Commit 6166caf3 authored by Heiko Carstens's avatar Heiko Carstens Committed by Vasily Gorbik
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s390/bitops: Disable arch_test_bit() optimization for PROFILE_ALL_BRANCHES 



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 63678eec ("s390/preempt: disable __preempt_count_add()
optimization for PROFILE_ALL_BRANCHES")

Fixes: b2bc1b1a ("s390/bitops: Provide optimized arch_test_bit()")
Reported-by: default avatarkernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202502091912.xL2xTCGw-lkp@intel.com/


Acked-by: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent 32ae4a29

arch/s390/include/asm/bitops.h

+5 −1
Original line number Diff line number Diff line
@@ -53,7 +53,11 @@ static __always_inline bool arch_test_bit(unsigned long nr, const volatile unsig 
	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));