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Message-ID: <28e63e2c890661dc9bcdbe172eba06b26220d455.1765044697.git.jpoimboe@kernel.org>
Date: Sat, 6 Dec 2025 13:41:12 -0800
From: Josh Poimboeuf <jpoimboe@...nel.org>
To: x86@...nel.org
Cc: linux-kernel@...r.kernel.org,
Linus Torvalds <torvalds@...ux-foundation.org>,
Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Borislav Petkov <bp@...en8.de>,
Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 5/8] objtool: Convert annotations to assembler macros
Improve code generation readability by converting the objtool
annotations into assembler macros which are created when annotate.h is
included.
Before:
.pushsection .discard.annotate_insn, "M", @progbits, 8; .long 1b - ., 8; .popsection
After:
ANNOTATE_REACHABLE loc=1b
Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
---
arch/x86/include/asm/asm.h | 8 +-
arch/x86/include/asm/jump_label.h | 1 +
include/linux/annotate.h | 132 +++++++++++++++---------------
3 files changed, 72 insertions(+), 69 deletions(-)
diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index 0e8c611bc9e2..770321c908e5 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -2,15 +2,15 @@
#ifndef _ASM_X86_ASM_H
#define _ASM_X86_ASM_H
-#include <linux/annotate.h>
-
#ifdef __ASSEMBLER__
+# define __ASM_C(a,b) a
# define __ASM_FORM(x, ...) x,## __VA_ARGS__
# define __ASM_FORM_RAW(x, ...) x,## __VA_ARGS__
# define __ASM_FORM_COMMA(x, ...) x,## __VA_ARGS__,
# define __ASM_REGPFX %
#else
#include <linux/stringify.h>
+# define __ASM_C(a,b) b
# define __ASM_FORM(x, ...) " " __stringify(x,##__VA_ARGS__) " "
# define __ASM_FORM_RAW(x, ...) __stringify(x,##__VA_ARGS__)
# define __ASM_FORM_COMMA(x, ...) " " __stringify(x,##__VA_ARGS__) ","
@@ -115,6 +115,10 @@
#endif
+#define DEFINE_MACRO(name) \
+ __ASM_C(DEFINE_ ## name, \
+ asm(__stringify(DEFINE_ ## name)))
+
#ifndef __ASSEMBLER__
static __always_inline __pure void *rip_rel_ptr(void *p)
{
diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h
index 05b16299588d..d34a16a4d305 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -11,6 +11,7 @@
#include <linux/stringify.h>
#include <linux/types.h>
+#include <linux/annotate.h>
#define JUMP_TABLE_ENTRY(key, label) \
".pushsection __jump_table, \"aw\" \n\t" \
diff --git a/include/linux/annotate.h b/include/linux/annotate.h
index 1678410efa1b..8b28f1a81ec4 100644
--- a/include/linux/annotate.h
+++ b/include/linux/annotate.h
@@ -3,53 +3,43 @@
#define _LINUX_ANNOTATE_H
#include <linux/objtool_types.h>
+#include <linux/stringify.h>
+#include <asm/asm.h>
+
+#define DEFINE___ANNOTATE \
+ .macro __ANNOTATE sec, type, loc; \
+ .pushsection __ASM_C(\sec, \\sec), "M", @progbits, 8; \
+ .long __ASM_C(\loc, \\loc) - .; \
+ .long __ASM_C(\type, \\type); \
+ .popsection; \
+ .endm
+
+#define __DEFINE_ANNOTATE(sec, name, type) \
+ .macro name loc=910b; \
+ 910: __ANNOTATE sec, type, __ASM_C(\loc, \\loc); \
+ .endm
+
+#define DEFINE_ANNOTATE(type) \
+ __DEFINE_ANNOTATE(.discard.annotate_insn, \
+ ANNOTATE_ ## type, ANNOTYPE_ ## type)
+
+#define DEFINE_ANNOTATE_DATA(type) \
+ __DEFINE_ANNOTATE(.discard.annotate_data, \
+ ANNOTATE_ ## type, ANNOTYPE_ ## type)
#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 */
+DEFINE_MACRO(__ANNOTATE);
+DEFINE_MACRO(ANNOTATE(NOENDBR));
+DEFINE_MACRO(ANNOTATE(RETPOLINE_SAFE));
+DEFINE_MACRO(ANNOTATE(INSTR_BEGIN));
+DEFINE_MACRO(ANNOTATE(INSTR_END));
+DEFINE_MACRO(ANNOTATE(IGNORE_ALTERNATIVE));
+DEFINE_MACRO(ANNOTATE(INTRA_FUNCTION_CALL));
+DEFINE_MACRO(ANNOTATE(UNRET_BEGIN));
+DEFINE_MACRO(ANNOTATE(REACHABLE));
+DEFINE_MACRO(ANNOTATE(NOCFI));
+DEFINE_MACRO(ANNOTATE_DATA(DATA_SPECIAL));
#ifndef __ASSEMBLY__
@@ -57,30 +47,30 @@
* 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))
+#define ANNOTATE_NOENDBR "ANNOTATE_NOENDBR"
+#define ANNOTATE_NOENDBR_SYM(sym) asm("ANNOTATE_NOENDBR loc=" __stringify(sym))
/*
* 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)
+#define ANNOTATE_RETPOLINE_SAFE "ANNOTATE_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)
+#define ANNOTATE_INSTR_BEGIN(label) "ANNOTATE_INSTR_BEGIN loc=" __stringify(label)
+#define ANNOTATE_INSTR_END(label) "ANNOTATE_INSTR_END loc=" __stringify(label)
/*
* objtool annotation to ignore the alternatives and only consider the original
* instruction(s).
*/
-#define ANNOTATE_IGNORE_ALTERNATIVE ASM_ANNOTATE(ANNOTYPE_IGNORE_ALTERNATIVE)
+#define ANNOTATE_IGNORE_ALTERNATIVE "ANNOTATE_IGNORE_ALTERNATIVE"
/*
* 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)
+#define ANNOTATE_INTRA_FUNCTION_CALL "ANNOTATE_INTRA_FUNCTION_CALL"
/*
* Use objtool to validate the entry requirement that all code paths do
* VALIDATE_UNRET_END before RET.
@@ -88,13 +78,13 @@
* 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)
+#define ANNOTATE_UNRET_BEGIN "ANNOTATE_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(label) ASM_ANNOTATE_LABEL(label, ANNOTYPE_REACHABLE)
+#define ANNOTATE_REACHABLE_LABEL(label) "ANNOTATE_REACHABLE loc=" __stringify(label)
/*
* 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
@@ -103,25 +93,33 @@
* 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))
+#define ANNOTATE_NOCFI_SYM(sym) asm("ANNOTATE_NOCFI loc=" __stringify(sym))
/*
* 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)
+#define ANNOTATE_DATA_SPECIAL "ANNOTATE_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_ALTERNATIVE
-#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 ANNOTATE type=ANNOTYPE_NOCFI
-#define ANNOTATE_DATA_SPECIAL ANNOTATE_DATA type=ANNOTYPE_DATA_SPECIAL
-#endif /* __ASSEMBLY__ */
+#endif /* !__ASSEMBLY__ */
+
+#else /* !OBJTOOL */
+
+#define ANNOTATE_NOENDBR
+#define ANNOTATE_NOENDBR_SYM(sym)
+#define ANNOTATE_RETPOLINE_SAFE
+#define ANNOTATE_INSTR_BEGIN(label)
+#define ANNOTATE_INSTR_END(label)
+#define ANNOTATE_IGNORE_ALTERNATIVE
+#define ANNOTATE_INTRA_FUNCTION_CALL
+#define ANNOTATE_UNRET_BEGIN
+#define ANNOTATE_REACHABLE
+#define ANNOTATE_REACHABLE_LABEL(label)
+#define ANNOTATE_NOCFI
+#define ANNOTATE_NOCFI_SYM(sym)
+#define ANNOTATE_DATA_SPECIAL
+#define __ANNOTATE_DATA_SPECIAL(l)
+
+#endif /* !OBJTOOL */
#endif /* _LINUX_ANNOTATE_H */
--
2.52.0
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