Commit c4691712 authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

x86/linkage: Add ENDBR to SYM_FUNC_START*() 



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: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154317.992708941@infradead.org
parent 8f93402b

arch/x86/include/asm/linkage.h

+31 −0
Original line number Diff line number Diff line
@@ -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 */