[PATCH 2/3] gcc-plugins: sanemaker: make the no-op trap macros statement-safe

[Kees Cook <kees@kernel.org>]

With CONFIG_SPSLR=y and CONFIG_SANEMAKER=n -- the baseline configuration
named in the cover letter -- the build fails:

  kernel/module/main.c:105:63: error: suggest braces around empty body
    in an 'if' statement [-Werror=empty-body]
    105 |                 (const char *)text->base + text->size);
  cc1: all warnings being treated as errors

The sanemaker_*() stubs expand to nothing when CONFIG_SANEMAKER is off,
and sanemaker_register_module_image() uses them as the body of an if:

	if (text->base && text->size)
		sanemaker_new_image_text(...);

which leaves "if (cond) ;".

Give the stubs the usual do { } while (0) body so they are valid
statements. No change when CONFIG_SANEMAKER=y.

Build tested ARCH=x86_64 defconfig+CONFIG_SPSLR=y with the patched
GCC 16.1.0 / GAS 2.46.1 toolchain, CONFIG_SANEMAKER unset.

Assisted-by: Claude:claude-opus-5[1m]
Signed-off-by: Kees Cook <kees@kernel.org>
---
 include/sanemaker/traps.h | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/include/sanemaker/traps.h b/include/sanemaker/traps.h
index bcb75198b18b..b9a39584de27 100644
--- a/include/sanemaker/traps.h
+++ b/include/sanemaker/traps.h
@@ -17,7 +17,7 @@ void __sanemaker_target_tag_trap(const void *ptr, const unsigned char *target);
 
 #else
 
-#define sanemaker_target_tag(ptr, type)
+#define sanemaker_target_tag(ptr, type) do { } while (0)
 
 #endif
 
@@ -32,7 +32,7 @@ void __sanemaker_target_untag_trap(const void *ptr);
 
 #else
 
-#define sanemaker_target_untag(ptr)
+#define sanemaker_target_untag(ptr) do { } while (0)
 
 #endif
 
@@ -50,7 +50,7 @@ void __sanemaker_finish_layout_trap(const void *fields,
 
 #else
 
-#define sanemaker_finish_layout(fields, target)
+#define sanemaker_finish_layout(fields, target) do { } while (0)
 
 #endif
 
@@ -90,7 +90,7 @@ void __sanemaker_signal_trap(sanemaker_signal_t signal);
 
 #else
 
-#define sanemaker_signal(signal)
+#define sanemaker_signal(signal) do { } while (0)
 
 #endif
 
@@ -125,10 +125,10 @@ void __sanemaker_drop_image_text_trap(const char *image, const void *begin,
 
 #else
 
-#define sanemaker_new_image(name, base)
-#define sanemaker_new_image_text(image, begin, end)
-#define sanemaker_drop_image(image)
-#define sanemaker_drop_image_text(image, begin, end)
+#define sanemaker_new_image(name, base) do { } while (0)
+#define sanemaker_new_image_text(image, begin, end) do { } while (0)
+#define sanemaker_drop_image(image) do { } while (0)
+#define sanemaker_drop_image_text(image, begin, end) do { } while (0)
 
 #endif
 
-- 
2.34.1