Turns out that my last rework for the word size check broke it:
I originally had the size > wordsize check in __read_once_size/
/__write_once_size as empty extern function in a newly created file
lib/access.c and marked it with a __compiletime_warning.
Unfortunately this broke arm rpcdefconfig due to this line
CFLAGS_font.o := -Dstatic=
in
arch/arm/boot/compressed/Makefile.
This define made it impossible for the compiler to get rid of
the unused __write_once_size and __read_once_size and the linker
complained about the missing data_access_exceeds_word_size
as the compressed boot thing did not include lib/access.o.
So I wanted to be clever and changed data_access_exceeds_word_size
to a static inline function. Turns out that this actually disabled
the compiletime warning.
Next try, have it as a weak function. This actually does enable
the warning. It will create an empty data_access_exceeds_word_size
function in each object file, though and it will trigger a warning
for arm rpcdefconfig:
CC arch/arm/boot/compressed/font.o
include/linux/compiler.h: In function '__write_once_size':
include/linux/compiler.h:231: warning: call to 'data_access_exceeds_word_size' declared with attribute warning: data access exceeds word size and won't be atomic
include/linux/compiler.h: In function '__read_once_size':
include/linux/compiler.h:214: warning: call to 'data_access_exceeds_word_size' declared with attribute warning: data access exceeds word size and won't be atomic
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
include/linux/compiler.h | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 1b45e4a..37943c4 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -192,13 +192,10 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
#include <uapi/linux/types.h>
-static __always_inline void data_access_exceeds_word_size(void)
#ifdef __compiletime_warning
__compiletime_warning("data access exceeds word size and won't be atomic")
#endif
-;
-
-static __always_inline void data_access_exceeds_word_size(void)
+__weak notrace void data_access_exceeds_word_size(void)
{
}
--
2.1.4
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