On Wed, Aug 27, 2025 at 03:36:45PM -0400, Steven Rostedt wrote:
quoted hunk ↗ jump to hunk
From: Josh Poimboeuf <jpoimboe@kernel.org>
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>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.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 58d890fe2100..8f94c58d4de8 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -299,6 +299,7 @@ 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 */
Moo, and now you have me look at unwind/user.c:
/* Make sure that the address is word aligned */
shift = sizeof(long) == 4 ? 2 : 3;
if (cfa & ((1 << shift) - 1))
return -EINVAL;
Isn't that just:
if (cfa & (sizeof(long) - 1))
?
Let me go add a patch to clean that up...