[PATCH v2 01/10] x86, bitops: remove use of "sbb" to return CF
From: H. Peter Anvin
Date: Wed Jun 08 2016 - 15:38:59 EST
From: "H. Peter Anvin" <hpa@xxxxxxxxx>
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@xxxxxxxxx>
Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
arch/x86/include/asm/bitops.h | 24 ++++++++++++------------
arch/x86/include/asm/percpu.h | 12 ++++++------
arch/x86/include/asm/signal.h | 6 +++---
arch/x86/include/asm/sync_bitops.h | 18 +++++++++---------
arch/x86/kernel/vm86_32.c | 5 +----
5 files changed, 31 insertions(+), 34 deletions(-)
diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h
index 7766d1c..b2b797d 100644
--- a/arch/x86/include/asm/bitops.h
+++ b/arch/x86/include/asm/bitops.h
@@ -230,11 +230,11 @@ test_and_set_bit_lock(long nr, volatile unsigned long *addr)
*/
static __always_inline int __test_and_set_bit(long nr, volatile unsigned long *addr)
{
- int oldbit;
+ unsigned char oldbit;
asm("bts %2,%1\n\t"
- "sbb %0,%0"
- : "=r" (oldbit), ADDR
+ "setc %0"
+ : "=qm" (oldbit), ADDR
: "Ir" (nr));
return oldbit;
}
@@ -270,11 +270,11 @@ static __always_inline int test_and_clear_bit(long nr, volatile unsigned long *a
*/
static __always_inline int __test_and_clear_bit(long nr, volatile unsigned long *addr)
{
- int oldbit;
+ unsigned char oldbit;
asm volatile("btr %2,%1\n\t"
- "sbb %0,%0"
- : "=r" (oldbit), ADDR
+ "setc %0"
+ : "=qm" (oldbit), ADDR
: "Ir" (nr));
return oldbit;
}
@@ -282,11 +282,11 @@ static __always_inline int __test_and_clear_bit(long nr, volatile unsigned long
/* WARNING: non atomic and it can be reordered! */
static __always_inline int __test_and_change_bit(long nr, volatile unsigned long *addr)
{
- int oldbit;
+ unsigned char oldbit;
asm volatile("btc %2,%1\n\t"
- "sbb %0,%0"
- : "=r" (oldbit), ADDR
+ "setc %0"
+ : "=qm" (oldbit), ADDR
: "Ir" (nr) : "memory");
return oldbit;
@@ -313,11 +313,11 @@ static __always_inline int constant_test_bit(long nr, const volatile unsigned lo
static __always_inline int variable_test_bit(long nr, volatile const unsigned long *addr)
{
- int oldbit;
+ unsigned char oldbit;
asm volatile("bt %2,%1\n\t"
- "sbb %0,%0"
- : "=r" (oldbit)
+ "setc %0"
+ : "=qm" (oldbit)
: "m" (*(unsigned long *)addr), "Ir" (nr));
return oldbit;
diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index e0ba66c..65039e9 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -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;
diff --git a/arch/x86/include/asm/signal.h b/arch/x86/include/asm/signal.h
index 2138c9a..dd1e7d6 100644
--- a/arch/x86/include/asm/signal.h
+++ b/arch/x86/include/asm/signal.h
@@ -81,9 +81,9 @@ static inline int __const_sigismember(sigset_t *set, int _sig)
static inline int __gen_sigismember(sigset_t *set, int _sig)
{
- int ret;
- asm("btl %2,%1\n\tsbbl %0,%0"
- : "=r"(ret) : "m"(*set), "Ir"(_sig-1) : "cc");
+ unsigned char ret;
+ asm("btl %2,%1\n\tsetc %0"
+ : "=qm"(ret) : "m"(*set), "Ir"(_sig-1) : "cc");
return ret;
}
diff --git a/arch/x86/include/asm/sync_bitops.h b/arch/x86/include/asm/sync_bitops.h
index f28a24b..cbf8847 100644
--- a/arch/x86/include/asm/sync_bitops.h
+++ b/arch/x86/include/asm/sync_bitops.h
@@ -79,10 +79,10 @@ static inline void sync_change_bit(long nr, volatile unsigned long *addr)
*/
static inline int sync_test_and_set_bit(long nr, volatile unsigned long *addr)
{
- int oldbit;
+ unsigned char oldbit;
- asm volatile("lock; bts %2,%1\n\tsbbl %0,%0"
- : "=r" (oldbit), "+m" (ADDR)
+ asm volatile("lock; bts %2,%1\n\tsetc %0"
+ : "=qm" (oldbit), "+m" (ADDR)
: "Ir" (nr) : "memory");
return oldbit;
}
@@ -97,10 +97,10 @@ static inline int sync_test_and_set_bit(long nr, volatile unsigned long *addr)
*/
static inline int sync_test_and_clear_bit(long nr, volatile unsigned long *addr)
{
- int oldbit;
+ unsigned char oldbit;
- asm volatile("lock; btr %2,%1\n\tsbbl %0,%0"
- : "=r" (oldbit), "+m" (ADDR)
+ asm volatile("lock; btr %2,%1\n\tsetc %0"
+ : "=qm" (oldbit), "+m" (ADDR)
: "Ir" (nr) : "memory");
return oldbit;
}
@@ -115,10 +115,10 @@ static inline int sync_test_and_clear_bit(long nr, volatile unsigned long *addr)
*/
static inline int sync_test_and_change_bit(long nr, volatile unsigned long *addr)
{
- int oldbit;
+ unsigned char oldbit;
- asm volatile("lock; btc %2,%1\n\tsbbl %0,%0"
- : "=r" (oldbit), "+m" (ADDR)
+ asm volatile("lock; btc %2,%1\n\tsetc %0"
+ : "=qm" (oldbit), "+m" (ADDR)
: "Ir" (nr) : "memory");
return oldbit;
}
diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index 3dce1ca..01f30e5 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -440,10 +440,7 @@ static inline unsigned long get_vflags(struct kernel_vm86_regs *regs)
static inline int is_revectored(int nr, struct revectored_struct *bitmap)
{
- __asm__ __volatile__("btl %2,%1\n\tsbbl %0,%0"
- :"=r" (nr)
- :"m" (*bitmap), "r" (nr));
- return nr;
+ return test_bit(nr, bitmap->__map);
}
#define val_byte(val, n) (((__u8 *)&val)[n])
--
2.7.3.0.11.gd79db92