL-2.0-only */
+ /*
+- * arch/arm/include/asm/bugs.h
+- *
+ * Copyright (C) 1995-2003 Russell King
+ */
+ #ifndef __ASM_BUGS_H
+@@ -10,10 +8,8 @@
+ extern void check_writebuffer_bugs(void);
+
+ #ifdef CONFIG_MMU
+-extern void check_bugs(void);
+ extern void check_other_bugs(void);
+ #else
+-#define check_bugs() do { } while (0)
+ #define check_other_bugs() do { } while (0)
+ #endif
+
+--- a/arch/arm/kernel/bugs.c
++++ b/arch/arm/kernel/bugs.c
+@@ -1,5 +1,6 @@
+ // SPDX-License-Identifier: GPL-2.0
+ #include <linux/init.h>
++#include <linux/cpu.h>
+ #include <asm/bugs.h>
+ #include <asm/proc-fns.h>
+
+@@ -11,7 +12,7 @@ void check_other_bugs(void)
+ #endif
+ }
+
+-void __init check_bugs(void)
++void __init arch_cpu_finalize_init(void)
+ {
+ check_writebuffer_bugs();
+ check_other_bugs();
--- /dev/null
+From 1b0fc0345f2852ffe54fb9ae0e12e2ee69ad6a20 Mon Sep 17 00:00:00 2001
+From: Dave Hansen <dave.hansen@linux.intel.com>
+Date: Tue, 1 Aug 2023 07:31:07 -0700
+Subject: Documentation/x86: Fix backwards on/off logic about YMM support
+
+From: Dave Hansen <dave.hansen@linux.intel.com>
+
+commit 1b0fc0345f2852ffe54fb9ae0e12e2ee69ad6a20 upstream
+
+These options clearly turn *off* XSAVE YMM support. Correct the
+typo.
+
+Reported-by: Ben Hutchings <ben@decadent.org.uk>
+Fixes: 553a5c03e90a ("x86/speculation: Add force option to GDS mitigation")
+Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ Documentation/admin-guide/hw-vuln/gather_data_sampling.rst | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/Documentation/admin-guide/hw-vuln/gather_data_sampling.rst
++++ b/Documentation/admin-guide/hw-vuln/gather_data_sampling.rst
+@@ -63,7 +63,7 @@ GDS can also be mitigated on systems tha
+ disabling AVX. This can be done by setting gather_data_sampling="force" or
+ "clearcpuid=avx" on the kernel command-line.
+
+-If used, these options will disable AVX use by turning on XSAVE YMM support.
++If used, these options will disable AVX use by turning off XSAVE YMM support.
+ However, the processor will still enumerate AVX support. Userspace that
+ does not follow proper AVX enumeration to check both AVX *and* XSAVE YMM
+ support will break.
--- /dev/null
+From 61e7082cb2b45de89543b4ea8891e55552261ba1 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:01 +0200
+Subject: ia64/cpu: Switch to arch_cpu_finalize_init()
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 6c38e3005621800263f117fb00d6787a76e16de7 upstream
+
+check_bugs() is about to be phased out. Switch over to the new
+arch_cpu_finalize_init() implementation.
+
+No functional change.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20230613224545.137045745@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/ia64/Kconfig | 1 +
+ arch/ia64/include/asm/bugs.h | 20 --------------------
+ arch/ia64/kernel/setup.c | 3 +--
+ 3 files changed, 2 insertions(+), 22 deletions(-)
+ delete mode 100644 arch/ia64/include/asm/bugs.h
+
+--- a/arch/ia64/Kconfig
++++ b/arch/ia64/Kconfig
+@@ -9,6 +9,7 @@ menu "Processor type and features"
+ config IA64
+ bool
+ select ARCH_BINFMT_ELF_EXTRA_PHDRS
++ select ARCH_HAS_CPU_FINALIZE_INIT
+ select ARCH_HAS_DMA_MARK_CLEAN
+ select ARCH_HAS_STRNCPY_FROM_USER
+ select ARCH_HAS_STRNLEN_USER
+--- a/arch/ia64/include/asm/bugs.h
++++ /dev/null
+@@ -1,20 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-/*
+- * This is included by init/main.c to check for architecture-dependent bugs.
+- *
+- * Needs:
+- * void check_bugs(void);
+- *
+- * Based on <asm-alpha/bugs.h>.
+- *
+- * Modified 1998, 1999, 2003
+- * David Mosberger-Tang <davidm@hpl.hp.com>, Hewlett-Packard Co.
+- */
+-#ifndef _ASM_IA64_BUGS_H
+-#define _ASM_IA64_BUGS_H
+-
+-#include <asm/processor.h>
+-
+-extern void check_bugs (void);
+-
+-#endif /* _ASM_IA64_BUGS_H */
+--- a/arch/ia64/kernel/setup.c
++++ b/arch/ia64/kernel/setup.c
+@@ -1067,8 +1067,7 @@ cpu_init (void)
+ }
+ }
+
+-void __init
+-check_bugs (void)
++void __init arch_cpu_finalize_init(void)
+ {
+ ia64_patch_mckinley_e9((unsigned long) __start___mckinley_e9_bundles,
+ (unsigned long) __end___mckinley_e9_bundles);
--- /dev/null
+From 4fdd6f04b4ca81df1d5dcd14cbc6d81032d8cbcc Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:11 +0200
+Subject: init: Invoke arch_cpu_finalize_init() earlier
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 9df9d2f0471b4c4702670380b8d8a45b40b23a7d upstream
+
+X86 is reworking the boot process so that initializations which are not
+required during early boot can be moved into the late boot process and out
+of the fragile and restricted initial boot phase.
+
+arch_cpu_finalize_init() is the obvious place to do such initializations,
+but arch_cpu_finalize_init() is invoked too late in start_kernel() e.g. for
+initializing the FPU completely. fork_init() requires that the FPU is
+initialized as the size of task_struct on X86 depends on the size of the
+required FPU register buffer.
+
+Fortunately none of the init calls between calibrate_delay() and
+arch_cpu_finalize_init() is relevant for the functionality of
+arch_cpu_finalize_init().
+
+Invoke it right after calibrate_delay() where everything which is relevant
+for arch_cpu_finalize_init() has been set up already.
+
+No functional change intended.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
+Link: https://lore.kernel.org/r/20230613224545.612182854@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ init/main.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/init/main.c
++++ b/init/main.c
+@@ -1042,6 +1042,8 @@ void start_kernel(void)
+ sched_clock_init();
+ calibrate_delay();
+
++ arch_cpu_finalize_init();
++
+ /*
+ * This needs to be called before any devices perform DMA
+ * operations that might use the SWIOTLB bounce buffers. It will
+@@ -1078,8 +1080,6 @@ void start_kernel(void)
+ taskstats_init_early();
+ delayacct_init();
+
+- arch_cpu_finalize_init();
+-
+ acpi_subsystem_init();
+ arch_post_acpi_subsys_init();
+ kcsan_init();
--- /dev/null
+From ceb84c9ee5096a55fa0abe6f393b56731db31b95 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:01 +0200
+Subject: init: Provide arch_cpu_finalize_init()
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 7725acaa4f0c04fbefb0e0d342635b967bb7d414 upstream
+
+check_bugs() has become a dumping ground for all sorts of activities to
+finalize the CPU initialization before running the rest of the init code.
+
+Most are empty, a few do actual bug checks, some do alternative patching
+and some cobble a CPU advertisement string together....
+
+Aside of that the current implementation requires duplicated function
+declaration and mostly empty header files for them.
+
+Provide a new function arch_cpu_finalize_init(). Provide a generic
+declaration if CONFIG_ARCH_HAS_CPU_FINALIZE_INIT is selected and a stub
+inline otherwise.
+
+This requires a temporary #ifdef in start_kernel() which will be removed
+along with check_bugs() once the architectures are converted over.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20230613224544.957805717@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/Kconfig | 3 +++
+ include/linux/cpu.h | 6 ++++++
+ init/main.c | 4 ++++
+ 3 files changed, 13 insertions(+)
+
+--- a/arch/Kconfig
++++ b/arch/Kconfig
+@@ -285,6 +285,9 @@ config ARCH_HAS_DMA_SET_UNCACHED
+ config ARCH_HAS_DMA_CLEAR_UNCACHED
+ bool
+
++config ARCH_HAS_CPU_FINALIZE_INIT
++ bool
++
+ # Select if arch init_task must go in the __init_task_data section
+ config ARCH_TASK_STRUCT_ON_STACK
+ bool
+--- a/include/linux/cpu.h
++++ b/include/linux/cpu.h
+@@ -184,6 +184,12 @@ void arch_cpu_idle_enter(void);
+ void arch_cpu_idle_exit(void);
+ void __noreturn arch_cpu_idle_dead(void);
+
++#ifdef CONFIG_ARCH_HAS_CPU_FINALIZE_INIT
++void arch_cpu_finalize_init(void);
++#else
++static inline void arch_cpu_finalize_init(void) { }
++#endif
++
+ int cpu_report_state(int cpu);
+ int cpu_check_up_prepare(int cpu);
+ void cpu_set_state_online(int cpu);
+--- a/init/main.c
++++ b/init/main.c
+@@ -1079,7 +1079,11 @@ void start_kernel(void)
+ taskstats_init_early();
+ delayacct_init();
+
++ arch_cpu_finalize_init();
++ /* Temporary conditional until everything has been converted */
++#ifndef CONFIG_ARCH_HAS_CPU_FINALIZE_INIT
+ check_bugs();
++#endif
+
+ acpi_subsystem_init();
+ arch_post_acpi_subsys_init();
--- /dev/null
+From 5faac9b05f3be6723a9875ef0ffe53dbcb6f4f37 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:11 +0200
+Subject: init: Remove check_bugs() leftovers
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 61235b24b9cb37c13fcad5b9596d59a1afdcec30 upstream
+
+Everything is converted over to arch_cpu_finalize_init(). Remove the
+check_bugs() leftovers including the empty stubs in asm-generic, alpha,
+parisc, powerpc and xtensa.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
+Link: https://lore.kernel.org/r/20230613224545.553215951@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/alpha/include/asm/bugs.h | 20 --------------------
+ arch/parisc/include/asm/bugs.h | 20 --------------------
+ arch/powerpc/include/asm/bugs.h | 15 ---------------
+ arch/xtensa/include/asm/bugs.h | 18 ------------------
+ include/asm-generic/bugs.h | 11 -----------
+ init/main.c | 5 -----
+ 6 files changed, 89 deletions(-)
+ delete mode 100644 arch/alpha/include/asm/bugs.h
+ delete mode 100644 arch/parisc/include/asm/bugs.h
+ delete mode 100644 arch/powerpc/include/asm/bugs.h
+ delete mode 100644 arch/xtensa/include/asm/bugs.h
+ delete mode 100644 include/asm-generic/bugs.h
+
+--- a/arch/alpha/include/asm/bugs.h
++++ /dev/null
+@@ -1,20 +0,0 @@
+-/*
+- * include/asm-alpha/bugs.h
+- *
+- * Copyright (C) 1994 Linus Torvalds
+- */
+-
+-/*
+- * This is included by init/main.c to check for architecture-dependent bugs.
+- *
+- * Needs:
+- * void check_bugs(void);
+- */
+-
+-/*
+- * I don't know of any alpha bugs yet.. Nice chip
+- */
+-
+-static void check_bugs(void)
+-{
+-}
+--- a/arch/parisc/include/asm/bugs.h
++++ /dev/null
+@@ -1,20 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-/*
+- * include/asm-parisc/bugs.h
+- *
+- * Copyright (C) 1999 Mike Shaver
+- */
+-
+-/*
+- * This is included by init/main.c to check for architecture-dependent bugs.
+- *
+- * Needs:
+- * void check_bugs(void);
+- */
+-
+-#include <asm/processor.h>
+-
+-static inline void check_bugs(void)
+-{
+-// identify_cpu(&boot_cpu_data);
+-}
+--- a/arch/powerpc/include/asm/bugs.h
++++ /dev/null
+@@ -1,15 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0-or-later */
+-#ifndef _ASM_POWERPC_BUGS_H
+-#define _ASM_POWERPC_BUGS_H
+-
+-/*
+- */
+-
+-/*
+- * This file is included by 'init/main.c' to check for
+- * architecture-dependent bugs.
+- */
+-
+-static inline void check_bugs(void) { }
+-
+-#endif /* _ASM_POWERPC_BUGS_H */
+--- a/arch/xtensa/include/asm/bugs.h
++++ /dev/null
+@@ -1,18 +0,0 @@
+-/*
+- * include/asm-xtensa/bugs.h
+- *
+- * This is included by init/main.c to check for architecture-dependent bugs.
+- *
+- * Xtensa processors don't have any bugs. :)
+- *
+- * This file is subject to the terms and conditions of the GNU General
+- * Public License. See the file "COPYING" in the main directory of
+- * this archive for more details.
+- */
+-
+-#ifndef _XTENSA_BUGS_H
+-#define _XTENSA_BUGS_H
+-
+-static void check_bugs(void) { }
+-
+-#endif /* _XTENSA_BUGS_H */
+--- a/include/asm-generic/bugs.h
++++ /dev/null
+@@ -1,11 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-#ifndef __ASM_GENERIC_BUGS_H
+-#define __ASM_GENERIC_BUGS_H
+-/*
+- * This file is included by 'init/main.c' to check for
+- * architecture-dependent bugs.
+- */
+-
+-static inline void check_bugs(void) { }
+-
+-#endif /* __ASM_GENERIC_BUGS_H */
+--- a/init/main.c
++++ b/init/main.c
+@@ -103,7 +103,6 @@
+ #include <net/net_namespace.h>
+
+ #include <asm/io.h>
+-#include <asm/bugs.h>
+ #include <asm/setup.h>
+ #include <asm/sections.h>
+ #include <asm/cacheflush.h>
+@@ -1080,10 +1079,6 @@ void start_kernel(void)
+ delayacct_init();
+
+ arch_cpu_finalize_init();
+- /* Temporary conditional until everything has been converted */
+-#ifndef CONFIG_ARCH_HAS_CPU_FINALIZE_INIT
+- check_bugs();
+-#endif
+
+ acpi_subsystem_init();
+ arch_post_acpi_subsys_init();
--- /dev/null
+From 3c4b3e3fb4b9456bf58eafd307f0297145da23ed Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:11 +0200
+Subject: init, x86: Move mem_encrypt_init() into arch_cpu_finalize_init()
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 439e17576eb47f26b78c5bbc72e344d4206d2327 upstream
+
+Invoke the X86ism mem_encrypt_init() from X86 arch_cpu_finalize_init() and
+remove the weak fallback from the core code.
+
+No functional change.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20230613224545.670360645@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/include/asm/mem_encrypt.h | 7 ++++---
+ arch/x86/kernel/cpu/common.c | 11 +++++++++++
+ init/main.c | 13 -------------
+ 3 files changed, 15 insertions(+), 16 deletions(-)
+
+--- a/arch/x86/include/asm/mem_encrypt.h
++++ b/arch/x86/include/asm/mem_encrypt.h
+@@ -51,6 +51,8 @@ void __init mem_encrypt_free_decrypted_m
+
+ void __init sev_es_init_vc_handling(void);
+
++void __init mem_encrypt_init(void);
++
+ #define __bss_decrypted __section(".bss..decrypted")
+
+ #else /* !CONFIG_AMD_MEM_ENCRYPT */
+@@ -83,13 +85,12 @@ early_set_mem_enc_dec_hypercall(unsigned
+
+ static inline void mem_encrypt_free_decrypted_mem(void) { }
+
++static inline void mem_encrypt_init(void) { }
++
+ #define __bss_decrypted
+
+ #endif /* CONFIG_AMD_MEM_ENCRYPT */
+
+-/* Architecture __weak replacement functions */
+-void __init mem_encrypt_init(void);
+-
+ void add_encrypt_protection_map(void);
+
+ /*
+--- a/arch/x86/kernel/cpu/common.c
++++ b/arch/x86/kernel/cpu/common.c
+@@ -18,6 +18,7 @@
+ #include <linux/init.h>
+ #include <linux/kprobes.h>
+ #include <linux/kgdb.h>
++#include <linux/mem_encrypt.h>
+ #include <linux/smp.h>
+ #include <linux/cpu.h>
+ #include <linux/io.h>
+@@ -2416,4 +2417,14 @@ void __init arch_cpu_finalize_init(void)
+ } else {
+ fpu__init_check_bugs();
+ }
++
++ /*
++ * This needs to be called before any devices perform DMA
++ * operations that might use the SWIOTLB bounce buffers. It will
++ * mark the bounce buffers as decrypted so that their usage will
++ * not cause "plain-text" data to be decrypted when accessed. It
++ * must be called after late_time_init() so that Hyper-V x86/x64
++ * hypercalls work when the SWIOTLB bounce buffers are decrypted.
++ */
++ mem_encrypt_init();
+ }
+--- a/init/main.c
++++ b/init/main.c
+@@ -95,7 +95,6 @@
+ #include <linux/cache.h>
+ #include <linux/rodata_test.h>
+ #include <linux/jump_label.h>
+-#include <linux/mem_encrypt.h>
+ #include <linux/kcsan.h>
+ #include <linux/init_syscalls.h>
+ #include <linux/stackdepot.h>
+@@ -786,8 +785,6 @@ void __init __weak thread_stack_cache_in
+ }
+ #endif
+
+-void __init __weak mem_encrypt_init(void) { }
+-
+ void __init __weak poking_init(void) { }
+
+ void __init __weak pgtable_cache_init(void) { }
+@@ -1044,16 +1041,6 @@ void start_kernel(void)
+
+ arch_cpu_finalize_init();
+
+- /*
+- * This needs to be called before any devices perform DMA
+- * operations that might use the SWIOTLB bounce buffers. It will
+- * mark the bounce buffers as decrypted so that their usage will
+- * not cause "plain-text" data to be decrypted when accessed. It
+- * must be called after late_time_init() so that Hyper-V x86/x64
+- * hypercalls work when the SWIOTLB bounce buffers are decrypted.
+- */
+- mem_encrypt_init();
+-
+ pid_idr_init();
+ anon_vma_init();
+ #ifdef CONFIG_X86
--- /dev/null
+From 1d5122ddea93de52adc82ef3b98759a9eda73da2 Mon Sep 17 00:00:00 2001
+From: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Date: Tue, 1 Aug 2023 16:07:15 +0200
+Subject: KVM: Add GDS_NO support to KVM
+
+From: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+
+commit 81ac7e5d741742d650b4ed6186c4826c1a0631a7 upstream
+
+Gather Data Sampling (GDS) is a transient execution attack using
+gather instructions from the AVX2 and AVX512 extensions. This attack
+allows malicious code to infer data that was previously stored in
+vector registers. Systems that are not vulnerable to GDS will set the
+GDS_NO bit of the IA32_ARCH_CAPABILITIES MSR. This is useful for VM
+guests that may think they are on vulnerable systems that are, in
+fact, not affected. Guests that are running on affected hosts where
+the mitigation is enabled are protected as if they were running
+on an unaffected system.
+
+On all hosts that are not affected or that are mitigated, set the
+GDS_NO bit.
+
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
+Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/kernel/cpu/bugs.c | 7 +++++++
+ arch/x86/kvm/x86.c | 7 ++++++-
+ 2 files changed, 13 insertions(+), 1 deletion(-)
+
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -674,6 +674,13 @@ static const char * const gds_strings[]
+ [GDS_MITIGATION_HYPERVISOR] = "Unknown: Dependent on hypervisor status",
+ };
+
++bool gds_ucode_mitigated(void)
++{
++ return (gds_mitigation == GDS_MITIGATION_FULL ||
++ gds_mitigation == GDS_MITIGATION_FULL_LOCKED);
++}
++EXPORT_SYMBOL_GPL(gds_ucode_mitigated);
++
+ void update_gds_msr(void)
+ {
+ u64 mcu_ctrl_after;
+--- a/arch/x86/kvm/x86.c
++++ b/arch/x86/kvm/x86.c
+@@ -314,6 +314,8 @@ u64 __read_mostly host_xcr0;
+
+ static struct kmem_cache *x86_emulator_cache;
+
++extern bool gds_ucode_mitigated(void);
++
+ /*
+ * When called, it means the previous get/set msr reached an invalid msr.
+ * Return true if we want to ignore/silent this failed msr access.
+@@ -1617,7 +1619,7 @@ static bool kvm_is_immutable_feature_msr
+ ARCH_CAP_SKIP_VMENTRY_L1DFLUSH | ARCH_CAP_SSB_NO | ARCH_CAP_MDS_NO | \
+ ARCH_CAP_PSCHANGE_MC_NO | ARCH_CAP_TSX_CTRL_MSR | ARCH_CAP_TAA_NO | \
+ ARCH_CAP_SBDR_SSDP_NO | ARCH_CAP_FBSDP_NO | ARCH_CAP_PSDP_NO | \
+- ARCH_CAP_FB_CLEAR | ARCH_CAP_RRSBA | ARCH_CAP_PBRSB_NO)
++ ARCH_CAP_FB_CLEAR | ARCH_CAP_RRSBA | ARCH_CAP_PBRSB_NO | ARCH_CAP_GDS_NO)
+
+ static u64 kvm_get_arch_capabilities(void)
+ {
+@@ -1674,6 +1676,9 @@ static u64 kvm_get_arch_capabilities(voi
+ */
+ }
+
++ if (!boot_cpu_has_bug(X86_BUG_GDS) || gds_ucode_mitigated())
++ data |= ARCH_CAP_GDS_NO;
++
+ return data;
+ }
+
--- /dev/null
+From 7d5118648e6aced4e497409be3115f9df88f2069 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:01 +0200
+Subject: loongarch/cpu: Switch to arch_cpu_finalize_init()
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 9841c423164787feb8f1442f922b7d80a70c82f1 upstream
+
+check_bugs() is about to be phased out. Switch over to the new
+arch_cpu_finalize_init() implementation.
+
+No functional change.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20230613224545.195288218@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/loongarch/Kconfig | 1 +
+ arch/loongarch/include/asm/bugs.h | 15 ---------------
+ arch/loongarch/kernel/setup.c | 4 ++--
+ 3 files changed, 3 insertions(+), 17 deletions(-)
+ delete mode 100644 arch/loongarch/include/asm/bugs.h
+
+--- a/arch/loongarch/Kconfig
++++ b/arch/loongarch/Kconfig
+@@ -10,6 +10,7 @@ config LOONGARCH
+ select ARCH_ENABLE_MEMORY_HOTPLUG
+ select ARCH_ENABLE_MEMORY_HOTREMOVE
+ select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
++ select ARCH_HAS_CPU_FINALIZE_INIT
+ select ARCH_HAS_FORTIFY_SOURCE
+ select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
+ select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+--- a/arch/loongarch/include/asm/bugs.h
++++ /dev/null
+@@ -1,15 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-/*
+- * This is included by init/main.c to check for architecture-dependent bugs.
+- *
+- * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+- */
+-#ifndef _ASM_BUGS_H
+-#define _ASM_BUGS_H
+-
+-#include <asm/cpu.h>
+-#include <asm/cpu-info.h>
+-
+-extern void check_bugs(void);
+-
+-#endif /* _ASM_BUGS_H */
+--- a/arch/loongarch/kernel/setup.c
++++ b/arch/loongarch/kernel/setup.c
+@@ -12,6 +12,7 @@
+ */
+ #include <linux/init.h>
+ #include <linux/acpi.h>
++#include <linux/cpu.h>
+ #include <linux/dmi.h>
+ #include <linux/efi.h>
+ #include <linux/export.h>
+@@ -37,7 +38,6 @@
+ #include <asm/addrspace.h>
+ #include <asm/alternative.h>
+ #include <asm/bootinfo.h>
+-#include <asm/bugs.h>
+ #include <asm/cache.h>
+ #include <asm/cpu.h>
+ #include <asm/dma.h>
+@@ -87,7 +87,7 @@ const char *get_system_type(void)
+ return "generic-loongson-machine";
+ }
+
+-void __init check_bugs(void)
++void __init arch_cpu_finalize_init(void)
+ {
+ alternative_instructions();
+ }
--- /dev/null
+From 4e7bd983cb22029f0de97f9111c48ebce22a3dd7 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:01 +0200
+Subject: m68k/cpu: Switch to arch_cpu_finalize_init()
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 9ceecc2589b9d7cef6b321339ed8de484eac4b20 upstream
+
+check_bugs() is about to be phased out. Switch over to the new
+arch_cpu_finalize_init() implementation.
+
+No functional change.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
+Link: https://lore.kernel.org/r/20230613224545.254342916@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/m68k/Kconfig | 1 +
+ arch/m68k/include/asm/bugs.h | 21 ---------------------
+ arch/m68k/kernel/setup_mm.c | 3 ++-
+ 3 files changed, 3 insertions(+), 22 deletions(-)
+ delete mode 100644 arch/m68k/include/asm/bugs.h
+
+--- a/arch/m68k/Kconfig
++++ b/arch/m68k/Kconfig
+@@ -4,6 +4,7 @@ config M68K
+ default y
+ select ARCH_32BIT_OFF_T
+ select ARCH_HAS_BINFMT_FLAT
++ select ARCH_HAS_CPU_FINALIZE_INIT if MMU
+ select ARCH_HAS_CURRENT_STACK_POINTER
+ select ARCH_HAS_DMA_PREP_COHERENT if HAS_DMA && MMU && !COLDFIRE
+ select ARCH_HAS_SYNC_DMA_FOR_DEVICE if HAS_DMA
+--- a/arch/m68k/include/asm/bugs.h
++++ /dev/null
+@@ -1,21 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-/*
+- * include/asm-m68k/bugs.h
+- *
+- * Copyright (C) 1994 Linus Torvalds
+- */
+-
+-/*
+- * This is included by init/main.c to check for architecture-dependent bugs.
+- *
+- * Needs:
+- * void check_bugs(void);
+- */
+-
+-#ifdef CONFIG_MMU
+-extern void check_bugs(void); /* in arch/m68k/kernel/setup.c */
+-#else
+-static void check_bugs(void)
+-{
+-}
+-#endif
+--- a/arch/m68k/kernel/setup_mm.c
++++ b/arch/m68k/kernel/setup_mm.c
+@@ -10,6 +10,7 @@
+ */
+
+ #include <linux/kernel.h>
++#include <linux/cpu.h>
+ #include <linux/mm.h>
+ #include <linux/sched.h>
+ #include <linux/delay.h>
+@@ -504,7 +505,7 @@ static int __init proc_hardware_init(voi
+ module_init(proc_hardware_init);
+ #endif
+
+-void check_bugs(void)
++void __init arch_cpu_finalize_init(void)
+ {
+ #if defined(CONFIG_FPU) && !defined(CONFIG_M68KFPU_EMU)
+ if (m68k_fputype == 0) {
--- /dev/null
+From 76b76cd878a982ad3ef0c1a74bc5424550024d0b Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:02 +0200
+Subject: mips/cpu: Switch to arch_cpu_finalize_init()
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 7f066a22fe353a827a402ee2835e81f045b1574d upstream
+
+check_bugs() is about to be phased out. Switch over to the new
+arch_cpu_finalize_init() implementation.
+
+No functional change.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20230613224545.312438573@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/mips/Kconfig | 1 +
+ arch/mips/include/asm/bugs.h | 17 -----------------
+ arch/mips/kernel/setup.c | 13 +++++++++++++
+ 3 files changed, 14 insertions(+), 17 deletions(-)
+
+--- a/arch/mips/Kconfig
++++ b/arch/mips/Kconfig
+@@ -4,6 +4,7 @@ config MIPS
+ default y
+ select ARCH_32BIT_OFF_T if !64BIT
+ select ARCH_BINFMT_ELF_STATE if MIPS_FP_SUPPORT
++ select ARCH_HAS_CPU_FINALIZE_INIT
+ select ARCH_HAS_CURRENT_STACK_POINTER if !CC_IS_CLANG || CLANG_VERSION >= 140000
+ select ARCH_HAS_DEBUG_VIRTUAL if !64BIT
+ select ARCH_HAS_FORTIFY_SOURCE
+--- a/arch/mips/include/asm/bugs.h
++++ b/arch/mips/include/asm/bugs.h
+@@ -1,17 +1,11 @@
+ /* SPDX-License-Identifier: GPL-2.0 */
+ /*
+- * This is included by init/main.c to check for architecture-dependent bugs.
+- *
+ * Copyright (C) 2007 Maciej W. Rozycki
+- *
+- * Needs:
+- * void check_bugs(void);
+ */
+ #ifndef _ASM_BUGS_H
+ #define _ASM_BUGS_H
+
+ #include <linux/bug.h>
+-#include <linux/delay.h>
+ #include <linux/smp.h>
+
+ #include <asm/cpu.h>
+@@ -24,17 +18,6 @@ extern void check_bugs64_early(void);
+ extern void check_bugs32(void);
+ extern void check_bugs64(void);
+
+-static inline void __init check_bugs(void)
+-{
+- unsigned int cpu = smp_processor_id();
+-
+- cpu_data[cpu].udelay_val = loops_per_jiffy;
+- check_bugs32();
+-
+- if (IS_ENABLED(CONFIG_CPU_R4X00_BUGS64))
+- check_bugs64();
+-}
+-
+ static inline int r4k_daddiu_bug(void)
+ {
+ if (!IS_ENABLED(CONFIG_CPU_R4X00_BUGS64))
+--- a/arch/mips/kernel/setup.c
++++ b/arch/mips/kernel/setup.c
+@@ -11,6 +11,8 @@
+ * Copyright (C) 2000, 2001, 2002, 2007 Maciej W. Rozycki
+ */
+ #include <linux/init.h>
++#include <linux/cpu.h>
++#include <linux/delay.h>
+ #include <linux/ioport.h>
+ #include <linux/export.h>
+ #include <linux/screen_info.h>
+@@ -841,3 +843,14 @@ static int __init setnocoherentio(char *
+ }
+ early_param("nocoherentio", setnocoherentio);
+ #endif
++
++void __init arch_cpu_finalize_init(void)
++{
++ unsigned int cpu = smp_processor_id();
++
++ cpu_data[cpu].udelay_val = loops_per_jiffy;
++ check_bugs32();
++
++ if (IS_ENABLED(CONFIG_CPU_R4X00_BUGS64))
++ check_bugs64();
++}
--- /dev/null
+init-provide-arch_cpu_finalize_init.patch
+x86-cpu-switch-to-arch_cpu_finalize_init.patch
+arm-cpu-switch-to-arch_cpu_finalize_init.patch
+ia64-cpu-switch-to-arch_cpu_finalize_init.patch
+loongarch-cpu-switch-to-arch_cpu_finalize_init.patch
+m68k-cpu-switch-to-arch_cpu_finalize_init.patch
+mips-cpu-switch-to-arch_cpu_finalize_init.patch
+sh-cpu-switch-to-arch_cpu_finalize_init.patch
+sparc-cpu-switch-to-arch_cpu_finalize_init.patch
+um-cpu-switch-to-arch_cpu_finalize_init.patch
+init-remove-check_bugs-leftovers.patch
+init-invoke-arch_cpu_finalize_init-earlier.patch
+init-x86-move-mem_encrypt_init-into-arch_cpu_finalize_init.patch
+x86-init-initialize-signal-frame-size-late.patch
+x86-fpu-remove-cpuinfo-argument-from-init-functions.patch
+x86-fpu-mark-init-functions-__init.patch
+x86-fpu-move-fpu-initialization-into-arch_cpu_finalize_init.patch
+x86-speculation-add-gather-data-sampling-mitigation.patch
+x86-speculation-add-force-option-to-gds-mitigation.patch
+x86-speculation-add-kconfig-option-for-gds.patch
+kvm-add-gds_no-support-to-kvm.patch
+x86-mem_encrypt-unbreak-the-amd_mem_encrypt-n-build.patch
+x86-xen-fix-secondary-processors-fpu-initialization.patch
+documentation-x86-fix-backwards-on-off-logic-about-ymm-support.patch
+x86-bugs-increase-the-x86-bugs-vector-size-to-two-u32s.patch
+x86-srso-add-a-speculative-ras-overflow-mitigation.patch
+x86-srso-add-ibpb_brtype-support.patch
+x86-srso-add-srso_no-support.patch
+x86-srso-add-ibpb.patch
+x86-srso-add-ibpb-on-vmexit.patch
+x86-srso-fix-return-thunks-in-generated-code.patch
+x86-srso-add-a-forgotten-noendbr-annotation.patch
+x86-srso-tie-sbpb-bit-setting-to-microcode-patch-detection.patch
+xen-netback-fix-buffer-overrun-triggered-by-unusual-packet.patch
+x86-fix-backwards-merge-of-gds-srso-bit.patch
--- /dev/null
+From 2cab3404534154a98538ac21ffbe0ba62d50d213 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:02 +0200
+Subject: sh/cpu: Switch to arch_cpu_finalize_init()
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 01eb454e9bfe593f320ecbc9aaec60bf87cd453d upstream
+
+check_bugs() is about to be phased out. Switch over to the new
+arch_cpu_finalize_init() implementation.
+
+No functional change.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20230613224545.371697797@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/sh/Kconfig | 1
+ arch/sh/include/asm/bugs.h | 74 ----------------------------------------
+ arch/sh/include/asm/processor.h | 2 +
+ arch/sh/kernel/idle.c | 1
+ arch/sh/kernel/setup.c | 55 +++++++++++++++++++++++++++++
+ 5 files changed, 59 insertions(+), 74 deletions(-)
+ delete mode 100644 arch/sh/include/asm/bugs.h
+
+--- a/arch/sh/Kconfig
++++ b/arch/sh/Kconfig
+@@ -6,6 +6,7 @@ config SUPERH
+ select ARCH_ENABLE_MEMORY_HOTREMOVE if SPARSEMEM && MMU
+ select ARCH_HAVE_NMI_SAFE_CMPXCHG if (GUSA_RB || CPU_SH4A)
+ select ARCH_HAS_BINFMT_FLAT if !MMU
++ select ARCH_HAS_CPU_FINALIZE_INIT
+ select ARCH_HAS_CURRENT_STACK_POINTER
+ select ARCH_HAS_GIGANTIC_PAGE
+ select ARCH_HAS_GCOV_PROFILE_ALL
+--- a/arch/sh/include/asm/bugs.h
++++ /dev/null
+@@ -1,74 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-#ifndef __ASM_SH_BUGS_H
+-#define __ASM_SH_BUGS_H
+-
+-/*
+- * This is included by init/main.c to check for architecture-dependent bugs.
+- *
+- * Needs:
+- * void check_bugs(void);
+- */
+-
+-/*
+- * I don't know of any Super-H bugs yet.
+- */
+-
+-#include <asm/processor.h>
+-
+-extern void select_idle_routine(void);
+-
+-static void __init check_bugs(void)
+-{
+- extern unsigned long loops_per_jiffy;
+- char *p = &init_utsname()->machine[2]; /* "sh" */
+-
+- select_idle_routine();
+-
+- current_cpu_data.loops_per_jiffy = loops_per_jiffy;
+-
+- switch (current_cpu_data.family) {
+- case CPU_FAMILY_SH2:
+- *p++ = '2';
+- break;
+- case CPU_FAMILY_SH2A:
+- *p++ = '2';
+- *p++ = 'a';
+- break;
+- case CPU_FAMILY_SH3:
+- *p++ = '3';
+- break;
+- case CPU_FAMILY_SH4:
+- *p++ = '4';
+- break;
+- case CPU_FAMILY_SH4A:
+- *p++ = '4';
+- *p++ = 'a';
+- break;
+- case CPU_FAMILY_SH4AL_DSP:
+- *p++ = '4';
+- *p++ = 'a';
+- *p++ = 'l';
+- *p++ = '-';
+- *p++ = 'd';
+- *p++ = 's';
+- *p++ = 'p';
+- break;
+- case CPU_FAMILY_UNKNOWN:
+- /*
+- * Specifically use CPU_FAMILY_UNKNOWN rather than
+- * default:, so we're able to have the compiler whine
+- * about unhandled enumerations.
+- */
+- break;
+- }
+-
+- printk("CPU: %s\n", get_cpu_subtype(¤t_cpu_data));
+-
+-#ifndef __LITTLE_ENDIAN__
+- /* 'eb' means 'Endian Big' */
+- *p++ = 'e';
+- *p++ = 'b';
+-#endif
+- *p = '\0';
+-}
+-#endif /* __ASM_SH_BUGS_H */
+--- a/arch/sh/include/asm/processor.h
++++ b/arch/sh/include/asm/processor.h
+@@ -166,6 +166,8 @@ extern unsigned int instruction_size(uns
+ #define instruction_size(insn) (2)
+ #endif
+
++void select_idle_routine(void);
++
+ #endif /* __ASSEMBLY__ */
+
+ #include <asm/processor_32.h>
+--- a/arch/sh/kernel/idle.c
++++ b/arch/sh/kernel/idle.c
+@@ -15,6 +15,7 @@
+ #include <linux/irqflags.h>
+ #include <linux/smp.h>
+ #include <linux/atomic.h>
++#include <asm/processor.h>
+ #include <asm/smp.h>
+ #include <asm/bl_bit.h>
+
+--- a/arch/sh/kernel/setup.c
++++ b/arch/sh/kernel/setup.c
+@@ -43,6 +43,7 @@
+ #include <asm/smp.h>
+ #include <asm/mmu_context.h>
+ #include <asm/mmzone.h>
++#include <asm/processor.h>
+ #include <asm/sparsemem.h>
+ #include <asm/platform_early.h>
+
+@@ -354,3 +355,57 @@ int test_mode_pin(int pin)
+ {
+ return sh_mv.mv_mode_pins() & pin;
+ }
++
++void __init arch_cpu_finalize_init(void)
++{
++ char *p = &init_utsname()->machine[2]; /* "sh" */
++
++ select_idle_routine();
++
++ current_cpu_data.loops_per_jiffy = loops_per_jiffy;
++
++ switch (current_cpu_data.family) {
++ case CPU_FAMILY_SH2:
++ *p++ = '2';
++ break;
++ case CPU_FAMILY_SH2A:
++ *p++ = '2';
++ *p++ = 'a';
++ break;
++ case CPU_FAMILY_SH3:
++ *p++ = '3';
++ break;
++ case CPU_FAMILY_SH4:
++ *p++ = '4';
++ break;
++ case CPU_FAMILY_SH4A:
++ *p++ = '4';
++ *p++ = 'a';
++ break;
++ case CPU_FAMILY_SH4AL_DSP:
++ *p++ = '4';
++ *p++ = 'a';
++ *p++ = 'l';
++ *p++ = '-';
++ *p++ = 'd';
++ *p++ = 's';
++ *p++ = 'p';
++ break;
++ case CPU_FAMILY_UNKNOWN:
++ /*
++ * Specifically use CPU_FAMILY_UNKNOWN rather than
++ * default:, so we're able to have the compiler whine
++ * about unhandled enumerations.
++ */
++ break;
++ }
++
++ pr_info("CPU: %s\n", get_cpu_subtype(¤t_cpu_data));
++
++#ifndef __LITTLE_ENDIAN__
++ /* 'eb' means 'Endian Big' */
++ *p++ = 'e';
++ *p++ = 'b';
++#endif
++ *p = '\0';
++}
--- /dev/null
+From be37d2c178f4fdf4c9c37329c8c82aa513a7a9fa Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:02 +0200
+Subject: sparc/cpu: Switch to arch_cpu_finalize_init()
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 44ade508e3bfac45ae97864587de29eb1a881ec0 upstream
+
+check_bugs() is about to be phased out. Switch over to the new
+arch_cpu_finalize_init() implementation.
+
+No functional change.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
+Link: https://lore.kernel.org/r/20230613224545.431995857@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/sparc/Kconfig | 1 +
+ arch/sparc/include/asm/bugs.h | 18 ------------------
+ arch/sparc/kernel/setup_32.c | 7 +++++++
+ 3 files changed, 8 insertions(+), 18 deletions(-)
+ delete mode 100644 arch/sparc/include/asm/bugs.h
+
+--- a/arch/sparc/Kconfig
++++ b/arch/sparc/Kconfig
+@@ -52,6 +52,7 @@ config SPARC
+ config SPARC32
+ def_bool !64BIT
+ select ARCH_32BIT_OFF_T
++ select ARCH_HAS_CPU_FINALIZE_INIT if !SMP
+ select ARCH_HAS_SYNC_DMA_FOR_CPU
+ select CLZ_TAB
+ select DMA_DIRECT_REMAP
+--- a/arch/sparc/include/asm/bugs.h
++++ /dev/null
+@@ -1,18 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-/* include/asm/bugs.h: Sparc probes for various bugs.
+- *
+- * Copyright (C) 1996, 2007 David S. Miller (davem@davemloft.net)
+- */
+-
+-#ifdef CONFIG_SPARC32
+-#include <asm/cpudata.h>
+-#endif
+-
+-extern unsigned long loops_per_jiffy;
+-
+-static void __init check_bugs(void)
+-{
+-#if defined(CONFIG_SPARC32) && !defined(CONFIG_SMP)
+- cpu_data(0).udelay_val = loops_per_jiffy;
+-#endif
+-}
+--- a/arch/sparc/kernel/setup_32.c
++++ b/arch/sparc/kernel/setup_32.c
+@@ -412,3 +412,10 @@ static int __init topology_init(void)
+ }
+
+ subsys_initcall(topology_init);
++
++#if defined(CONFIG_SPARC32) && !defined(CONFIG_SMP)
++void __init arch_cpu_finalize_init(void)
++{
++ cpu_data(0).udelay_val = loops_per_jiffy;
++}
++#endif
--- /dev/null
+From 712de00666271bfcc9f89a5db0b753ecef331117 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:11 +0200
+Subject: um/cpu: Switch to arch_cpu_finalize_init()
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 9349b5cd0908f8afe95529fc7a8cbb1417df9b0c upstream
+
+check_bugs() is about to be phased out. Switch over to the new
+arch_cpu_finalize_init() implementation.
+
+No functional change.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Acked-by: Richard Weinberger <richard@nod.at>
+Link: https://lore.kernel.org/r/20230613224545.493148694@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/um/Kconfig | 1 +
+ arch/um/include/asm/bugs.h | 7 -------
+ arch/um/kernel/um_arch.c | 3 ++-
+ 3 files changed, 3 insertions(+), 8 deletions(-)
+ delete mode 100644 arch/um/include/asm/bugs.h
+
+--- a/arch/um/Kconfig
++++ b/arch/um/Kconfig
+@@ -6,6 +6,7 @@ config UML
+ bool
+ default y
+ select ARCH_EPHEMERAL_INODES
++ select ARCH_HAS_CPU_FINALIZE_INIT
+ select ARCH_HAS_FORTIFY_SOURCE
+ select ARCH_HAS_GCOV_PROFILE_ALL
+ select ARCH_HAS_KCOV
+--- a/arch/um/include/asm/bugs.h
++++ /dev/null
+@@ -1,7 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-#ifndef __UM_BUGS_H
+-#define __UM_BUGS_H
+-
+-void check_bugs(void);
+-
+-#endif
+--- a/arch/um/kernel/um_arch.c
++++ b/arch/um/kernel/um_arch.c
+@@ -3,6 +3,7 @@
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
++#include <linux/cpu.h>
+ #include <linux/delay.h>
+ #include <linux/init.h>
+ #include <linux/mm.h>
+@@ -430,7 +431,7 @@ void __init setup_arch(char **cmdline_p)
+ }
+ }
+
+-void __init check_bugs(void)
++void __init arch_cpu_finalize_init(void)
+ {
+ arch_check_bugs();
+ os_check_bugs();
--- /dev/null
+From 81299478c88c84d0d3b02f28803ee9fb30ac423e Mon Sep 17 00:00:00 2001
+From: "Borislav Petkov (AMD)" <bp@alien8.de>
+Date: Sat, 8 Jul 2023 10:21:35 +0200
+Subject: x86/bugs: Increase the x86 bugs vector size to two u32s
+
+From: "Borislav Petkov (AMD)" <bp@alien8.de>
+
+Upstream commit: 0e52740ffd10c6c316837c6c128f460f1aaba1ea
+
+There was never a doubt in my mind that they would not fit into a single
+u32 eventually.
+
+Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/include/asm/cpufeatures.h | 2 +-
+ tools/arch/x86/include/asm/cpufeatures.h | 2 +-
+ 2 files changed, 2 insertions(+), 2 deletions(-)
+
+--- a/arch/x86/include/asm/cpufeatures.h
++++ b/arch/x86/include/asm/cpufeatures.h
+@@ -14,7 +14,7 @@
+ * Defines x86 CPU feature bits
+ */
+ #define NCAPINTS 21 /* N 32-bit words worth of info */
+-#define NBUGINTS 1 /* N 32-bit bug flags */
++#define NBUGINTS 2 /* N 32-bit bug flags */
+
+ /*
+ * Note: If the comment begins with a quoted string, that string is used
+--- a/tools/arch/x86/include/asm/cpufeatures.h
++++ b/tools/arch/x86/include/asm/cpufeatures.h
+@@ -14,7 +14,7 @@
+ * Defines x86 CPU feature bits
+ */
+ #define NCAPINTS 21 /* N 32-bit words worth of info */
+-#define NBUGINTS 1 /* N 32-bit bug flags */
++#define NBUGINTS 2 /* N 32-bit bug flags */
+
+ /*
+ * Note: If the comment begins with a quoted string, that string is used
--- /dev/null
+From b1af65dde6b15b823ea6de054f9b94c2d6477a55 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:01 +0200
+Subject: x86/cpu: Switch to arch_cpu_finalize_init()
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 7c7077a72674402654f3291354720cd73cdf649e upstream
+
+check_bugs() is a dumping ground for finalizing the CPU bringup. Only parts of
+it has to do with actual CPU bugs.
+
+Split it apart into arch_cpu_finalize_init() and cpu_select_mitigations().
+
+Fixup the bogus 32bit comments while at it.
+
+No functional change.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
+Link: https://lore.kernel.org/r/20230613224545.019583869@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/Kconfig | 1
+ arch/x86/include/asm/bugs.h | 2 -
+ arch/x86/kernel/cpu/bugs.c | 51 -----------------------------------------
+ arch/x86/kernel/cpu/common.c | 53 +++++++++++++++++++++++++++++++++++++++++++
+ arch/x86/kernel/cpu/cpu.h | 1
+ 5 files changed, 56 insertions(+), 52 deletions(-)
+
+--- a/arch/x86/Kconfig
++++ b/arch/x86/Kconfig
+@@ -71,6 +71,7 @@ config X86
+ select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
+ select ARCH_HAS_CACHE_LINE_SIZE
+ select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
++ select ARCH_HAS_CPU_FINALIZE_INIT
+ select ARCH_HAS_CURRENT_STACK_POINTER
+ select ARCH_HAS_DEBUG_VIRTUAL
+ select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE
+--- a/arch/x86/include/asm/bugs.h
++++ b/arch/x86/include/asm/bugs.h
+@@ -4,8 +4,6 @@
+
+ #include <asm/processor.h>
+
+-extern void check_bugs(void);
+-
+ #if defined(CONFIG_CPU_SUP_INTEL) && defined(CONFIG_X86_32)
+ int ppro_with_ram_bug(void);
+ #else
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -9,7 +9,6 @@
+ * - Andrew D. Balsa (code cleanup).
+ */
+ #include <linux/init.h>
+-#include <linux/utsname.h>
+ #include <linux/cpu.h>
+ #include <linux/module.h>
+ #include <linux/nospec.h>
+@@ -27,8 +26,6 @@
+ #include <asm/msr.h>
+ #include <asm/vmx.h>
+ #include <asm/paravirt.h>
+-#include <asm/alternative.h>
+-#include <asm/set_memory.h>
+ #include <asm/intel-family.h>
+ #include <asm/e820/api.h>
+ #include <asm/hypervisor.h>
+@@ -125,21 +122,8 @@ DEFINE_STATIC_KEY_FALSE(switch_mm_cond_l
+ DEFINE_STATIC_KEY_FALSE(mmio_stale_data_clear);
+ EXPORT_SYMBOL_GPL(mmio_stale_data_clear);
+
+-void __init check_bugs(void)
++void __init cpu_select_mitigations(void)
+ {
+- identify_boot_cpu();
+-
+- /*
+- * identify_boot_cpu() initialized SMT support information, let the
+- * core code know.
+- */
+- cpu_smt_check_topology();
+-
+- if (!IS_ENABLED(CONFIG_SMP)) {
+- pr_info("CPU: ");
+- print_cpu_info(&boot_cpu_data);
+- }
+-
+ /*
+ * Read the SPEC_CTRL MSR to account for reserved bits which may
+ * have unknown values. AMD64_LS_CFG MSR is cached in the early AMD
+@@ -176,39 +160,6 @@ void __init check_bugs(void)
+ md_clear_select_mitigation();
+ srbds_select_mitigation();
+ l1d_flush_select_mitigation();
+-
+- arch_smt_update();
+-
+-#ifdef CONFIG_X86_32
+- /*
+- * Check whether we are able to run this kernel safely on SMP.
+- *
+- * - i386 is no longer supported.
+- * - In order to run on anything without a TSC, we need to be
+- * compiled for a i486.
+- */
+- if (boot_cpu_data.x86 < 4)
+- panic("Kernel requires i486+ for 'invlpg' and other features");
+-
+- init_utsname()->machine[1] =
+- '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86);
+- alternative_instructions();
+-
+- fpu__init_check_bugs();
+-#else /* CONFIG_X86_64 */
+- alternative_instructions();
+-
+- /*
+- * Make sure the first 2MB area is not mapped by huge pages
+- * There are typically fixed size MTRRs in there and overlapping
+- * MTRRs into large pages causes slow downs.
+- *
+- * Right now we don't do that with gbpages because there seems
+- * very little benefit for that case.
+- */
+- if (!direct_gbpages)
+- set_memory_4k((unsigned long)__va(0), 1);
+-#endif
+ }
+
+ /*
+--- a/arch/x86/kernel/cpu/common.c
++++ b/arch/x86/kernel/cpu/common.c
+@@ -19,11 +19,14 @@
+ #include <linux/kprobes.h>
+ #include <linux/kgdb.h>
+ #include <linux/smp.h>
++#include <linux/cpu.h>
+ #include <linux/io.h>
+ #include <linux/syscore_ops.h>
+ #include <linux/pgtable.h>
+ #include <linux/stackprotector.h>
++#include <linux/utsname.h>
+
++#include <asm/alternative.h>
+ #include <asm/cmdline.h>
+ #include <asm/perf_event.h>
+ #include <asm/mmu_context.h>
+@@ -59,6 +62,7 @@
+ #include <asm/intel-family.h>
+ #include <asm/cpu_device_id.h>
+ #include <asm/uv/uv.h>
++#include <asm/set_memory.h>
+ #include <asm/sigframe.h>
+ #include <asm/traps.h>
+ #include <asm/sev.h>
+@@ -2364,3 +2368,52 @@ void arch_smt_update(void)
+ /* Check whether IPI broadcasting can be enabled */
+ apic_smt_update();
+ }
++
++void __init arch_cpu_finalize_init(void)
++{
++ identify_boot_cpu();
++
++ /*
++ * identify_boot_cpu() initialized SMT support information, let the
++ * core code know.
++ */
++ cpu_smt_check_topology();
++
++ if (!IS_ENABLED(CONFIG_SMP)) {
++ pr_info("CPU: ");
++ print_cpu_info(&boot_cpu_data);
++ }
++
++ cpu_select_mitigations();
++
++ arch_smt_update();
++
++ if (IS_ENABLED(CONFIG_X86_32)) {
++ /*
++ * Check whether this is a real i386 which is not longer
++ * supported and fixup the utsname.
++ */
++ if (boot_cpu_data.x86 < 4)
++ panic("Kernel requires i486+ for 'invlpg' and other features");
++
++ init_utsname()->machine[1] =
++ '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86);
++ }
++
++ alternative_instructions();
++
++ if (IS_ENABLED(CONFIG_X86_64)) {
++ /*
++ * Make sure the first 2MB area is not mapped by huge pages
++ * There are typically fixed size MTRRs in there and overlapping
++ * MTRRs into large pages causes slow downs.
++ *
++ * Right now we don't do that with gbpages because there seems
++ * very little benefit for that case.
++ */
++ if (!direct_gbpages)
++ set_memory_4k((unsigned long)__va(0), 1);
++ } else {
++ fpu__init_check_bugs();
++ }
++}
+--- a/arch/x86/kernel/cpu/cpu.h
++++ b/arch/x86/kernel/cpu/cpu.h
+@@ -79,6 +79,7 @@ extern void detect_ht(struct cpuinfo_x86
+ extern void check_null_seg_clears_base(struct cpuinfo_x86 *c);
+
+ unsigned int aperfmperf_get_khz(int cpu);
++void cpu_select_mitigations(void);
+
+ extern void x86_spec_ctrl_setup_ap(void);
+ extern void update_srbds_msr(void);
--- /dev/null
+From foo@baz Tue Aug 8 07:20:48 PM CEST 2023
+Date: Tue, 08 Aug 2023 19:20:48 +0200
+To: Greg KH <gregkh@linuxfoundation.org>
+From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Subject: x86: fix backwards merge of GDS/SRSO bit
+
+Stable-tree-only change.
+
+Due to the way the GDS and SRSO patches flowed into the stable tree, it
+was a 50% chance that the merge of the which value GDS and SRSO should
+be. Of course, I lost that bet, and chose the opposite of what Linus
+chose in commit 64094e7e3118 ("Merge tag 'gds-for-linus-2023-08-01' of
+git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")
+
+Fix this up by switching the values to match what is now in Linus's tree
+as that is the correct value to mirror.
+
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/kernel/cpu/common.c | 6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+--- a/arch/x86/kernel/cpu/common.c
++++ b/arch/x86/kernel/cpu/common.c
+@@ -1267,10 +1267,10 @@ static const __initconst struct x86_cpu_
+ #define RETBLEED BIT(3)
+ /* CPU is affected by SMT (cross-thread) return predictions */
+ #define SMT_RSB BIT(4)
+-/* CPU is affected by GDS */
+-#define GDS BIT(5)
+ /* CPU is affected by SRSO */
+-#define SRSO BIT(6)
++#define SRSO BIT(5)
++/* CPU is affected by GDS */
++#define GDS BIT(6)
+
+ static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
+ VULNBL_INTEL_STEPPINGS(IVYBRIDGE, X86_STEPPING_ANY, SRBDS),
--- /dev/null
+From 8bec01e9799922f37a59c64cc05b86e692b84e90 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:11 +0200
+Subject: x86/fpu: Mark init functions __init
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 1703db2b90c91b2eb2d699519fc505fe431dde0e upstream
+
+No point in keeping them around.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20230613224545.841685728@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/kernel/fpu/init.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/arch/x86/kernel/fpu/init.c
++++ b/arch/x86/kernel/fpu/init.c
+@@ -53,7 +53,7 @@ void fpu__init_cpu(void)
+ fpu__init_cpu_xstate();
+ }
+
+-static bool fpu__probe_without_cpuid(void)
++static bool __init fpu__probe_without_cpuid(void)
+ {
+ unsigned long cr0;
+ u16 fsw, fcw;
+@@ -71,7 +71,7 @@ static bool fpu__probe_without_cpuid(voi
+ return fsw == 0 && (fcw & 0x103f) == 0x003f;
+ }
+
+-static void fpu__init_system_early_generic(void)
++static void __init fpu__init_system_early_generic(void)
+ {
+ if (!boot_cpu_has(X86_FEATURE_CPUID) &&
+ !test_bit(X86_FEATURE_FPU, (unsigned long *)cpu_caps_cleared)) {
--- /dev/null
+From 009507c1cdfb8f4d0b01ec7d3353fe66c8350c42 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:11 +0200
+Subject: x86/fpu: Move FPU initialization into arch_cpu_finalize_init()
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit b81fac906a8f9e682e513ddd95697ec7a20878d4 upstream
+
+Initializing the FPU during the early boot process is a pointless
+exercise. Early boot is convoluted and fragile enough.
+
+Nothing requires that the FPU is set up early. It has to be initialized
+before fork_init() because the task_struct size depends on the FPU register
+buffer size.
+
+Move the initialization to arch_cpu_finalize_init() which is the perfect
+place to do so.
+
+No functional change.
+
+This allows to remove quite some of the custom early command line parsing,
+but that's subject to the next installment.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20230613224545.902376621@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/kernel/cpu/common.c | 12 ++++++++----
+ 1 file changed, 8 insertions(+), 4 deletions(-)
+
+--- a/arch/x86/kernel/cpu/common.c
++++ b/arch/x86/kernel/cpu/common.c
+@@ -1604,8 +1604,6 @@ static void __init early_identify_cpu(st
+
+ sld_setup(c);
+
+- fpu__init_system();
+-
+ #ifdef CONFIG_X86_32
+ /*
+ * Regardless of whether PCID is enumerated, the SDM says
+@@ -2287,8 +2285,6 @@ void cpu_init(void)
+
+ doublefault_init_cpu_tss();
+
+- fpu__init_cpu();
+-
+ if (is_uv_system())
+ uv_cpu_init();
+
+@@ -2304,6 +2300,7 @@ void cpu_init_secondary(void)
+ */
+ cpu_init_exception_handling();
+ cpu_init();
++ fpu__init_cpu();
+ }
+ #endif
+
+@@ -2398,6 +2395,13 @@ void __init arch_cpu_finalize_init(void)
+ '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86);
+ }
+
++ /*
++ * Must be before alternatives because it might set or clear
++ * feature bits.
++ */
++ fpu__init_system();
++ fpu__init_cpu();
++
+ alternative_instructions();
+
+ if (IS_ENABLED(CONFIG_X86_64)) {
--- /dev/null
+From a017c5d9540fe53c2bac910a170be9186dc74c8b Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:11 +0200
+Subject: x86/fpu: Remove cpuinfo argument from init functions
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 1f34bb2a24643e0087652d81078e4f616562738d upstream
+
+Nothing in the call chain requires it
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20230613224545.783704297@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/include/asm/fpu/api.h | 2 +-
+ arch/x86/kernel/cpu/common.c | 2 +-
+ arch/x86/kernel/fpu/init.c | 6 +++---
+ 3 files changed, 5 insertions(+), 5 deletions(-)
+
+--- a/arch/x86/include/asm/fpu/api.h
++++ b/arch/x86/include/asm/fpu/api.h
+@@ -109,7 +109,7 @@ extern void fpu_reset_from_exception_fix
+
+ /* Boot, hotplug and resume */
+ extern void fpu__init_cpu(void);
+-extern void fpu__init_system(struct cpuinfo_x86 *c);
++extern void fpu__init_system(void);
+ extern void fpu__init_check_bugs(void);
+ extern void fpu__resume_cpu(void);
+
+--- a/arch/x86/kernel/cpu/common.c
++++ b/arch/x86/kernel/cpu/common.c
+@@ -1604,7 +1604,7 @@ static void __init early_identify_cpu(st
+
+ sld_setup(c);
+
+- fpu__init_system(c);
++ fpu__init_system();
+
+ #ifdef CONFIG_X86_32
+ /*
+--- a/arch/x86/kernel/fpu/init.c
++++ b/arch/x86/kernel/fpu/init.c
+@@ -71,7 +71,7 @@ static bool fpu__probe_without_cpuid(voi
+ return fsw == 0 && (fcw & 0x103f) == 0x003f;
+ }
+
+-static void fpu__init_system_early_generic(struct cpuinfo_x86 *c)
++static void fpu__init_system_early_generic(void)
+ {
+ if (!boot_cpu_has(X86_FEATURE_CPUID) &&
+ !test_bit(X86_FEATURE_FPU, (unsigned long *)cpu_caps_cleared)) {
+@@ -211,10 +211,10 @@ static void __init fpu__init_system_xsta
+ * Called on the boot CPU once per system bootup, to set up the initial
+ * FPU state that is later cloned into all processes:
+ */
+-void __init fpu__init_system(struct cpuinfo_x86 *c)
++void __init fpu__init_system(void)
+ {
+ fpstate_reset(¤t->thread.fpu);
+- fpu__init_system_early_generic(c);
++ fpu__init_system_early_generic();
+
+ /*
+ * The FPU has to be operational for some of the
--- /dev/null
+From 500503624771a86c720614167828e7950dedc918 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 1 Aug 2023 16:07:11 +0200
+Subject: x86/init: Initialize signal frame size late
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 54d9a91a3d6713d1332e93be13b4eaf0fa54349d upstream
+
+No point in doing this during really early boot. Move it to an early
+initcall so that it is set up before possible user mode helpers are started
+during device initialization.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20230613224545.727330699@linutronix.de
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/include/asm/sigframe.h | 2 --
+ arch/x86/kernel/cpu/common.c | 3 ---
+ arch/x86/kernel/signal.c | 4 +++-
+ 3 files changed, 3 insertions(+), 6 deletions(-)
+
+--- a/arch/x86/include/asm/sigframe.h
++++ b/arch/x86/include/asm/sigframe.h
+@@ -85,6 +85,4 @@ struct rt_sigframe_x32 {
+
+ #endif /* CONFIG_X86_64 */
+
+-void __init init_sigframe_size(void);
+-
+ #endif /* _ASM_X86_SIGFRAME_H */
+--- a/arch/x86/kernel/cpu/common.c
++++ b/arch/x86/kernel/cpu/common.c
+@@ -64,7 +64,6 @@
+ #include <asm/cpu_device_id.h>
+ #include <asm/uv/uv.h>
+ #include <asm/set_memory.h>
+-#include <asm/sigframe.h>
+ #include <asm/traps.h>
+ #include <asm/sev.h>
+
+@@ -1607,8 +1606,6 @@ static void __init early_identify_cpu(st
+
+ fpu__init_system(c);
+
+- init_sigframe_size();
+-
+ #ifdef CONFIG_X86_32
+ /*
+ * Regardless of whether PCID is enumerated, the SDM says
+--- a/arch/x86/kernel/signal.c
++++ b/arch/x86/kernel/signal.c
+@@ -182,7 +182,7 @@ get_sigframe(struct ksignal *ksig, struc
+ static unsigned long __ro_after_init max_frame_size;
+ static unsigned int __ro_after_init fpu_default_state_size;
+
+-void __init init_sigframe_size(void)
++static int __init init_sigframe_size(void)
+ {
+ fpu_default_state_size = fpu__get_fpstate_size();
+
+@@ -194,7 +194,9 @@ void __init init_sigframe_size(void)
+ max_frame_size = round_up(max_frame_size, FRAME_ALIGNMENT);
+
+ pr_info("max sigframe size: %lu\n", max_frame_size);
++ return 0;
+ }
++early_initcall(init_sigframe_size);
+
+ unsigned long get_sigframe_size(void)
+ {
--- /dev/null
+From 0a9567ac5e6a40cdd9c8cd15b19a62a15250f450 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 16 Jun 2023 22:15:31 +0200
+Subject: x86/mem_encrypt: Unbreak the AMD_MEM_ENCRYPT=n build
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 0a9567ac5e6a40cdd9c8cd15b19a62a15250f450 upstream.
+
+Moving mem_encrypt_init() broke the AMD_MEM_ENCRYPT=n because the
+declaration of that function was under #ifdef CONFIG_AMD_MEM_ENCRYPT and
+the obvious placement for the inline stub was the #else path.
+
+This is a leftover of commit 20f07a044a76 ("x86/sev: Move common memory
+encryption code to mem_encrypt.c") which made mem_encrypt_init() depend on
+X86_MEM_ENCRYPT without moving the prototype. That did not fail back then
+because there was no stub inline as the core init code had a weak function.
+
+Move both the declaration and the stub out of the CONFIG_AMD_MEM_ENCRYPT
+section and guard it with CONFIG_X86_MEM_ENCRYPT.
+
+Fixes: 439e17576eb4 ("init, x86: Move mem_encrypt_init() into arch_cpu_finalize_init()")
+Reported-by: kernel test robot <lkp@intel.com>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Closes: https://lore.kernel.org/oe-kbuild-all/202306170247.eQtCJPE8-lkp@intel.com/
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/include/asm/mem_encrypt.h | 10 ++++++----
+ 1 file changed, 6 insertions(+), 4 deletions(-)
+
+--- a/arch/x86/include/asm/mem_encrypt.h
++++ b/arch/x86/include/asm/mem_encrypt.h
+@@ -17,6 +17,12 @@
+
+ #include <asm/bootparam.h>
+
++#ifdef CONFIG_X86_MEM_ENCRYPT
++void __init mem_encrypt_init(void);
++#else
++static inline void mem_encrypt_init(void) { }
++#endif
++
+ #ifdef CONFIG_AMD_MEM_ENCRYPT
+
+ extern u64 sme_me_mask;
+@@ -51,8 +57,6 @@ void __init mem_encrypt_free_decrypted_m
+
+ void __init sev_es_init_vc_handling(void);
+
+-void __init mem_encrypt_init(void);
+-
+ #define __bss_decrypted __section(".bss..decrypted")
+
+ #else /* !CONFIG_AMD_MEM_ENCRYPT */
+@@ -85,8 +89,6 @@ early_set_mem_enc_dec_hypercall(unsigned
+
+ static inline void mem_encrypt_free_decrypted_mem(void) { }
+
+-static inline void mem_encrypt_init(void) { }
+-
+ #define __bss_decrypted
+
+ #endif /* CONFIG_AMD_MEM_ENCRYPT */
--- /dev/null
+From d9094016758575d1651bdde3ae3dd14aac20cfc5 Mon Sep 17 00:00:00 2001
+From: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Date: Tue, 1 Aug 2023 16:07:11 +0200
+Subject: x86/speculation: Add force option to GDS mitigation
+
+From: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+
+commit 553a5c03e90a6087e88f8ff878335ef0621536fb upstream
+
+The Gather Data Sampling (GDS) vulnerability allows malicious software
+to infer stale data previously stored in vector registers. This may
+include sensitive data such as cryptographic keys. GDS is mitigated in
+microcode, and systems with up-to-date microcode are protected by
+default. However, any affected system that is running with older
+microcode will still be vulnerable to GDS attacks.
+
+Since the gather instructions used by the attacker are part of the
+AVX2 and AVX512 extensions, disabling these extensions prevents gather
+instructions from being executed, thereby mitigating the system from
+GDS. Disabling AVX2 is sufficient, but we don't have the granularity
+to do this. The XCR0[2] disables AVX, with no option to just disable
+AVX2.
+
+Add a kernel parameter gather_data_sampling=force that will enable the
+microcode mitigation if available, otherwise it will disable AVX on
+affected systems.
+
+This option will be ignored if cmdline mitigations=off.
+
+This is a *big* hammer. It is known to break buggy userspace that
+uses incomplete, buggy AVX enumeration. Unfortunately, such userspace
+does exist in the wild:
+
+ https://www.mail-archive.com/bug-coreutils@gnu.org/msg33046.html
+
+[ dhansen: add some more ominous warnings about disabling AVX ]
+
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
+Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ Documentation/admin-guide/hw-vuln/gather_data_sampling.rst | 18 +++++++++--
+ Documentation/admin-guide/kernel-parameters.txt | 8 ++++-
+ arch/x86/kernel/cpu/bugs.c | 20 ++++++++++++-
+ 3 files changed, 40 insertions(+), 6 deletions(-)
+
+--- a/Documentation/admin-guide/hw-vuln/gather_data_sampling.rst
++++ b/Documentation/admin-guide/hw-vuln/gather_data_sampling.rst
+@@ -60,14 +60,21 @@ bits:
+ ================================ === ============================
+
+ GDS can also be mitigated on systems that don't have updated microcode by
+-disabling AVX. This can be done by setting "clearcpuid=avx" on the kernel
+-command-line.
++disabling AVX. This can be done by setting gather_data_sampling="force" or
++"clearcpuid=avx" on the kernel command-line.
++
++If used, these options will disable AVX use by turning on XSAVE YMM support.
++However, the processor will still enumerate AVX support. Userspace that
++does not follow proper AVX enumeration to check both AVX *and* XSAVE YMM
++support will break.
+
+ Mitigation control on the kernel command line
+ ---------------------------------------------
+ The mitigation can be disabled by setting "gather_data_sampling=off" or
+-"mitigations=off" on the kernel command line. Not specifying either will
+-default to the mitigation being enabled.
++"mitigations=off" on the kernel command line. Not specifying either will default
++to the mitigation being enabled. Specifying "gather_data_sampling=force" will
++use the microcode mitigation when available or disable AVX on affected systems
++where the microcode hasn't been updated to include the mitigation.
+
+ GDS System Information
+ ------------------------
+@@ -83,6 +90,9 @@ The possible values contained in this fi
+ Vulnerable Processor vulnerable and mitigation disabled.
+ Vulnerable: No microcode Processor vulnerable and microcode is missing
+ mitigation.
++ Mitigation: AVX disabled,
++ no microcode Processor is vulnerable and microcode is missing
++ mitigation. AVX disabled as mitigation.
+ Mitigation: Microcode Processor is vulnerable and mitigation is in
+ effect.
+ Mitigation: Microcode (locked) Processor is vulnerable and mitigation is in
+--- a/Documentation/admin-guide/kernel-parameters.txt
++++ b/Documentation/admin-guide/kernel-parameters.txt
+@@ -1637,7 +1637,13 @@
+
+ This issue is mitigated by default in updated microcode.
+ The mitigation may have a performance impact but can be
+- disabled.
++ disabled. On systems without the microcode mitigation
++ disabling AVX serves as a mitigation.
++
++ force: Disable AVX to mitigate systems without
++ microcode mitigation. No effect if the microcode
++ mitigation is present. Known to cause crashes in
++ userspace with buggy AVX enumeration.
+
+ off: Disable GDS mitigation.
+
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -653,6 +653,7 @@ early_param("l1d_flush", l1d_flush_parse
+ enum gds_mitigations {
+ GDS_MITIGATION_OFF,
+ GDS_MITIGATION_UCODE_NEEDED,
++ GDS_MITIGATION_FORCE,
+ GDS_MITIGATION_FULL,
+ GDS_MITIGATION_FULL_LOCKED,
+ GDS_MITIGATION_HYPERVISOR,
+@@ -663,6 +664,7 @@ static enum gds_mitigations gds_mitigati
+ static const char * const gds_strings[] = {
+ [GDS_MITIGATION_OFF] = "Vulnerable",
+ [GDS_MITIGATION_UCODE_NEEDED] = "Vulnerable: No microcode",
++ [GDS_MITIGATION_FORCE] = "Mitigation: AVX disabled, no microcode",
+ [GDS_MITIGATION_FULL] = "Mitigation: Microcode",
+ [GDS_MITIGATION_FULL_LOCKED] = "Mitigation: Microcode (locked)",
+ [GDS_MITIGATION_HYPERVISOR] = "Unknown: Dependent on hypervisor status",
+@@ -688,6 +690,7 @@ void update_gds_msr(void)
+ rdmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl);
+ mcu_ctrl &= ~GDS_MITG_DIS;
+ break;
++ case GDS_MITIGATION_FORCE:
+ case GDS_MITIGATION_UCODE_NEEDED:
+ case GDS_MITIGATION_HYPERVISOR:
+ return;
+@@ -722,10 +725,23 @@ static void __init gds_select_mitigation
+
+ /* No microcode */
+ if (!(x86_read_arch_cap_msr() & ARCH_CAP_GDS_CTRL)) {
+- gds_mitigation = GDS_MITIGATION_UCODE_NEEDED;
++ if (gds_mitigation == GDS_MITIGATION_FORCE) {
++ /*
++ * This only needs to be done on the boot CPU so do it
++ * here rather than in update_gds_msr()
++ */
++ setup_clear_cpu_cap(X86_FEATURE_AVX);
++ pr_warn("Microcode update needed! Disabling AVX as mitigation.\n");
++ } else {
++ gds_mitigation = GDS_MITIGATION_UCODE_NEEDED;
++ }
+ goto out;
+ }
+
++ /* Microcode has mitigation, use it */
++ if (gds_mitigation == GDS_MITIGATION_FORCE)
++ gds_mitigation = GDS_MITIGATION_FULL;
++
+ rdmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl);
+ if (mcu_ctrl & GDS_MITG_LOCKED) {
+ if (gds_mitigation == GDS_MITIGATION_OFF)
+@@ -756,6 +772,8 @@ static int __init gds_parse_cmdline(char
+
+ if (!strcmp(str, "off"))
+ gds_mitigation = GDS_MITIGATION_OFF;
++ else if (!strcmp(str, "force"))
++ gds_mitigation = GDS_MITIGATION_FORCE;
+
+ return 0;
+ }
--- /dev/null
+From 35799f249eeea4ee34639ff29479c5f5762acf31 Mon Sep 17 00:00:00 2001
+From: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Date: Tue, 1 Aug 2023 16:07:11 +0200
+Subject: x86/speculation: Add Gather Data Sampling mitigation
+
+From: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+
+commit 8974eb588283b7d44a7c91fa09fcbaf380339f3a upstream
+
+Gather Data Sampling (GDS) is a hardware vulnerability which allows
+unprivileged speculative access to data which was previously stored in
+vector registers.
+
+Intel processors that support AVX2 and AVX512 have gather instructions
+that fetch non-contiguous data elements from memory. On vulnerable
+hardware, when a gather instruction is transiently executed and
+encounters a fault, stale data from architectural or internal vector
+registers may get transiently stored to the destination vector
+register allowing an attacker to infer the stale data using typical
+side channel techniques like cache timing attacks.
+
+This mitigation is different from many earlier ones for two reasons.
+First, it is enabled by default and a bit must be set to *DISABLE* it.
+This is the opposite of normal mitigation polarity. This means GDS can
+be mitigated simply by updating microcode and leaving the new control
+bit alone.
+
+Second, GDS has a "lock" bit. This lock bit is there because the
+mitigation affects the hardware security features KeyLocker and SGX.
+It needs to be enabled and *STAY* enabled for these features to be
+mitigated against GDS.
+
+The mitigation is enabled in the microcode by default. Disable it by
+setting gather_data_sampling=off or by disabling all mitigations with
+mitigations=off. The mitigation status can be checked by reading:
+
+ /sys/devices/system/cpu/vulnerabilities/gather_data_sampling
+
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
+Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ Documentation/ABI/testing/sysfs-devices-system-cpu | 13 -
+ Documentation/admin-guide/hw-vuln/gather_data_sampling.rst | 99 +++++++++
+ Documentation/admin-guide/hw-vuln/index.rst | 1
+ Documentation/admin-guide/kernel-parameters.txt | 41 ++--
+ arch/x86/include/asm/cpufeatures.h | 1
+ arch/x86/include/asm/msr-index.h | 11 +
+ arch/x86/kernel/cpu/bugs.c | 129 +++++++++++++
+ arch/x86/kernel/cpu/common.c | 34 ++-
+ arch/x86/kernel/cpu/cpu.h | 1
+ drivers/base/cpu.c | 8
+ 10 files changed, 310 insertions(+), 28 deletions(-)
+ create mode 100644 Documentation/admin-guide/hw-vuln/gather_data_sampling.rst
+
+--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
++++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
+@@ -513,17 +513,18 @@ Description: information about CPUs hete
+ cpu_capacity: capacity of cpuX.
+
+ What: /sys/devices/system/cpu/vulnerabilities
++ /sys/devices/system/cpu/vulnerabilities/gather_data_sampling
++ /sys/devices/system/cpu/vulnerabilities/itlb_multihit
++ /sys/devices/system/cpu/vulnerabilities/l1tf
++ /sys/devices/system/cpu/vulnerabilities/mds
+ /sys/devices/system/cpu/vulnerabilities/meltdown
++ /sys/devices/system/cpu/vulnerabilities/mmio_stale_data
++ /sys/devices/system/cpu/vulnerabilities/retbleed
++ /sys/devices/system/cpu/vulnerabilities/spec_store_bypass
+ /sys/devices/system/cpu/vulnerabilities/spectre_v1
+ /sys/devices/system/cpu/vulnerabilities/spectre_v2
+- /sys/devices/system/cpu/vulnerabilities/spec_store_bypass
+- /sys/devices/system/cpu/vulnerabilities/l1tf
+- /sys/devices/system/cpu/vulnerabilities/mds
+ /sys/devices/system/cpu/vulnerabilities/srbds
+ /sys/devices/system/cpu/vulnerabilities/tsx_async_abort
+- /sys/devices/system/cpu/vulnerabilities/itlb_multihit
+- /sys/devices/system/cpu/vulnerabilities/mmio_stale_data
+- /sys/devices/system/cpu/vulnerabilities/retbleed
+ Date: January 2018
+ Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
+ Description: Information about CPU vulnerabilities
+--- /dev/null
++++ b/Documentation/admin-guide/hw-vuln/gather_data_sampling.rst
+@@ -0,0 +1,99 @@
++.. SPDX-License-Identifier: GPL-2.0
++
++GDS - Gather Data Sampling
++==========================
++
++Gather Data Sampling is a hardware vulnerability which allows unprivileged
++speculative access to data which was previously stored in vector registers.
++
++Problem
++-------
++When a gather instruction performs loads from memory, different data elements
++are merged into the destination vector register. However, when a gather
++instruction that is transiently executed encounters a fault, stale data from
++architectural or internal vector registers may get transiently forwarded to the
++destination vector register instead. This will allow a malicious attacker to
++infer stale data using typical side channel techniques like cache timing
++attacks. GDS is a purely sampling-based attack.
++
++The attacker uses gather instructions to infer the stale vector register data.
++The victim does not need to do anything special other than use the vector
++registers. The victim does not need to use gather instructions to be
++vulnerable.
++
++Because the buffers are shared between Hyper-Threads cross Hyper-Thread attacks
++are possible.
++
++Attack scenarios
++----------------
++Without mitigation, GDS can infer stale data across virtually all
++permission boundaries:
++
++ Non-enclaves can infer SGX enclave data
++ Userspace can infer kernel data
++ Guests can infer data from hosts
++ Guest can infer guest from other guests
++ Users can infer data from other users
++
++Because of this, it is important to ensure that the mitigation stays enabled in
++lower-privilege contexts like guests and when running outside SGX enclaves.
++
++The hardware enforces the mitigation for SGX. Likewise, VMMs should ensure
++that guests are not allowed to disable the GDS mitigation. If a host erred and
++allowed this, a guest could theoretically disable GDS mitigation, mount an
++attack, and re-enable it.
++
++Mitigation mechanism
++--------------------
++This issue is mitigated in microcode. The microcode defines the following new
++bits:
++
++ ================================ === ============================
++ IA32_ARCH_CAPABILITIES[GDS_CTRL] R/O Enumerates GDS vulnerability
++ and mitigation support.
++ IA32_ARCH_CAPABILITIES[GDS_NO] R/O Processor is not vulnerable.
++ IA32_MCU_OPT_CTRL[GDS_MITG_DIS] R/W Disables the mitigation
++ 0 by default.
++ IA32_MCU_OPT_CTRL[GDS_MITG_LOCK] R/W Locks GDS_MITG_DIS=0. Writes
++ to GDS_MITG_DIS are ignored
++ Can't be cleared once set.
++ ================================ === ============================
++
++GDS can also be mitigated on systems that don't have updated microcode by
++disabling AVX. This can be done by setting "clearcpuid=avx" on the kernel
++command-line.
++
++Mitigation control on the kernel command line
++---------------------------------------------
++The mitigation can be disabled by setting "gather_data_sampling=off" or
++"mitigations=off" on the kernel command line. Not specifying either will
++default to the mitigation being enabled.
++
++GDS System Information
++------------------------
++The kernel provides vulnerability status information through sysfs. For
++GDS this can be accessed by the following sysfs file:
++
++/sys/devices/system/cpu/vulnerabilities/gather_data_sampling
++
++The possible values contained in this file are:
++
++ ============================== =============================================
++ Not affected Processor not vulnerable.
++ Vulnerable Processor vulnerable and mitigation disabled.
++ Vulnerable: No microcode Processor vulnerable and microcode is missing
++ mitigation.
++ Mitigation: Microcode Processor is vulnerable and mitigation is in
++ effect.
++ Mitigation: Microcode (locked) Processor is vulnerable and mitigation is in
++ effect and cannot be disabled.
++ Unknown: Dependent on
++ hypervisor status Running on a virtual guest processor that is
++ affected but with no way to know if host
++ processor is mitigated or vulnerable.
++ ============================== =============================================
++
++GDS Default mitigation
++----------------------
++The updated microcode will enable the mitigation by default. The kernel's
++default action is to leave the mitigation enabled.
+--- a/Documentation/admin-guide/hw-vuln/index.rst
++++ b/Documentation/admin-guide/hw-vuln/index.rst
+@@ -19,3 +19,4 @@ are configurable at compile, boot or run
+ l1d_flush.rst
+ processor_mmio_stale_data.rst
+ cross-thread-rsb.rst
++ gather_data_sampling.rst
+--- a/Documentation/admin-guide/kernel-parameters.txt
++++ b/Documentation/admin-guide/kernel-parameters.txt
+@@ -1627,6 +1627,20 @@
+ Format: off | on
+ default: on
+
++ gather_data_sampling=
++ [X86,INTEL] Control the Gather Data Sampling (GDS)
++ mitigation.
++
++ Gather Data Sampling is a hardware vulnerability which
++ allows unprivileged speculative access to data which was
++ previously stored in vector registers.
++
++ This issue is mitigated by default in updated microcode.
++ The mitigation may have a performance impact but can be
++ disabled.
++
++ off: Disable GDS mitigation.
++
+ gcov_persist= [GCOV] When non-zero (default), profiling data for
+ kernel modules is saved and remains accessible via
+ debugfs, even when the module is unloaded/reloaded.
+@@ -3262,24 +3276,25 @@
+ Disable all optional CPU mitigations. This
+ improves system performance, but it may also
+ expose users to several CPU vulnerabilities.
+- Equivalent to: nopti [X86,PPC]
+- if nokaslr then kpti=0 [ARM64]
+- nospectre_v1 [X86,PPC]
+- nobp=0 [S390]
+- nospectre_v2 [X86,PPC,S390,ARM64]
+- spectre_v2_user=off [X86]
+- spec_store_bypass_disable=off [X86,PPC]
+- ssbd=force-off [ARM64]
+- nospectre_bhb [ARM64]
++ Equivalent to: if nokaslr then kpti=0 [ARM64]
++ gather_data_sampling=off [X86]
++ kvm.nx_huge_pages=off [X86]
+ l1tf=off [X86]
+ mds=off [X86]
+- tsx_async_abort=off [X86]
+- kvm.nx_huge_pages=off [X86]
+- srbds=off [X86,INTEL]
++ mmio_stale_data=off [X86]
+ no_entry_flush [PPC]
+ no_uaccess_flush [PPC]
+- mmio_stale_data=off [X86]
++ nobp=0 [S390]
++ nopti [X86,PPC]
++ nospectre_bhb [ARM64]
++ nospectre_v1 [X86,PPC]
++ nospectre_v2 [X86,PPC,S390,ARM64]
+ retbleed=off [X86]
++ spec_store_bypass_disable=off [X86,PPC]
++ spectre_v2_user=off [X86]
++ srbds=off [X86,INTEL]
++ ssbd=force-off [ARM64]
++ tsx_async_abort=off [X86]
+
+ Exceptions:
+ This does not have any effect on
+--- a/arch/x86/include/asm/cpufeatures.h
++++ b/arch/x86/include/asm/cpufeatures.h
+@@ -483,5 +483,6 @@
+ #define X86_BUG_RETBLEED X86_BUG(27) /* CPU is affected by RETBleed */
+ #define X86_BUG_EIBRS_PBRSB X86_BUG(28) /* EIBRS is vulnerable to Post Barrier RSB Predictions */
+ #define X86_BUG_SMT_RSB X86_BUG(29) /* CPU is vulnerable to Cross-Thread Return Address Predictions */
++#define X86_BUG_GDS X86_BUG(30) /* CPU is affected by Gather Data Sampling */
+
+ #endif /* _ASM_X86_CPUFEATURES_H */
+--- a/arch/x86/include/asm/msr-index.h
++++ b/arch/x86/include/asm/msr-index.h
+@@ -155,6 +155,15 @@
+ * Not susceptible to Post-Barrier
+ * Return Stack Buffer Predictions.
+ */
++#define ARCH_CAP_GDS_CTRL BIT(25) /*
++ * CPU is vulnerable to Gather
++ * Data Sampling (GDS) and
++ * has controls for mitigation.
++ */
++#define ARCH_CAP_GDS_NO BIT(26) /*
++ * CPU is not vulnerable to Gather
++ * Data Sampling (GDS).
++ */
+
+ #define ARCH_CAP_XAPIC_DISABLE BIT(21) /*
+ * IA32_XAPIC_DISABLE_STATUS MSR
+@@ -178,6 +187,8 @@
+ #define RNGDS_MITG_DIS BIT(0) /* SRBDS support */
+ #define RTM_ALLOW BIT(1) /* TSX development mode */
+ #define FB_CLEAR_DIS BIT(3) /* CPU Fill buffer clear disable */
++#define GDS_MITG_DIS BIT(4) /* Disable GDS mitigation */
++#define GDS_MITG_LOCKED BIT(5) /* GDS mitigation locked */
+
+ #define MSR_IA32_SYSENTER_CS 0x00000174
+ #define MSR_IA32_SYSENTER_ESP 0x00000175
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -47,6 +47,7 @@ static void __init taa_select_mitigation
+ static void __init mmio_select_mitigation(void);
+ static void __init srbds_select_mitigation(void);
+ static void __init l1d_flush_select_mitigation(void);
++static void __init gds_select_mitigation(void);
+
+ /* The base value of the SPEC_CTRL MSR without task-specific bits set */
+ u64 x86_spec_ctrl_base;
+@@ -160,6 +161,7 @@ void __init cpu_select_mitigations(void)
+ md_clear_select_mitigation();
+ srbds_select_mitigation();
+ l1d_flush_select_mitigation();
++ gds_select_mitigation();
+ }
+
+ /*
+@@ -646,6 +648,120 @@ static int __init l1d_flush_parse_cmdlin
+ early_param("l1d_flush", l1d_flush_parse_cmdline);
+
+ #undef pr_fmt
++#define pr_fmt(fmt) "GDS: " fmt
++
++enum gds_mitigations {
++ GDS_MITIGATION_OFF,
++ GDS_MITIGATION_UCODE_NEEDED,
++ GDS_MITIGATION_FULL,
++ GDS_MITIGATION_FULL_LOCKED,
++ GDS_MITIGATION_HYPERVISOR,
++};
++
++static enum gds_mitigations gds_mitigation __ro_after_init = GDS_MITIGATION_FULL;
++
++static const char * const gds_strings[] = {
++ [GDS_MITIGATION_OFF] = "Vulnerable",
++ [GDS_MITIGATION_UCODE_NEEDED] = "Vulnerable: No microcode",
++ [GDS_MITIGATION_FULL] = "Mitigation: Microcode",
++ [GDS_MITIGATION_FULL_LOCKED] = "Mitigation: Microcode (locked)",
++ [GDS_MITIGATION_HYPERVISOR] = "Unknown: Dependent on hypervisor status",
++};
++
++void update_gds_msr(void)
++{
++ u64 mcu_ctrl_after;
++ u64 mcu_ctrl;
++
++ switch (gds_mitigation) {
++ case GDS_MITIGATION_OFF:
++ rdmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl);
++ mcu_ctrl |= GDS_MITG_DIS;
++ break;
++ case GDS_MITIGATION_FULL_LOCKED:
++ /*
++ * The LOCKED state comes from the boot CPU. APs might not have
++ * the same state. Make sure the mitigation is enabled on all
++ * CPUs.
++ */
++ case GDS_MITIGATION_FULL:
++ rdmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl);
++ mcu_ctrl &= ~GDS_MITG_DIS;
++ break;
++ case GDS_MITIGATION_UCODE_NEEDED:
++ case GDS_MITIGATION_HYPERVISOR:
++ return;
++ };
++
++ wrmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl);
++
++ /*
++ * Check to make sure that the WRMSR value was not ignored. Writes to
++ * GDS_MITG_DIS will be ignored if this processor is locked but the boot
++ * processor was not.
++ */
++ rdmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl_after);
++ WARN_ON_ONCE(mcu_ctrl != mcu_ctrl_after);
++}
++
++static void __init gds_select_mitigation(void)
++{
++ u64 mcu_ctrl;
++
++ if (!boot_cpu_has_bug(X86_BUG_GDS))
++ return;
++
++ if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
++ gds_mitigation = GDS_MITIGATION_HYPERVISOR;
++ goto out;
++ }
++
++ if (cpu_mitigations_off())
++ gds_mitigation = GDS_MITIGATION_OFF;
++ /* Will verify below that mitigation _can_ be disabled */
++
++ /* No microcode */
++ if (!(x86_read_arch_cap_msr() & ARCH_CAP_GDS_CTRL)) {
++ gds_mitigation = GDS_MITIGATION_UCODE_NEEDED;
++ goto out;
++ }
++
++ rdmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl);
++ if (mcu_ctrl & GDS_MITG_LOCKED) {
++ if (gds_mitigation == GDS_MITIGATION_OFF)
++ pr_warn("Mitigation locked. Disable failed.\n");
++
++ /*
++ * The mitigation is selected from the boot CPU. All other CPUs
++ * _should_ have the same state. If the boot CPU isn't locked
++ * but others are then update_gds_msr() will WARN() of the state
++ * mismatch. If the boot CPU is locked update_gds_msr() will
++ * ensure the other CPUs have the mitigation enabled.
++ */
++ gds_mitigation = GDS_MITIGATION_FULL_LOCKED;
++ }
++
++ update_gds_msr();
++out:
++ pr_info("%s\n", gds_strings[gds_mitigation]);
++}
++
++static int __init gds_parse_cmdline(char *str)
++{
++ if (!str)
++ return -EINVAL;
++
++ if (!boot_cpu_has_bug(X86_BUG_GDS))
++ return 0;
++
++ if (!strcmp(str, "off"))
++ gds_mitigation = GDS_MITIGATION_OFF;
++
++ return 0;
++}
++early_param("gather_data_sampling", gds_parse_cmdline);
++
++#undef pr_fmt
+ #define pr_fmt(fmt) "Spectre V1 : " fmt
+
+ enum spectre_v1_mitigation {
+@@ -2385,6 +2501,11 @@ static ssize_t retbleed_show_state(char
+ return sysfs_emit(buf, "%s\n", retbleed_strings[retbleed_mitigation]);
+ }
+
++static ssize_t gds_show_state(char *buf)
++{
++ return sysfs_emit(buf, "%s\n", gds_strings[gds_mitigation]);
++}
++
+ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr,
+ char *buf, unsigned int bug)
+ {
+@@ -2434,6 +2555,9 @@ static ssize_t cpu_show_common(struct de
+ case X86_BUG_RETBLEED:
+ return retbleed_show_state(buf);
+
++ case X86_BUG_GDS:
++ return gds_show_state(buf);
++
+ default:
+ break;
+ }
+@@ -2498,4 +2622,9 @@ ssize_t cpu_show_retbleed(struct device
+ {
+ return cpu_show_common(dev, attr, buf, X86_BUG_RETBLEED);
+ }
++
++ssize_t cpu_show_gds(struct device *dev, struct device_attribute *attr, char *buf)
++{
++ return cpu_show_common(dev, attr, buf, X86_BUG_GDS);
++}
+ #endif
+--- a/arch/x86/kernel/cpu/common.c
++++ b/arch/x86/kernel/cpu/common.c
+@@ -1267,6 +1267,8 @@ static const __initconst struct x86_cpu_
+ #define RETBLEED BIT(3)
+ /* CPU is affected by SMT (cross-thread) return predictions */
+ #define SMT_RSB BIT(4)
++/* CPU is affected by GDS */
++#define GDS BIT(5)
+
+ static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
+ VULNBL_INTEL_STEPPINGS(IVYBRIDGE, X86_STEPPING_ANY, SRBDS),
+@@ -1279,19 +1281,21 @@ static const struct x86_cpu_id cpu_vuln_
+ VULNBL_INTEL_STEPPINGS(BROADWELL_X, X86_STEPPING_ANY, MMIO),
+ VULNBL_INTEL_STEPPINGS(BROADWELL, X86_STEPPING_ANY, SRBDS),
+ VULNBL_INTEL_STEPPINGS(SKYLAKE_L, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED),
+- VULNBL_INTEL_STEPPINGS(SKYLAKE_X, X86_STEPPING_ANY, MMIO | RETBLEED),
++ VULNBL_INTEL_STEPPINGS(SKYLAKE_X, X86_STEPPING_ANY, MMIO | RETBLEED | GDS),
+ VULNBL_INTEL_STEPPINGS(SKYLAKE, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED),
+- VULNBL_INTEL_STEPPINGS(KABYLAKE_L, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED),
+- VULNBL_INTEL_STEPPINGS(KABYLAKE, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED),
++ VULNBL_INTEL_STEPPINGS(KABYLAKE_L, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED | GDS),
++ VULNBL_INTEL_STEPPINGS(KABYLAKE, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED | GDS),
+ VULNBL_INTEL_STEPPINGS(CANNONLAKE_L, X86_STEPPING_ANY, RETBLEED),
+- VULNBL_INTEL_STEPPINGS(ICELAKE_L, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED),
+- VULNBL_INTEL_STEPPINGS(ICELAKE_D, X86_STEPPING_ANY, MMIO),
+- VULNBL_INTEL_STEPPINGS(ICELAKE_X, X86_STEPPING_ANY, MMIO),
+- VULNBL_INTEL_STEPPINGS(COMETLAKE, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED),
++ VULNBL_INTEL_STEPPINGS(ICELAKE_L, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED | GDS),
++ VULNBL_INTEL_STEPPINGS(ICELAKE_D, X86_STEPPING_ANY, MMIO | GDS),
++ VULNBL_INTEL_STEPPINGS(ICELAKE_X, X86_STEPPING_ANY, MMIO | GDS),
++ VULNBL_INTEL_STEPPINGS(COMETLAKE, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED | GDS),
+ VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x0, 0x0), MMIO | RETBLEED),
+- VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED),
++ VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED | GDS),
++ VULNBL_INTEL_STEPPINGS(TIGERLAKE_L, X86_STEPPING_ANY, GDS),
++ VULNBL_INTEL_STEPPINGS(TIGERLAKE, X86_STEPPING_ANY, GDS),
+ VULNBL_INTEL_STEPPINGS(LAKEFIELD, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED),
+- VULNBL_INTEL_STEPPINGS(ROCKETLAKE, X86_STEPPING_ANY, MMIO | RETBLEED),
++ VULNBL_INTEL_STEPPINGS(ROCKETLAKE, X86_STEPPING_ANY, MMIO | RETBLEED | GDS),
+ VULNBL_INTEL_STEPPINGS(ATOM_TREMONT, X86_STEPPING_ANY, MMIO | MMIO_SBDS),
+ VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_D, X86_STEPPING_ANY, MMIO),
+ VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_L, X86_STEPPING_ANY, MMIO | MMIO_SBDS),
+@@ -1423,6 +1427,16 @@ static void __init cpu_set_bug_bits(stru
+ if (cpu_matches(cpu_vuln_blacklist, SMT_RSB))
+ setup_force_cpu_bug(X86_BUG_SMT_RSB);
+
++ /*
++ * Check if CPU is vulnerable to GDS. If running in a virtual machine on
++ * an affected processor, the VMM may have disabled the use of GATHER by
++ * disabling AVX2. The only way to do this in HW is to clear XCR0[2],
++ * which means that AVX will be disabled.
++ */
++ if (cpu_matches(cpu_vuln_blacklist, GDS) && !(ia32_cap & ARCH_CAP_GDS_NO) &&
++ boot_cpu_has(X86_FEATURE_AVX))
++ setup_force_cpu_bug(X86_BUG_GDS);
++
+ if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN))
+ return;
+
+@@ -1983,6 +1997,8 @@ void identify_secondary_cpu(struct cpuin
+ validate_apic_and_package_id(c);
+ x86_spec_ctrl_setup_ap();
+ update_srbds_msr();
++ if (boot_cpu_has_bug(X86_BUG_GDS))
++ update_gds_msr();
+
+ tsx_ap_init();
+ }
+--- a/arch/x86/kernel/cpu/cpu.h
++++ b/arch/x86/kernel/cpu/cpu.h
+@@ -83,6 +83,7 @@ void cpu_select_mitigations(void);
+
+ extern void x86_spec_ctrl_setup_ap(void);
+ extern void update_srbds_msr(void);
++extern void update_gds_msr(void);
+
+ extern enum spectre_v2_mitigation spectre_v2_enabled;
+
+--- a/drivers/base/cpu.c
++++ b/drivers/base/cpu.c
+@@ -577,6 +577,12 @@ ssize_t __weak cpu_show_retbleed(struct
+ return sysfs_emit(buf, "Not affected\n");
+ }
+
++ssize_t __weak cpu_show_gds(struct device *dev,
++ struct device_attribute *attr, char *buf)
++{
++ return sysfs_emit(buf, "Not affected\n");
++}
++
+ static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
+ static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
+ static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
+@@ -588,6 +594,7 @@ static DEVICE_ATTR(itlb_multihit, 0444,
+ static DEVICE_ATTR(srbds, 0444, cpu_show_srbds, NULL);
+ static DEVICE_ATTR(mmio_stale_data, 0444, cpu_show_mmio_stale_data, NULL);
+ static DEVICE_ATTR(retbleed, 0444, cpu_show_retbleed, NULL);
++static DEVICE_ATTR(gather_data_sampling, 0444, cpu_show_gds, NULL);
+
+ static struct attribute *cpu_root_vulnerabilities_attrs[] = {
+ &dev_attr_meltdown.attr,
+@@ -601,6 +608,7 @@ static struct attribute *cpu_root_vulner
+ &dev_attr_srbds.attr,
+ &dev_attr_mmio_stale_data.attr,
+ &dev_attr_retbleed.attr,
++ &dev_attr_gather_data_sampling.attr,
+ NULL
+ };
+
--- /dev/null
+From 777c80a2542a8374308dc03c4c70a4adb42f6d37 Mon Sep 17 00:00:00 2001
+From: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Date: Tue, 1 Aug 2023 16:07:15 +0200
+Subject: x86/speculation: Add Kconfig option for GDS
+
+From: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+
+commit 53cf5797f114ba2bd86d23a862302119848eff19 upstream
+
+Gather Data Sampling (GDS) is mitigated in microcode. However, on
+systems that haven't received the updated microcode, disabling AVX
+can act as a mitigation. Add a Kconfig option that uses the microcode
+mitigation if available and disables AVX otherwise. Setting this
+option has no effect on systems not affected by GDS. This is the
+equivalent of setting gather_data_sampling=force.
+
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
+Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
+Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/Kconfig | 19 +++++++++++++++++++
+ arch/x86/kernel/cpu/bugs.c | 4 ++++
+ 2 files changed, 23 insertions(+)
+
+--- a/arch/x86/Kconfig
++++ b/arch/x86/Kconfig
+@@ -2651,6 +2651,25 @@ config SLS
+ against straight line speculation. The kernel image might be slightly
+ larger.
+
++config GDS_FORCE_MITIGATION
++ bool "Force GDS Mitigation"
++ depends on CPU_SUP_INTEL
++ default n
++ help
++ Gather Data Sampling (GDS) is a hardware vulnerability which allows
++ unprivileged speculative access to data which was previously stored in
++ vector registers.
++
++ This option is equivalent to setting gather_data_sampling=force on the
++ command line. The microcode mitigation is used if present, otherwise
++ AVX is disabled as a mitigation. On affected systems that are missing
++ the microcode any userspace code that unconditionally uses AVX will
++ break with this option set.
++
++ Setting this option on systems not vulnerable to GDS has no effect.
++
++ If in doubt, say N.
++
+ endif
+
+ config ARCH_HAS_ADD_PAGES
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -659,7 +659,11 @@ enum gds_mitigations {
+ GDS_MITIGATION_HYPERVISOR,
+ };
+
++#if IS_ENABLED(CONFIG_GDS_FORCE_MITIGATION)
++static enum gds_mitigations gds_mitigation __ro_after_init = GDS_MITIGATION_FORCE;
++#else
+ static enum gds_mitigations gds_mitigation __ro_after_init = GDS_MITIGATION_FULL;
++#endif
+
+ static const char * const gds_strings[] = {
+ [GDS_MITIGATION_OFF] = "Vulnerable",
--- /dev/null
+From 97676a7265a04fd039780399a713b0fa52cef6ab Mon Sep 17 00:00:00 2001
+From: "Borislav Petkov (AMD)" <bp@alien8.de>
+Date: Fri, 28 Jul 2023 23:03:22 +0200
+Subject: x86/srso: Add a forgotten NOENDBR annotation
+
+From: "Borislav Petkov (AMD)" <bp@alien8.de>
+
+Upstream commit: 3bbbe97ad83db8d9df06daf027b0840188de625d
+
+Fix:
+
+ vmlinux.o: warning: objtool: .export_symbol+0x29e40: data relocation to !ENDBR: srso_untrain_ret_alias+0x0
+
+Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/lib/retpoline.S | 1 +
+ 1 file changed, 1 insertion(+)
+
+--- a/arch/x86/lib/retpoline.S
++++ b/arch/x86/lib/retpoline.S
+@@ -151,6 +151,7 @@ SYM_CODE_END(__x86_indirect_jump_thunk_a
+ .section .text.__x86.rethunk_untrain
+
+ SYM_START(srso_untrain_ret_alias, SYM_L_GLOBAL, SYM_A_NONE)
++ ANNOTATE_NOENDBR
+ ASM_NOP2
+ lfence
+ jmp __x86_return_thunk
--- /dev/null
+From de9967e90c4f4a383eba17a82dff922e7f0429ae Mon Sep 17 00:00:00 2001
+From: "Borislav Petkov (AMD)" <bp@alien8.de>
+Date: Wed, 28 Jun 2023 11:02:39 +0200
+Subject: x86/srso: Add a Speculative RAS Overflow mitigation
+
+From: "Borislav Petkov (AMD)" <bp@alien8.de>
+
+Upstream commit: fb3bd914b3ec28f5fb697ac55c4846ac2d542855
+
+Add a mitigation for the speculative return address stack overflow
+vulnerability found on AMD processors.
+
+The mitigation works by ensuring all RET instructions speculate to
+a controlled location, similar to how speculation is controlled in the
+retpoline sequence. To accomplish this, the __x86_return_thunk forces
+the CPU to mispredict every function return using a 'safe return'
+sequence.
+
+To ensure the safety of this mitigation, the kernel must ensure that the
+safe return sequence is itself free from attacker interference. In Zen3
+and Zen4, this is accomplished by creating a BTB alias between the
+untraining function srso_untrain_ret_alias() and the safe return
+function srso_safe_ret_alias() which results in evicting a potentially
+poisoned BTB entry and using that safe one for all function returns.
+
+In older Zen1 and Zen2, this is accomplished using a reinterpretation
+technique similar to Retbleed one: srso_untrain_ret() and
+srso_safe_ret().
+
+Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ Documentation/admin-guide/hw-vuln/srso.rst | 133 ++++++++++++++++++++++++
+ Documentation/admin-guide/kernel-parameters.txt | 11 +
+ arch/x86/Kconfig | 7 +
+ arch/x86/include/asm/cpufeatures.h | 5
+ arch/x86/include/asm/nospec-branch.h | 15 ++
+ arch/x86/include/asm/processor.h | 2
+ arch/x86/kernel/alternative.c | 4
+ arch/x86/kernel/cpu/amd.c | 14 ++
+ arch/x86/kernel/cpu/bugs.c | 106 +++++++++++++++++++
+ arch/x86/kernel/cpu/common.c | 8 +
+ arch/x86/kernel/vmlinux.lds.S | 31 +++++
+ arch/x86/lib/retpoline.S | 82 ++++++++++++++
+ drivers/base/cpu.c | 8 +
+ include/linux/cpu.h | 2
+ tools/objtool/arch/x86/decode.c | 5
+ 15 files changed, 424 insertions(+), 9 deletions(-)
+ create mode 100644 Documentation/admin-guide/hw-vuln/srso.rst
+
+--- /dev/null
++++ b/Documentation/admin-guide/hw-vuln/srso.rst
+@@ -0,0 +1,133 @@
++.. SPDX-License-Identifier: GPL-2.0
++
++Speculative Return Stack Overflow (SRSO)
++========================================
++
++This is a mitigation for the speculative return stack overflow (SRSO)
++vulnerability found on AMD processors. The mechanism is by now the well
++known scenario of poisoning CPU functional units - the Branch Target
++Buffer (BTB) and Return Address Predictor (RAP) in this case - and then
++tricking the elevated privilege domain (the kernel) into leaking
++sensitive data.
++
++AMD CPUs predict RET instructions using a Return Address Predictor (aka
++Return Address Stack/Return Stack Buffer). In some cases, a non-architectural
++CALL instruction (i.e., an instruction predicted to be a CALL but is
++not actually a CALL) can create an entry in the RAP which may be used
++to predict the target of a subsequent RET instruction.
++
++The specific circumstances that lead to this varies by microarchitecture
++but the concern is that an attacker can mis-train the CPU BTB to predict
++non-architectural CALL instructions in kernel space and use this to
++control the speculative target of a subsequent kernel RET, potentially
++leading to information disclosure via a speculative side-channel.
++
++The issue is tracked under CVE-2023-20569.
++
++Affected processors
++-------------------
++
++AMD Zen, generations 1-4. That is, all families 0x17 and 0x19. Older
++processors have not been investigated.
++
++System information and options
++------------------------------
++
++First of all, it is required that the latest microcode be loaded for
++mitigations to be effective.
++
++The sysfs file showing SRSO mitigation status is:
++
++ /sys/devices/system/cpu/vulnerabilities/spec_rstack_overflow
++
++The possible values in this file are:
++
++ - 'Not affected' The processor is not vulnerable
++
++ - 'Vulnerable: no microcode' The processor is vulnerable, no
++ microcode extending IBPB functionality
++ to address the vulnerability has been
++ applied.
++
++ - 'Mitigation: microcode' Extended IBPB functionality microcode
++ patch has been applied. It does not
++ address User->Kernel and Guest->Host
++ transitions protection but it does
++ address User->User and VM->VM attack
++ vectors.
++
++ (spec_rstack_overflow=microcode)
++
++ - 'Mitigation: safe RET' Software-only mitigation. It complements
++ the extended IBPB microcode patch
++ functionality by addressing User->Kernel
++ and Guest->Host transitions protection.
++
++ Selected by default or by
++ spec_rstack_overflow=safe-ret
++
++ - 'Mitigation: IBPB' Similar protection as "safe RET" above
++ but employs an IBPB barrier on privilege
++ domain crossings (User->Kernel,
++ Guest->Host).
++
++ (spec_rstack_overflow=ibpb)
++
++ - 'Mitigation: IBPB on VMEXIT' Mitigation addressing the cloud provider
++ scenario - the Guest->Host transitions
++ only.
++
++ (spec_rstack_overflow=ibpb-vmexit)
++
++In order to exploit vulnerability, an attacker needs to:
++
++ - gain local access on the machine
++
++ - break kASLR
++
++ - find gadgets in the running kernel in order to use them in the exploit
++
++ - potentially create and pin an additional workload on the sibling
++ thread, depending on the microarchitecture (not necessary on fam 0x19)
++
++ - run the exploit
++
++Considering the performance implications of each mitigation type, the
++default one is 'Mitigation: safe RET' which should take care of most
++attack vectors, including the local User->Kernel one.
++
++As always, the user is advised to keep her/his system up-to-date by
++applying software updates regularly.
++
++The default setting will be reevaluated when needed and especially when
++new attack vectors appear.
++
++As one can surmise, 'Mitigation: safe RET' does come at the cost of some
++performance depending on the workload. If one trusts her/his userspace
++and does not want to suffer the performance impact, one can always
++disable the mitigation with spec_rstack_overflow=off.
++
++Similarly, 'Mitigation: IBPB' is another full mitigation type employing
++an indrect branch prediction barrier after having applied the required
++microcode patch for one's system. This mitigation comes also at
++a performance cost.
++
++Mitigation: safe RET
++--------------------
++
++The mitigation works by ensuring all RET instructions speculate to
++a controlled location, similar to how speculation is controlled in the
++retpoline sequence. To accomplish this, the __x86_return_thunk forces
++the CPU to mispredict every function return using a 'safe return'
++sequence.
++
++To ensure the safety of this mitigation, the kernel must ensure that the
++safe return sequence is itself free from attacker interference. In Zen3
++and Zen4, this is accomplished by creating a BTB alias between the
++untraining function srso_untrain_ret_alias() and the safe return
++function srso_safe_ret_alias() which results in evicting a potentially
++poisoned BTB entry and using that safe one for all function returns.
++
++In older Zen1 and Zen2, this is accomplished using a reinterpretation
++technique similar to Retbleed one: srso_untrain_ret() and
++srso_safe_ret().
+--- a/Documentation/admin-guide/kernel-parameters.txt
++++ b/Documentation/admin-guide/kernel-parameters.txt
+@@ -5860,6 +5860,17 @@
+ Not specifying this option is equivalent to
+ spectre_v2_user=auto.
+
++ spec_rstack_overflow=
++ [X86] Control RAS overflow mitigation on AMD Zen CPUs
++
++ off - Disable mitigation
++ microcode - Enable microcode mitigation only
++ safe-ret - Enable sw-only safe RET mitigation (default)
++ ibpb - Enable mitigation by issuing IBPB on
++ kernel entry
++ ibpb-vmexit - Issue IBPB only on VMEXIT
++ (cloud-specific mitigation)
++
+ spec_store_bypass_disable=
+ [HW] Control Speculative Store Bypass (SSB) Disable mitigation
+ (Speculative Store Bypass vulnerability)
+--- a/arch/x86/Kconfig
++++ b/arch/x86/Kconfig
+@@ -2641,6 +2641,13 @@ config CPU_IBRS_ENTRY
+ This mitigates both spectre_v2 and retbleed at great cost to
+ performance.
+
++config CPU_SRSO
++ bool "Mitigate speculative RAS overflow on AMD"
++ depends on CPU_SUP_AMD && X86_64 && RETHUNK
++ default y
++ help
++ Enable the SRSO mitigation needed on AMD Zen1-4 machines.
++
+ config SLS
+ bool "Mitigate Straight-Line-Speculation"
+ depends on CC_HAS_SLS && X86_64
+--- a/arch/x86/include/asm/cpufeatures.h
++++ b/arch/x86/include/asm/cpufeatures.h
+@@ -309,6 +309,9 @@
+ #define X86_FEATURE_SMBA (11*32+21) /* "" Slow Memory Bandwidth Allocation */
+ #define X86_FEATURE_BMEC (11*32+22) /* "" Bandwidth Monitoring Event Configuration */
+
++#define X86_FEATURE_SRSO (11*32+24) /* "" AMD BTB untrain RETs */
++#define X86_FEATURE_SRSO_ALIAS (11*32+25) /* "" AMD BTB untrain RETs through aliasing */
++
+ /* Intel-defined CPU features, CPUID level 0x00000007:1 (EAX), word 12 */
+ #define X86_FEATURE_AVX_VNNI (12*32+ 4) /* AVX VNNI instructions */
+ #define X86_FEATURE_AVX512_BF16 (12*32+ 5) /* AVX512 BFLOAT16 instructions */
+@@ -485,4 +488,6 @@
+ #define X86_BUG_SMT_RSB X86_BUG(29) /* CPU is vulnerable to Cross-Thread Return Address Predictions */
+ #define X86_BUG_GDS X86_BUG(30) /* CPU is affected by Gather Data Sampling */
+
++/* BUG word 2 */
++#define X86_BUG_SRSO X86_BUG(1*32 + 0) /* AMD SRSO bug */
+ #endif /* _ASM_X86_CPUFEATURES_H */
+--- a/arch/x86/include/asm/nospec-branch.h
++++ b/arch/x86/include/asm/nospec-branch.h
+@@ -211,7 +211,8 @@
+ * eventually turn into it's own annotation.
+ */
+ .macro VALIDATE_UNRET_END
+-#if defined(CONFIG_NOINSTR_VALIDATION) && defined(CONFIG_CPU_UNRET_ENTRY)
++#if defined(CONFIG_NOINSTR_VALIDATION) && \
++ (defined(CONFIG_CPU_UNRET_ENTRY) || defined(CONFIG_CPU_SRSO))
+ ANNOTATE_RETPOLINE_SAFE
+ nop
+ #endif
+@@ -292,6 +293,11 @@
+ "call entry_ibpb", X86_FEATURE_ENTRY_IBPB, \
+ __stringify(RESET_CALL_DEPTH), X86_FEATURE_CALL_DEPTH
+ #endif
++
++#ifdef CONFIG_CPU_SRSO
++ ALTERNATIVE_2 "", "call srso_untrain_ret", X86_FEATURE_SRSO, \
++ "call srso_untrain_ret_alias", X86_FEATURE_SRSO_ALIAS
++#endif
+ .endm
+
+ .macro UNTRAIN_RET_FROM_CALL
+@@ -303,6 +309,11 @@
+ "call entry_ibpb", X86_FEATURE_ENTRY_IBPB, \
+ __stringify(RESET_CALL_DEPTH_FROM_CALL), X86_FEATURE_CALL_DEPTH
+ #endif
++
++#ifdef CONFIG_CPU_SRSO
++ ALTERNATIVE_2 "", "call srso_untrain_ret", X86_FEATURE_SRSO, \
++ "call srso_untrain_ret_alias", X86_FEATURE_SRSO_ALIAS
++#endif
+ .endm
+
+
+@@ -328,6 +339,8 @@ extern retpoline_thunk_t __x86_indirect_
+
+ extern void __x86_return_thunk(void);
+ extern void zen_untrain_ret(void);
++extern void srso_untrain_ret(void);
++extern void srso_untrain_ret_alias(void);
+ extern void entry_ibpb(void);
+
+ #ifdef CONFIG_CALL_THUNKS
+--- a/arch/x86/include/asm/processor.h
++++ b/arch/x86/include/asm/processor.h
+@@ -683,9 +683,11 @@ extern u16 get_llc_id(unsigned int cpu);
+ #ifdef CONFIG_CPU_SUP_AMD
+ extern u32 amd_get_nodes_per_socket(void);
+ extern u32 amd_get_highest_perf(void);
++extern bool cpu_has_ibpb_brtype_microcode(void);
+ #else
+ static inline u32 amd_get_nodes_per_socket(void) { return 0; }
+ static inline u32 amd_get_highest_perf(void) { return 0; }
++static inline bool cpu_has_ibpb_brtype_microcode(void) { return false; }
+ #endif
+
+ extern unsigned long arch_align_stack(unsigned long sp);
+--- a/arch/x86/kernel/alternative.c
++++ b/arch/x86/kernel/alternative.c
+@@ -590,7 +590,9 @@ static int patch_return(void *addr, stru
+ {
+ int i = 0;
+
+- if (cpu_feature_enabled(X86_FEATURE_RETHUNK)) {
++ if (cpu_feature_enabled(X86_FEATURE_RETHUNK) ||
++ cpu_feature_enabled(X86_FEATURE_SRSO) ||
++ cpu_feature_enabled(X86_FEATURE_SRSO_ALIAS)) {
+ if (x86_return_thunk == __x86_return_thunk)
+ return -1;
+
+--- a/arch/x86/kernel/cpu/amd.c
++++ b/arch/x86/kernel/cpu/amd.c
+@@ -1279,6 +1279,20 @@ u32 amd_get_highest_perf(void)
+ }
+ EXPORT_SYMBOL_GPL(amd_get_highest_perf);
+
++bool cpu_has_ibpb_brtype_microcode(void)
++{
++ u8 fam = boot_cpu_data.x86;
++
++ if (fam == 0x17) {
++ /* Zen1/2 IBPB flushes branch type predictions too. */
++ return boot_cpu_has(X86_FEATURE_AMD_IBPB);
++ } else if (fam == 0x19) {
++ return false;
++ }
++
++ return false;
++}
++
+ static void zenbleed_check_cpu(void *unused)
+ {
+ struct cpuinfo_x86 *c = &cpu_data(smp_processor_id());
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -48,6 +48,7 @@ static void __init mmio_select_mitigatio
+ static void __init srbds_select_mitigation(void);
+ static void __init l1d_flush_select_mitigation(void);
+ static void __init gds_select_mitigation(void);
++static void __init srso_select_mitigation(void);
+
+ /* The base value of the SPEC_CTRL MSR without task-specific bits set */
+ u64 x86_spec_ctrl_base;
+@@ -162,6 +163,7 @@ void __init cpu_select_mitigations(void)
+ srbds_select_mitigation();
+ l1d_flush_select_mitigation();
+ gds_select_mitigation();
++ srso_select_mitigation();
+ }
+
+ /*
+@@ -2333,6 +2335,95 @@ static int __init l1tf_cmdline(char *str
+ early_param("l1tf", l1tf_cmdline);
+
+ #undef pr_fmt
++#define pr_fmt(fmt) "Speculative Return Stack Overflow: " fmt
++
++enum srso_mitigation {
++ SRSO_MITIGATION_NONE,
++ SRSO_MITIGATION_MICROCODE,
++ SRSO_MITIGATION_SAFE_RET,
++};
++
++enum srso_mitigation_cmd {
++ SRSO_CMD_OFF,
++ SRSO_CMD_MICROCODE,
++ SRSO_CMD_SAFE_RET,
++};
++
++static const char * const srso_strings[] = {
++ [SRSO_MITIGATION_NONE] = "Vulnerable",
++ [SRSO_MITIGATION_MICROCODE] = "Mitigation: microcode",
++ [SRSO_MITIGATION_SAFE_RET] = "Mitigation: safe RET",
++};
++
++static enum srso_mitigation srso_mitigation __ro_after_init = SRSO_MITIGATION_NONE;
++static enum srso_mitigation_cmd srso_cmd __ro_after_init = SRSO_CMD_SAFE_RET;
++
++static int __init srso_parse_cmdline(char *str)
++{
++ if (!str)
++ return -EINVAL;
++
++ if (!strcmp(str, "off"))
++ srso_cmd = SRSO_CMD_OFF;
++ else if (!strcmp(str, "microcode"))
++ srso_cmd = SRSO_CMD_MICROCODE;
++ else if (!strcmp(str, "safe-ret"))
++ srso_cmd = SRSO_CMD_SAFE_RET;
++ else
++ pr_err("Ignoring unknown SRSO option (%s).", str);
++
++ return 0;
++}
++early_param("spec_rstack_overflow", srso_parse_cmdline);
++
++#define SRSO_NOTICE "WARNING: See https://kernel.org/doc/html/latest/admin-guide/hw-vuln/srso.html for mitigation options."
++
++static void __init srso_select_mitigation(void)
++{
++ bool has_microcode;
++
++ if (!boot_cpu_has_bug(X86_BUG_SRSO) || cpu_mitigations_off())
++ return;
++
++ has_microcode = cpu_has_ibpb_brtype_microcode();
++ if (!has_microcode) {
++ pr_warn("IBPB-extending microcode not applied!\n");
++ pr_warn(SRSO_NOTICE);
++ }
++
++ switch (srso_cmd) {
++ case SRSO_CMD_OFF:
++ return;
++
++ case SRSO_CMD_MICROCODE:
++ if (has_microcode) {
++ srso_mitigation = SRSO_MITIGATION_MICROCODE;
++ pr_warn(SRSO_NOTICE);
++ }
++ break;
++
++ case SRSO_CMD_SAFE_RET:
++ if (IS_ENABLED(CONFIG_CPU_SRSO)) {
++ if (boot_cpu_data.x86 == 0x19)
++ setup_force_cpu_cap(X86_FEATURE_SRSO_ALIAS);
++ else
++ setup_force_cpu_cap(X86_FEATURE_SRSO);
++ srso_mitigation = SRSO_MITIGATION_SAFE_RET;
++ } else {
++ pr_err("WARNING: kernel not compiled with CPU_SRSO.\n");
++ return;
++ }
++ break;
++
++ default:
++ break;
++
++ }
++
++ pr_info("%s%s\n", srso_strings[srso_mitigation], (has_microcode ? "" : ", no microcode"));
++}
++
++#undef pr_fmt
+ #define pr_fmt(fmt) fmt
+
+ #ifdef CONFIG_SYSFS
+@@ -2535,6 +2626,13 @@ static ssize_t gds_show_state(char *buf)
+ return sysfs_emit(buf, "%s\n", gds_strings[gds_mitigation]);
+ }
+
++static ssize_t srso_show_state(char *buf)
++{
++ return sysfs_emit(buf, "%s%s\n",
++ srso_strings[srso_mitigation],
++ (cpu_has_ibpb_brtype_microcode() ? "" : ", no microcode"));
++}
++
+ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr,
+ char *buf, unsigned int bug)
+ {
+@@ -2587,6 +2685,9 @@ static ssize_t cpu_show_common(struct de
+ case X86_BUG_GDS:
+ return gds_show_state(buf);
+
++ case X86_BUG_SRSO:
++ return srso_show_state(buf);
++
+ default:
+ break;
+ }
+@@ -2656,4 +2757,9 @@ ssize_t cpu_show_gds(struct device *dev,
+ {
+ return cpu_show_common(dev, attr, buf, X86_BUG_GDS);
+ }
++
++ssize_t cpu_show_spec_rstack_overflow(struct device *dev, struct device_attribute *attr, char *buf)
++{
++ return cpu_show_common(dev, attr, buf, X86_BUG_SRSO);
++}
+ #endif
+--- a/arch/x86/kernel/cpu/common.c
++++ b/arch/x86/kernel/cpu/common.c
+@@ -1269,6 +1269,8 @@ static const __initconst struct x86_cpu_
+ #define SMT_RSB BIT(4)
+ /* CPU is affected by GDS */
+ #define GDS BIT(5)
++/* CPU is affected by SRSO */
++#define SRSO BIT(6)
+
+ static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
+ VULNBL_INTEL_STEPPINGS(IVYBRIDGE, X86_STEPPING_ANY, SRBDS),
+@@ -1302,8 +1304,9 @@ static const struct x86_cpu_id cpu_vuln_
+
+ VULNBL_AMD(0x15, RETBLEED),
+ VULNBL_AMD(0x16, RETBLEED),
+- VULNBL_AMD(0x17, RETBLEED | SMT_RSB),
++ VULNBL_AMD(0x17, RETBLEED | SMT_RSB | SRSO),
+ VULNBL_HYGON(0x18, RETBLEED | SMT_RSB),
++ VULNBL_AMD(0x19, SRSO),
+ {}
+ };
+
+@@ -1437,6 +1440,9 @@ static void __init cpu_set_bug_bits(stru
+ boot_cpu_has(X86_FEATURE_AVX))
+ setup_force_cpu_bug(X86_BUG_GDS);
+
++ if (cpu_matches(cpu_vuln_blacklist, SRSO))
++ setup_force_cpu_bug(X86_BUG_SRSO);
++
+ if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN))
+ return;
+
+--- a/arch/x86/kernel/vmlinux.lds.S
++++ b/arch/x86/kernel/vmlinux.lds.S
+@@ -134,13 +134,27 @@ SECTIONS
+ SOFTIRQENTRY_TEXT
+ #ifdef CONFIG_RETPOLINE
+ __indirect_thunk_start = .;
+- *(.text.__x86.*)
++ *(.text.__x86.indirect_thunk)
++ *(.text.__x86.return_thunk)
+ __indirect_thunk_end = .;
+ #endif
+ STATIC_CALL_TEXT
+
+ ALIGN_ENTRY_TEXT_BEGIN
++#ifdef CONFIG_CPU_SRSO
++ *(.text.__x86.rethunk_untrain)
++#endif
++
+ ENTRY_TEXT
++
++#ifdef CONFIG_CPU_SRSO
++ /*
++ * See the comment above srso_untrain_ret_alias()'s
++ * definition.
++ */
++ . = srso_untrain_ret_alias | (1 << 2) | (1 << 8) | (1 << 14) | (1 << 20);
++ *(.text.__x86.rethunk_safe)
++#endif
+ ALIGN_ENTRY_TEXT_END
+ *(.gnu.warning)
+
+@@ -508,4 +522,19 @@ INIT_PER_CPU(irq_stack_backing_store);
+ "fixed_percpu_data is not at start of per-cpu area");
+ #endif
+
++ #ifdef CONFIG_RETHUNK
++. = ASSERT((__ret & 0x3f) == 0, "__ret not cacheline-aligned");
++. = ASSERT((srso_safe_ret & 0x3f) == 0, "srso_safe_ret not cacheline-aligned");
++#endif
++
++#ifdef CONFIG_CPU_SRSO
++/*
++ * GNU ld cannot do XOR so do: (A | B) - (A & B) in order to compute the XOR
++ * of the two function addresses:
++ */
++. = ASSERT(((srso_untrain_ret_alias | srso_safe_ret_alias) -
++ (srso_untrain_ret_alias & srso_safe_ret_alias)) == ((1 << 2) | (1 << 8) | (1 << 14) | (1 << 20)),
++ "SRSO function pair won't alias");
++#endif
++
+ #endif /* CONFIG_X86_64 */
+--- a/arch/x86/lib/retpoline.S
++++ b/arch/x86/lib/retpoline.S
+@@ -11,6 +11,7 @@
+ #include <asm/unwind_hints.h>
+ #include <asm/percpu.h>
+ #include <asm/frame.h>
++#include <asm/nops.h>
+
+ .section .text.__x86.indirect_thunk
+
+@@ -131,6 +132,45 @@ SYM_CODE_END(__x86_indirect_jump_thunk_a
+ */
+ #ifdef CONFIG_RETHUNK
+
++/*
++ * srso_untrain_ret_alias() and srso_safe_ret_alias() are placed at
++ * special addresses:
++ *
++ * - srso_untrain_ret_alias() is 2M aligned
++ * - srso_safe_ret_alias() is also in the same 2M page but bits 2, 8, 14
++ * and 20 in its virtual address are set (while those bits in the
++ * srso_untrain_ret_alias() function are cleared).
++ *
++ * This guarantees that those two addresses will alias in the branch
++ * target buffer of Zen3/4 generations, leading to any potential
++ * poisoned entries at that BTB slot to get evicted.
++ *
++ * As a result, srso_safe_ret_alias() becomes a safe return.
++ */
++#ifdef CONFIG_CPU_SRSO
++ .section .text.__x86.rethunk_untrain
++
++SYM_START(srso_untrain_ret_alias, SYM_L_GLOBAL, SYM_A_NONE)
++ ASM_NOP2
++ lfence
++ jmp __x86_return_thunk
++SYM_FUNC_END(srso_untrain_ret_alias)
++__EXPORT_THUNK(srso_untrain_ret_alias)
++
++ .section .text.__x86.rethunk_safe
++#endif
++
++/* Needs a definition for the __x86_return_thunk alternative below. */
++SYM_START(srso_safe_ret_alias, SYM_L_GLOBAL, SYM_A_NONE)
++#ifdef CONFIG_CPU_SRSO
++ add $8, %_ASM_SP
++ UNWIND_HINT_FUNC
++#endif
++ ANNOTATE_UNRET_SAFE
++ ret
++ int3
++SYM_FUNC_END(srso_safe_ret_alias)
++
+ .section .text.__x86.return_thunk
+
+ /*
+@@ -143,7 +183,7 @@ SYM_CODE_END(__x86_indirect_jump_thunk_a
+ * from re-poisioning the BTB prediction.
+ */
+ .align 64
+- .skip 63, 0xcc
++ .skip 64 - (__ret - zen_untrain_ret), 0xcc
+ SYM_START(zen_untrain_ret, SYM_L_GLOBAL, SYM_A_NONE)
+ ANNOTATE_NOENDBR
+ /*
+@@ -175,10 +215,10 @@ SYM_START(zen_untrain_ret, SYM_L_GLOBAL,
+ * evicted, __x86_return_thunk will suffer Straight Line Speculation
+ * which will be contained safely by the INT3.
+ */
+-SYM_INNER_LABEL(__x86_return_thunk, SYM_L_GLOBAL)
++SYM_INNER_LABEL(__ret, SYM_L_GLOBAL)
+ ret
+ int3
+-SYM_CODE_END(__x86_return_thunk)
++SYM_CODE_END(__ret)
+
+ /*
+ * Ensure the TEST decoding / BTB invalidation is complete.
+@@ -189,11 +229,45 @@ SYM_CODE_END(__x86_return_thunk)
+ * Jump back and execute the RET in the middle of the TEST instruction.
+ * INT3 is for SLS protection.
+ */
+- jmp __x86_return_thunk
++ jmp __ret
+ int3
+ SYM_FUNC_END(zen_untrain_ret)
+ __EXPORT_THUNK(zen_untrain_ret)
+
++/*
++ * SRSO untraining sequence for Zen1/2, similar to zen_untrain_ret()
++ * above. On kernel entry, srso_untrain_ret() is executed which is a
++ *
++ * movabs $0xccccccc308c48348,%rax
++ *
++ * and when the return thunk executes the inner label srso_safe_ret()
++ * later, it is a stack manipulation and a RET which is mispredicted and
++ * thus a "safe" one to use.
++ */
++ .align 64
++ .skip 64 - (srso_safe_ret - srso_untrain_ret), 0xcc
++SYM_START(srso_untrain_ret, SYM_L_GLOBAL, SYM_A_NONE)
++ ANNOTATE_NOENDBR
++ .byte 0x48, 0xb8
++
++SYM_INNER_LABEL(srso_safe_ret, SYM_L_GLOBAL)
++ add $8, %_ASM_SP
++ ret
++ int3
++ int3
++ int3
++ lfence
++ call srso_safe_ret
++ int3
++SYM_CODE_END(srso_safe_ret)
++SYM_FUNC_END(srso_untrain_ret)
++__EXPORT_THUNK(srso_untrain_ret)
++
++SYM_FUNC_START(__x86_return_thunk)
++ ALTERNATIVE_2 "jmp __ret", "call srso_safe_ret", X86_FEATURE_SRSO, \
++ "call srso_safe_ret_alias", X86_FEATURE_SRSO_ALIAS
++ int3
++SYM_CODE_END(__x86_return_thunk)
+ EXPORT_SYMBOL(__x86_return_thunk)
+
+ #endif /* CONFIG_RETHUNK */
+--- a/drivers/base/cpu.c
++++ b/drivers/base/cpu.c
+@@ -583,6 +583,12 @@ ssize_t __weak cpu_show_gds(struct devic
+ return sysfs_emit(buf, "Not affected\n");
+ }
+
++ssize_t __weak cpu_show_spec_rstack_overflow(struct device *dev,
++ struct device_attribute *attr, char *buf)
++{
++ return sysfs_emit(buf, "Not affected\n");
++}
++
+ static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
+ static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
+ static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
+@@ -595,6 +601,7 @@ static DEVICE_ATTR(srbds, 0444, cpu_show
+ static DEVICE_ATTR(mmio_stale_data, 0444, cpu_show_mmio_stale_data, NULL);
+ static DEVICE_ATTR(retbleed, 0444, cpu_show_retbleed, NULL);
+ static DEVICE_ATTR(gather_data_sampling, 0444, cpu_show_gds, NULL);
++static DEVICE_ATTR(spec_rstack_overflow, 0444, cpu_show_spec_rstack_overflow, NULL);
+
+ static struct attribute *cpu_root_vulnerabilities_attrs[] = {
+ &dev_attr_meltdown.attr,
+@@ -609,6 +616,7 @@ static struct attribute *cpu_root_vulner
+ &dev_attr_mmio_stale_data.attr,
+ &dev_attr_retbleed.attr,
+ &dev_attr_gather_data_sampling.attr,
++ &dev_attr_spec_rstack_overflow.attr,
+ NULL
+ };
+
+--- a/include/linux/cpu.h
++++ b/include/linux/cpu.h
+@@ -70,6 +70,8 @@ extern ssize_t cpu_show_mmio_stale_data(
+ char *buf);
+ extern ssize_t cpu_show_retbleed(struct device *dev,
+ struct device_attribute *attr, char *buf);
++extern ssize_t cpu_show_spec_rstack_overflow(struct device *dev,
++ struct device_attribute *attr, char *buf);
+
+ extern __printf(4, 5)
+ struct device *cpu_device_create(struct device *parent, void *drvdata,
+--- a/tools/objtool/arch/x86/decode.c
++++ b/tools/objtool/arch/x86/decode.c
+@@ -824,5 +824,8 @@ bool arch_is_retpoline(struct symbol *sy
+
+ bool arch_is_rethunk(struct symbol *sym)
+ {
+- return !strcmp(sym->name, "__x86_return_thunk");
++ return !strcmp(sym->name, "__x86_return_thunk") ||
++ !strcmp(sym->name, "srso_untrain_ret") ||
++ !strcmp(sym->name, "srso_safe_ret") ||
++ !strcmp(sym->name, "__ret");
+ }
--- /dev/null
+From 3102b30a758da0528aea83f334faf79df74fe950 Mon Sep 17 00:00:00 2001
+From: "Borislav Petkov (AMD)" <bp@alien8.de>
+Date: Fri, 7 Jul 2023 13:53:41 +0200
+Subject: x86/srso: Add IBPB on VMEXIT
+
+From: "Borislav Petkov (AMD)" <bp@alien8.de>
+
+Upstream commit: d893832d0e1ef41c72cdae444268c1d64a2be8ad
+
+Add the option to flush IBPB only on VMEXIT in order to protect from
+malicious guests but one otherwise trusts the software that runs on the
+hypervisor.
+
+Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/include/asm/cpufeatures.h | 1 +
+ arch/x86/kernel/cpu/bugs.c | 19 +++++++++++++++++++
+ arch/x86/kvm/svm/svm.c | 4 +++-
+ arch/x86/kvm/svm/vmenter.S | 3 +++
+ 4 files changed, 26 insertions(+), 1 deletion(-)
+
+--- a/arch/x86/include/asm/cpufeatures.h
++++ b/arch/x86/include/asm/cpufeatures.h
+@@ -311,6 +311,7 @@
+
+ #define X86_FEATURE_SRSO (11*32+24) /* "" AMD BTB untrain RETs */
+ #define X86_FEATURE_SRSO_ALIAS (11*32+25) /* "" AMD BTB untrain RETs through aliasing */
++#define X86_FEATURE_IBPB_ON_VMEXIT (11*32+26) /* "" Issue an IBPB only on VMEXIT */
+
+ /* Intel-defined CPU features, CPUID level 0x00000007:1 (EAX), word 12 */
+ #define X86_FEATURE_AVX_VNNI (12*32+ 4) /* AVX VNNI instructions */
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -2345,6 +2345,7 @@ enum srso_mitigation {
+ SRSO_MITIGATION_MICROCODE,
+ SRSO_MITIGATION_SAFE_RET,
+ SRSO_MITIGATION_IBPB,
++ SRSO_MITIGATION_IBPB_ON_VMEXIT,
+ };
+
+ enum srso_mitigation_cmd {
+@@ -2352,6 +2353,7 @@ enum srso_mitigation_cmd {
+ SRSO_CMD_MICROCODE,
+ SRSO_CMD_SAFE_RET,
+ SRSO_CMD_IBPB,
++ SRSO_CMD_IBPB_ON_VMEXIT,
+ };
+
+ static const char * const srso_strings[] = {
+@@ -2359,6 +2361,7 @@ static const char * const srso_strings[]
+ [SRSO_MITIGATION_MICROCODE] = "Mitigation: microcode",
+ [SRSO_MITIGATION_SAFE_RET] = "Mitigation: safe RET",
+ [SRSO_MITIGATION_IBPB] = "Mitigation: IBPB",
++ [SRSO_MITIGATION_IBPB_ON_VMEXIT] = "Mitigation: IBPB on VMEXIT only"
+ };
+
+ static enum srso_mitigation srso_mitigation __ro_after_init = SRSO_MITIGATION_NONE;
+@@ -2377,6 +2380,8 @@ static int __init srso_parse_cmdline(cha
+ srso_cmd = SRSO_CMD_SAFE_RET;
+ else if (!strcmp(str, "ibpb"))
+ srso_cmd = SRSO_CMD_IBPB;
++ else if (!strcmp(str, "ibpb-vmexit"))
++ srso_cmd = SRSO_CMD_IBPB_ON_VMEXIT;
+ else
+ pr_err("Ignoring unknown SRSO option (%s).", str);
+
+@@ -2460,6 +2465,20 @@ static void __init srso_select_mitigatio
+ pr_err("WARNING: kernel not compiled with CPU_IBPB_ENTRY.\n");
+ goto pred_cmd;
+ }
++ break;
++
++ case SRSO_CMD_IBPB_ON_VMEXIT:
++ if (IS_ENABLED(CONFIG_CPU_SRSO)) {
++ if (!boot_cpu_has(X86_FEATURE_ENTRY_IBPB) && has_microcode) {
++ setup_force_cpu_cap(X86_FEATURE_IBPB_ON_VMEXIT);
++ srso_mitigation = SRSO_MITIGATION_IBPB_ON_VMEXIT;
++ }
++ } else {
++ pr_err("WARNING: kernel not compiled with CPU_SRSO.\n");
++ goto pred_cmd;
++ }
++ break;
++
+ default:
+ break;
+ }
+--- a/arch/x86/kvm/svm/svm.c
++++ b/arch/x86/kvm/svm/svm.c
+@@ -1511,7 +1511,9 @@ static void svm_vcpu_load(struct kvm_vcp
+
+ if (sd->current_vmcb != svm->vmcb) {
+ sd->current_vmcb = svm->vmcb;
+- indirect_branch_prediction_barrier();
++
++ if (!cpu_feature_enabled(X86_FEATURE_IBPB_ON_VMEXIT))
++ indirect_branch_prediction_barrier();
+ }
+ if (kvm_vcpu_apicv_active(vcpu))
+ avic_vcpu_load(vcpu, cpu);
+--- a/arch/x86/kvm/svm/vmenter.S
++++ b/arch/x86/kvm/svm/vmenter.S
+@@ -224,6 +224,9 @@ SYM_FUNC_START(__svm_vcpu_run)
+ */
+ UNTRAIN_RET
+
++ /* SRSO */
++ ALTERNATIVE "", "call entry_ibpb", X86_FEATURE_IBPB_ON_VMEXIT
++
+ /*
+ * Clear all general purpose registers except RSP and RAX to prevent
+ * speculative use of the guest's values, even those that are reloaded
--- /dev/null
+From 9591b96628d84709452182f2fd38ca889f995c53 Mon Sep 17 00:00:00 2001
+From: "Borislav Petkov (AMD)" <bp@alien8.de>
+Date: Thu, 6 Jul 2023 15:04:35 +0200
+Subject: x86/srso: Add IBPB
+
+From: "Borislav Petkov (AMD)" <bp@alien8.de>
+
+Upstream commit: 233d6f68b98d480a7c42ebe78c38f79d44741ca9
+
+Add the option to mitigate using IBPB on a kernel entry. Pull in the
+Retbleed alternative so that the IBPB call from there can be used. Also,
+if Retbleed mitigation is done using IBPB, the same mitigation can and
+must be used here.
+
+Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/include/asm/nospec-branch.h | 2 +-
+ arch/x86/kernel/cpu/bugs.c | 23 +++++++++++++++++++++++
+ 2 files changed, 24 insertions(+), 1 deletion(-)
+
+--- a/arch/x86/include/asm/nospec-branch.h
++++ b/arch/x86/include/asm/nospec-branch.h
+@@ -286,7 +286,7 @@
+ */
+ .macro UNTRAIN_RET
+ #if defined(CONFIG_CPU_UNRET_ENTRY) || defined(CONFIG_CPU_IBPB_ENTRY) || \
+- defined(CONFIG_CALL_DEPTH_TRACKING)
++ defined(CONFIG_CALL_DEPTH_TRACKING) || defined(CONFIG_CPU_SRSO)
+ VALIDATE_UNRET_END
+ ALTERNATIVE_3 "", \
+ CALL_ZEN_UNTRAIN_RET, X86_FEATURE_UNRET, \
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -2344,18 +2344,21 @@ enum srso_mitigation {
+ SRSO_MITIGATION_NONE,
+ SRSO_MITIGATION_MICROCODE,
+ SRSO_MITIGATION_SAFE_RET,
++ SRSO_MITIGATION_IBPB,
+ };
+
+ enum srso_mitigation_cmd {
+ SRSO_CMD_OFF,
+ SRSO_CMD_MICROCODE,
+ SRSO_CMD_SAFE_RET,
++ SRSO_CMD_IBPB,
+ };
+
+ static const char * const srso_strings[] = {
+ [SRSO_MITIGATION_NONE] = "Vulnerable",
+ [SRSO_MITIGATION_MICROCODE] = "Mitigation: microcode",
+ [SRSO_MITIGATION_SAFE_RET] = "Mitigation: safe RET",
++ [SRSO_MITIGATION_IBPB] = "Mitigation: IBPB",
+ };
+
+ static enum srso_mitigation srso_mitigation __ro_after_init = SRSO_MITIGATION_NONE;
+@@ -2372,6 +2375,8 @@ static int __init srso_parse_cmdline(cha
+ srso_cmd = SRSO_CMD_MICROCODE;
+ else if (!strcmp(str, "safe-ret"))
+ srso_cmd = SRSO_CMD_SAFE_RET;
++ else if (!strcmp(str, "ibpb"))
++ srso_cmd = SRSO_CMD_IBPB;
+ else
+ pr_err("Ignoring unknown SRSO option (%s).", str);
+
+@@ -2413,6 +2418,14 @@ static void __init srso_select_mitigatio
+ setup_force_cpu_cap(X86_FEATURE_SRSO_NO);
+ }
+
++ if (retbleed_mitigation == RETBLEED_MITIGATION_IBPB) {
++ if (has_microcode) {
++ pr_err("Retbleed IBPB mitigation enabled, using same for SRSO\n");
++ srso_mitigation = SRSO_MITIGATION_IBPB;
++ goto pred_cmd;
++ }
++ }
++
+ switch (srso_cmd) {
+ case SRSO_CMD_OFF:
+ return;
+@@ -2437,6 +2450,16 @@ static void __init srso_select_mitigatio
+ }
+ break;
+
++ case SRSO_CMD_IBPB:
++ if (IS_ENABLED(CONFIG_CPU_IBPB_ENTRY)) {
++ if (has_microcode) {
++ setup_force_cpu_cap(X86_FEATURE_ENTRY_IBPB);
++ srso_mitigation = SRSO_MITIGATION_IBPB;
++ }
++ } else {
++ pr_err("WARNING: kernel not compiled with CPU_IBPB_ENTRY.\n");
++ goto pred_cmd;
++ }
+ default:
+ break;
+ }
--- /dev/null
+From 0455bf33008369a190abef060fd912c8a4c676cb Mon Sep 17 00:00:00 2001
+From: "Borislav Petkov (AMD)" <bp@alien8.de>
+Date: Tue, 18 Jul 2023 11:13:40 +0200
+Subject: x86/srso: Add IBPB_BRTYPE support
+
+From: "Borislav Petkov (AMD)" <bp@alien8.de>
+
+Upstream commit: 79113e4060aba744787a81edb9014f2865193854
+
+Add support for the synthetic CPUID flag which "if this bit is 1,
+it indicates that MSR 49h (PRED_CMD) bit 0 (IBPB) flushes all branch
+type predictions from the CPU branch predictor."
+
+This flag is there so that this capability in guests can be detected
+easily (otherwise one would have to track microcode revisions which is
+impossible for guests).
+
+It is also needed only for Zen3 and -4. The other two (Zen1 and -2)
+always flush branch type predictions by default.
+
+Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/include/asm/cpufeatures.h | 2 ++
+ arch/x86/kernel/cpu/bugs.c | 12 +++++++++++-
+ 2 files changed, 13 insertions(+), 1 deletion(-)
+
+--- a/arch/x86/include/asm/cpufeatures.h
++++ b/arch/x86/include/asm/cpufeatures.h
+@@ -445,6 +445,8 @@
+ #define X86_FEATURE_AUTOIBRS (20*32+ 8) /* "" Automatic IBRS */
+ #define X86_FEATURE_NO_SMM_CTL_MSR (20*32+ 9) /* "" SMM_CTL MSR is not present */
+
++#define X86_FEATURE_IBPB_BRTYPE (20*32+28) /* "" MSR_PRED_CMD[IBPB] flushes all branch type predictions */
++
+ /*
+ * BUG word(s)
+ */
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -2385,10 +2385,20 @@ static void __init srso_select_mitigatio
+ if (!boot_cpu_has_bug(X86_BUG_SRSO) || cpu_mitigations_off())
+ return;
+
+- has_microcode = cpu_has_ibpb_brtype_microcode();
++ /*
++ * The first check is for the kernel running as a guest in order
++ * for guests to verify whether IBPB is a viable mitigation.
++ */
++ has_microcode = boot_cpu_has(X86_FEATURE_IBPB_BRTYPE) || cpu_has_ibpb_brtype_microcode();
+ if (!has_microcode) {
+ pr_warn("IBPB-extending microcode not applied!\n");
+ pr_warn(SRSO_NOTICE);
++ } else {
++ /*
++ * Enable the synthetic (even if in a real CPUID leaf)
++ * flag for guests.
++ */
++ setup_force_cpu_cap(X86_FEATURE_IBPB_BRTYPE);
+ }
+
+ switch (srso_cmd) {
--- /dev/null
+From ed8daa0749de9f3a0a2bead5b68787d7fab58d89 Mon Sep 17 00:00:00 2001
+From: "Borislav Petkov (AMD)" <bp@alien8.de>
+Date: Thu, 29 Jun 2023 17:43:40 +0200
+Subject: x86/srso: Add SRSO_NO support
+
+From: "Borislav Petkov (AMD)" <bp@alien8.de>
+
+Upstream commit: 1b5277c0ea0b247393a9c426769fde18cff5e2f6
+
+Add support for the CPUID flag which denotes that the CPU is not
+affected by SRSO.
+
+Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/include/asm/cpufeatures.h | 2 ++
+ arch/x86/include/asm/msr-index.h | 1 +
+ arch/x86/include/asm/nospec-branch.h | 6 +++---
+ arch/x86/kernel/cpu/amd.c | 12 ++++++------
+ arch/x86/kernel/cpu/bugs.c | 24 ++++++++++++++++++++----
+ arch/x86/kernel/cpu/common.c | 6 ++++--
+ arch/x86/kvm/cpuid.c | 3 +++
+ 7 files changed, 39 insertions(+), 15 deletions(-)
+
+--- a/arch/x86/include/asm/cpufeatures.h
++++ b/arch/x86/include/asm/cpufeatures.h
+@@ -445,7 +445,9 @@
+ #define X86_FEATURE_AUTOIBRS (20*32+ 8) /* "" Automatic IBRS */
+ #define X86_FEATURE_NO_SMM_CTL_MSR (20*32+ 9) /* "" SMM_CTL MSR is not present */
+
++#define X86_FEATURE_SBPB (20*32+27) /* "" Selective Branch Prediction Barrier */
+ #define X86_FEATURE_IBPB_BRTYPE (20*32+28) /* "" MSR_PRED_CMD[IBPB] flushes all branch type predictions */
++#define X86_FEATURE_SRSO_NO (20*32+29) /* "" CPU is not affected by SRSO */
+
+ /*
+ * BUG word(s)
+--- a/arch/x86/include/asm/msr-index.h
++++ b/arch/x86/include/asm/msr-index.h
+@@ -57,6 +57,7 @@
+
+ #define MSR_IA32_PRED_CMD 0x00000049 /* Prediction Command */
+ #define PRED_CMD_IBPB BIT(0) /* Indirect Branch Prediction Barrier */
++#define PRED_CMD_SBPB BIT(7) /* Selective Branch Prediction Barrier */
+
+ #define MSR_PPIN_CTL 0x0000004e
+ #define MSR_PPIN 0x0000004f
+--- a/arch/x86/include/asm/nospec-branch.h
++++ b/arch/x86/include/asm/nospec-branch.h
+@@ -488,11 +488,11 @@ void alternative_msr_write(unsigned int
+ : "memory");
+ }
+
++extern u64 x86_pred_cmd;
++
+ static inline void indirect_branch_prediction_barrier(void)
+ {
+- u64 val = PRED_CMD_IBPB;
+-
+- alternative_msr_write(MSR_IA32_PRED_CMD, val, X86_FEATURE_USE_IBPB);
++ alternative_msr_write(MSR_IA32_PRED_CMD, x86_pred_cmd, X86_FEATURE_USE_IBPB);
+ }
+
+ /* The Intel SPEC CTRL MSR base value cache */
+--- a/arch/x86/kernel/cpu/amd.c
++++ b/arch/x86/kernel/cpu/amd.c
+@@ -1283,14 +1283,14 @@ bool cpu_has_ibpb_brtype_microcode(void)
+ {
+ u8 fam = boot_cpu_data.x86;
+
+- if (fam == 0x17) {
+- /* Zen1/2 IBPB flushes branch type predictions too. */
++ /* Zen1/2 IBPB flushes branch type predictions too. */
++ if (fam == 0x17)
+ return boot_cpu_has(X86_FEATURE_AMD_IBPB);
+- } else if (fam == 0x19) {
++ /* Poke the MSR bit on Zen3/4 to check its presence. */
++ else if (fam == 0x19)
++ return !wrmsrl_safe(MSR_IA32_PRED_CMD, PRED_CMD_SBPB);
++ else
+ return false;
+- }
+-
+- return false;
+ }
+
+ static void zenbleed_check_cpu(void *unused)
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -58,6 +58,9 @@ EXPORT_SYMBOL_GPL(x86_spec_ctrl_base);
+ DEFINE_PER_CPU(u64, x86_spec_ctrl_current);
+ EXPORT_SYMBOL_GPL(x86_spec_ctrl_current);
+
++u64 x86_pred_cmd __ro_after_init = PRED_CMD_IBPB;
++EXPORT_SYMBOL_GPL(x86_pred_cmd);
++
+ static DEFINE_MUTEX(spec_ctrl_mutex);
+
+ /* Update SPEC_CTRL MSR and its cached copy unconditionally */
+@@ -2383,7 +2386,7 @@ static void __init srso_select_mitigatio
+ bool has_microcode;
+
+ if (!boot_cpu_has_bug(X86_BUG_SRSO) || cpu_mitigations_off())
+- return;
++ goto pred_cmd;
+
+ /*
+ * The first check is for the kernel running as a guest in order
+@@ -2396,9 +2399,18 @@ static void __init srso_select_mitigatio
+ } else {
+ /*
+ * Enable the synthetic (even if in a real CPUID leaf)
+- * flag for guests.
++ * flags for guests.
+ */
+ setup_force_cpu_cap(X86_FEATURE_IBPB_BRTYPE);
++ setup_force_cpu_cap(X86_FEATURE_SBPB);
++
++ /*
++ * Zen1/2 with SMT off aren't vulnerable after the right
++ * IBPB microcode has been applied.
++ */
++ if ((boot_cpu_data.x86 < 0x19) &&
++ (cpu_smt_control == CPU_SMT_DISABLED))
++ setup_force_cpu_cap(X86_FEATURE_SRSO_NO);
+ }
+
+ switch (srso_cmd) {
+@@ -2421,16 +2433,20 @@ static void __init srso_select_mitigatio
+ srso_mitigation = SRSO_MITIGATION_SAFE_RET;
+ } else {
+ pr_err("WARNING: kernel not compiled with CPU_SRSO.\n");
+- return;
++ goto pred_cmd;
+ }
+ break;
+
+ default:
+ break;
+-
+ }
+
+ pr_info("%s%s\n", srso_strings[srso_mitigation], (has_microcode ? "" : ", no microcode"));
++
++pred_cmd:
++ if (boot_cpu_has(X86_FEATURE_SRSO_NO) ||
++ srso_cmd == SRSO_CMD_OFF)
++ x86_pred_cmd = PRED_CMD_SBPB;
+ }
+
+ #undef pr_fmt
+--- a/arch/x86/kernel/cpu/common.c
++++ b/arch/x86/kernel/cpu/common.c
+@@ -1440,8 +1440,10 @@ static void __init cpu_set_bug_bits(stru
+ boot_cpu_has(X86_FEATURE_AVX))
+ setup_force_cpu_bug(X86_BUG_GDS);
+
+- if (cpu_matches(cpu_vuln_blacklist, SRSO))
+- setup_force_cpu_bug(X86_BUG_SRSO);
++ if (!cpu_has(c, X86_FEATURE_SRSO_NO)) {
++ if (cpu_matches(cpu_vuln_blacklist, SRSO))
++ setup_force_cpu_bug(X86_BUG_SRSO);
++ }
+
+ if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN))
+ return;
+--- a/arch/x86/kvm/cpuid.c
++++ b/arch/x86/kvm/cpuid.c
+@@ -734,6 +734,9 @@ void kvm_set_cpu_caps(void)
+ F(NULL_SEL_CLR_BASE) | F(AUTOIBRS) | 0 /* PrefetchCtlMsr */
+ );
+
++ if (cpu_feature_enabled(X86_FEATURE_SRSO_NO))
++ kvm_cpu_cap_set(X86_FEATURE_SRSO_NO);
++
+ /*
+ * Synthesize "LFENCE is serializing" into the AMD-defined entry in
+ * KVM's supported CPUID if the feature is reported as supported by the
--- /dev/null
+From 4b1b4045a8941a7b11820c016182e7df74a07e3e Mon Sep 17 00:00:00 2001
+From: Josh Poimboeuf <jpoimboe@kernel.org>
+Date: Fri, 28 Jul 2023 17:28:43 -0500
+Subject: x86/srso: Fix return thunks in generated code
+
+From: Josh Poimboeuf <jpoimboe@kernel.org>
+
+Upstream commit: 238ec850b95a02dcdff3edc86781aa913549282f
+
+Set X86_FEATURE_RETHUNK when enabling the SRSO mitigation so that
+generated code (e.g., ftrace, static call, eBPF) generates "jmp
+__x86_return_thunk" instead of RET.
+
+ [ bp: Add a comment. ]
+
+Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation")
+Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
+Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/kernel/alternative.c | 4 +---
+ arch/x86/kernel/cpu/bugs.c | 6 ++++++
+ 2 files changed, 7 insertions(+), 3 deletions(-)
+
+--- a/arch/x86/kernel/alternative.c
++++ b/arch/x86/kernel/alternative.c
+@@ -590,9 +590,7 @@ static int patch_return(void *addr, stru
+ {
+ int i = 0;
+
+- if (cpu_feature_enabled(X86_FEATURE_RETHUNK) ||
+- cpu_feature_enabled(X86_FEATURE_SRSO) ||
+- cpu_feature_enabled(X86_FEATURE_SRSO_ALIAS)) {
++ if (cpu_feature_enabled(X86_FEATURE_RETHUNK)) {
+ if (x86_return_thunk == __x86_return_thunk)
+ return -1;
+
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -2444,6 +2444,12 @@ static void __init srso_select_mitigatio
+
+ case SRSO_CMD_SAFE_RET:
+ if (IS_ENABLED(CONFIG_CPU_SRSO)) {
++ /*
++ * Enable the return thunk for generated code
++ * like ftrace, static_call, etc.
++ */
++ setup_force_cpu_cap(X86_FEATURE_RETHUNK);
++
+ if (boot_cpu_data.x86 == 0x19)
+ setup_force_cpu_cap(X86_FEATURE_SRSO_ALIAS);
+ else
--- /dev/null
+From 5a15d8348881e9371afdf9f5357a135489496955 Mon Sep 17 00:00:00 2001
+From: "Borislav Petkov (AMD)" <bp@alien8.de>
+Date: Mon, 7 Aug 2023 10:46:04 +0200
+Subject: x86/srso: Tie SBPB bit setting to microcode patch detection
+
+From: Borislav Petkov (AMD) <bp@alien8.de>
+
+commit 5a15d8348881e9371afdf9f5357a135489496955 upstream.
+
+The SBPB bit in MSR_IA32_PRED_CMD is supported only after a microcode
+patch has been applied so set X86_FEATURE_SBPB only then. Otherwise,
+guests would attempt to set that bit and #GP on the MSR write.
+
+While at it, make SMT detection more robust as some guests - depending
+on how and what CPUID leafs their report - lead to cpu_smt_control
+getting set to CPU_SMT_NOT_SUPPORTED but SRSO_NO should be set for any
+guest incarnation where one simply cannot do SMT, for whatever reason.
+
+Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation")
+Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Reported-by: Salvatore Bonaccorso <carnil@debian.org>
+Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/kernel/cpu/amd.c | 19 ++++++++++++-------
+ arch/x86/kernel/cpu/bugs.c | 7 +++----
+ 2 files changed, 15 insertions(+), 11 deletions(-)
+
+--- a/arch/x86/kernel/cpu/amd.c
++++ b/arch/x86/kernel/cpu/amd.c
+@@ -1281,16 +1281,21 @@ EXPORT_SYMBOL_GPL(amd_get_highest_perf);
+
+ bool cpu_has_ibpb_brtype_microcode(void)
+ {
+- u8 fam = boot_cpu_data.x86;
+-
++ switch (boot_cpu_data.x86) {
+ /* Zen1/2 IBPB flushes branch type predictions too. */
+- if (fam == 0x17)
++ case 0x17:
+ return boot_cpu_has(X86_FEATURE_AMD_IBPB);
+- /* Poke the MSR bit on Zen3/4 to check its presence. */
+- else if (fam == 0x19)
+- return !wrmsrl_safe(MSR_IA32_PRED_CMD, PRED_CMD_SBPB);
+- else
++ case 0x19:
++ /* Poke the MSR bit on Zen3/4 to check its presence. */
++ if (!wrmsrl_safe(MSR_IA32_PRED_CMD, PRED_CMD_SBPB)) {
++ setup_force_cpu_cap(X86_FEATURE_SBPB);
++ return true;
++ } else {
++ return false;
++ }
++ default:
+ return false;
++ }
+ }
+
+ static void zenbleed_check_cpu(void *unused)
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -2412,14 +2412,13 @@ static void __init srso_select_mitigatio
+ * flags for guests.
+ */
+ setup_force_cpu_cap(X86_FEATURE_IBPB_BRTYPE);
+- setup_force_cpu_cap(X86_FEATURE_SBPB);
+
+ /*
+ * Zen1/2 with SMT off aren't vulnerable after the right
+ * IBPB microcode has been applied.
+ */
+ if ((boot_cpu_data.x86 < 0x19) &&
+- (cpu_smt_control == CPU_SMT_DISABLED))
++ (!cpu_smt_possible() || (cpu_smt_control == CPU_SMT_DISABLED)))
+ setup_force_cpu_cap(X86_FEATURE_SRSO_NO);
+ }
+
+@@ -2492,8 +2491,8 @@ static void __init srso_select_mitigatio
+ pr_info("%s%s\n", srso_strings[srso_mitigation], (has_microcode ? "" : ", no microcode"));
+
+ pred_cmd:
+- if (boot_cpu_has(X86_FEATURE_SRSO_NO) ||
+- srso_cmd == SRSO_CMD_OFF)
++ if ((boot_cpu_has(X86_FEATURE_SRSO_NO) || srso_cmd == SRSO_CMD_OFF) &&
++ boot_cpu_has(X86_FEATURE_SBPB))
+ x86_pred_cmd = PRED_CMD_SBPB;
+ }
+
--- /dev/null
+From fe3e0a13e597c1c8617814bf9b42ab732db5c26e Mon Sep 17 00:00:00 2001
+From: Juergen Gross <jgross@suse.com>
+Date: Mon, 3 Jul 2023 15:00:32 +0200
+Subject: x86/xen: Fix secondary processors' FPU initialization
+
+From: Juergen Gross <jgross@suse.com>
+
+commit fe3e0a13e597c1c8617814bf9b42ab732db5c26e upstream.
+
+Moving the call of fpu__init_cpu() from cpu_init() to start_secondary()
+broke Xen PV guests, as those don't call start_secondary() for APs.
+
+Call fpu__init_cpu() in Xen's cpu_bringup(), which is the Xen PV
+replacement of start_secondary().
+
+Fixes: b81fac906a8f ("x86/fpu: Move FPU initialization into arch_cpu_finalize_init()")
+Signed-off-by: Juergen Gross <jgross@suse.com>
+Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
+Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
+Acked-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20230703130032.22916-1-jgross@suse.com
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/xen/smp_pv.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+--- a/arch/x86/xen/smp_pv.c
++++ b/arch/x86/xen/smp_pv.c
+@@ -63,6 +63,7 @@ static void cpu_bringup(void)
+
+ cr4_init();
+ cpu_init();
++ fpu__init_cpu();
+ touch_softlockup_watchdog();
+
+ /* PVH runs in ring 0 and allows us to do native syscalls. Yay! */
--- /dev/null
+From 534fc31d09b706a16d83533e16b5dc855caf7576 Mon Sep 17 00:00:00 2001
+From: Ross Lagerwall <ross.lagerwall@citrix.com>
+Date: Thu, 3 Aug 2023 08:41:22 +0200
+Subject: xen/netback: Fix buffer overrun triggered by unusual packet
+
+From: Ross Lagerwall <ross.lagerwall@citrix.com>
+
+commit 534fc31d09b706a16d83533e16b5dc855caf7576 upstream.
+
+It is possible that a guest can send a packet that contains a head + 18
+slots and yet has a len <= XEN_NETBACK_TX_COPY_LEN. This causes nr_slots
+to underflow in xenvif_get_requests() which then causes the subsequent
+loop's termination condition to be wrong, causing a buffer overrun of
+queue->tx_map_ops.
+
+Rework the code to account for the extra frag_overflow slots.
+
+This is CVE-2023-34319 / XSA-432.
+
+Fixes: ad7f402ae4f4 ("xen/netback: Ensure protocol headers don't fall in the non-linear area")
+Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
+Reviewed-by: Paul Durrant <paul@xen.org>
+Reviewed-by: Wei Liu <wei.liu@kernel.org>
+Signed-off-by: Juergen Gross <jgross@suse.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/net/xen-netback/netback.c | 15 ++++++++++-----
+ 1 file changed, 10 insertions(+), 5 deletions(-)
+
+--- a/drivers/net/xen-netback/netback.c
++++ b/drivers/net/xen-netback/netback.c
+@@ -396,7 +396,7 @@ static void xenvif_get_requests(struct x
+ struct gnttab_map_grant_ref *gop = queue->tx_map_ops + *map_ops;
+ struct xen_netif_tx_request *txp = first;
+
+- nr_slots = shinfo->nr_frags + 1;
++ nr_slots = shinfo->nr_frags + frag_overflow + 1;
+
+ copy_count(skb) = 0;
+ XENVIF_TX_CB(skb)->split_mask = 0;
+@@ -462,8 +462,8 @@ static void xenvif_get_requests(struct x
+ }
+ }
+
+- for (shinfo->nr_frags = 0; shinfo->nr_frags < nr_slots;
+- shinfo->nr_frags++, gop++) {
++ for (shinfo->nr_frags = 0; nr_slots > 0 && shinfo->nr_frags < MAX_SKB_FRAGS;
++ shinfo->nr_frags++, gop++, nr_slots--) {
+ index = pending_index(queue->pending_cons++);
+ pending_idx = queue->pending_ring[index];
+ xenvif_tx_create_map_op(queue, pending_idx, txp,
+@@ -476,12 +476,12 @@ static void xenvif_get_requests(struct x
+ txp++;
+ }
+
+- if (frag_overflow) {
++ if (nr_slots > 0) {
+
+ shinfo = skb_shinfo(nskb);
+ frags = shinfo->frags;
+
+- for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
++ for (shinfo->nr_frags = 0; shinfo->nr_frags < nr_slots;
+ shinfo->nr_frags++, txp++, gop++) {
+ index = pending_index(queue->pending_cons++);
+ pending_idx = queue->pending_ring[index];
+@@ -492,6 +492,11 @@ static void xenvif_get_requests(struct x
+ }
+
+ skb_shinfo(skb)->frag_list = nskb;
++ } else if (nskb) {
++ /* A frag_list skb was allocated but it is no longer needed
++ * because enough slots were converted to copy ops above.
++ */
++ kfree_skb(nskb);
+ }
+
+ (*copy_ops) = cop - queue->tx_copy_ops;
projects / thirdparty / kernel / stable-queue.git / commitdiff
