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>
---

Notes (jremus):
    Changes in v3:
    - Move includes into more common UNWIND_USER guard at the top of the
      source.  asm/ptrace.h is required for struct pt_regs.

 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

 Random nit...

On Fri, 5 Dec 2025 at 09:15, Jens Remus <jremus@linux.ibm.com> wrote:
>
> +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);
> +}

I realize you just moved this around, but since I see it in the patch,
the #ifdef annoys me.

That user_64bit_mode() should work equally well on 32-bit, and this
can be written as

        return user_64bit_mode(regs) ? 8 : 4;

which avoids the #ifdef, and makes a lot more sense ("sizeof(long)"
together with "user_64bit_mode()"? It's literally testing 32 vs 64
bitness, not "int vs long").

              Linus