linux-kernel - [PATCH v2 47/62] x86/orc: Define ELF section entry size for unwind hints

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <43e3ed230c982e35e43a9c66247b995336253d2d.1746821544.git.jpoimboe@kernel.org>
Date: Fri,  9 May 2025 13:17:11 -0700
From: Josh Poimboeuf <jpoimboe@...nel.org>
To: x86@...nel.org
Cc: linux-kernel@...r.kernel.org,
	Petr Mladek <pmladek@...e.com>,
	Miroslav Benes <mbenes@...e.cz>,
	Joe Lawrence <joe.lawrence@...hat.com>,
	live-patching@...r.kernel.org,
	Song Liu <song@...nel.org>,
	laokz <laokz@...mail.com>,
	Jiri Kosina <jikos@...nel.org>,
	Marcos Paulo de Souza <mpdesouza@...e.com>,
	Weinan Liu <wnliu@...gle.com>,
	Fazla Mehrab <a.mehrab@...edance.com>,
	Chen Zhongjin <chenzhongjin@...wei.com>,
	Puranjay Mohan <puranjay@...nel.org>
Subject: [PATCH v2 47/62] x86/orc: Define ELF section entry size for unwind hints

In preparation for the objtool klp diff subcommand, define the entry
size for the discard.unwind_hints section in its ELF header.  This will
allow tooling to extract individual entries.

Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
---
 arch/x86/kernel/unwind_orc.c | 2 ++
 include/linux/objtool.h      | 9 ++++++---
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index 977ee75e047c..4624d6d916a2 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -199,6 +199,8 @@ static struct orc_entry *orc_find(unsigned long ip)
 {
 	static struct orc_entry *orc;
 
+	BUILD_BUG_ON(UNWIND_HINT_SIZE != sizeof(struct unwind_hint));
+
 	if (ip == 0)
 		return &null_orc_entry;
 
diff --git a/include/linux/objtool.h b/include/linux/objtool.h
index 366ad004d794..483dd3131826 100644
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -8,11 +8,14 @@
 
 #include <asm/asm.h>
 
+#define UNWIND_HINT_SIZE 12
+
 #ifndef __ASSEMBLY__
 
-#define UNWIND_HINT(type, sp_reg, sp_offset, signal)	\
+#define UNWIND_HINT(type, sp_reg, sp_offset, signal)		\
 	"987: \n\t"						\
-	".pushsection .discard.unwind_hints\n\t"		\
+	".pushsection .discard.unwind_hints, \"M\", @progbits, "\
+		      __stringify(UNWIND_HINT_SIZE) "\n\t"	\
 	/* struct unwind_hint */				\
 	".long 987b - .\n\t"					\
 	".short " __stringify(sp_offset) "\n\t"			\
@@ -88,7 +91,7 @@
  */
 .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
 .Lhere_\@:
-	.pushsection .discard.unwind_hints
+	.pushsection .discard.unwind_hints, "M", @progbits, UNWIND_HINT_SIZE
 		/* struct unwind_hint */
 		.long .Lhere_\@ - .
 		.short \sp_offset
-- 
2.49.0