[kbuild-all] arch/mips/include/asm/atomic.h:49:1: warning: converting the result of '<<' to a boolean always evaluates to true

Monday, 17 August 2020

Hi Nathan,

FYI, the error/warning still remains.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   2cc3c4b3c2e9c99e90aaf19cd801ff2c160f283c
commit: afe956c577b2d5a3d9834e4424587c1ebcf90c4c kbuild: Enable -Wtautological-compare
date:   4 months ago
config: mips-randconfig-r001-20200817 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project
ab9fc8bae805c785066779e76e7846aabad5609e)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install mips cross compiling tool for clang build
        # apt-get install binutils-mips-linux-gnu
        git checkout afe956c577b2d5a3d9834e4424587c1ebcf90c4c
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp(a)intel.com&gt;

All warnings (new ones prefixed by >>):

   clang-12: warning: argument unused during compilation: '-mno-branch-likely'
[-Wunused-command-line-argument]
   clang-12: warning: argument unused during compilation: '-mno-branch-likely'
[-Wunused-command-line-argument]
   In file included from kernel/bounds.c:14:
   In file included from include/linux/spinlock_types.h:18:
   In file included from include/linux/lockdep.h:44:
   In file included from include/linux/debug_locks.h:6:
   In file included from include/linux/atomic.h:7:
...
> arch/mips/include/asm/atomic.h:49:1: warning: converting the
result of '<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]    ATOMIC_OPS(atomic, int)
   ^
   arch/mips/include/asm/atomic.h:40:9: note: expanded from macro 'ATOMIC_OPS'
           return cmpxchg(&v->counter, o, n);                              \
                  ^
   arch/mips/include/asm/cmpxchg.h:194:7: note: expanded from macro 'cmpxchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from kernel/bounds.c:14:
   In file included from include/linux/spinlock_types.h:18:
   In file included from include/linux/lockdep.h:44:
   In file included from include/linux/debug_locks.h:6:
   In file included from include/linux/atomic.h:7:
...
> arch/mips/include/asm/atomic.h:49:1: warning: converting the
result of '<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]    arch/mips/include/asm/atomic.h:40:9: note:
expanded from macro 'ATOMIC_OPS'
           return cmpxchg(&v->counter, o, n);                              \
                  ^
   arch/mips/include/asm/cmpxchg.h:204:7: note: expanded from macro 'cmpxchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from kernel/bounds.c:14:
   In file included from include/linux/spinlock_types.h:18:
   In file included from include/linux/lockdep.h:44:
   In file included from include/linux/debug_locks.h:6:
   In file included from include/linux/atomic.h:7:
...
> arch/mips/include/asm/atomic.h:49:1: warning: converting the
result of '<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]    arch/mips/include/asm/atomic.h:45:9: note:
expanded from macro 'ATOMIC_OPS'
           return xchg(&v->counter, n);                                    \
                  ^
   arch/mips/include/asm/cmpxchg.h:102:7: note: expanded from macro 'xchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from kernel/bounds.c:14:
   In file included from include/linux/spinlock_types.h:18:
   In file included from include/linux/lockdep.h:44:
   In file included from include/linux/debug_locks.h:6:
   In file included from include/linux/atomic.h:7:
   arch/mips/include/asm/atomic.h:53:1: warning: converting the result of
'<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]
   ATOMIC_OPS(atomic64, s64)
   ^
   arch/mips/include/asm/atomic.h:40:9: note: expanded from macro 'ATOMIC_OPS'
           return cmpxchg(&v->counter, o, n);                              \
                  ^
   arch/mips/include/asm/cmpxchg.h:194:7: note: expanded from macro 'cmpxchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from kernel/bounds.c:14:
   In file included from include/linux/spinlock_types.h:18:
   In file included from include/linux/lockdep.h:44:
   In file included from include/linux/debug_locks.h:6:
   In file included from include/linux/atomic.h:7:
   arch/mips/include/asm/atomic.h:53:1: warning: converting the result of
'<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]
   arch/mips/include/asm/atomic.h:40:9: note: expanded from macro 'ATOMIC_OPS'
           return cmpxchg(&v->counter, o, n);                              \
                  ^
   arch/mips/include/asm/cmpxchg.h:204:7: note: expanded from macro 'cmpxchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from kernel/bounds.c:14:
   In file included from include/linux/spinlock_types.h:18:
   In file included from include/linux/lockdep.h:44:
   In file included from include/linux/debug_locks.h:6:
   In file included from include/linux/atomic.h:7:
   arch/mips/include/asm/atomic.h:53:1: warning: converting the result of
'<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]
   arch/mips/include/asm/atomic.h:45:9: note: expanded from macro 'ATOMIC_OPS'
           return xchg(&v->counter, n);                                    \
                  ^
   arch/mips/include/asm/cmpxchg.h:102:7: note: expanded from macro 'xchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from kernel/bounds.c:14:
   In file included from include/linux/spinlock_types.h:18:
   In file included from include/linux/lockdep.h:44:
   In file included from include/linux/debug_locks.h:6:
   In file included from include/linux/atomic.h:7:
   arch/mips/include/asm/atomic.h:258:1: warning: converting the result of
'<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]
   ATOMIC_SIP_OP(atomic, int, subu, ll, sc)
   ^
   arch/mips/include/asm/atomic.h:252:7: note: expanded from macro
'ATOMIC_SIP_OP'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from kernel/bounds.c:14:
   In file included from include/linux/spinlock_types.h:18:
   In file included from include/linux/lockdep.h:44:
   In file included from include/linux/debug_locks.h:6:
   In file included from include/linux/atomic.h:7:
   arch/mips/include/asm/atomic.h:262:1: warning: converting the result of
'<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]
   ATOMIC_SIP_OP(atomic64, s64, dsubu, lld, scd)
   ^
   arch/mips/include/asm/atomic.h:252:7: note: expanded from macro
'ATOMIC_SIP_OP'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from kernel/bounds.c:14:
   In file included from include/linux/spinlock_types.h:18:
   In file included from include/linux/lockdep.h:44:
...
> include/linux/debug_locks.h:17:9: warning: converting the result
of '<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]            return xchg(&debug_locks, 0);
                  ^
   arch/mips/include/asm/cmpxchg.h:102:7: note: expanded from macro 'xchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   9 warnings generated.
   In file included from arch/mips/kernel/asm-offsets.c:12:
   In file included from include/linux/compat.h:10:
   In file included from include/linux/time.h:6:
   In file included from include/linux/seqlock.h:36:
   In file included from include/linux/spinlock.h:51:
   In file included from include/linux/preempt.h:78:
   In file included from ./arch/mips/include/generated/asm/preempt.h:1:
   In file included from include/asm-generic/preempt.h:5:
   In file included from include/linux/thread_info.h:38:
   In file included from arch/mips/include/asm/thread_info.h:16:
   In file included from arch/mips/include/asm/processor.h:14:
   In file included from include/linux/atomic.h:7:
...
> arch/mips/include/asm/atomic.h:49:1: warning: converting the
result of '<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]    ATOMIC_OPS(atomic, int)
   ^
   arch/mips/include/asm/atomic.h:40:9: note: expanded from macro 'ATOMIC_OPS'
           return cmpxchg(&v->counter, o, n);                              \
                  ^
   arch/mips/include/asm/cmpxchg.h:194:7: note: expanded from macro 'cmpxchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from arch/mips/kernel/asm-offsets.c:12:
   In file included from include/linux/compat.h:10:
   In file included from include/linux/time.h:6:
   In file included from include/linux/seqlock.h:36:
   In file included from include/linux/spinlock.h:51:
   In file included from include/linux/preempt.h:78:
   In file included from ./arch/mips/include/generated/asm/preempt.h:1:
   In file included from include/asm-generic/preempt.h:5:
   In file included from include/linux/thread_info.h:38:
   In file included from arch/mips/include/asm/thread_info.h:16:
   In file included from arch/mips/include/asm/processor.h:14:
   In file included from include/linux/atomic.h:7:
...
> arch/mips/include/asm/atomic.h:49:1: warning: converting the
result of '<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]    arch/mips/include/asm/atomic.h:40:9: note:
expanded from macro 'ATOMIC_OPS'
           return cmpxchg(&v->counter, o, n);                              \
                  ^
   arch/mips/include/asm/cmpxchg.h:204:7: note: expanded from macro 'cmpxchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from arch/mips/kernel/asm-offsets.c:12:
   In file included from include/linux/compat.h:10:
   In file included from include/linux/time.h:6:
   In file included from include/linux/seqlock.h:36:
   In file included from include/linux/spinlock.h:51:
   In file included from include/linux/preempt.h:78:
   In file included from ./arch/mips/include/generated/asm/preempt.h:1:
   In file included from include/asm-generic/preempt.h:5:
   In file included from include/linux/thread_info.h:38:
   In file included from arch/mips/include/asm/thread_info.h:16:
   In file included from arch/mips/include/asm/processor.h:14:
   In file included from include/linux/atomic.h:7:
...
> arch/mips/include/asm/atomic.h:49:1: warning: converting the
result of '<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]    arch/mips/include/asm/atomic.h:45:9: note:
expanded from macro 'ATOMIC_OPS'
           return xchg(&v->counter, n);                                    \
                  ^
   arch/mips/include/asm/cmpxchg.h:102:7: note: expanded from macro 'xchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from arch/mips/kernel/asm-offsets.c:12:
   In file included from include/linux/compat.h:10:
   In file included from include/linux/time.h:6:
   In file included from include/linux/seqlock.h:36:
   In file included from include/linux/spinlock.h:51:
   In file included from include/linux/preempt.h:78:
   In file included from ./arch/mips/include/generated/asm/preempt.h:1:
   In file included from include/asm-generic/preempt.h:5:
   In file included from include/linux/thread_info.h:38:
   In file included from arch/mips/include/asm/thread_info.h:16:
   In file included from arch/mips/include/asm/processor.h:14:
   In file included from include/linux/atomic.h:7:
   arch/mips/include/asm/atomic.h:53:1: warning: converting the result of
'<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]
   ATOMIC_OPS(atomic64, s64)
   ^
   arch/mips/include/asm/atomic.h:40:9: note: expanded from macro 'ATOMIC_OPS'
           return cmpxchg(&v->counter, o, n);                              \
                  ^
   arch/mips/include/asm/cmpxchg.h:194:7: note: expanded from macro 'cmpxchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from arch/mips/kernel/asm-offsets.c:12:
   In file included from include/linux/compat.h:10:
   In file included from include/linux/time.h:6:
   In file included from include/linux/seqlock.h:36:
   In file included from include/linux/spinlock.h:51:
   In file included from include/linux/preempt.h:78:
   In file included from ./arch/mips/include/generated/asm/preempt.h:1:
   In file included from include/asm-generic/preempt.h:5:
   In file included from include/linux/thread_info.h:38:
   In file included from arch/mips/include/asm/thread_info.h:16:
   In file included from arch/mips/include/asm/processor.h:14:
   In file included from include/linux/atomic.h:7:
   arch/mips/include/asm/atomic.h:53:1: warning: converting the result of
'<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]
   arch/mips/include/asm/atomic.h:40:9: note: expanded from macro 'ATOMIC_OPS'
           return cmpxchg(&v->counter, o, n);                              \
                  ^
   arch/mips/include/asm/cmpxchg.h:204:7: note: expanded from macro 'cmpxchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from arch/mips/kernel/asm-offsets.c:12:
   In file included from include/linux/compat.h:10:
   In file included from include/linux/time.h:6:
   In file included from include/linux/seqlock.h:36:
   In file included from include/linux/spinlock.h:51:
   In file included from include/linux/preempt.h:78:
   In file included from ./arch/mips/include/generated/asm/preempt.h:1:
   In file included from include/asm-generic/preempt.h:5:
   In file included from include/linux/thread_info.h:38:
   In file included from arch/mips/include/asm/thread_info.h:16:
   In file included from arch/mips/include/asm/processor.h:14:
   In file included from include/linux/atomic.h:7:
   arch/mips/include/asm/atomic.h:53:1: warning: converting the result of
'<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]
   arch/mips/include/asm/atomic.h:45:9: note: expanded from macro 'ATOMIC_OPS'
           return xchg(&v->counter, n);                                    \
                  ^
   arch/mips/include/asm/cmpxchg.h:102:7: note: expanded from macro 'xchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from arch/mips/kernel/asm-offsets.c:12:
   In file included from include/linux/compat.h:10:
   In file included from include/linux/time.h:6:
   In file included from include/linux/seqlock.h:36:
   In file included from include/linux/spinlock.h:51:
   In file included from include/linux/preempt.h:78:
   In file included from ./arch/mips/include/generated/asm/preempt.h:1:
   In file included from include/asm-generic/preempt.h:5:
   In file included from include/linux/thread_info.h:38:
   In file included from arch/mips/include/asm/thread_info.h:16:
   In file included from arch/mips/include/asm/processor.h:14:
   In file included from include/linux/atomic.h:7:
   arch/mips/include/asm/atomic.h:258:1: warning: converting the result of
'<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]
   ATOMIC_SIP_OP(atomic, int, subu, ll, sc)
   ^
   arch/mips/include/asm/atomic.h:252:7: note: expanded from macro
'ATOMIC_SIP_OP'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from arch/mips/kernel/asm-offsets.c:12:
   In file included from include/linux/compat.h:10:
   In file included from include/linux/time.h:6:
   In file included from include/linux/seqlock.h:36:
   In file included from include/linux/spinlock.h:51:
   In file included from include/linux/preempt.h:78:
   In file included from ./arch/mips/include/generated/asm/preempt.h:1:
   In file included from include/asm-generic/preempt.h:5:
   In file included from include/linux/thread_info.h:38:
   In file included from arch/mips/include/asm/thread_info.h:16:
   In file included from arch/mips/include/asm/processor.h:14:
   In file included from include/linux/atomic.h:7:
   arch/mips/include/asm/atomic.h:262:1: warning: converting the result of
'<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]
   ATOMIC_SIP_OP(atomic64, s64, dsubu, lld, scd)
   ^
   arch/mips/include/asm/atomic.h:252:7: note: expanded from macro
'ATOMIC_SIP_OP'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from arch/mips/kernel/asm-offsets.c:12:
   In file included from include/linux/compat.h:10:
   In file included from include/linux/time.h:6:
   In file included from include/linux/seqlock.h:36:
   In file included from include/linux/spinlock.h:83:
   In file included from include/linux/spinlock_types.h:18:
   In file included from include/linux/lockdep.h:44:
...
> include/linux/debug_locks.h:17:9: warning: converting the result
of '<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]            return xchg(&debug_locks, 0);
                  ^
   arch/mips/include/asm/cmpxchg.h:102:7: note: expanded from macro 'xchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from arch/mips/kernel/asm-offsets.c:12:
   In file included from include/linux/compat.h:10:
   In file included from include/linux/time.h:74:
   In file included from include/linux/time32.h:13:
   In file included from include/linux/timex.h:65:
   In file included from arch/mips/include/asm/timex.h:19:
   In file included from arch/mips/include/asm/cpu-type.h:12:
   In file included from include/linux/smp.h:15:
...
> include/linux/llist.h:222:9: warning: converting the result of
'<<' to a boolean always evaluates to true [-Wtautological-constant-compare]
           return xchg(&head->first, NULL);
                  ^
   arch/mips/include/asm/cmpxchg.h:102:7: note: expanded from macro 'xchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from arch/mips/kernel/asm-offsets.c:12:
   In file included from include/linux/compat.h:15:
   In file included from include/linux/socket.h:8:
   In file included from include/linux/uio.h:10:
   In file included from include/crypto/hash.h:11:
   In file included from include/linux/crypto.h:19:
   In file included from include/linux/slab.h:15:
   In file included from include/linux/gfp.h:9:
   include/linux/topology.h:119:9: error: implicit declaration of function
'cpu_logical_map' [-Werror,-Wimplicit-function-declaration]
           return cpu_to_node(raw_smp_processor_id());
                  ^
   arch/mips/include/asm/mach-loongson64/topology.h:7:27: note: expanded from macro
'cpu_to_node'
   #define cpu_to_node(cpu)        (cpu_logical_map(cpu) >> 2)
                                    ^
   In file included from arch/mips/kernel/asm-offsets.c:12:
   In file included from include/linux/compat.h:15:
   In file included from include/linux/socket.h:8:
   In file included from include/linux/uio.h:10:
   In file included from include/crypto/hash.h:11:
   In file included from include/linux/crypto.h:19:
   In file included from include/linux/slab.h:15:
   In file included from include/linux/gfp.h:9:
   include/linux/topology.h:176:9: error: implicit declaration of function
'cpu_logical_map' [-Werror,-Wimplicit-function-declaration]
           return cpu_to_node(cpu);
                  ^
   arch/mips/include/asm/mach-loongson64/topology.h:7:27: note: expanded from macro
'cpu_to_node'
   #define cpu_to_node(cpu)        (cpu_logical_map(cpu) >> 2)
                                    ^
   In file included from arch/mips/kernel/asm-offsets.c:12:
   In file included from include/linux/compat.h:15:
   In file included from include/linux/socket.h:8:
   In file included from include/linux/uio.h:10:
   In file included from include/crypto/hash.h:11:
   In file included from include/linux/crypto.h:19:
   In file included from include/linux/slab.h:15:
   In file included from include/linux/gfp.h:9:
   include/linux/topology.h:210:25: error: implicit declaration of function
'cpu_logical_map' [-Werror,-Wimplicit-function-declaration]
           return cpumask_of_node(cpu_to_node(cpu));
                                  ^
   arch/mips/include/asm/mach-loongson64/topology.h:7:27: note: expanded from macro
'cpu_to_node'
   #define cpu_to_node(cpu)        (cpu_logical_map(cpu) >> 2)
                                    ^
   In file included from arch/mips/kernel/asm-offsets.c:15:
   In file included from include/linux/mm.h:95:
...
> arch/mips/include/asm/pgtable.h:210:3: warning: converting the
result of '<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]                    cmpxchg64(&buddy->pte,
0, _PAGE_GLOBAL);
                   ^
   arch/mips/include/asm/cmpxchg.h:220:2: note: expanded from macro 'cmpxchg64'
           cmpxchg((ptr), (o), (n));                                       \
           ^
   arch/mips/include/asm/cmpxchg.h:194:7: note: expanded from macro 'cmpxchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from arch/mips/kernel/asm-offsets.c:15:
   In file included from include/linux/mm.h:95:
...
> arch/mips/include/asm/pgtable.h:210:3: warning: converting the
result of '<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]    arch/mips/include/asm/cmpxchg.h:220:2: note:
expanded from macro 'cmpxchg64'
           cmpxchg((ptr), (o), (n));                                       \
           ^
   arch/mips/include/asm/cmpxchg.h:204:7: note: expanded from macro 'cmpxchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from arch/mips/kernel/asm-offsets.c:24:
...
> include/linux/kvm_host.h:332:9: warning: converting the result of
'<<' to a boolean always evaluates to true [-Wtautological-constant-compare]
           return cmpxchg(&vcpu->mode, IN_GUEST_MODE, EXITING_GUEST_MODE);
                  ^
   arch/mips/include/asm/cmpxchg.h:194:7: note: expanded from macro 'cmpxchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from arch/mips/kernel/asm-offsets.c:24:
...
> include/linux/kvm_host.h:332:9: warning: converting the result of
'<<' to a boolean always evaluates to true [-Wtautological-constant-compare]
   arch/mips/include/asm/cmpxchg.h:204:7: note: expanded from macro
'cmpxchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   arch/mips/kernel/asm-offsets.c:26:6: warning: no previous prototype for function
'output_ptreg_defines' [-Wmissing-prototypes]
   void output_ptreg_defines(void)
        ^
   arch/mips/kernel/asm-offsets.c:26:1: note: declare 'static' if the function is
not intended to be used outside of this translation unit
   void output_ptreg_defines(void)
   ^
   static 
   arch/mips/kernel/asm-offsets.c:78:6: warning: no previous prototype for function
'output_task_defines' [-Wmissing-prototypes]
   void output_task_defines(void)
        ^
   arch/mips/kernel/asm-offsets.c:78:1: note: declare 'static' if the function is
not intended to be used outside of this translation unit
   void output_task_defines(void)
   ^
   static 
   arch/mips/kernel/asm-offsets.c:93:6: warning: no previous prototype for function
'output_thread_info_defines' [-Wmissing-prototypes]
   void output_thread_info_defines(void)
        ^
   arch/mips/kernel/asm-offsets.c:93:1: note: declare 'static' if the function is
not intended to be used outside of this translation unit
   void output_thread_info_defines(void)
   ^
   static 
   arch/mips/kernel/asm-offsets.c:110:6: warning: no previous prototype for function
'output_thread_defines' [-Wmissing-prototypes]
   void output_thread_defines(void)
        ^
   arch/mips/kernel/asm-offsets.c:110:1: note: declare 'static' if the function is
not intended to be used outside of this translation unit
   void output_thread_defines(void)
   ^
   static 
   arch/mips/kernel/asm-offsets.c:181:6: warning: no previous prototype for function
'output_mm_defines' [-Wmissing-prototypes]
   void output_mm_defines(void)
        ^
   arch/mips/kernel/asm-offsets.c:181:1: note: declare 'static' if the function is
not intended to be used outside of this translation unit
   void output_mm_defines(void)
   ^
   static 
   arch/mips/kernel/asm-offsets.c:242:6: warning: no previous prototype for function
'output_sc_defines' [-Wmissing-prototypes]
   void output_sc_defines(void)
        ^
   arch/mips/kernel/asm-offsets.c:242:1: note: declare 'static' if the function is
not intended to be used outside of this translation unit
   void output_sc_defines(void)
   ^
   static 
   arch/mips/kernel/asm-offsets.c:255:6: warning: no previous prototype for function
'output_signal_defined' [-Wmissing-prototypes]
   void output_signal_defined(void)
        ^
   arch/mips/kernel/asm-offsets.c:255:1: note: declare 'static' if the function is
not intended to be used outside of this translation unit
   void output_signal_defined(void)
   ^
   static 
   arch/mips/kernel/asm-offsets.c:322:6: warning: no previous prototype for function
'output_pbe_defines' [-Wmissing-prototypes]
   void output_pbe_defines(void)
        ^
   arch/mips/kernel/asm-offsets.c:322:1: note: declare 'static' if the function is
not intended to be used outside of this translation unit
   void output_pbe_defines(void)
   ^
   static 
   22 warnings and 3 errors generated.
   make[2]: *** [scripts/Makefile.build:101: arch/mips/kernel/asm-offsets.s] Error 1
   make[2]: Target 'missing-syscalls' not remade because of errors.
   make[1]: *** [arch/mips/Makefile:414: archprepare] Error 2
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:180: sub-make] Error 2
   make: Target 'prepare' not remade because of errors.

#
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit...
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout afe956c577b2d5a3d9834e4424587c1ebcf90c4c
vim +49 arch/mips/include/asm/atomic.h

^1da177e4c3f41 include/asm-mips/atomic.h      Linus Torvalds 2005-04-16  47  
1da7bce8591d58 arch/mips/include/asm/atomic.h Paul Burton    2019-10-01  48  #define
ATOMIC_INIT(i)		{ (i) }
1da7bce8591d58 arch/mips/include/asm/atomic.h Paul Burton    2019-10-01 @49 
ATOMIC_OPS(atomic, int)
^1da177e4c3f41 include/asm-mips/atomic.h      Linus Torvalds 2005-04-16  50  

:::::: The code at line 49 was first introduced by commit
:::::: 1da7bce8591d58bf2a442b0324659af7390401c2 MIPS: atomic: Deduplicate 32b & 64b
read, set, xchg, cmpxchg

:::::: TO: Paul Burton <paul.burton(a)mips.com&gt;
:::::: CC: Paul Burton <paul.burton(a)mips.com&gt;

---
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https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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[kbuild-all] arch/mips/include/asm/atomic.h:49:1: warning: converting the result of '<<' to a boolean always evaluates to true