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d49a062621
Generic function-alignment infrastructure.
Architectures can select FUNCTION_ALIGNMENT_xxB symbols; the
FUNCTION_ALIGNMENT symbol is then set to the largest such selected
size, 0 otherwise.
From this the -falign-functions compiler argument and __ALIGN macro
are set.
This incorporates the DEBUG_FORCE_FUNCTION_ALIGN_64B knob and future
alignment requirements for x86_64 (later in this series) into a single
place.
NOTE: also removes the 0x90 filler byte from the generic __ALIGN
primitive, that value makes no sense outside of x86.
NOTE: .balign 0 reverts to a no-op.
Requested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111143.719248727@infradead.org
88 lines
2.3 KiB
C
88 lines
2.3 KiB
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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#include <asm/ibt.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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#define __ALIGN .balign CONFIG_FUNCTION_ALIGNMENT, 0x90;
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#define __ALIGN_STR __stringify(__ALIGN)
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#if defined(CONFIG_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
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#define RET jmp __x86_return_thunk
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#else /* CONFIG_RETPOLINE */
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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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#endif /* CONFIG_RETPOLINE */
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#else /* __ASSEMBLY__ */
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#if defined(CONFIG_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
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#define ASM_RET "jmp __x86_return_thunk\n\t"
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#else /* CONFIG_RETPOLINE */
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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 /* CONFIG_RETPOLINE */
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#endif /* __ASSEMBLY__ */
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#define __CFI_TYPE(name) \
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SYM_START(__cfi_##name, SYM_L_LOCAL, SYM_A_NONE) \
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.fill 11, 1, 0x90 ASM_NL \
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.byte 0xb8 ASM_NL \
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.long __kcfi_typeid_##name ASM_NL \
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SYM_FUNC_END(__cfi_##name)
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/* SYM_TYPED_FUNC_START -- use for indirectly called globals, w/ CFI type */
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#define SYM_TYPED_FUNC_START(name) \
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SYM_TYPED_START(name, SYM_L_GLOBAL, SYM_A_ALIGN) \
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ENDBR
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/* SYM_FUNC_START -- use for global functions */
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#define SYM_FUNC_START(name) \
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SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN) \
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ENDBR
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/* SYM_FUNC_START_NOALIGN -- use for global functions, w/o alignment */
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#define SYM_FUNC_START_NOALIGN(name) \
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SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE) \
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ENDBR
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/* SYM_FUNC_START_LOCAL -- use for local functions */
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#define SYM_FUNC_START_LOCAL(name) \
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SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN) \
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ENDBR
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/* SYM_FUNC_START_LOCAL_NOALIGN -- use for local functions, w/o alignment */
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#define SYM_FUNC_START_LOCAL_NOALIGN(name) \
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SYM_START(name, SYM_L_LOCAL, SYM_A_NONE) \
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ENDBR
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/* SYM_FUNC_START_WEAK -- use for weak functions */
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#define SYM_FUNC_START_WEAK(name) \
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SYM_START(name, SYM_L_WEAK, SYM_A_ALIGN) \
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ENDBR
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/* SYM_FUNC_START_WEAK_NOALIGN -- use for weak functions, w/o alignment */
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#define SYM_FUNC_START_WEAK_NOALIGN(name) \
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SYM_START(name, SYM_L_WEAK, SYM_A_NONE) \
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ENDBR
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#endif /* _ASM_X86_LINKAGE_H */
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