[drm-tip:drm-tip 4/6] arch/x86/include/asm/string_32.h:195:29: warning: '__builtin_memset' writing 16 bytes into a region of size 0 overflows the destination

[kernel test robot]

tree:   git://anongit.freedesktop.org/drm/drm-tip drm-tip
head:   e1973de2c4516e9130157e538014e79c8aa57b41
commit: a59bb8e436a090adb48ed2723fd6864cd82bf8c8 [4/6] Merge remote-tracking branch 'drm-intel/drm-intel-gt-next' into drm-tip
config: i386-buildonly-randconfig-005-20230924 (https://download.01.org/0day-ci/archive/20230924/202309240849.DfoxxSha-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230924/202309240849.DfoxxSha-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 at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202309240849.DfoxxSha-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from arch/x86/include/asm/string.h:3,
                    from include/linux/string.h:20,
                    from arch/x86/include/asm/page_32.h:18,
                    from arch/x86/include/asm/page.h:14,
                    from arch/x86/include/asm/thread_info.h:12,
                    from include/linux/thread_info.h:60,
                    from arch/x86/include/asm/preempt.h:9,
                    from include/linux/preempt.h:79,
                    from include/linux/rcupdate.h:27,
                    from include/linux/rculist.h:11,
                    from include/linux/pid.h:5,
                    from include/linux/sched.h:14,
                    from include/linux/ratelimit.h:6,
                    from include/linux/dev_printk.h:16,
                    from include/linux/device.h:15,
                    from include/linux/pm_runtime.h:11,
                    from drivers/gpu/drm/i915/gt/intel_rc6.c:6:
   In function 'rc6_res_reg_init',
       inlined from 'intel_rc6_init' at drivers/gpu/drm/i915/gt/intel_rc6.c:610:2:
>> arch/x86/include/asm/string_32.h:195:29: warning: '__builtin_memset' writing 16 bytes into a region of size 0 overflows the destination [-Wstringop-overflow=]
     195 | #define memset(s, c, count) __builtin_memset(s, c, count)
         |                             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/gpu/drm/i915/gt/intel_rc6.c:584:9: note: in expansion of macro 'memset'
     584 |         memset(rc6->res_reg, INVALID_MMIO_REG.reg, sizeof(rc6->res_reg));
         |         ^~~~~~


vim +/__builtin_memset +195 arch/x86/include/asm/string_32.h

^1da177e4c3f41 include/asm-i386/string.h        Linus Torvalds   2005-04-16  186  
^1da177e4c3f41 include/asm-i386/string.h        Linus Torvalds   2005-04-16  187  #define __memset(s, c, count)				\
78d64fc21d2aa4 include/asm-x86/string_32.h      Joe Perches      2008-05-12  188  	(__builtin_constant_p(count)			\
78d64fc21d2aa4 include/asm-x86/string_32.h      Joe Perches      2008-05-12  189  	 ? __constant_count_memset((s), (c), (count))	\
78d64fc21d2aa4 include/asm-x86/string_32.h      Joe Perches      2008-05-12  190  	 : __memset_generic((s), (c), (count)))
^1da177e4c3f41 include/asm-i386/string.h        Linus Torvalds   2005-04-16  191  
^1da177e4c3f41 include/asm-i386/string.h        Linus Torvalds   2005-04-16  192  #define __HAVE_ARCH_MEMSET
6974f0c4555e28 arch/x86/include/asm/string_32.h Daniel Micay     2017-07-12  193  extern void *memset(void *, int, size_t);
6974f0c4555e28 arch/x86/include/asm/string_32.h Daniel Micay     2017-07-12  194  #ifndef CONFIG_FORTIFY_SOURCE
ff60fab71bb3b4 arch/x86/include/asm/string_32.h Arjan van de Ven 2009-09-28 @195  #define memset(s, c, count) __builtin_memset(s, c, count)
6974f0c4555e28 arch/x86/include/asm/string_32.h Daniel Micay     2017-07-12  196  #endif /* !CONFIG_FORTIFY_SOURCE */
^1da177e4c3f41 include/asm-i386/string.h        Linus Torvalds   2005-04-16  197  

:::::: The code at line 195 was first introduced by commit
:::::: ff60fab71bb3b4fdbf8caf57ff3739ffd0887396 x86: Use __builtin_memset and __builtin_memcpy for memset/memcpy

:::::: TO: Arjan van de Ven <arjan at infradead.org>
:::::: CC: H. Peter Anvin <hpa at zytor.com>

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