diff options
| author | Borislav Petkov <bp@alien8.de> | 2018-01-27 17:24:33 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-01-27 19:10:45 +0100 |
| commit | 1dde7415e99933bb7293d6b2843752cbdb43ec11 (patch) | |
| tree | d78520e6c433ab33c8edd45746895b9be08855b7 /arch/x86/entry | |
| parent | x86/cpufeatures: Clean up Spectre v2 related CPUID flags (diff) | |
| download | linux-1dde7415e99933bb7293d6b2843752cbdb43ec11.tar.xz linux-1dde7415e99933bb7293d6b2843752cbdb43ec11.zip | |
x86/retpoline: Simplify vmexit_fill_RSB()
Simplify it to call an asm-function instead of pasting 41 insn bytes at
every call site. Also, add alignment to the macro as suggested here:
https://support.google.com/faqs/answer/7625886
[dwmw2: Clean up comments, let it clobber %ebx and just tell the compiler]
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: ak@linux.intel.com
Cc: dave.hansen@intel.com
Cc: karahmed@amazon.de
Cc: arjan@linux.intel.com
Cc: torvalds@linux-foundation.org
Cc: peterz@infradead.org
Cc: bp@alien8.de
Cc: pbonzini@redhat.com
Cc: tim.c.chen@linux.intel.com
Cc: gregkh@linux-foundation.org
Link: https://lkml.kernel.org/r/1517070274-12128-3-git-send-email-dwmw@amazon.co.uk
Diffstat (limited to 'arch/x86/entry')
| -rw-r--r-- | arch/x86/entry/entry_32.S | 3 | ||||
| -rw-r--r-- | arch/x86/entry/entry_64.S | 3 |
2 files changed, 4 insertions, 2 deletions
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 60c4c342316c..2a35b1e0fb90 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -252,7 +252,8 @@ ENTRY(__switch_to_asm) * exist, overwrite the RSB with entries which capture * speculative execution to prevent attack. */ - FILL_RETURN_BUFFER %ebx, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW + /* Clobbers %ebx */ + FILL_RETURN_BUFFER RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW #endif /* restore callee-saved registers */ diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 63f4320602a3..b4f00984089e 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -495,7 +495,8 @@ ENTRY(__switch_to_asm) * exist, overwrite the RSB with entries which capture * speculative execution to prevent attack. */ - FILL_RETURN_BUFFER %r12, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW + /* Clobbers %rbx */ + FILL_RETURN_BUFFER RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW #endif /* restore callee-saved registers */ |