diff mbox series

[1/3] compiler.h: Move C string helpers into C-only kernel section

Message ID 20250206181133.3450635-1-kees@kernel.org (mailing list archive)
State Superseded
Headers show
Series string.h: Use ARRAY_SIZE() for memtostr*()/strtomem*() | expand

Commit Message

Kees Cook Feb. 6, 2025, 6:11 p.m. UTC 
The C kernel helpers for evaluating C Strings were placed outside of the
assembly ifdef. Move them to the correct place so future changes won't
confuse the assembler.

Fixes: d7a516c6eeae ("compiler.h: Fix undefined BUILD_BUG_ON_ZERO()")
Fixes: 559048d156ff ("string: Check for "nonstring" attribute on strscpy() arguments")
Signed-off-by: Kees Cook <kees@kernel.org>
---
 include/linux/compiler.h | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

Comments

Miguel Ojeda Feb. 6, 2025, 8:07 p.m. UTC | #1 
On Thu, Feb 6, 2025 at 7:11 PM Kees Cook <kees@kernel.org> wrote:
>
> The C kernel helpers for evaluating C Strings were placed outside of the
> assembly ifdef. Move them to the correct place so future changes won't
> confuse the assembler.

This moves it also into the kernel ifdef too -- I assume that is
intentional. (Perhaps mention ifndef instead of ifdef?)

I checked that this is indeed a pure move, so:

Reviewed-by: Miguel Ojeda <ojeda@kernel.org>

Cheers,
Miguel
Kees Cook Feb. 6, 2025, 9:28 p.m. UTC | #2 
On Thu, Feb 06, 2025 at 09:07:05PM +0100, Miguel Ojeda wrote:
> On Thu, Feb 6, 2025 at 7:11 PM Kees Cook <kees@kernel.org> wrote:
> >
> > The C kernel helpers for evaluating C Strings were placed outside of the
> > assembly ifdef. Move them to the correct place so future changes won't
> > confuse the assembler.
> 
> This moves it also into the kernel ifdef too -- I assume that is
> intentional. (Perhaps mention ifndef instead of ifdef?)

Right, yeah. I guess I only mentioned that in the Subject. I'll clarify.

> 
> I checked that this is indeed a pure move, so:
> 
> Reviewed-by: Miguel Ojeda <ojeda@kernel.org>

Thanks!

-Kees
diff mbox series

Patch

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 240c632c5b95..7af999a131cb 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -214,6 +214,19 @@  void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 	__v;								\
 })
 
+#ifdef __CHECKER__
+#define __BUILD_BUG_ON_ZERO_MSG(e, msg) (0)
+#else /* __CHECKER__ */
+#define __BUILD_BUG_ON_ZERO_MSG(e, msg) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
+#endif /* __CHECKER__ */
+
+/* &a[0] degrades to a pointer: a different type from an array */
+#define __must_be_array(a)	__BUILD_BUG_ON_ZERO_MSG(__same_type((a), &(a)[0]), "must be array")
+
+/* Require C Strings (i.e. NUL-terminated) lack the "nonstring" attribute. */
+#define __must_be_cstr(p) \
+	__BUILD_BUG_ON_ZERO_MSG(__annotated(p, nonstring), "must be cstr (NUL-terminated)")
+
 #endif /* __KERNEL__ */
 
 /**
@@ -254,19 +267,6 @@  static inline void *offset_to_ptr(const int *off)
 
 #define __ADDRESSABLE_ASM_STR(sym) __stringify(__ADDRESSABLE_ASM(sym))
 
-#ifdef __CHECKER__
-#define __BUILD_BUG_ON_ZERO_MSG(e, msg) (0)
-#else /* __CHECKER__ */
-#define __BUILD_BUG_ON_ZERO_MSG(e, msg) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
-#endif /* __CHECKER__ */
-
-/* &a[0] degrades to a pointer: a different type from an array */
-#define __must_be_array(a)	__BUILD_BUG_ON_ZERO_MSG(__same_type((a), &(a)[0]), "must be array")
-
-/* Require C Strings (i.e. NUL-terminated) lack the "nonstring" attribute. */
-#define __must_be_cstr(p) \
-	__BUILD_BUG_ON_ZERO_MSG(__annotated(p, nonstring), "must be cstr (NUL-terminated)")
-
 /*
  * This returns a constant expression while determining if an argument is
  * a constant expression, most importantly without evaluating the argument.