Commit 42964a18 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'objtool_urgent_for_v5.17_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull objtool fix from Borislav Petkov:
 "Fix a case where objtool would mistakenly warn about instructions
  being unreachable"

* tag 'objtool_urgent_for_v5.17_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/bug: Merge annotate_reachable() into _BUG_FLAGS() asm
parents 6f357367 bfb1a7c9

arch/x86/include/asm/bug.h

+11 −9
Original line number Diff line number Diff line
@@ -22,7 +22,7 @@ 


#ifdef CONFIG_DEBUG_BUGVERBOSE



#define _BUG_FLAGS(ins, flags)						\

#define _BUG_FLAGS(ins, flags, extra)					\

do {									\

	asm_inline volatile("1:\t" ins "\n"				\

		     ".pushsection __bug_table,\"aw\"\n"		\
@@ -31,7 +31,8 @@ do { \ 
		     "\t.word %c1"        "\t# bug_entry::line\n"	\

		     "\t.word %c2"        "\t# bug_entry::flags\n"	\

		     "\t.org 2b+%c3\n"					\

		     ".popsection"					\

		     ".popsection\n"					\

		     extra						\

		     : : "i" (__FILE__), "i" (__LINE__),		\

			 "i" (flags),					\

			 "i" (sizeof(struct bug_entry)));		\
@@ -39,14 +40,15 @@ do { \ 


#else /* !CONFIG_DEBUG_BUGVERBOSE */



#define _BUG_FLAGS(ins, flags)						\

#define _BUG_FLAGS(ins, flags, extra)					\

do {									\

	asm_inline volatile("1:\t" ins "\n"				\

		     ".pushsection __bug_table,\"aw\"\n"		\

		     "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n"	\

		     "\t.word %c0"        "\t# bug_entry::flags\n"	\

		     "\t.org 2b+%c1\n"					\

		     ".popsection"					\

		     ".popsection\n"					\

		     extra						\

		     : : "i" (flags),					\

			 "i" (sizeof(struct bug_entry)));		\

} while (0)
@@ -55,7 +57,7 @@ do { \ 


#else



#define _BUG_FLAGS(ins, flags)  asm volatile(ins)

#define _BUG_FLAGS(ins, flags, extra)  asm volatile(ins)



#endif /* CONFIG_GENERIC_BUG */
@@ -63,8 +65,8 @@ do { \ 
#define BUG()							\

do {								\

	instrumentation_begin();				\

	_BUG_FLAGS(ASM_UD2, 0);					\

	unreachable();						\

	_BUG_FLAGS(ASM_UD2, 0, "");				\

	__builtin_unreachable();				\

} while (0)



/*
@@ -75,9 +77,9 @@ do { \ 
 */

#define __WARN_FLAGS(flags)					\

do {								\

	__auto_type f = BUGFLAG_WARNING|(flags);		\

	instrumentation_begin();				\

	_BUG_FLAGS(ASM_UD2, BUGFLAG_WARNING|(flags));		\

	annotate_reachable();					\

	_BUG_FLAGS(ASM_UD2, f, ASM_REACHABLE);			\

	instrumentation_end();					\

} while (0)

include/linux/compiler.h

+5 −16
Original line number Diff line number Diff line
@@ -117,14 +117,6 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, 
 */

#define __stringify_label(n) #n



#define __annotate_reachable(c) ({					\

	asm volatile(__stringify_label(c) ":\n\t"			\

		     ".pushsection .discard.reachable\n\t"		\

		     ".long " __stringify_label(c) "b - .\n\t"		\

		     ".popsection\n\t" : : "i" (c));			\

})

#define annotate_reachable() __annotate_reachable(__COUNTER__)



#define __annotate_unreachable(c) ({					\

	asm volatile(__stringify_label(c) ":\n\t"			\

		     ".pushsection .discard.unreachable\n\t"		\
@@ -133,24 +125,21 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, 
})

#define annotate_unreachable() __annotate_unreachable(__COUNTER__)



#define ASM_UNREACHABLE							\

	"999:\n\t"							\

	".pushsection .discard.unreachable\n\t"				\

	".long 999b - .\n\t"						\

#define ASM_REACHABLE							\

	"998:\n\t"							\

	".pushsection .discard.reachable\n\t"				\

	".long 998b - .\n\t"						\

	".popsection\n\t"



/* Annotate a C jump table to allow objtool to follow the code flow */

#define __annotate_jump_table __section(".rodata..c_jump_table")



#else

#define annotate_reachable()

#define annotate_unreachable()

# define ASM_REACHABLE

#define __annotate_jump_table

#endif



#ifndef ASM_UNREACHABLE

# define ASM_UNREACHABLE

#endif

#ifndef unreachable

# define unreachable() do {		\

	annotate_unreachable();		\