| Date | Tue, 08 Mar 2022 16:30:25 +0100 | From | Peter Zijlstra <> | Subject | [PATCH v4 14/45] x86/linkage: Add ENDBR to SYM_FUNC_START*() |
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Ensure the ASM functions have ENDBR on for IBT builds, this follows the ARM64 example. Unlike ARM64, we'll likely end up overwriting them with poison.
Suggested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Kees Cook <keescook@chromium.org> --- arch/x86/include/asm/linkage.h | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+)
--- a/arch/x86/include/asm/linkage.h +++ b/arch/x86/include/asm/linkage.h @@ -3,6 +3,7 @@ #define _ASM_X86_LINKAGE_H #include <linux/stringify.h> +#include <asm/ibt.h> #undef notrace #define notrace __attribute__((no_instrument_function)) @@ -34,5 +35,35 @@ #endif /* __ASSEMBLY__ */ +/* SYM_FUNC_START -- use for global functions */ +#define SYM_FUNC_START(name) \ + SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN) \ + ENDBR + +/* SYM_FUNC_START_NOALIGN -- use for global functions, w/o alignment */ +#define SYM_FUNC_START_NOALIGN(name) \ + SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE) \ + ENDBR + +/* SYM_FUNC_START_LOCAL -- use for local functions */ +#define SYM_FUNC_START_LOCAL(name) \ + SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN) \ + ENDBR + +/* SYM_FUNC_START_LOCAL_NOALIGN -- use for local functions, w/o alignment */ +#define SYM_FUNC_START_LOCAL_NOALIGN(name) \ + SYM_START(name, SYM_L_LOCAL, SYM_A_NONE) \ + ENDBR + +/* SYM_FUNC_START_WEAK -- use for weak functions */ +#define SYM_FUNC_START_WEAK(name) \ + SYM_START(name, SYM_L_WEAK, SYM_A_ALIGN) \ + ENDBR + +/* SYM_FUNC_START_WEAK_NOALIGN -- use for weak functions, w/o alignment */ +#define SYM_FUNC_START_WEAK_NOALIGN(name) \ + SYM_START(name, SYM_L_WEAK, SYM_A_NONE) \ + ENDBR + #endif /* _ASM_X86_LINKAGE_H */
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