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x86, bitops: remove use of "sbb" to return CF

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Use SETC instead of SBB to return the value of CF from assembly. Using
SETcc enables uniformity with other flags-returning pieces of assembly
code.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1465414726-197858-2-git-send-email-hpa@linux.intel.com
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
This commit is contained in:
H. Peter Anvin
2016-06-08 12:38:37 -07:00
committed by H. Peter Anvin
parent f5967101e9
commit 2823d4da5d
5 changed files with 31 additions and 34 deletions
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12
arch/x86/include/asm/percpu.h
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@@ -510,9 +510,9 @@ do { \
/* This is not atomic against other CPUs -- CPU preemption needs to be off */
#define x86_test_and_clear_bit_percpu(bit, var) \
({ \
int old__; \
asm volatile("btr %2,"__percpu_arg(1)"\n\tsbbl %0,%0" \
: "=r" (old__), "+m" (var) \
unsigned char old__; \
asm volatile("btr %2,"__percpu_arg(1)"\n\tsetc %0" \
: "=qm" (old__), "+m" (var) \
: "dIr" (bit)); \
old__; \
})
@@ -532,11 +532,11 @@ static __always_inline int x86_this_cpu_constant_test_bit(unsigned int nr,
static inline int x86_this_cpu_variable_test_bit(int nr,
const unsigned long __percpu *addr)
{
int oldbit;
unsigned char oldbit;
asm volatile("bt "__percpu_arg(2)",%1\n\t"
"sbb %0,%0"
: "=r" (oldbit)
"setc %0"
: "=qm" (oldbit)
: "m" (*(unsigned long *)addr), "Ir" (nr));
return oldbit;