Commit 58f36a57 authored by Josh Poimboeuf's avatar Josh Poimboeuf
Browse files

objtool: Add ANNOTATE_DATA_SPECIAL 



In preparation for the objtool klp diff subcommand, add an
ANNOTATE_DATA_SPECIAL macro which annotates special section entries so
that objtool can determine their size and location and extract them
when needed.

Acked-by: default avatarPetr Mladek <pmladek@suse.com>
Tested-by: default avatarJoe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
parent d2c60bde

include/linux/annotate.h

+37 −12
Original line number Diff line number Diff line
@@ -8,34 +8,52 @@ 


#ifndef __ASSEMBLY__



#define __ASM_ANNOTATE(label, type)					\

	".pushsection .discard.annotate_insn,\"M\",@progbits,8\n\t"	\

#define __ASM_ANNOTATE(section, label, type)				\

	".pushsection " section ",\"M\", @progbits, 8\n\t"		\

	".long " __stringify(label) " - .\n\t"				\

	".long " __stringify(type) "\n\t"				\

	".popsection\n\t"



#define ASM_ANNOTATE_LABEL(label, type)					\

	__ASM_ANNOTATE(".discard.annotate_insn", label, type)



#define ASM_ANNOTATE(type)						\

	"911:\n\t"							\

	__ASM_ANNOTATE(911b, type)

	ASM_ANNOTATE_LABEL(911b, type)



#define ASM_ANNOTATE_DATA(type)						\

	"912:\n\t"							\

	__ASM_ANNOTATE(".discard.annotate_data", 912b, type)



#else /* __ASSEMBLY__ */



.macro ANNOTATE type:req

.macro __ANNOTATE section, type

.Lhere_\@:

	.pushsection .discard.annotate_insn,"M",@progbits,8

	.pushsection \section, "M", @progbits, 8

	.long	.Lhere_\@ - .

	.long	\type

	.popsection

.endm



.macro ANNOTATE type

	__ANNOTATE ".discard.annotate_insn", \type

.endm



.macro ANNOTATE_DATA type

	__ANNOTATE ".discard.annotate_data", \type

.endm



#endif /* __ASSEMBLY__ */



#else /* !CONFIG_OBJTOOL */

#ifndef __ASSEMBLY__

#define __ASM_ANNOTATE(label, type) ""

#define ASM_ANNOTATE_LABEL(label, type) ""

#define ASM_ANNOTATE(type)

#define ASM_ANNOTATE_DATA(type)

#else /* __ASSEMBLY__ */

.macro ANNOTATE type:req

.macro ANNOTATE type

.endm

.macro ANNOTATE_DATA type

.endm

#endif /* __ASSEMBLY__ */

#endif /* !CONFIG_OBJTOOL */
@@ -47,7 +65,7 @@ 
 * these relocations will never be used for indirect calls.

 */

#define ANNOTATE_NOENDBR		ASM_ANNOTATE(ANNOTYPE_NOENDBR)

#define ANNOTATE_NOENDBR_SYM(sym)	asm(__ASM_ANNOTATE(sym, ANNOTYPE_NOENDBR))

#define ANNOTATE_NOENDBR_SYM(sym)	asm(ASM_ANNOTATE_LABEL(sym, ANNOTYPE_NOENDBR))



/*

 * This should be used immediately before an indirect jump/call. It tells
@@ -58,8 +76,8 @@ 
/*

 * See linux/instrumentation.h

 */

#define ANNOTATE_INSTR_BEGIN(label)	__ASM_ANNOTATE(label, ANNOTYPE_INSTR_BEGIN)

#define ANNOTATE_INSTR_END(label)	__ASM_ANNOTATE(label, ANNOTYPE_INSTR_END)

#define ANNOTATE_INSTR_BEGIN(label)	ASM_ANNOTATE_LABEL(label, ANNOTYPE_INSTR_BEGIN)

#define ANNOTATE_INSTR_END(label)	ASM_ANNOTATE_LABEL(label, ANNOTYPE_INSTR_END)

/*

 * objtool annotation to ignore the alternatives and only consider the original

 * instruction(s).
@@ -83,7 +101,7 @@ 
 * terminating, like a noreturn CALL or UD2 when we know they are not -- eg

 * WARN using UD2.

 */

#define ANNOTATE_REACHABLE(label)	__ASM_ANNOTATE(label, ANNOTYPE_REACHABLE)

#define ANNOTATE_REACHABLE(label)	ASM_ANNOTATE_LABEL(label, ANNOTYPE_REACHABLE)

/*

 * This should not be used; it annotates away CFI violations. There are a few

 * valid use cases like kexec handover to the next kernel image, and there is
@@ -92,7 +110,13 @@ 
 * There are also a few real issues annotated away, like EFI because we can't

 * control the EFI code.

 */

#define ANNOTATE_NOCFI_SYM(sym)		asm(__ASM_ANNOTATE(sym, ANNOTYPE_NOCFI))

#define ANNOTATE_NOCFI_SYM(sym)		asm(ASM_ANNOTATE_LABEL(sym, ANNOTYPE_NOCFI))



/*

 * Annotate a special section entry.  This emables livepatch module generation

 * to find and extract individual special section entries as needed.

 */

#define ANNOTATE_DATA_SPECIAL		ASM_ANNOTATE_DATA(ANNOTYPE_DATA_SPECIAL)



#else /* __ASSEMBLY__ */

#define ANNOTATE_NOENDBR		ANNOTATE type=ANNOTYPE_NOENDBR
@@ -104,6 +128,7 @@ 
#define ANNOTATE_UNRET_BEGIN		ANNOTATE type=ANNOTYPE_UNRET_BEGIN

#define ANNOTATE_REACHABLE		ANNOTATE type=ANNOTYPE_REACHABLE

#define ANNOTATE_NOCFI_SYM		ANNOTATE type=ANNOTYPE_NOCFI

#define ANNOTATE_DATA_SPECIAL		ANNOTATE_DATA type=ANNOTYPE_DATA_SPECIAL

#endif /* __ASSEMBLY__ */



#endif /* _LINUX_ANNOTATE_H */

include/linux/objtool_types.h

+2 −0
Original line number Diff line number Diff line
@@ -67,4 +67,6 @@ struct unwind_hint { 
#define ANNOTYPE_REACHABLE		8

#define ANNOTYPE_NOCFI			9



#define ANNOTYPE_DATA_SPECIAL		1



#endif /* _LINUX_OBJTOOL_TYPES_H */

tools/include/linux/objtool_types.h

+2 −0
Original line number Diff line number Diff line
@@ -67,4 +67,6 @@ struct unwind_hint { 
#define ANNOTYPE_REACHABLE		8

#define ANNOTYPE_NOCFI			9



#define ANNOTYPE_DATA_SPECIAL		1



#endif /* _LINUX_OBJTOOL_TYPES_H */