[PATCH 1/1] regulator: hi6421v530: fix building with GCC 15

[PATCH 1/1] regulator: hi6421v530: fix building with GCC 15

[Brahmajit Das]

Since the Linux kernel initializes many non-C-string char arrays with
literals. While it would be possible to convert initializers from:
   { "BOOP", ... }
to something like:
   { { 'B', 'O', 'O', 'P' }, ... }
that is annoying.
Making -Wunterminated-string-initialization stay silent about char
arrays marked with nonstring would be much better.

Without the __attribute__((nonstring)) we would get the following build
error:
drivers/regulator/hi6421v530-regulator.c:189:19: error: initializer-string for array of ‘char’ truncates NUL terminator but destination lacks ‘nonstring’ attribute (21 chars into 20 available) [-Werror=unterminated-string-initialization]
  189 |         { .name = "hi6421v530-regulator" },
      |                   ^~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors

Upstream GCC has added this commit
622968990beee7499e951590258363545b4a3b57[0][1] which silences warning
about truncating NUL char when initializing nonstring arrays.

[0]: https://gcc.gnu.org/cgit/gcc/commit/?id=622968990beee7499e951590258363545b4a3b57
[1]: https://gcc.gnu.org/cgit/gcc/commit/?id=afb46540d3921e96c4cd7ba8fa2c8b0901759455

Thanks to Jakub Jelinek <jakub@gcc.gnu.org> for the gcc patch.

Signed-off-by: Brahmajit Das <listout@listout.xyz>
---
 include/linux/mod_devicetable.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index bd7e60c0b72f..f9bb623d0949 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -605,7 +605,7 @@ struct dmi_system_id {
 #define PLATFORM_MODULE_PREFIX	"platform:"
 
 struct platform_device_id {
-	char name[PLATFORM_NAME_SIZE];
+	char name[PLATFORM_NAME_SIZE] __attribute__((nonstring));
 	kernel_ulong_t driver_data;
 };
 
-- 
2.49.0

Re: [PATCH 1/1] regulator: hi6421v530: fix building with GCC 15

[kernel test robot]

Hi Brahmajit,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on v6.15-rc2 next-20250416]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Brahmajit-Das/regulator-hi6421v530-fix-building-with-GCC-15/20250415-191555
base:   linus/master
patch link:    https://lore.kernel.org/r/20250415111411.6331-1-listout%40listout.xyz
patch subject: [PATCH 1/1] regulator: hi6421v530: fix building with GCC 15
config: hexagon-randconfig-001-20250416 (https://download.01.org/0day-ci/archive/20250416/202504161823.huZUOtmg-lkp@intel.com/config)
compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project f819f46284f2a79790038e1f6649172789734ae8)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250416/202504161823.huZUOtmg-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202504161823.huZUOtmg-lkp@intel.com/

All warnings (new ones prefixed by >>):

   scripts/kernel-doc: 1: kernel-doc.py: not found
   make[3]: *** [scripts/Makefile.build:203: scripts/mod/empty.o] Error 127 shuffle=4166761562
   make[3]: *** Deleting file 'scripts/mod/empty.o'
   In file included from scripts/mod/devicetable-offsets.c:3:
>> include/linux/mod_devicetable.h:608:47: warning: unknown attribute 'nonstring' ignored [-Wunknown-attributes]
     608 |         char name[PLATFORM_NAME_SIZE] __attribute__((nonstring));
         |                                                      ^~~~~~~~~
   1 warning generated.
   make[3]: Target 'scripts/mod/' not remade because of errors.
   make[2]: *** [Makefile:1279: prepare0] Error 2 shuffle=4166761562
   make[2]: Target 'prepare' not remade because of errors.
   make[1]: *** [Makefile:248: __sub-make] Error 2 shuffle=4166761562
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:248: __sub-make] Error 2 shuffle=4166761562
   make: Target 'prepare' not remade because of errors.


vim +/nonstring +608 include/linux/mod_devicetable.h

   606	
   607	struct platform_device_id {
 > 608		char name[PLATFORM_NAME_SIZE] __attribute__((nonstring));
   609		kernel_ulong_t driver_data;
   610	};
   611	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 1/1] regulator: hi6421v530: fix building with GCC 15

[kernel test robot]

Hi Brahmajit,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on v6.15-rc2 next-20250416]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Brahmajit-Das/regulator-hi6421v530-fix-building-with-GCC-15/20250415-191555
base:   linus/master
patch link:    https://lore.kernel.org/r/20250415111411.6331-1-listout%40listout.xyz
patch subject: [PATCH 1/1] regulator: hi6421v530: fix building with GCC 15
config: arm-randconfig-002-20250416 (https://download.01.org/0day-ci/archive/20250416/202504161944.iNjyTvch-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 7.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250416/202504161944.iNjyTvch-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202504161944.iNjyTvch-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from scripts/mod/devicetable-offsets.c:3:0:
>> include/linux/mod_devicetable.h:608:2: warning: 'nonstring' attribute directive ignored [-Wattributes]
     char name[PLATFORM_NAME_SIZE] __attribute__((nonstring));
     ^~~~
   scripts/kernel-doc: 1: kernel-doc.py: not found
   make[3]: *** [scripts/Makefile.build:203: scripts/mod/empty.o] Error 127 shuffle=3373171021
   make[3]: *** Deleting file 'scripts/mod/empty.o'
   make[3]: Target 'scripts/mod/' not remade because of errors.
   make[2]: *** [Makefile:1279: prepare0] Error 2 shuffle=3373171021
   make[2]: Target 'prepare' not remade because of errors.
   make[1]: *** [Makefile:248: __sub-make] Error 2 shuffle=3373171021
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:248: __sub-make] Error 2 shuffle=3373171021
   make: Target 'prepare' not remade because of errors.


vim +/nonstring +608 include/linux/mod_devicetable.h

   606	
   607	struct platform_device_id {
 > 608		char name[PLATFORM_NAME_SIZE] __attribute__((nonstring));
   609		kernel_ulong_t driver_data;
   610	};
   611	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

[PATCH v2 1/1] regulator: hi6421v530: fix building with GCC 15

[Brahmajit Das]

Since the Linux kernel initializes many non-C-string char arrays with
literals. While it would be possible to convert initializers from:
   { "BOOP", ... }
to something like:
   { { 'B', 'O', 'O', 'P' }, ... }
that is annoying.
Making -Wunterminated-string-initialization stay silent about char
arrays marked with nonstring would be much better.

Without the __nonstring we would get the following build error:
drivers/regulator/hi6421v530-regulator.c:189:19: error: initializer-string for array of ‘char’ truncates NUL terminator but destination lacks ‘nonstring’ attribute (21 chars into 20 available) [-Werror=unterminated-string-initialization]
  189 |         { .name = "hi6421v530-regulator" },
      |                   ^~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors

Upstream GCC has added this commit
622968990beee7499e951590258363545b4a3b57[0][1] which silences warning
about truncating NUL char when initializing nonstring arrays.

[0]: https://gcc.gnu.org/cgit/gcc/commit/?id=622968990beee7499e951590258363545b4a3b57
[1]: https://gcc.gnu.org/cgit/gcc/commit/?id=afb46540d3921e96c4cd7ba8fa2c8b0901759455

Thanks to Jakub Jelinek <jakub@gcc.gnu.org> for the gcc patch.

Signed-off-by: Brahmajit Das <listout@listout.xyz>
---
 include/linux/mod_devicetable.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index bd7e60c0b72f..e3c9c427443d 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -605,7 +605,7 @@ struct dmi_system_id {
 #define PLATFORM_MODULE_PREFIX	"platform:"
 
 struct platform_device_id {
-	char name[PLATFORM_NAME_SIZE];
+	char name[PLATFORM_NAME_SIZE] __nonstring;
 	kernel_ulong_t driver_data;
 };
 
-- 
2.49.0

Re: [PATCH v2 1/1] regulator: hi6421v530: fix building with GCC 15

[kernel test robot]

Hi Brahmajit,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on v6.15-rc5 next-20250506]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Brahmajit-Das/regulator-hi6421v530-fix-building-with-GCC-15/20250416-211351
base:   linus/master
patch link:    https://lore.kernel.org/r/20250416121305.13469-1-listout%40listout.xyz
patch subject: [PATCH v2 1/1] regulator: hi6421v530: fix building with GCC 15
config: nios2-allmodconfig (https://download.01.org/0day-ci/archive/20250507/202505071639.PQ4TVkSG-lkp@intel.com/config)
compiler: nios2-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250507/202505071639.PQ4TVkSG-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202505071639.PQ4TVkSG-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from scripts/mod/file2alias.c:123:
>> scripts/mod/../../include/linux/mod_devicetable.h:608:39: error: expected ':', ',', ';', '}' or '__attribute__' before '__nonstring'
     608 |         char name[PLATFORM_NAME_SIZE] __nonstring;
         |                                       ^~~~~~~~~~~
   scripts/mod/file2alias.c: In function 'do_platform_entry':
>> scripts/mod/file2alias.c:143:35: error: 'struct platform_device_id' has no member named 'name'
     143 |         typeof(((struct devid *)0)->f) *f = ((m) + OFF_##devid##_##f)
         |                                   ^~
   scripts/mod/file2alias.c:932:9: note: in expansion of macro 'DEF_FIELD_ADDR'
     932 |         DEF_FIELD_ADDR(symval, platform_device_id, name);
         |         ^~~~~~~~~~~~~~
   scripts/mod/../../include/linux/mod_devicetable.h:605:33: warning: format '%s' expects argument of type 'char *', but argument 4 has type 'int' [-Wformat=]
     605 | #define PLATFORM_MODULE_PREFIX  "platform:"
         |                                 ^~~~~~~~~~~
   scripts/mod/file2alias.c:934:41: note: in expansion of macro 'PLATFORM_MODULE_PREFIX'
     934 |         module_alias_printf(mod, false, PLATFORM_MODULE_PREFIX "%s", *name);
         |                                         ^~~~~~~~~~~~~~~~~~~~~~
   scripts/mod/file2alias.c:934:66: note: format string is defined here
     934 |         module_alias_printf(mod, false, PLATFORM_MODULE_PREFIX "%s", *name);
         |                                                                 ~^
         |                                                                  |
         |                                                                  char *
         |                                                                 %d
   make[3]: *** [scripts/Makefile.host:131: scripts/mod/file2alias.o] Error 1
   make[3]: Target 'scripts/mod/' not remade because of errors.
   make[2]: *** [Makefile:1279: prepare0] Error 2
   make[2]: Target 'prepare' not remade because of errors.
   make[1]: *** [Makefile:248: __sub-make] Error 2
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:248: __sub-make] Error 2
   make: Target 'prepare' not remade because of errors.


vim +608 scripts/mod/../../include/linux/mod_devicetable.h

   606	
   607	struct platform_device_id {
 > 608		char name[PLATFORM_NAME_SIZE] __nonstring;
   609		kernel_ulong_t driver_data;
   610	};
   611	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki