include/linux/annotate.h

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

#include <linux/objtool_types.h>

#ifdef CONFIG_OBJTOOL

#define __ASM_ANNOTATE(section, label, type)				\
	.pushsection section, "M", @progbits, 8;			\
	.long label - ., type;						\
	.popsection

#ifndef __ASSEMBLY__

#define ASM_ANNOTATE_LABEL(label, type)					\
	__stringify(__ASM_ANNOTATE(.discard.annotate_insn, label, type))

#define ASM_ANNOTATE(type)						\
	"911: "								\
	__stringify(__ASM_ANNOTATE(.discard.annotate_insn, 911b, type))

#define ASM_ANNOTATE_DATA(type)						\
	"912: "								\
	__stringify(__ASM_ANNOTATE(.discard.annotate_data, 912b, type))

#else /* __ASSEMBLY__ */

.macro ANNOTATE type
.Lhere_\@:
	__ASM_ANNOTATE(.discard.annotate_insn, .Lhere_\@, \type)
.endm

.macro ANNOTATE_DATA type
.Lhere_\@:
	__ASM_ANNOTATE(.discard.annotate_data, .Lhere_\@, \type)
.endm

#endif /* __ASSEMBLY__ */

#else /* !CONFIG_OBJTOOL */
#ifndef __ASSEMBLY__
#define ASM_ANNOTATE_LABEL(label, type) ""
#define ASM_ANNOTATE(type)
#define ASM_ANNOTATE_DATA(type)
#else /* __ASSEMBLY__ */
.macro ANNOTATE type
.endm
.macro ANNOTATE_DATA type
.endm
#endif /* __ASSEMBLY__ */
#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)
#define ANNOTATE_NOENDBR_SYM(sym)	asm(ASM_ANNOTATE_LABEL(sym, 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(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).
 */
#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(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
 * no security concern there.
 *
 * 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_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
#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
#define ANNOTATE_NOCFI_SYM		ANNOTATE type=ANNOTYPE_NOCFI
#define ANNOTATE_DATA_SPECIAL		ANNOTATE_DATA type=ANNOTYPE_DATA_SPECIAL
#endif /* __ASSEMBLY__ */

#endif /* _LINUX_ANNOTATE_H */