With PROFILE_ALL_BRANCHES enabled gcc sometimes fails to handle
__builtin_constant_p() correctly:
In function 'arch_test_bit',
inlined from 'node_state' at include/linux/nodemask.h:423:9,
inlined from 'warn_if_node_offline' at include/linux/gfp.h:252:2,
inlined from '__alloc_pages_node_noprof' at include/linux/gfp.h:267:2,
inlined from 'alloc_pages_node_noprof' at include/linux/gfp.h:296:9,
inlined from 'vm_area_alloc_pages.constprop' at mm/vmalloc.c:3591:11:
>> arch/s390/include/asm/bitops.h:60:17: warning: 'asm' operand 2 probably does not match constraints
60 | asm volatile(
| ^~~
>> arch/s390/include/asm/bitops.h:60:17: error: impossible constraint in 'asm'
Therefore disable the optimization for this case. This is similar to
commit
63678eecec57 ("s390/preempt: disable __preempt_count_add()
optimization for PROFILE_ALL_BRANCHES")
Fixes: b2bc1b1a77c0 ("s390/bitops: Provide optimized arch_test_bit()")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202502091912.xL2xTCGw-lkp@intel.com/
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
unsigned long mask;
int cc;
- if (__builtin_constant_p(nr)) {
+ /*
+ * With CONFIG_PROFILE_ALL_BRANCHES enabled gcc fails to
+ * handle __builtin_constant_p() in some cases.
+ */
+ if (!IS_ENABLED(CONFIG_PROFILE_ALL_BRANCHES) && __builtin_constant_p(nr)) {
addr = (const volatile unsigned char *)ptr;
addr += (nr ^ (BITS_PER_LONG - BITS_PER_BYTE)) / BITS_PER_BYTE;
mask = 1UL << (nr & (BITS_PER_BYTE - 1));