[linux-block.git] / tools / include / linux / objtool.h

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

#ifndef __ASSEMBLY__

#include <linux/types.h>

/*
 * This struct is used by asm and inline asm code to manually annotate the
 * location of registers on the stack.
 */
struct unwind_hint {
	u32		ip;
	s16		sp_offset;
	u8		sp_reg;
	u8		type;
	u8		end;
};
#endif

/*
 * UNWIND_HINT_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP
 * (the caller's SP right before it made the call).  Used for all callable
 * functions, i.e. all C code and all callable asm functions.
 *
 * UNWIND_HINT_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset
 * points to a fully populated pt_regs from a syscall, interrupt, or exception.
 *
 * UNWIND_HINT_TYPE_REGS_PARTIAL: Used in entry code to indicate that
 * sp_reg+sp_offset points to the iret return frame.
 *
 * UNWIND_HINT_FUNC: Generate the unwind metadata of a callable function.
 * Useful for code which doesn't have an ELF function annotation.
 */
#define UNWIND_HINT_TYPE_CALL		0
#define UNWIND_HINT_TYPE_REGS		1
#define UNWIND_HINT_TYPE_REGS_PARTIAL	2
#define UNWIND_HINT_TYPE_FUNC		3

#ifdef CONFIG_OBJTOOL

#include <asm/asm.h>

#ifndef __ASSEMBLY__

#define UNWIND_HINT(sp_reg, sp_offset, type, end)		\
	"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(end) "\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/stack-validation.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 ANNOTATE_NOENDBR					\
	"986: \n\t"						\
	".pushsection .discard.noendbr\n\t"			\
	_ASM_PTR " 986b\n\t"					\
	".popsection\n\t"

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

#else /* __ASSEMBLY__ */

/*
 * 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				\
	999:							\
	.pushsection .discard.intra_function_calls;		\
	.long 999b;						\
	.popsection;

/*
 * 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 sp_reg:req sp_offset=0 type:req end=0
.Lunwind_hint_ip_\@:
	.pushsection .discard.unwind_hints
		/* struct unwind_hint */
		.long .Lunwind_hint_ip_\@ - .
		.short \sp_offset
		.byte \sp_reg
		.byte \type
		.byte \end
		.balign 4
	.popsection
.endm

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

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

.macro ANNOTATE_NOENDBR
.Lhere_\@:
	.pushsection .discard.noendbr
	.quad	.Lhere_\@
	.popsection
.endm

.macro REACHABLE
.Lhere_\@:
	.pushsection .discard.reachable
	.long	.Lhere_\@ - .
	.popsection
.endm

#endif /* __ASSEMBLY__ */

#else /* !CONFIG_OBJTOOL */

#ifndef __ASSEMBLY__

#define UNWIND_HINT(sp_reg, sp_offset, type, end)	\
	"\n\t"
#define STACK_FRAME_NON_STANDARD(func)
#define STACK_FRAME_NON_STANDARD_FP(func)
#define ANNOTATE_NOENDBR
#define ASM_REACHABLE
#else
#define ANNOTATE_INTRA_FUNCTION_CALL
.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
.endm
.macro STACK_FRAME_NON_STANDARD func:req
.endm
.macro ANNOTATE_NOENDBR
.endm
.macro REACHABLE
.endm
#endif

#endif /* CONFIG_OBJTOOL */

#endif /* _LINUX_OBJTOOL_H */
Commit	Line	Data
ee819aed JT	1	/* SPDX-License-Identifier: GPL-2.0 */
	2	#ifndef _LINUX_OBJTOOL_H
	3	#define _LINUX_OBJTOOL_H
	4
	5	#ifndef __ASSEMBLY__
	6
	7	#include <linux/types.h>
	8
	9	/*
	10	* This struct is used by asm and inline asm code to manually annotate the
	11	* location of registers on the stack.
	12	*/
	13	struct unwind_hint {
	14	u32 ip;
	15	s16 sp_offset;
	16	u8 sp_reg;
	17	u8 type;
	18	u8 end;
	19	};
	20	#endif
	21
	22	/*
	23	* UNWIND_HINT_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP
	24	* (the caller's SP right before it made the call). Used for all callable
	25	* functions, i.e. all C code and all callable asm functions.
	26	*
	27	* UNWIND_HINT_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset
	28	* points to a fully populated pt_regs from a syscall, interrupt, or exception.
	29	*
	30	* UNWIND_HINT_TYPE_REGS_PARTIAL: Used in entry code to indicate that
	31	* sp_reg+sp_offset points to the iret return frame.
b735bd3e JP	32	*
	33	* UNWIND_HINT_FUNC: Generate the unwind metadata of a callable function.
	34	* Useful for code which doesn't have an ELF function annotation.
ee819aed JT	35	*/
	36	#define UNWIND_HINT_TYPE_CALL 0
	37	#define UNWIND_HINT_TYPE_REGS 1
	38	#define UNWIND_HINT_TYPE_REGS_PARTIAL 2
b735bd3e	39	#define UNWIND_HINT_TYPE_FUNC 3
ee819aed	40
03f16cd0	41	#ifdef CONFIG_OBJTOOL
ee819aed	42
e2ef1158 PZ	43	#include <asm/asm.h>
e2ef1158 PZ	44
ee819aed JT	45	#ifndef __ASSEMBLY__
	46
	47	#define UNWIND_HINT(sp_reg, sp_offset, type, end) \
	48	"987: \n\t" \
	49	".pushsection .discard.unwind_hints\n\t" \
	50	/* struct unwind_hint */ \
	51	".long 987b - .\n\t" \
	52	".short " __stringify(sp_offset) "\n\t" \
	53	".byte " __stringify(sp_reg) "\n\t" \
	54	".byte " __stringify(type) "\n\t" \
	55	".byte " __stringify(end) "\n\t" \
	56	".balign 4 \n\t" \
	57	".popsection\n\t"
	58
	59	/*
	60	* This macro marks the given function's stack frame as "non-standard", which
	61	* tells objtool to ignore the function when doing stack metadata validation.
	62	* It should only be used in special cases where you're 100% sure it won't
	63	* affect the reliability of frame pointers and kernel stack traces.
	64	*
	65	* For more information, see tools/objtool/Documentation/stack-validation.txt.
	66	*/
	67	#define STACK_FRAME_NON_STANDARD(func) \
33def849	68	static void __used __section(".discard.func_stack_frame_non_standard") \
ee819aed JT	69	*__func_stack_frame_non_standard_##func = func
ee819aed JT	70
e028c4f7 JP	71	/*
	72	* STACK_FRAME_NON_STANDARD_FP() is a frame-pointer-specific function ignore
	73	* for the case where a function is intentionally missing frame pointer setup,
	74	* but otherwise needs objtool/ORC coverage when frame pointers are disabled.
	75	*/
	76	#ifdef CONFIG_FRAME_POINTER
	77	#define STACK_FRAME_NON_STANDARD_FP(func) STACK_FRAME_NON_STANDARD(func)
	78	#else
	79	#define STACK_FRAME_NON_STANDARD_FP(func)
	80	#endif
	81
c8c301ab PZ	82	#define ANNOTATE_NOENDBR \
	83	"986: \n\t" \
	84	".pushsection .discard.noendbr\n\t" \
	85	_ASM_PTR " 986b\n\t" \
	86	".popsection\n\t"
	87
dca5da2a PZ	88	#define ASM_REACHABLE \
	89	"998:\n\t" \
	90	".pushsection .discard.reachable\n\t" \
	91	".long 998b - .\n\t" \
	92	".popsection\n\t"
	93
ee819aed JT	94	#else /* __ASSEMBLY__ */
	95
	96	/*
	97	* This macro indicates that the following intra-function call is valid.
	98	* Any non-annotated intra-function call will cause objtool to issue a warning.
	99	*/
	100	#define ANNOTATE_INTRA_FUNCTION_CALL \
	101	999: \
	102	.pushsection .discard.intra_function_calls; \
	103	.long 999b; \
	104	.popsection;
	105
	106	/*
	107	* In asm, there are two kinds of code: normal C-type callable functions and
	108	* the rest. The normal callable functions can be called by other code, and
	109	* don't do anything unusual with the stack. Such normal callable functions
	110	* are annotated with the ENTRY/ENDPROC macros. Most asm code falls in this
	111	* category. In this case, no special debugging annotations are needed because
	112	* objtool can automatically generate the ORC data for the ORC unwinder to read
	113	* at runtime.
	114	*
	115	* Anything which doesn't fall into the above category, such as syscall and
	116	* interrupt handlers, tends to not be called directly by other functions, and
	117	* often does unusual non-C-function-type things with the stack pointer. Such
	118	* code needs to be annotated such that objtool can understand it. The
	119	* following CFI hint macros are for this type of code.
	120	*
	121	* These macros provide hints to objtool about the state of the stack at each
	122	* instruction. Objtool starts from the hints and follows the code flow,
	123	* making automatic CFI adjustments when it sees pushes and pops, filling out
	124	* the debuginfo as necessary. It will also warn if it sees any
	125	* inconsistencies.
	126	*/
	127	.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
	128	.Lunwind_hint_ip_\@:
	129	.pushsection .discard.unwind_hints
	130	/* struct unwind_hint */
	131	.long .Lunwind_hint_ip_\@ - .
	132	.short \sp_offset
	133	.byte \sp_reg
	134	.byte \type
	135	.byte \end
	136	.balign 4
	137	.popsection
	138	.endm
	139
081df943 JP	140	.macro STACK_FRAME_NON_STANDARD func:req
081df943 JP	141	.pushsection .discard.func_stack_frame_non_standard, "aw"
e2ef1158	142	_ASM_PTR \func
081df943 JP	143	.popsection
	144	.endm
	145
7b6c7a87 JP	146	.macro STACK_FRAME_NON_STANDARD_FP func:req
	147	#ifdef CONFIG_FRAME_POINTER
	148	STACK_FRAME_NON_STANDARD \func
	149	#endif
	150	.endm
	151
c8c301ab PZ	152	.macro ANNOTATE_NOENDBR
	153	.Lhere_\@:
	154	.pushsection .discard.noendbr
	155	.quad .Lhere_\@
	156	.popsection
	157	.endm
	158
dca5da2a PZ	159	.macro REACHABLE
	160	.Lhere_\@:
	161	.pushsection .discard.reachable
	162	.long .Lhere_\@ - .
	163	.popsection
	164	.endm
	165
ee819aed JT	166	#endif /* __ASSEMBLY__ */
ee819aed JT	167
03f16cd0	168	#else /* !CONFIG_OBJTOOL */
ee819aed JT	169
	170	#ifndef __ASSEMBLY__
	171
	172	#define UNWIND_HINT(sp_reg, sp_offset, type, end) \
	173	"\n\t"
	174	#define STACK_FRAME_NON_STANDARD(func)
e028c4f7	175	#define STACK_FRAME_NON_STANDARD_FP(func)
c8c301ab	176	#define ANNOTATE_NOENDBR
dca5da2a	177	#define ASM_REACHABLE
ee819aed JT	178	#else
	179	#define ANNOTATE_INTRA_FUNCTION_CALL
	180	.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
	181	.endm
081df943 JP	182	.macro STACK_FRAME_NON_STANDARD func:req
081df943 JP	183	.endm
c8c301ab PZ	184	.macro ANNOTATE_NOENDBR
c8c301ab PZ	185	.endm
dca5da2a PZ	186	.macro REACHABLE
dca5da2a PZ	187	.endm
ee819aed JT	188	#endif
ee819aed JT	189
03f16cd0	190	#endif /* CONFIG_OBJTOOL */
ee819aed JT	191
ee819aed JT	192	#endif /* _LINUX_OBJTOOL_H */