e9925a4584
commit e463a09af2f0677b9485a7e8e4e70b396b2ffb6f upstream. 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 Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [bwh: Backported to 5.10: - In scripts/Makefile.build, add the objtool option with an ifdef block, same as for other options - Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
39 lines
720 B
C
39 lines
720 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_LINKAGE_H
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#define _ASM_X86_LINKAGE_H
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#include <linux/stringify.h>
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#undef notrace
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#define notrace __attribute__((no_instrument_function))
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#ifdef CONFIG_X86_32
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#define asmlinkage CPP_ASMLINKAGE __attribute__((regparm(0)))
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#endif /* CONFIG_X86_32 */
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#ifdef __ASSEMBLY__
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#if defined(CONFIG_X86_64) || defined(CONFIG_X86_ALIGNMENT_16)
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#define __ALIGN .p2align 4, 0x90
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#define __ALIGN_STR __stringify(__ALIGN)
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#endif
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#ifdef CONFIG_SLS
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#define RET ret; int3
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#else
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#define RET ret
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#endif
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#else /* __ASSEMBLY__ */
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#ifdef CONFIG_SLS
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#define ASM_RET "ret; int3\n\t"
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#else
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#define ASM_RET "ret\n\t"
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#endif
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_X86_LINKAGE_H */
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