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742a15b1a2
Now we have a macro for BTI C that looks like a regular instruction change all the users of the current BTI_C macro to just emit a BTI C directly and remove the macro. This does mean that we now unconditionally BTI annotate all assembly functions, meaning that they are worse in this respect than code generated by the compiler. The overhead should be minimal for implementations with a reasonable HINT implementation. Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20211214152714.2380849-4-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
62 lines
1.6 KiB
C
62 lines
1.6 KiB
C
#ifndef __ASM_LINKAGE_H
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#define __ASM_LINKAGE_H
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#define __ALIGN .align 2
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#define __ALIGN_STR ".align 2"
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/*
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* When using in-kernel BTI we need to ensure that PCS-conformant
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* assembly functions have suitable annotations. Override
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* SYM_FUNC_START to insert a BTI landing pad at the start of
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* everything, the override is done unconditionally so we're more
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* likely to notice any drift from the overridden definitions.
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*/
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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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bti c ;
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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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bti c ;
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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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bti c ;
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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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bti c ;
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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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bti c ;
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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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bti c ;
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/*
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* Annotate a function as position independent, i.e., safe to be called before
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* the kernel virtual mapping is activated.
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*/
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#define SYM_FUNC_START_PI(x) \
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SYM_FUNC_START_ALIAS(__pi_##x); \
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SYM_FUNC_START(x)
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#define SYM_FUNC_START_WEAK_PI(x) \
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SYM_FUNC_START_ALIAS(__pi_##x); \
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SYM_FUNC_START_WEAK(x)
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#define SYM_FUNC_START_WEAK_ALIAS_PI(x) \
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SYM_FUNC_START_ALIAS(__pi_##x); \
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SYM_START(x, SYM_L_WEAK, SYM_A_ALIGN)
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#define SYM_FUNC_END_PI(x) \
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SYM_FUNC_END(x); \
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SYM_FUNC_END_ALIAS(__pi_##x)
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#define SYM_FUNC_END_ALIAS_PI(x) \
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SYM_FUNC_END_ALIAS(x); \
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SYM_FUNC_END_ALIAS(__pi_##x)
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#endif
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