[PATCH v4 13/39] unwind_user/x86: Enable frame pointer unwinding on x86

Josh Poimboeuf
2025-01-22T02:32:05Z

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@kernel.org>
---
arch/x86/Kconfig | 1 +
arch/x86/include/asm/unwind_user.h | 11 +++++++++++
2 files changed, 12 insertions(+)
create mode 100644 arch/x86/include/asm/unwind_user.h

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ef6cfea9df73..f938b957a927 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -291,6 +291,7 @@ 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 000000000000..8597857bf896
--- /dev/null
+++ b/arch/x86/include/asm/unwind_user.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_UNWIND_USER_H
+#define _ASM_X86_UNWIND_USER_H
+
+#define ARCH_INIT_USER_FP_FRAME \
+ .cfa_off = (s32)sizeof(long) * 2, \
+ .ra_off = (s32)sizeof(long) * -1, \
+ .fp_off = (s32)sizeof(long) * -2, \
+ .use_fp = true,
+
+#endif /* _ASM_X86_UNWIND_USER_H */
--
2.48.1