nilfs2-fix-null-pointer-dereference-at-nilfs_segctor_do_construct.patch
spi-bcm2835aux-fix-controller-unregister-order.patch
alsa-pcm-disallow-linking-stream-to-itself.patch
+x86-speculation-change-misspelled-stipb-to-stibp.patch
+x86-speculation-add-support-for-stibp-always-on-pref.patch
+x86-speculation-avoid-force-disabling-ibpb-based-on-.patch
+x86-speculation-pr_spec_force_disable-enforcement-fo.patch
--- /dev/null
+From 4002daba617dab6effd1e2f1aa5ef6cc654cf701 Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Thu, 13 Dec 2018 23:03:54 +0000
+Subject: x86/speculation: Add support for STIBP always-on preferred mode
+
+From: Thomas Lendacky <Thomas.Lendacky@amd.com>
+
+[ Upstream commit 20c3a2c33e9fdc82e9e8e8d2a6445b3256d20191 ]
+
+Different AMD processors may have different implementations of STIBP.
+When STIBP is conditionally enabled, some implementations would benefit
+from having STIBP always on instead of toggling the STIBP bit through MSR
+writes. This preference is advertised through a CPUID feature bit.
+
+When conditional STIBP support is requested at boot and the CPU advertises
+STIBP always-on mode as preferred, switch to STIBP "on" support. To show
+that this transition has occurred, create a new spectre_v2_user_mitigation
+value and a new spectre_v2_user_strings message. The new mitigation value
+is used in spectre_v2_user_select_mitigation() to print the new mitigation
+message as well as to return a new string from stibp_state().
+
+Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Andrea Arcangeli <aarcange@redhat.com>
+Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Cc: Jiri Kosina <jkosina@suse.cz>
+Cc: Borislav Petkov <bp@alien8.de>
+Cc: Tim Chen <tim.c.chen@linux.intel.com>
+Cc: David Woodhouse <dwmw@amazon.co.uk>
+Link: https://lkml.kernel.org/r/20181213230352.6937.74943.stgit@tlendack-t1.amdoffice.net
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ arch/x86/include/asm/cpufeatures.h | 2 +-
+ arch/x86/include/asm/nospec-branch.h | 1 +
+ arch/x86/kernel/cpu/bugs.c | 28 ++++++++++++++++++++++------
+ 3 files changed, 24 insertions(+), 7 deletions(-)
+
+diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
+index 492889d92146..7c7fc5006017 100644
+--- a/arch/x86/include/asm/cpufeatures.h
++++ b/arch/x86/include/asm/cpufeatures.h
+@@ -270,6 +270,7 @@
+ #define X86_FEATURE_AMD_IBPB (13*32+12) /* "" Indirect Branch Prediction Barrier */
+ #define X86_FEATURE_AMD_IBRS (13*32+14) /* "" Indirect Branch Restricted Speculation */
+ #define X86_FEATURE_AMD_STIBP (13*32+15) /* "" Single Thread Indirect Branch Predictors */
++#define X86_FEATURE_AMD_STIBP_ALWAYS_ON (13*32+17) /* "" Single Thread Indirect Branch Predictors always-on preferred */
+ #define X86_FEATURE_AMD_SSBD (13*32+24) /* "" Speculative Store Bypass Disable */
+ #define X86_FEATURE_VIRT_SSBD (13*32+25) /* Virtualized Speculative Store Bypass Disable */
+ #define X86_FEATURE_AMD_SSB_NO (13*32+26) /* "" Speculative Store Bypass is fixed in hardware. */
+@@ -308,7 +309,6 @@
+ #define X86_FEATURE_SUCCOR (17*32+1) /* Uncorrectable error containment and recovery */
+ #define X86_FEATURE_SMCA (17*32+3) /* Scalable MCA */
+
+-
+ /* Intel-defined CPU features, CPUID level 0x00000007:0 (EDX), word 18 */
+ #define X86_FEATURE_AVX512_4VNNIW (18*32+ 2) /* AVX-512 Neural Network Instructions */
+ #define X86_FEATURE_AVX512_4FMAPS (18*32+ 3) /* AVX-512 Multiply Accumulation Single precision */
+diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
+index 783f0711895b..664e8505ccd6 100644
+--- a/arch/x86/include/asm/nospec-branch.h
++++ b/arch/x86/include/asm/nospec-branch.h
+@@ -178,6 +178,7 @@ enum spectre_v2_mitigation {
+ enum spectre_v2_user_mitigation {
+ SPECTRE_V2_USER_NONE,
+ SPECTRE_V2_USER_STRICT,
++ SPECTRE_V2_USER_STRICT_PREFERRED,
+ SPECTRE_V2_USER_PRCTL,
+ SPECTRE_V2_USER_SECCOMP,
+ };
+diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
+index 9fddbdcc1874..6ee7d81fe339 100644
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -609,10 +609,11 @@ enum spectre_v2_user_cmd {
+ };
+
+ static const char * const spectre_v2_user_strings[] = {
+- [SPECTRE_V2_USER_NONE] = "User space: Vulnerable",
+- [SPECTRE_V2_USER_STRICT] = "User space: Mitigation: STIBP protection",
+- [SPECTRE_V2_USER_PRCTL] = "User space: Mitigation: STIBP via prctl",
+- [SPECTRE_V2_USER_SECCOMP] = "User space: Mitigation: STIBP via seccomp and prctl",
++ [SPECTRE_V2_USER_NONE] = "User space: Vulnerable",
++ [SPECTRE_V2_USER_STRICT] = "User space: Mitigation: STIBP protection",
++ [SPECTRE_V2_USER_STRICT_PREFERRED] = "User space: Mitigation: STIBP always-on protection",
++ [SPECTRE_V2_USER_PRCTL] = "User space: Mitigation: STIBP via prctl",
++ [SPECTRE_V2_USER_SECCOMP] = "User space: Mitigation: STIBP via seccomp and prctl",
+ };
+
+ static const struct {
+@@ -701,6 +702,15 @@ spectre_v2_user_select_mitigation(enum spectre_v2_mitigation_cmd v2_cmd)
+ break;
+ }
+
++ /*
++ * At this point, an STIBP mode other than "off" has been set.
++ * If STIBP support is not being forced, check if STIBP always-on
++ * is preferred.
++ */
++ if (mode != SPECTRE_V2_USER_STRICT &&
++ boot_cpu_has(X86_FEATURE_AMD_STIBP_ALWAYS_ON))
++ mode = SPECTRE_V2_USER_STRICT_PREFERRED;
++
+ /* Initialize Indirect Branch Prediction Barrier */
+ if (boot_cpu_has(X86_FEATURE_IBPB)) {
+ setup_force_cpu_cap(X86_FEATURE_USE_IBPB);
+@@ -983,6 +993,7 @@ void arch_smt_update(void)
+ case SPECTRE_V2_USER_NONE:
+ break;
+ case SPECTRE_V2_USER_STRICT:
++ case SPECTRE_V2_USER_STRICT_PREFERRED:
+ update_stibp_strict();
+ break;
+ case SPECTRE_V2_USER_PRCTL:
+@@ -1217,7 +1228,8 @@ static int ib_prctl_set(struct task_struct *task, unsigned long ctrl)
+ * Indirect branch speculation is always disabled in strict
+ * mode.
+ */
+- if (spectre_v2_user == SPECTRE_V2_USER_STRICT)
++ if (spectre_v2_user == SPECTRE_V2_USER_STRICT ||
++ spectre_v2_user == SPECTRE_V2_USER_STRICT_PREFERRED)
+ return -EPERM;
+ task_clear_spec_ib_disable(task);
+ task_update_spec_tif(task);
+@@ -1230,7 +1242,8 @@ static int ib_prctl_set(struct task_struct *task, unsigned long ctrl)
+ */
+ if (spectre_v2_user == SPECTRE_V2_USER_NONE)
+ return -EPERM;
+- if (spectre_v2_user == SPECTRE_V2_USER_STRICT)
++ if (spectre_v2_user == SPECTRE_V2_USER_STRICT ||
++ spectre_v2_user == SPECTRE_V2_USER_STRICT_PREFERRED)
+ return 0;
+ task_set_spec_ib_disable(task);
+ if (ctrl == PR_SPEC_FORCE_DISABLE)
+@@ -1301,6 +1314,7 @@ static int ib_prctl_get(struct task_struct *task)
+ return PR_SPEC_PRCTL | PR_SPEC_DISABLE;
+ return PR_SPEC_PRCTL | PR_SPEC_ENABLE;
+ case SPECTRE_V2_USER_STRICT:
++ case SPECTRE_V2_USER_STRICT_PREFERRED:
+ return PR_SPEC_DISABLE;
+ default:
+ return PR_SPEC_NOT_AFFECTED;
+@@ -1450,6 +1464,8 @@ static char *stibp_state(void)
+ return ", STIBP: disabled";
+ case SPECTRE_V2_USER_STRICT:
+ return ", STIBP: forced";
++ case SPECTRE_V2_USER_STRICT_PREFERRED:
++ return ", STIBP: always-on";
+ case SPECTRE_V2_USER_PRCTL:
+ case SPECTRE_V2_USER_SECCOMP:
+ if (static_key_enabled(&switch_to_cond_stibp))
+--
+2.25.1
+
--- /dev/null
+From aa7f67713382c74acfbc1783cf21af553426af1f Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Tue, 19 May 2020 06:40:42 -0700
+Subject: x86/speculation: Avoid force-disabling IBPB based on STIBP and
+ enhanced IBRS.
+
+From: Anthony Steinhauser <asteinhauser@google.com>
+
+[ Upstream commit 21998a351512eba4ed5969006f0c55882d995ada ]
+
+When STIBP is unavailable or enhanced IBRS is available, Linux
+force-disables the IBPB mitigation of Spectre-BTB even when simultaneous
+multithreading is disabled. While attempts to enable IBPB using
+prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_INDIRECT_BRANCH, ...) fail with
+EPERM, the seccomp syscall (or its prctl(PR_SET_SECCOMP, ...) equivalent)
+which are used e.g. by Chromium or OpenSSH succeed with no errors but the
+application remains silently vulnerable to cross-process Spectre v2 attacks
+(classical BTB poisoning). At the same time the SYSFS reporting
+(/sys/devices/system/cpu/vulnerabilities/spectre_v2) displays that IBPB is
+conditionally enabled when in fact it is unconditionally disabled.
+
+STIBP is useful only when SMT is enabled. When SMT is disabled and STIBP is
+unavailable, it makes no sense to force-disable also IBPB, because IBPB
+protects against cross-process Spectre-BTB attacks regardless of the SMT
+state. At the same time since missing STIBP was only observed on AMD CPUs,
+AMD does not recommend using STIBP, but recommends using IBPB, so disabling
+IBPB because of missing STIBP goes directly against AMD's advice:
+https://developer.amd.com/wp-content/resources/Architecture_Guidelines_Update_Indirect_Branch_Control.pdf
+
+Similarly, enhanced IBRS is designed to protect cross-core BTB poisoning
+and BTB-poisoning attacks from user space against kernel (and
+BTB-poisoning attacks from guest against hypervisor), it is not designed
+to prevent cross-process (or cross-VM) BTB poisoning between processes (or
+VMs) running on the same core. Therefore, even with enhanced IBRS it is
+necessary to flush the BTB during context-switches, so there is no reason
+to force disable IBPB when enhanced IBRS is available.
+
+Enable the prctl control of IBPB even when STIBP is unavailable or enhanced
+IBRS is available.
+
+Fixes: 7cc765a67d8e ("x86/speculation: Enable prctl mode for spectre_v2_user")
+Signed-off-by: Anthony Steinhauser <asteinhauser@google.com>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: stable@vger.kernel.org
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ arch/x86/kernel/cpu/bugs.c | 86 ++++++++++++++++++++++----------------
+ 1 file changed, 49 insertions(+), 37 deletions(-)
+
+diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
+index 6ee7d81fe339..94e10898126a 100644
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -558,7 +558,8 @@ early_param("nospectre_v1", nospectre_v1_cmdline);
+
+ static enum spectre_v2_mitigation spectre_v2_enabled = SPECTRE_V2_NONE;
+
+-static enum spectre_v2_user_mitigation spectre_v2_user = SPECTRE_V2_USER_NONE;
++static enum spectre_v2_user_mitigation spectre_v2_user_stibp = SPECTRE_V2_USER_NONE;
++static enum spectre_v2_user_mitigation spectre_v2_user_ibpb = SPECTRE_V2_USER_NONE;
+
+ #ifdef RETPOLINE
+ static bool spectre_v2_bad_module;
+@@ -702,15 +703,6 @@ spectre_v2_user_select_mitigation(enum spectre_v2_mitigation_cmd v2_cmd)
+ break;
+ }
+
+- /*
+- * At this point, an STIBP mode other than "off" has been set.
+- * If STIBP support is not being forced, check if STIBP always-on
+- * is preferred.
+- */
+- if (mode != SPECTRE_V2_USER_STRICT &&
+- boot_cpu_has(X86_FEATURE_AMD_STIBP_ALWAYS_ON))
+- mode = SPECTRE_V2_USER_STRICT_PREFERRED;
+-
+ /* Initialize Indirect Branch Prediction Barrier */
+ if (boot_cpu_has(X86_FEATURE_IBPB)) {
+ setup_force_cpu_cap(X86_FEATURE_USE_IBPB);
+@@ -733,23 +725,36 @@ spectre_v2_user_select_mitigation(enum spectre_v2_mitigation_cmd v2_cmd)
+ pr_info("mitigation: Enabling %s Indirect Branch Prediction Barrier\n",
+ static_key_enabled(&switch_mm_always_ibpb) ?
+ "always-on" : "conditional");
++
++ spectre_v2_user_ibpb = mode;
+ }
+
+- /* If enhanced IBRS is enabled no STIBP required */
+- if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED)
++ /*
++ * If enhanced IBRS is enabled or SMT impossible, STIBP is not
++ * required.
++ */
++ if (!smt_possible || spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED)
+ return;
+
+ /*
+- * If SMT is not possible or STIBP is not available clear the STIBP
+- * mode.
++ * At this point, an STIBP mode other than "off" has been set.
++ * If STIBP support is not being forced, check if STIBP always-on
++ * is preferred.
+ */
+- if (!smt_possible || !boot_cpu_has(X86_FEATURE_STIBP))
++ if (mode != SPECTRE_V2_USER_STRICT &&
++ boot_cpu_has(X86_FEATURE_AMD_STIBP_ALWAYS_ON))
++ mode = SPECTRE_V2_USER_STRICT_PREFERRED;
++
++ /*
++ * If STIBP is not available, clear the STIBP mode.
++ */
++ if (!boot_cpu_has(X86_FEATURE_STIBP))
+ mode = SPECTRE_V2_USER_NONE;
++
++ spectre_v2_user_stibp = mode;
++
+ set_mode:
+- spectre_v2_user = mode;
+- /* Only print the STIBP mode when SMT possible */
+- if (smt_possible)
+- pr_info("%s\n", spectre_v2_user_strings[mode]);
++ pr_info("%s\n", spectre_v2_user_strings[mode]);
+ }
+
+ static const char * const spectre_v2_strings[] = {
+@@ -989,7 +994,7 @@ void arch_smt_update(void)
+ {
+ mutex_lock(&spec_ctrl_mutex);
+
+- switch (spectre_v2_user) {
++ switch (spectre_v2_user_stibp) {
+ case SPECTRE_V2_USER_NONE:
+ break;
+ case SPECTRE_V2_USER_STRICT:
+@@ -1222,14 +1227,16 @@ static int ib_prctl_set(struct task_struct *task, unsigned long ctrl)
+ {
+ switch (ctrl) {
+ case PR_SPEC_ENABLE:
+- if (spectre_v2_user == SPECTRE_V2_USER_NONE)
++ if (spectre_v2_user_ibpb == SPECTRE_V2_USER_NONE &&
++ spectre_v2_user_stibp == SPECTRE_V2_USER_NONE)
+ return 0;
+ /*
+ * Indirect branch speculation is always disabled in strict
+ * mode.
+ */
+- if (spectre_v2_user == SPECTRE_V2_USER_STRICT ||
+- spectre_v2_user == SPECTRE_V2_USER_STRICT_PREFERRED)
++ if (spectre_v2_user_ibpb == SPECTRE_V2_USER_STRICT ||
++ spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT ||
++ spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED)
+ return -EPERM;
+ task_clear_spec_ib_disable(task);
+ task_update_spec_tif(task);
+@@ -1240,10 +1247,12 @@ static int ib_prctl_set(struct task_struct *task, unsigned long ctrl)
+ * Indirect branch speculation is always allowed when
+ * mitigation is force disabled.
+ */
+- if (spectre_v2_user == SPECTRE_V2_USER_NONE)
++ if (spectre_v2_user_ibpb == SPECTRE_V2_USER_NONE &&
++ spectre_v2_user_stibp == SPECTRE_V2_USER_NONE)
+ return -EPERM;
+- if (spectre_v2_user == SPECTRE_V2_USER_STRICT ||
+- spectre_v2_user == SPECTRE_V2_USER_STRICT_PREFERRED)
++ if (spectre_v2_user_ibpb == SPECTRE_V2_USER_STRICT ||
++ spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT ||
++ spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED)
+ return 0;
+ task_set_spec_ib_disable(task);
+ if (ctrl == PR_SPEC_FORCE_DISABLE)
+@@ -1274,7 +1283,8 @@ void arch_seccomp_spec_mitigate(struct task_struct *task)
+ {
+ if (ssb_mode == SPEC_STORE_BYPASS_SECCOMP)
+ ssb_prctl_set(task, PR_SPEC_FORCE_DISABLE);
+- if (spectre_v2_user == SPECTRE_V2_USER_SECCOMP)
++ if (spectre_v2_user_ibpb == SPECTRE_V2_USER_SECCOMP ||
++ spectre_v2_user_stibp == SPECTRE_V2_USER_SECCOMP)
+ ib_prctl_set(task, PR_SPEC_FORCE_DISABLE);
+ }
+ #endif
+@@ -1303,22 +1313,24 @@ static int ib_prctl_get(struct task_struct *task)
+ if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
+ return PR_SPEC_NOT_AFFECTED;
+
+- switch (spectre_v2_user) {
+- case SPECTRE_V2_USER_NONE:
++ if (spectre_v2_user_ibpb == SPECTRE_V2_USER_NONE &&
++ spectre_v2_user_stibp == SPECTRE_V2_USER_NONE)
+ return PR_SPEC_ENABLE;
+- case SPECTRE_V2_USER_PRCTL:
+- case SPECTRE_V2_USER_SECCOMP:
++ else if (spectre_v2_user_ibpb == SPECTRE_V2_USER_STRICT ||
++ spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT ||
++ spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED)
++ return PR_SPEC_DISABLE;
++ else if (spectre_v2_user_ibpb == SPECTRE_V2_USER_PRCTL ||
++ spectre_v2_user_ibpb == SPECTRE_V2_USER_SECCOMP ||
++ spectre_v2_user_stibp == SPECTRE_V2_USER_PRCTL ||
++ spectre_v2_user_stibp == SPECTRE_V2_USER_SECCOMP) {
+ if (task_spec_ib_force_disable(task))
+ return PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE;
+ if (task_spec_ib_disable(task))
+ return PR_SPEC_PRCTL | PR_SPEC_DISABLE;
+ return PR_SPEC_PRCTL | PR_SPEC_ENABLE;
+- case SPECTRE_V2_USER_STRICT:
+- case SPECTRE_V2_USER_STRICT_PREFERRED:
+- return PR_SPEC_DISABLE;
+- default:
++ } else
+ return PR_SPEC_NOT_AFFECTED;
+- }
+ }
+
+ int arch_prctl_spec_ctrl_get(struct task_struct *task, unsigned long which)
+@@ -1459,7 +1471,7 @@ static char *stibp_state(void)
+ if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED)
+ return "";
+
+- switch (spectre_v2_user) {
++ switch (spectre_v2_user_stibp) {
+ case SPECTRE_V2_USER_NONE:
+ return ", STIBP: disabled";
+ case SPECTRE_V2_USER_STRICT:
+--
+2.25.1
+
--- /dev/null
+From fca40c5b01fe4fa6f24609c6703c70ecee628fe3 Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Wed, 5 Dec 2018 14:49:27 -0500
+Subject: x86/speculation: Change misspelled STIPB to STIBP
+
+From: Waiman Long <longman@redhat.com>
+
+[ Upstream commit aa77bfb354c495fc4361199e63fc5765b9e1e783 ]
+
+STIBP stands for Single Thread Indirect Branch Predictors. The acronym,
+however, can be easily mis-spelled as STIPB. It is perhaps due to the
+presence of another related term - IBPB (Indirect Branch Predictor
+Barrier).
+
+Fix the mis-spelling in the code.
+
+Signed-off-by: Waiman Long <longman@redhat.com>
+Signed-off-by: Borislav Petkov <bp@suse.de>
+Cc: "H. Peter Anvin" <hpa@zytor.com>
+Cc: Andi Kleen <ak@linux.intel.com>
+Cc: David Woodhouse <dwmw@amazon.co.uk>
+Cc: Ingo Molnar <mingo@redhat.com>
+Cc: Jiri Kosina <jkosina@suse.cz>
+Cc: Josh Poimboeuf <jpoimboe@redhat.com>
+Cc: KarimAllah Ahmed <karahmed@amazon.de>
+Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Cc: Peter Zijlstra <peterz@infradead.org>
+Cc: Thomas Gleixner <tglx@linutronix.de>
+Cc: Tim Chen <tim.c.chen@linux.intel.com>
+Cc: x86-ml <x86@kernel.org>
+Link: https://lkml.kernel.org/r/1544039368-9009-1-git-send-email-longman@redhat.com
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ arch/x86/kernel/cpu/bugs.c | 6 +++---
+ arch/x86/kernel/process.h | 2 +-
+ 2 files changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
+index 1a0ab4af93b7..9fddbdcc1874 100644
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -59,7 +59,7 @@ static u64 x86_spec_ctrl_mask = SPEC_CTRL_IBRS;
+ u64 x86_amd_ls_cfg_base;
+ u64 x86_amd_ls_cfg_ssbd_mask;
+
+-/* Control conditional STIPB in switch_to() */
++/* Control conditional STIBP in switch_to() */
+ DEFINE_STATIC_KEY_FALSE(switch_to_cond_stibp);
+ /* Control conditional IBPB in switch_mm() */
+ DEFINE_STATIC_KEY_FALSE(switch_mm_cond_ibpb);
+@@ -725,12 +725,12 @@ spectre_v2_user_select_mitigation(enum spectre_v2_mitigation_cmd v2_cmd)
+ "always-on" : "conditional");
+ }
+
+- /* If enhanced IBRS is enabled no STIPB required */
++ /* If enhanced IBRS is enabled no STIBP required */
+ if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED)
+ return;
+
+ /*
+- * If SMT is not possible or STIBP is not available clear the STIPB
++ * If SMT is not possible or STIBP is not available clear the STIBP
+ * mode.
+ */
+ if (!smt_possible || !boot_cpu_has(X86_FEATURE_STIBP))
+diff --git a/arch/x86/kernel/process.h b/arch/x86/kernel/process.h
+index 898e97cf6629..320ab978fb1f 100644
+--- a/arch/x86/kernel/process.h
++++ b/arch/x86/kernel/process.h
+@@ -19,7 +19,7 @@ static inline void switch_to_extra(struct task_struct *prev,
+ if (IS_ENABLED(CONFIG_SMP)) {
+ /*
+ * Avoid __switch_to_xtra() invocation when conditional
+- * STIPB is disabled and the only different bit is
++ * STIBP is disabled and the only different bit is
+ * TIF_SPEC_IB. For CONFIG_SMP=n TIF_SPEC_IB is not
+ * in the TIF_WORK_CTXSW masks.
+ */
+--
+2.25.1
+
--- /dev/null
+From b59a48db9cb78035a97a48394c24768833856059 Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Sun, 7 Jun 2020 05:44:19 -0700
+Subject: x86/speculation: PR_SPEC_FORCE_DISABLE enforcement for indirect
+ branches.
+
+From: Anthony Steinhauser <asteinhauser@google.com>
+
+[ Upstream commit 4d8df8cbb9156b0a0ab3f802b80cb5db57acc0bf ]
+
+Currently, it is possible to enable indirect branch speculation even after
+it was force-disabled using the PR_SPEC_FORCE_DISABLE option. Moreover, the
+PR_GET_SPECULATION_CTRL command gives afterwards an incorrect result
+(force-disabled when it is in fact enabled). This also is inconsistent
+vs. STIBP and the documention which cleary states that
+PR_SPEC_FORCE_DISABLE cannot be undone.
+
+Fix this by actually enforcing force-disabled indirect branch
+speculation. PR_SPEC_ENABLE called after PR_SPEC_FORCE_DISABLE now fails
+with -EPERM as described in the documentation.
+
+Fixes: 9137bb27e60e ("x86/speculation: Add prctl() control for indirect branch speculation")
+Signed-off-by: Anthony Steinhauser <asteinhauser@google.com>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: stable@vger.kernel.org
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ arch/x86/kernel/cpu/bugs.c | 7 +++++--
+ 1 file changed, 5 insertions(+), 2 deletions(-)
+
+diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
+index 94e10898126a..2d2631f9a519 100644
+--- a/arch/x86/kernel/cpu/bugs.c
++++ b/arch/x86/kernel/cpu/bugs.c
+@@ -1232,11 +1232,14 @@ static int ib_prctl_set(struct task_struct *task, unsigned long ctrl)
+ return 0;
+ /*
+ * Indirect branch speculation is always disabled in strict
+- * mode.
++ * mode. It can neither be enabled if it was force-disabled
++ * by a previous prctl call.
++
+ */
+ if (spectre_v2_user_ibpb == SPECTRE_V2_USER_STRICT ||
+ spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT ||
+- spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED)
++ spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED ||
++ task_spec_ib_force_disable(task))
+ return -EPERM;
+ task_clear_spec_ib_disable(task);
+ task_update_spec_tif(task);
+--
+2.25.1
+
projects / thirdparty / kernel / stable-queue.git / commitdiff
