[linux-block.git] / arch / x86 / include / asm / linkage.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_LINKAGE_H
#define _ASM_X86_LINKAGE_H

#include <linux/stringify.h>
#include <asm/ibt.h>

#undef notrace
#define notrace __attribute__((no_instrument_function))

#ifdef CONFIG_64BIT
/*
 * The generic version tends to create spurious ENDBR instructions under
 * certain conditions.
 */
#define _THIS_IP_ ({ unsigned long __here; asm ("lea 0(%%rip), %0" : "=r" (__here)); __here; })
#endif

#ifdef CONFIG_X86_32
#define asmlinkage CPP_ASMLINKAGE __attribute__((regparm(0)))
#endif /* CONFIG_X86_32 */

#define __ALIGN		.balign CONFIG_FUNCTION_ALIGNMENT, 0x90;
#define __ALIGN_STR	__stringify(__ALIGN)

#if defined(CONFIG_CALL_PADDING) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
#define FUNCTION_PADDING	.skip CONFIG_FUNCTION_ALIGNMENT, 0x90;
#else
#define FUNCTION_PADDING
#endif

#if (CONFIG_FUNCTION_ALIGNMENT > 8) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
# define __FUNC_ALIGN		__ALIGN; FUNCTION_PADDING
#else
# define __FUNC_ALIGN		__ALIGN
#endif

#define ASM_FUNC_ALIGN		__stringify(__FUNC_ALIGN)
#define SYM_F_ALIGN		__FUNC_ALIGN

#ifdef __ASSEMBLER__

#if defined(CONFIG_MITIGATION_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
#define RET	jmp __x86_return_thunk
#else /* CONFIG_MITIGATION_RETPOLINE */
#ifdef CONFIG_MITIGATION_SLS
#define RET	ret; int3
#else
#define RET	ret
#endif
#endif /* CONFIG_MITIGATION_RETPOLINE */

#else /* __ASSEMBLER__ */

#if defined(CONFIG_MITIGATION_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
#define ASM_RET	"jmp __x86_return_thunk\n\t"
#else /* CONFIG_MITIGATION_RETPOLINE */
#ifdef CONFIG_MITIGATION_SLS
#define ASM_RET	"ret; int3\n\t"
#else
#define ASM_RET	"ret\n\t"
#endif
#endif /* CONFIG_MITIGATION_RETPOLINE */

#endif /* __ASSEMBLER__ */

/*
 * Depending on -fpatchable-function-entry=N,N usage (CONFIG_CALL_PADDING) the
 * CFI symbol layout changes.
 *
 * Without CALL_THUNKS:
 *
 * 	.align	FUNCTION_ALIGNMENT
 * __cfi_##name:
 * 	.skip	FUNCTION_PADDING, 0x90
 * 	.byte   0xb8
 * 	.long	__kcfi_typeid_##name
 * name:
 *
 * With CALL_THUNKS:
 *
 * 	.align FUNCTION_ALIGNMENT
 * __cfi_##name:
 * 	.byte	0xb8
 * 	.long	__kcfi_typeid_##name
 * 	.skip	FUNCTION_PADDING, 0x90
 * name:
 *
 * In both cases the whole thing is FUNCTION_ALIGNMENT aligned and sized.
 */

#ifdef CONFIG_CALL_PADDING
#define CFI_PRE_PADDING
#define CFI_POST_PADDING	.skip	CONFIG_FUNCTION_PADDING_BYTES, 0x90;
#else
#define CFI_PRE_PADDING		.skip	CONFIG_FUNCTION_PADDING_BYTES, 0x90;
#define CFI_POST_PADDING
#endif

#define __CFI_TYPE(name)					\
	SYM_START(__cfi_##name, SYM_L_LOCAL, SYM_A_NONE)	\
	CFI_PRE_PADDING						\
	.byte 0xb8 ASM_NL					\
	.long __kcfi_typeid_##name ASM_NL			\
	CFI_POST_PADDING					\
	SYM_FUNC_END(__cfi_##name)

/* UML needs to be able to override memcpy() and friends for KASAN. */
#ifdef CONFIG_UML
# define SYM_FUNC_ALIAS_MEMFUNC	SYM_FUNC_ALIAS_WEAK
#else
# define SYM_FUNC_ALIAS_MEMFUNC	SYM_FUNC_ALIAS
#endif

/* SYM_TYPED_FUNC_START -- use for indirectly called globals, w/ CFI type */
#define SYM_TYPED_FUNC_START(name)				\
	SYM_TYPED_START(name, SYM_L_GLOBAL, SYM_F_ALIGN)	\
	ENDBR

/* SYM_FUNC_START -- use for global functions */
#define SYM_FUNC_START(name)				\
	SYM_START(name, SYM_L_GLOBAL, SYM_F_ALIGN)

/* SYM_FUNC_START_NOALIGN -- use for global functions, w/o alignment */
#define SYM_FUNC_START_NOALIGN(name)			\
	SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE)

/* SYM_FUNC_START_LOCAL -- use for local functions */
#define SYM_FUNC_START_LOCAL(name)			\
	SYM_START(name, SYM_L_LOCAL, SYM_F_ALIGN)

/* SYM_FUNC_START_LOCAL_NOALIGN -- use for local functions, w/o alignment */
#define SYM_FUNC_START_LOCAL_NOALIGN(name)		\
	SYM_START(name, SYM_L_LOCAL, SYM_A_NONE)

/* SYM_FUNC_START_WEAK -- use for weak functions */
#define SYM_FUNC_START_WEAK(name)			\
	SYM_START(name, SYM_L_WEAK, SYM_F_ALIGN)

/* SYM_FUNC_START_WEAK_NOALIGN -- use for weak functions, w/o alignment */
#define SYM_FUNC_START_WEAK_NOALIGN(name)		\
	SYM_START(name, SYM_L_WEAK, SYM_A_NONE)

/*
 * Expose 'sym' to the startup code in arch/x86/boot/startup/, by emitting an
 * alias prefixed with __pi_
 */
#ifdef __ASSEMBLER__
#define SYM_PIC_ALIAS(sym)	SYM_ALIAS(__pi_ ## sym, sym, SYM_L_GLOBAL)
#else
#define SYM_PIC_ALIAS(sym)	extern typeof(sym) __PASTE(__pi_, sym) __alias(sym)
#endif

#endif /* _ASM_X86_LINKAGE_H */
Commit	Line	Data
	1	/* SPDX-License-Identifier: GPL-2.0 */
	2	#ifndef _ASM_X86_LINKAGE_H
	3	#define _ASM_X86_LINKAGE_H
	4
	5	#include <linux/stringify.h>
	6	#include <asm/ibt.h>
	7
	8	#undef notrace
	9	#define notrace __attribute__((no_instrument_function))
	10
	11	#ifdef CONFIG_64BIT
	12	/*
	13	* The generic version tends to create spurious ENDBR instructions under
	14	* certain conditions.
	15	*/
	16	#define _THIS_IP_ ({ unsigned long __here; asm ("lea 0(%%rip), %0" : "=r" (__here)); __here; })
	17	#endif
	18
	19	#ifdef CONFIG_X86_32
	20	#define asmlinkage CPP_ASMLINKAGE __attribute__((regparm(0)))
	21	#endif /* CONFIG_X86_32 */
	22
	23	#define __ALIGN .balign CONFIG_FUNCTION_ALIGNMENT, 0x90;
	24	#define __ALIGN_STR __stringify(__ALIGN)
	25
	26	#if defined(CONFIG_CALL_PADDING) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
	27	#define FUNCTION_PADDING .skip CONFIG_FUNCTION_ALIGNMENT, 0x90;
	28	#else
	29	#define FUNCTION_PADDING
	30	#endif
	31
	32	#if (CONFIG_FUNCTION_ALIGNMENT > 8) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
	33	# define __FUNC_ALIGN __ALIGN; FUNCTION_PADDING
	34	#else
	35	# define __FUNC_ALIGN __ALIGN
	36	#endif
	37
	38	#define ASM_FUNC_ALIGN __stringify(__FUNC_ALIGN)
	39	#define SYM_F_ALIGN __FUNC_ALIGN
	40
	41	#ifdef __ASSEMBLER__
	42
	43	#if defined(CONFIG_MITIGATION_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
	44	#define RET jmp __x86_return_thunk
	45	#else /* CONFIG_MITIGATION_RETPOLINE */
	46	#ifdef CONFIG_MITIGATION_SLS
	47	#define RET ret; int3
	48	#else
	49	#define RET ret
	50	#endif
	51	#endif /* CONFIG_MITIGATION_RETPOLINE */
	52
	53	#else /* __ASSEMBLER__ */
	54
	55	#if defined(CONFIG_MITIGATION_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
	56	#define ASM_RET "jmp __x86_return_thunk\n\t"
	57	#else /* CONFIG_MITIGATION_RETPOLINE */
	58	#ifdef CONFIG_MITIGATION_SLS
	59	#define ASM_RET "ret; int3\n\t"
	60	#else
	61	#define ASM_RET "ret\n\t"
	62	#endif
	63	#endif /* CONFIG_MITIGATION_RETPOLINE */
	64
	65	#endif /* __ASSEMBLER__ */
	66
	67	/*
	68	* Depending on -fpatchable-function-entry=N,N usage (CONFIG_CALL_PADDING) the
	69	* CFI symbol layout changes.
	70	*
	71	* Without CALL_THUNKS:
	72	*
	73	* .align FUNCTION_ALIGNMENT
	74	* __cfi_##name:
	75	* .skip FUNCTION_PADDING, 0x90
	76	* .byte 0xb8
	77	* .long __kcfi_typeid_##name
	78	* name:
	79	*
	80	* With CALL_THUNKS:
	81	*
	82	* .align FUNCTION_ALIGNMENT
	83	* __cfi_##name:
	84	* .byte 0xb8
	85	* .long __kcfi_typeid_##name
	86	* .skip FUNCTION_PADDING, 0x90
	87	* name:
	88	*
	89	* In both cases the whole thing is FUNCTION_ALIGNMENT aligned and sized.
	90	*/
	91
	92	#ifdef CONFIG_CALL_PADDING
	93	#define CFI_PRE_PADDING
	94	#define CFI_POST_PADDING .skip CONFIG_FUNCTION_PADDING_BYTES, 0x90;
	95	#else
	96	#define CFI_PRE_PADDING .skip CONFIG_FUNCTION_PADDING_BYTES, 0x90;
	97	#define CFI_POST_PADDING
	98	#endif
	99
	100	#define __CFI_TYPE(name) \
	101	SYM_START(__cfi_##name, SYM_L_LOCAL, SYM_A_NONE) \
	102	CFI_PRE_PADDING \
	103	.byte 0xb8 ASM_NL \
	104	.long __kcfi_typeid_##name ASM_NL \
	105	CFI_POST_PADDING \
	106	SYM_FUNC_END(__cfi_##name)
	107
	108	/* UML needs to be able to override memcpy() and friends for KASAN. */
	109	#ifdef CONFIG_UML
	110	# define SYM_FUNC_ALIAS_MEMFUNC SYM_FUNC_ALIAS_WEAK
	111	#else
	112	# define SYM_FUNC_ALIAS_MEMFUNC SYM_FUNC_ALIAS
	113	#endif
	114
	115	/* SYM_TYPED_FUNC_START -- use for indirectly called globals, w/ CFI type */
	116	#define SYM_TYPED_FUNC_START(name) \
	117	SYM_TYPED_START(name, SYM_L_GLOBAL, SYM_F_ALIGN) \
	118	ENDBR
	119
	120	/* SYM_FUNC_START -- use for global functions */
	121	#define SYM_FUNC_START(name) \
	122	SYM_START(name, SYM_L_GLOBAL, SYM_F_ALIGN)
	123
	124	/* SYM_FUNC_START_NOALIGN -- use for global functions, w/o alignment */
	125	#define SYM_FUNC_START_NOALIGN(name) \
	126	SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE)
	127
	128	/* SYM_FUNC_START_LOCAL -- use for local functions */
	129	#define SYM_FUNC_START_LOCAL(name) \
	130	SYM_START(name, SYM_L_LOCAL, SYM_F_ALIGN)
	131
	132	/* SYM_FUNC_START_LOCAL_NOALIGN -- use for local functions, w/o alignment */
	133	#define SYM_FUNC_START_LOCAL_NOALIGN(name) \
	134	SYM_START(name, SYM_L_LOCAL, SYM_A_NONE)
	135
	136	/* SYM_FUNC_START_WEAK -- use for weak functions */
	137	#define SYM_FUNC_START_WEAK(name) \
	138	SYM_START(name, SYM_L_WEAK, SYM_F_ALIGN)
	139
	140	/* SYM_FUNC_START_WEAK_NOALIGN -- use for weak functions, w/o alignment */
	141	#define SYM_FUNC_START_WEAK_NOALIGN(name) \
	142	SYM_START(name, SYM_L_WEAK, SYM_A_NONE)
	143
	144	/*
	145	* Expose 'sym' to the startup code in arch/x86/boot/startup/, by emitting an
	146	* alias prefixed with __pi_
	147	*/
	148	#ifdef __ASSEMBLER__
	149	#define SYM_PIC_ALIAS(sym) SYM_ALIAS(__pi_ ## sym, sym, SYM_L_GLOBAL)
	150	#else
	151	#define SYM_PIC_ALIAS(sym) extern typeof(sym) __PASTE(__pi_, sym) __alias(sym)
	152	#endif
	153
	154	#endif /* _ASM_X86_LINKAGE_H */
	155