linux-kernel - [tip: perf/core] unwind_user/x86: Enable frame pointer unwinding on x86

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] [day] [month] [year] [list]

Message-ID: <176173056943.2601451.14884503049263976236.tip-bot2@tip-bot2>
Date: Wed, 29 Oct 2025 09:36:09 -0000
From: "tip-bot2 for Josh Poimboeuf" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Josh Poimboeuf <jpoimboe@...nel.org>,
 "Steven Rostedt (Google)" <rostedt@...dmis.org>,
 "Peter Zijlstra (Intel)" <peterz@...radead.org>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject:
 [tip: perf/core] unwind_user/x86: Enable frame pointer unwinding on x86

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     49cf34c0815f93fb2ea3ab5cfbac1124bd9b45d0
Gitweb:        https://git.kernel.org/tip/49cf34c0815f93fb2ea3ab5cfbac1124bd9b45d0
Author:        Josh Poimboeuf <jpoimboe@...nel.org>
AuthorDate:    Wed, 27 Aug 2025 15:36:45 -04:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Wed, 29 Oct 2025 10:29:58 +01:00

unwind_user/x86: Enable frame pointer unwinding on x86

Use ARCH_INIT_USER_FP_FRAME to describe how frame pointers are unwound
on x86, and enable CONFIG_HAVE_UNWIND_USER_FP accordingly so the
unwind_user interfaces can be used.

Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: https://patch.msgid.link/20250827193828.347397433@kernel.org
---
 arch/x86/Kconfig                   |  1 +
 arch/x86/include/asm/unwind_user.h | 25 +++++++++++++++++++++++++
 2 files changed, 26 insertions(+)
 create mode 100644 arch/x86/include/asm/unwind_user.h

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index fa3b616..5cf1afc 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -297,6 +297,7 @@ config X86
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
 	select HAVE_UNSTABLE_SCHED_CLOCK
+	select HAVE_UNWIND_USER_FP		if X86_64
 	select HAVE_USER_RETURN_NOTIFIER
 	select HAVE_GENERIC_VDSO
 	select VDSO_GETRANDOM			if X86_64
diff --git a/arch/x86/include/asm/unwind_user.h b/arch/x86/include/asm/unwind_user.h
new file mode 100644
index 0000000..b166e10
--- /dev/null
+++ b/arch/x86/include/asm/unwind_user.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_UNWIND_USER_H
+#define _ASM_X86_UNWIND_USER_H
+
+#include <asm/ptrace.h>
+
+#define ARCH_INIT_USER_FP_FRAME(ws)			\
+	.cfa_off	=  2*(ws),			\
+	.ra_off		= -1*(ws),			\
+	.fp_off		= -2*(ws),			\
+	.use_fp		= true,
+
+static inline int unwind_user_word_size(struct pt_regs *regs)
+{
+	/* We can't unwind VM86 stacks */
+	if (regs->flags & X86_VM_MASK)
+		return 0;
+#ifdef CONFIG_X86_64
+	if (!user_64bit_mode(regs))
+		return sizeof(int);
+#endif
+	return sizeof(long);
+}
+
+#endif /* _ASM_X86_UNWIND_USER_H */