[RFC PATCH v3 03/17] x86/unwind_user: Guard unwind_user_word_size() by UNWIND_USER

Jens Remus
2025-12-08T17:16:41Z

The unwind user framework in general requires an architecture-specific
implementation of unwind_user_word_size() to be present for any unwind
method, whether that is fp or a future other method, such as potentially
sframe.

Guard unwind_user_word_size() by the availability of the UNWIND_USER
framework instead of the specific HAVE_UNWIND_USER_FP method.

This facilitates to selectively disable HAVE_UNWIND_USER_FP on x86
(e.g. for test purposes) once a new unwind method is added to unwind
user.

Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
arch/x86/include/asm/unwind_user.h | 30 +++++++++++++++++-------------
1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/unwind_user.h b/arch/x86/include/asm/unwind_user.h
index a528eee80dd6..4d699e4954ed 100644
--- a/arch/x86/include/asm/unwind_user.h
+++ b/arch/x86/include/asm/unwind_user.h
@@ -2,11 +2,27 @@
#ifndef _ASM_X86_UNWIND_USER_H
#define _ASM_X86_UNWIND_USER_H

-#ifdef CONFIG_HAVE_UNWIND_USER_FP
+#ifdef CONFIG_UNWIND_USER

#include <asm/ptrace.h>
#include <asm/uprobes.h>

+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 /* CONFIG_UNWIND_USER */
+
+#ifdef CONFIG_HAVE_UNWIND_USER_FP
+
#define ARCH_INIT_USER_FP_FRAME(ws) \
.cfa_off = 2*(ws), \
.ra_off = -1*(ws), \
@@ -21,18 +37,6 @@
.use_fp = false, \
.outermost = false,

-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);
-}
-
static inline bool unwind_user_at_function_start(struct pt_regs *regs)
{
return is_uprobe_at_func_entry(regs);
--
2.51.0