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| author | Peter Zijlstra <peterz@infradead.org> | 2021-12-04 16:43:44 +0300 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-12-09 15:32:25 +0300 |
| commit | e463a09af2f0677b9485a7e8e4e70b396b2ffb6f (patch) | |
| tree | 169cdec1cc953df3619ae2e08e662784211fbc24 /arch/x86/lib/memmove_64.S | |
| parent | 26c44b776dba4ac692a0bf5a3836feb8a63fea6b (diff) | |
| download | linux-e463a09af2f0677b9485a7e8e4e70b396b2ffb6f.tar.xz | |
x86: Add straight-line-speculation mitigation
Make use of an upcoming GCC feature to mitigate
straight-line-speculation for x86:
https://gcc.gnu.org/g:53a643f8568067d7700a9f2facc8ba39974973d3
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102952
https://bugs.llvm.org/show_bug.cgi?id=52323
It's built tested on x86_64-allyesconfig using GCC-12 and GCC-11.
Maintenance overhead of this should be fairly low due to objtool
validation.
Size overhead of all these additional int3 instructions comes to:
text data bss dec hex filename
22267751 6933356 2011368 31212475 1dc43bb defconfig-build/vmlinux
22804126 6933356 1470696 31208178 1dc32f2 defconfig-build/vmlinux.sls
Or roughly 2.4% additional text.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211204134908.140103474@infradead.org
Diffstat (limited to 'arch/x86/lib/memmove_64.S')
| -rw-r--r-- | arch/x86/lib/memmove_64.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/lib/memmove_64.S b/arch/x86/lib/memmove_64.S index e84d649620c4..50ea390df712 100644 --- a/arch/x86/lib/memmove_64.S +++ b/arch/x86/lib/memmove_64.S @@ -40,7 +40,7 @@ SYM_FUNC_START(__memmove) /* FSRM implies ERMS => no length checks, do the copy directly */ .Lmemmove_begin_forward: ALTERNATIVE "cmp $0x20, %rdx; jb 1f", "", X86_FEATURE_FSRM - ALTERNATIVE "", "movq %rdx, %rcx; rep movsb; RET", X86_FEATURE_ERMS + ALTERNATIVE "", __stringify(movq %rdx, %rcx; rep movsb; RET), X86_FEATURE_ERMS /* * movsq instruction have many startup latency |