3ae90d7640
I found this when compiling a kbuild random config with GCC 11. The
config enables CONFIG_DEBUG_SECTION_MISMATCH, which sets CFLAGS
-fno-inline-functions-called-once. This causes the call to cache_loop in
cache.c to not be inlined causing the below compile error.
In file included from arch/openrisc/mm/cache.c:13:
arch/openrisc/mm/cache.c: In function 'cache_loop':
./arch/openrisc/include/asm/spr.h:16:27: warning: 'asm' operand 0 probably does not match constraints
16 | #define mtspr(_spr, _val) __asm__ __volatile__ ( \
| ^~~~~~~
arch/openrisc/mm/cache.c:25:3: note: in expansion of macro 'mtspr'
25 | mtspr(reg, line);
| ^~~~~
./arch/openrisc/include/asm/spr.h:16:27: error: impossible constraint in 'asm'
16 | #define mtspr(_spr, _val) __asm__ __volatile__ ( \
| ^~~~~~~
arch/openrisc/mm/cache.c:25:3: note: in expansion of macro 'mtspr'
25 | mtspr(reg, line);
| ^~~~~
make[1]: *** [scripts/Makefile.build:283: arch/openrisc/mm/cache.o] Error 1
The asm constraint "K" requires a immediate constant argument to mtspr,
however because of no inlining a register argument is passed causing a
failure. Fix this by using __always_inline.
Link: https://lore.kernel.org/lkml/202008200453.ohnhqkjQ%25lkp@intel.com/
Signed-off-by: Stafford Horne <shorne@gmail.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.