Commit a818f28f authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Ingo Molnar
Browse files

x86/alternative: Remove ANNOTATE_DATA_SPECIAL usage 



Instead of manually annotating each .altinstructions entry, just make
the section mergeable and store the entry size in the ELF section
header.

Either way works for objtool create_fake_symbols(), this way produces
cleaner code generation.

Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://patch.msgid.link/5ac04e6db5be6453dce8003a771ebb0c47b4cd7a.1764694625.git.jpoimboe@kernel.org
parent 0c314a88

arch/um/include/shared/common-offsets.h

+2 −0
Original line number Diff line number Diff line
@@ -18,3 +18,5 @@ DEFINE(UM_NSEC_PER_USEC, NSEC_PER_USEC); 
DEFINE(UM_KERN_GDT_ENTRY_TLS_ENTRIES, GDT_ENTRY_TLS_ENTRIES);



DEFINE(UM_SECCOMP_ARCH_NATIVE, SECCOMP_ARCH_NATIVE);



DEFINE(ALT_INSTR_SIZE, sizeof(struct alt_instr));

arch/x86/include/asm/alternative.h

+3 −4
Original line number Diff line number Diff line
@@ -197,8 +197,8 @@ static inline int alternatives_text_reserved(void *start, void *end) 
	"773:\n"



#define ALTINSTR_ENTRY(ft_flags)					      \

	".pushsection .altinstructions,\"a\"\n"				      \

	ANNOTATE_DATA_SPECIAL						      \

	".pushsection .altinstructions, \"aM\", @progbits, "		      \

		      __stringify(ALT_INSTR_SIZE) "\n"			      \

	" .long 771b - .\n"				/* label           */ \

	" .long 774f - .\n"				/* new instruction */ \

	" .4byte " __stringify(ft_flags) "\n"		/* feature + flags */ \
@@ -339,7 +339,6 @@ void nop_func(void); 
 * instruction. See apply_alternatives().

 */

.macro altinstr_entry orig alt ft_flags orig_len alt_len

	ANNOTATE_DATA_SPECIAL

	.long \orig - .

	.long \alt - .

	.4byte \ft_flags
@@ -363,7 +362,7 @@ void nop_func(void); 
741:									\

	.skip -(((744f-743f)-(741b-740b)) > 0) * ((744f-743f)-(741b-740b)),0x90	;\

742:									\

	.pushsection .altinstructions,"a" ;				\

	.pushsection .altinstructions, "aM", @progbits, ALT_INSTR_SIZE ;\

	altinstr_entry 740b,743f,flag,742b-740b,744f-743f ;		\

	.popsection ;							\

	.pushsection .altinstr_replacement,"ax"	;			\

arch/x86/kernel/asm-offsets.c

+2 −0
Original line number Diff line number Diff line
@@ -124,4 +124,6 @@ static void __used common(void) 
	OFFSET(ARIA_CTX_rounds, aria_ctx, rounds);

#endif



	BLANK();

	DEFINE(ALT_INSTR_SIZE,	sizeof(struct alt_instr));

}