include/linux/objtool.h - kernel/common - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LINUX_OBJTOOL_H
 #define _LINUX_OBJTOOL_H

 #include <linux/objtool_types.h>

 #ifdef CONFIG_OBJTOOL

 #include <asm/asm.h>

 #ifndef __ASSEMBLY__

 #define UNWIND_HINT(type, sp_reg, sp_offset, signal)	\
 	"987: \n\t"						\
 	".pushsection .discard.unwind_hints\n\t"		\
 	/* struct unwind_hint */				\
 	".long 987b - .\n\t"					\
 	".short " __stringify(sp_offset) "\n\t"			\
 	".byte " __stringify(sp_reg) "\n\t"			\
 	".byte " __stringify(type) "\n\t"			\
 	".byte " __stringify(signal) "\n\t"			\
 	".balign 4 \n\t"					\
 	".popsection\n\t"

 /*
  * This macro marks the given function's stack frame as "non-standard", which
  * tells objtool to ignore the function when doing stack metadata validation.
  * It should only be used in special cases where you're 100% sure it won't
  * affect the reliability of frame pointers and kernel stack traces.
  *
  * For more information, see tools/objtool/Documentation/objtool.txt.
  */
 #define STACK_FRAME_NON_STANDARD(func) \
 	static void __used __section(".discard.func_stack_frame_non_standard") \
 		*__func_stack_frame_non_standard_##func = func

 /*
  * STACK_FRAME_NON_STANDARD_FP() is a frame-pointer-specific function ignore
  * for the case where a function is intentionally missing frame pointer setup,
  * but otherwise needs objtool/ORC coverage when frame pointers are disabled.
  */
 #ifdef CONFIG_FRAME_POINTER
 #define STACK_FRAME_NON_STANDARD_FP(func) STACK_FRAME_NON_STANDARD(func)
 #else
 #define STACK_FRAME_NON_STANDARD_FP(func)
 #endif

 #define ASM_REACHABLE							\
 	"998:\n\t"							\
 	".pushsection .discard.reachable\n\t"				\
 	".long 998b\n\t"						\
 	".popsection\n\t"

 #define __ASM_BREF(label)	label ## b

 #define __ASM_ANNOTATE(label, type)					\
 	".pushsection .discard.annotate_insn,\"M\",@progbits,8\n\t"	\
 	".long " __stringify(label) " - .\n\t"			\
 	".long " __stringify(type) "\n\t"				\
 	".popsection\n\t"

 #define ASM_ANNOTATE(type)						\
 	"911:\n\t"						\
 	__ASM_ANNOTATE(911b, type)

 #else /* __ASSEMBLY__ */

 /*
  * In asm, there are two kinds of code: normal C-type callable functions and
  * the rest.  The normal callable functions can be called by other code, and
  * don't do anything unusual with the stack.  Such normal callable functions
  * are annotated with the ENTRY/ENDPROC macros.  Most asm code falls in this
  * category.  In this case, no special debugging annotations are needed because
  * objtool can automatically generate the ORC data for the ORC unwinder to read
  * at runtime.
  *
  * Anything which doesn't fall into the above category, such as syscall and
  * interrupt handlers, tends to not be called directly by other functions, and
  * often does unusual non-C-function-type things with the stack pointer.  Such
  * code needs to be annotated such that objtool can understand it.  The
  * following CFI hint macros are for this type of code.
  *
  * These macros provide hints to objtool about the state of the stack at each
  * instruction.  Objtool starts from the hints and follows the code flow,
  * making automatic CFI adjustments when it sees pushes and pops, filling out
  * the debuginfo as necessary.  It will also warn if it sees any
  * inconsistencies.
  */
 .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
 .Lhere_\@:
 	.pushsection .discard.unwind_hints
 		/* struct unwind_hint */
 		.long .Lhere_\@ - .
 		.short \sp_offset
 		.byte \sp_reg
 		.byte \type
 		.byte \signal
 		.balign 4
 	.popsection
 .endm

 .macro STACK_FRAME_NON_STANDARD func:req
 	.pushsection .discard.func_stack_frame_non_standard, "aw"
 	.long \func - .
 	.popsection
 .endm

 .macro STACK_FRAME_NON_STANDARD_FP func:req
 #ifdef CONFIG_FRAME_POINTER
 	STACK_FRAME_NON_STANDARD \func
 #endif
 .endm

 .macro ANNOTATE type:req
 .Lhere_\@:
 	.pushsection .discard.annotate_insn,"M",@progbits,8
 	.long	.Lhere_\@ - .
 	.long	\type
 	.popsection
 .endm

 #endif /* __ASSEMBLY__ */

 #else /* !CONFIG_OBJTOOL */

 #ifndef __ASSEMBLY__

 #define UNWIND_HINT(type, sp_reg, sp_offset, signal) "\n\t"
 #define STACK_FRAME_NON_STANDARD(func)
 #define STACK_FRAME_NON_STANDARD_FP(func)
 #define __ASM_ANNOTATE(label, type)
 #define ASM_ANNOTATE(type)
 #else
 .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
 .endm
 .macro STACK_FRAME_NON_STANDARD func:req
 .endm
 .macro ANNOTATE type:req
 .endm
 #endif

 #endif /* CONFIG_OBJTOOL */

 #ifndef __ASSEMBLY__
 /*
  * Annotate away the various 'relocation to !ENDBR` complaints; knowing that
  * these relocations will never be used for indirect calls.
  */
 #define ANNOTATE_NOENDBR		ASM_ANNOTATE(ANNOTYPE_NOENDBR)
 /*
  * This should be used immediately before an indirect jump/call. It tells
  * objtool the subsequent indirect jump/call is vouched safe for retpoline
  * builds.
  */
 #define ANNOTATE_RETPOLINE_SAFE		ASM_ANNOTATE(ANNOTYPE_RETPOLINE_SAFE)
 /*
  * 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)
 /*
  * objtool annotation to ignore the alternatives and only consider the original
  * instruction(s).
  */
 #define ANNOTATE_IGNORE_ALTERNATIVE	ASM_ANNOTATE(ANNOTYPE_IGNORE_ALTS)
 /*
  * This macro indicates that the following intra-function call is valid.
  * Any non-annotated intra-function call will cause objtool to issue a warning.
  */
 #define ANNOTATE_INTRA_FUNCTION_CALL	ASM_ANNOTATE(ANNOTYPE_INTRA_FUNCTION_CALL)
 /*
  * Use objtool to validate the entry requirement that all code paths do
  * VALIDATE_UNRET_END before RET.
  *
  * NOTE: The macro must be used at the beginning of a global symbol, otherwise
  * it will be ignored.
  */
 #define ANNOTATE_UNRET_BEGIN		ASM_ANNOTATE(ANNOTYPE_UNRET_BEGIN)
 /*
  * This should be used to refer to an instruction that is considered
  * 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)

 #else
 #define ANNOTATE_NOENDBR		ANNOTATE type=ANNOTYPE_NOENDBR
 #define ANNOTATE_RETPOLINE_SAFE		ANNOTATE type=ANNOTYPE_RETPOLINE_SAFE
 /*	ANNOTATE_INSTR_BEGIN		ANNOTATE type=ANNOTYPE_INSTR_BEGIN */
 /*	ANNOTATE_INSTR_END		ANNOTATE type=ANNOTYPE_INSTR_END */
 #define ANNOTATE_IGNORE_ALTERNATIVE	ANNOTATE type=ANNOTYPE_IGNORE_ALTS
 #define ANNOTATE_INTRA_FUNCTION_CALL	ANNOTATE type=ANNOTYPE_INTRA_FUNCTION_CALL
 #define ANNOTATE_UNRET_BEGIN		ANNOTATE type=ANNOTYPE_UNRET_BEGIN
 #define ANNOTATE_REACHABLE		ANNOTATE type=ANNOTYPE_REACHABLE
 #endif

 #if defined(CONFIG_NOINSTR_VALIDATION) && \
 	(defined(CONFIG_MITIGATION_UNRET_ENTRY) || defined(CONFIG_MITIGATION_SRSO))
 #define VALIDATE_UNRET_BEGIN	ANNOTATE_UNRET_BEGIN
 #else
 #define VALIDATE_UNRET_BEGIN
 #endif

 #endif /* _LINUX_OBJTOOL_H */
	/* SPDX-License-Identifier: GPL-2.0 */
	#ifndef _LINUX_OBJTOOL_H
	#define _LINUX_OBJTOOL_H

	#include <linux/objtool_types.h>

	#ifdef CONFIG_OBJTOOL

	#include <asm/asm.h>

	#ifndef __ASSEMBLY__

	#define UNWIND_HINT(type, sp_reg, sp_offset, signal) \
	"987: \n\t" \
	".pushsection .discard.unwind_hints\n\t" \
	/* struct unwind_hint */ \
	".long 987b - .\n\t" \
	".short " __stringify(sp_offset) "\n\t" \
	".byte " __stringify(sp_reg) "\n\t" \
	".byte " __stringify(type) "\n\t" \
	".byte " __stringify(signal) "\n\t" \
	".balign 4 \n\t" \
	".popsection\n\t"

	/*
	* This macro marks the given function's stack frame as "non-standard", which
	* tells objtool to ignore the function when doing stack metadata validation.
	* It should only be used in special cases where you're 100% sure it won't
	* affect the reliability of frame pointers and kernel stack traces.
	*
	* For more information, see tools/objtool/Documentation/objtool.txt.
	*/
	#define STACK_FRAME_NON_STANDARD(func) \
	static void __used __section(".discard.func_stack_frame_non_standard") \
	*__func_stack_frame_non_standard_##func = func

	/*
	* STACK_FRAME_NON_STANDARD_FP() is a frame-pointer-specific function ignore
	* for the case where a function is intentionally missing frame pointer setup,
	* but otherwise needs objtool/ORC coverage when frame pointers are disabled.
	*/
	#ifdef CONFIG_FRAME_POINTER
	#define STACK_FRAME_NON_STANDARD_FP(func) STACK_FRAME_NON_STANDARD(func)
	#else
	#define STACK_FRAME_NON_STANDARD_FP(func)
	#endif

	#define ASM_REACHABLE \
	"998:\n\t" \
	".pushsection .discard.reachable\n\t" \
	".long 998b\n\t" \
	".popsection\n\t"

	#define __ASM_BREF(label) label ## b

	#define __ASM_ANNOTATE(label, type) \
	".pushsection .discard.annotate_insn,\"M\",@progbits,8\n\t" \
	".long " __stringify(label) " - .\n\t" \
	".long " __stringify(type) "\n\t" \
	".popsection\n\t"

	#define ASM_ANNOTATE(type) \
	"911:\n\t" \
	__ASM_ANNOTATE(911b, type)

	#else /* __ASSEMBLY__ */

	/*
	* In asm, there are two kinds of code: normal C-type callable functions and
	* the rest. The normal callable functions can be called by other code, and
	* don't do anything unusual with the stack. Such normal callable functions
	* are annotated with the ENTRY/ENDPROC macros. Most asm code falls in this
	* category. In this case, no special debugging annotations are needed because
	* objtool can automatically generate the ORC data for the ORC unwinder to read
	* at runtime.
	*
	* Anything which doesn't fall into the above category, such as syscall and
	* interrupt handlers, tends to not be called directly by other functions, and
	* often does unusual non-C-function-type things with the stack pointer. Such
	* code needs to be annotated such that objtool can understand it. The
	* following CFI hint macros are for this type of code.
	*
	* These macros provide hints to objtool about the state of the stack at each
	* instruction. Objtool starts from the hints and follows the code flow,
	* making automatic CFI adjustments when it sees pushes and pops, filling out
	* the debuginfo as necessary. It will also warn if it sees any
	* inconsistencies.
	*/
	.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
	.Lhere_\@:
	.pushsection .discard.unwind_hints
	/* struct unwind_hint */
	.long .Lhere_\@ - .
	.short \sp_offset
	.byte \sp_reg
	.byte \type
	.byte \signal
	.balign 4
	.popsection
	.endm

	.macro STACK_FRAME_NON_STANDARD func:req
	.pushsection .discard.func_stack_frame_non_standard, "aw"
	.long \func - .
	.popsection
	.endm

	.macro STACK_FRAME_NON_STANDARD_FP func:req
	#ifdef CONFIG_FRAME_POINTER
	STACK_FRAME_NON_STANDARD \func
	#endif
	.endm

	.macro ANNOTATE type:req
	.Lhere_\@:
	.pushsection .discard.annotate_insn,"M",@progbits,8
	.long .Lhere_\@ - .
	.long \type
	.popsection
	.endm

	#endif /* __ASSEMBLY__ */

	#else /* !CONFIG_OBJTOOL */

	#ifndef __ASSEMBLY__

	#define UNWIND_HINT(type, sp_reg, sp_offset, signal) "\n\t"
	#define STACK_FRAME_NON_STANDARD(func)
	#define STACK_FRAME_NON_STANDARD_FP(func)
	#define __ASM_ANNOTATE(label, type)
	#define ASM_ANNOTATE(type)
	#else
	.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
	.endm
	.macro STACK_FRAME_NON_STANDARD func:req
	.endm
	.macro ANNOTATE type:req
	.endm
	#endif

	#endif /* CONFIG_OBJTOOL */

	#ifndef __ASSEMBLY__
	/*
	* Annotate away the various 'relocation to !ENDBR` complaints; knowing that
	* these relocations will never be used for indirect calls.
	*/
	#define ANNOTATE_NOENDBR ASM_ANNOTATE(ANNOTYPE_NOENDBR)
	/*
	* This should be used immediately before an indirect jump/call. It tells
	* objtool the subsequent indirect jump/call is vouched safe for retpoline
	* builds.
	*/
	#define ANNOTATE_RETPOLINE_SAFE ASM_ANNOTATE(ANNOTYPE_RETPOLINE_SAFE)
	/*
	* 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)
	/*
	* objtool annotation to ignore the alternatives and only consider the original
	* instruction(s).
	*/
	#define ANNOTATE_IGNORE_ALTERNATIVE ASM_ANNOTATE(ANNOTYPE_IGNORE_ALTS)
	/*
	* This macro indicates that the following intra-function call is valid.
	* Any non-annotated intra-function call will cause objtool to issue a warning.
	*/
	#define ANNOTATE_INTRA_FUNCTION_CALL ASM_ANNOTATE(ANNOTYPE_INTRA_FUNCTION_CALL)
	/*
	* Use objtool to validate the entry requirement that all code paths do
	* VALIDATE_UNRET_END before RET.
	*
	* NOTE: The macro must be used at the beginning of a global symbol, otherwise
	* it will be ignored.
	*/
	#define ANNOTATE_UNRET_BEGIN ASM_ANNOTATE(ANNOTYPE_UNRET_BEGIN)
	/*
	* This should be used to refer to an instruction that is considered
	* 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)

	#else
	#define ANNOTATE_NOENDBR ANNOTATE type=ANNOTYPE_NOENDBR
	#define ANNOTATE_RETPOLINE_SAFE ANNOTATE type=ANNOTYPE_RETPOLINE_SAFE
	/* ANNOTATE_INSTR_BEGIN ANNOTATE type=ANNOTYPE_INSTR_BEGIN */
	/* ANNOTATE_INSTR_END ANNOTATE type=ANNOTYPE_INSTR_END */
	#define ANNOTATE_IGNORE_ALTERNATIVE ANNOTATE type=ANNOTYPE_IGNORE_ALTS
	#define ANNOTATE_INTRA_FUNCTION_CALL ANNOTATE type=ANNOTYPE_INTRA_FUNCTION_CALL
	#define ANNOTATE_UNRET_BEGIN ANNOTATE type=ANNOTYPE_UNRET_BEGIN
	#define ANNOTATE_REACHABLE ANNOTATE type=ANNOTYPE_REACHABLE
	#endif

	#if defined(CONFIG_NOINSTR_VALIDATION) && \
	(defined(CONFIG_MITIGATION_UNRET_ENTRY) \|\| defined(CONFIG_MITIGATION_SRSO))
	#define VALIDATE_UNRET_BEGIN ANNOTATE_UNRET_BEGIN
	#else
	#define VALIDATE_UNRET_BEGIN
	#endif

	#endif /* _LINUX_OBJTOOL_H */