x86/entry: Rename ignore_sysret()

[ Upstream commit f71e1d2ff8e6a183bd4004bc97c453ba527b7dc6 ]

The SYSCALL instruction cannot really be disabled in compatibility mode.
The best that can be done is to configure the CSTAR msr to point to a
minimal handler. Currently this handler has a rather misleading name -
ignore_sysret() as it's not really doing anything with sysret.

Give it a more descriptive name.

Signed-off-by: Nikolay Borisov <nik.borisov@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230623111409.3047467-3-nik.borisov@suse.com
Stable-dep-of: ac8b270b61d4 ("x86/bhi: Avoid warning in #DB handler due to BHI mitigation")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 5d96561c0d6ad1d50b05ae26579fd26c857ecc11..1edb8e1b9e0188781780f84e7fcc61ac4902b814 100644 (file)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1527,13 +1527,13 @@ SYM_CODE_END(asm_exc_nmi)
  * This handles SYSCALL from 32-bit code.  There is no way to program
  * MSRs to fully disable 32-bit SYSCALL.
  */
-SYM_CODE_START(ignore_sysret)
+SYM_CODE_START(entry_SYSCALL32_ignore)
        UNWIND_HINT_END_OF_STACK
        ENDBR
        mov     $-ENOSYS, %eax
        CLEAR_CPU_BUFFERS
        sysretl
-SYM_CODE_END(ignore_sysret)
+SYM_CODE_END(entry_SYSCALL32_ignore)
 #endif
 
 .pushsection .text, "ax"

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 6e19d0f22600001671743ae459abe786f747af8e..67ad64efa9263f7d45161106ec90840bd0152415 100644 (file)
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -399,7 +399,7 @@ static inline unsigned long cpu_kernelmode_gs_base(int cpu)
        return (unsigned long)per_cpu(fixed_percpu_data.gs_base, cpu);
 }
 
-extern asmlinkage void ignore_sysret(void);
+extern asmlinkage void entry_SYSCALL32_ignore(void);
 
 /* Save actual FS/GS selectors and bases to current->thread */
 void current_save_fsgs(void);

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 340dd6cc11af4c7615c24ee1e186b0286f23f446..74d566263467edda27cd574541f6309337144500 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -2134,7 +2134,7 @@ void syscall_init(void)
                    (unsigned long)(cpu_entry_stack(smp_processor_id()) + 1));
        wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)entry_SYSENTER_compat);
 #else
-       wrmsrl_cstar((unsigned long)ignore_sysret);
+       wrmsrl_cstar((unsigned long)entry_SYSCALL32_ignore);
        wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)GDT_ENTRY_INVALID_SEG);
        wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL);
        wrmsrl_safe(MSR_IA32_SYSENTER_EIP, 0ULL);