i386: improve and correct inline asm memory constraints
Use "+m" rather than a combination of "=m" and "m" for improved clarity
and consistency.
This also fixes some inlines that incorrectly didn't tell the compiler
that they read the old value at all, potentially causing the compiler to
generate bogus code. It appear that all of those potential bugs were
hidden by the use of extra "volatile" specifiers on the data structures
in question, though.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/asm-i386/atomic.h b/include/asm-i386/atomic.h
index 4f061fa..51a1662 100644
--- a/include/asm-i386/atomic.h
+++ b/include/asm-i386/atomic.h
@@ -46,8 +46,8 @@
{
__asm__ __volatile__(
LOCK_PREFIX "addl %1,%0"
- :"=m" (v->counter)
- :"ir" (i), "m" (v->counter));
+ :"+m" (v->counter)
+ :"ir" (i));
}
/**
@@ -61,8 +61,8 @@
{
__asm__ __volatile__(
LOCK_PREFIX "subl %1,%0"
- :"=m" (v->counter)
- :"ir" (i), "m" (v->counter));
+ :"+m" (v->counter)
+ :"ir" (i));
}
/**
@@ -80,8 +80,8 @@
__asm__ __volatile__(
LOCK_PREFIX "subl %2,%0; sete %1"
- :"=m" (v->counter), "=qm" (c)
- :"ir" (i), "m" (v->counter) : "memory");
+ :"+m" (v->counter), "=qm" (c)
+ :"ir" (i) : "memory");
return c;
}
@@ -95,8 +95,7 @@
{
__asm__ __volatile__(
LOCK_PREFIX "incl %0"
- :"=m" (v->counter)
- :"m" (v->counter));
+ :"+m" (v->counter));
}
/**
@@ -109,8 +108,7 @@
{
__asm__ __volatile__(
LOCK_PREFIX "decl %0"
- :"=m" (v->counter)
- :"m" (v->counter));
+ :"+m" (v->counter));
}
/**
@@ -127,8 +125,8 @@
__asm__ __volatile__(
LOCK_PREFIX "decl %0; sete %1"
- :"=m" (v->counter), "=qm" (c)
- :"m" (v->counter) : "memory");
+ :"+m" (v->counter), "=qm" (c)
+ : : "memory");
return c != 0;
}
@@ -146,8 +144,8 @@
__asm__ __volatile__(
LOCK_PREFIX "incl %0; sete %1"
- :"=m" (v->counter), "=qm" (c)
- :"m" (v->counter) : "memory");
+ :"+m" (v->counter), "=qm" (c)
+ : : "memory");
return c != 0;
}
@@ -166,8 +164,8 @@
__asm__ __volatile__(
LOCK_PREFIX "addl %2,%0; sets %1"
- :"=m" (v->counter), "=qm" (c)
- :"ir" (i), "m" (v->counter) : "memory");
+ :"+m" (v->counter), "=qm" (c)
+ :"ir" (i) : "memory");
return c;
}
diff --git a/include/asm-i386/futex.h b/include/asm-i386/futex.h
index 7b8ceef..946d97c 100644
--- a/include/asm-i386/futex.h
+++ b/include/asm-i386/futex.h
@@ -20,8 +20,8 @@
.align 8\n\
.long 1b,3b\n\
.previous" \
- : "=r" (oldval), "=r" (ret), "=m" (*uaddr) \
- : "i" (-EFAULT), "m" (*uaddr), "0" (oparg), "1" (0))
+ : "=r" (oldval), "=r" (ret), "+m" (*uaddr) \
+ : "i" (-EFAULT), "0" (oparg), "1" (0))
#define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \
__asm__ __volatile ( \
@@ -38,9 +38,9 @@
.align 8\n\
.long 1b,4b,2b,4b\n\
.previous" \
- : "=&a" (oldval), "=&r" (ret), "=m" (*uaddr), \
+ : "=&a" (oldval), "=&r" (ret), "+m" (*uaddr), \
"=&r" (tem) \
- : "r" (oparg), "i" (-EFAULT), "m" (*uaddr), "1" (0))
+ : "r" (oparg), "i" (-EFAULT), "1" (0))
static inline int
futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
@@ -123,7 +123,7 @@
" .long 1b,3b \n"
" .previous \n"
- : "=a" (oldval), "=m" (*uaddr)
+ : "=a" (oldval), "+m" (*uaddr)
: "i" (-EFAULT), "r" (newval), "0" (oldval)
: "memory"
);
diff --git a/include/asm-i386/local.h b/include/asm-i386/local.h
index 3b4998c..12060e2 100644
--- a/include/asm-i386/local.h
+++ b/include/asm-i386/local.h
@@ -17,32 +17,30 @@
{
__asm__ __volatile__(
"incl %0"
- :"=m" (v->counter)
- :"m" (v->counter));
+ :"+m" (v->counter));
}
static __inline__ void local_dec(local_t *v)
{
__asm__ __volatile__(
"decl %0"
- :"=m" (v->counter)
- :"m" (v->counter));
+ :"+m" (v->counter));
}
static __inline__ void local_add(long i, local_t *v)
{
__asm__ __volatile__(
"addl %1,%0"
- :"=m" (v->counter)
- :"ir" (i), "m" (v->counter));
+ :"+m" (v->counter)
+ :"ir" (i));
}
static __inline__ void local_sub(long i, local_t *v)
{
__asm__ __volatile__(
"subl %1,%0"
- :"=m" (v->counter)
- :"ir" (i), "m" (v->counter));
+ :"+m" (v->counter)
+ :"ir" (i));
}
/* On x86, these are no better than the atomic variants. */
diff --git a/include/asm-i386/posix_types.h b/include/asm-i386/posix_types.h
index 4e47ed0..133e31e 100644
--- a/include/asm-i386/posix_types.h
+++ b/include/asm-i386/posix_types.h
@@ -51,12 +51,12 @@
#undef __FD_SET
#define __FD_SET(fd,fdsetp) \
__asm__ __volatile__("btsl %1,%0": \
- "=m" (*(__kernel_fd_set *) (fdsetp)):"r" ((int) (fd)))
+ "+m" (*(__kernel_fd_set *) (fdsetp)):"r" ((int) (fd)))
#undef __FD_CLR
#define __FD_CLR(fd,fdsetp) \
__asm__ __volatile__("btrl %1,%0": \
- "=m" (*(__kernel_fd_set *) (fdsetp)):"r" ((int) (fd)))
+ "+m" (*(__kernel_fd_set *) (fdsetp)):"r" ((int) (fd)))
#undef __FD_ISSET
#define __FD_ISSET(fd,fdsetp) (__extension__ ({ \
diff --git a/include/asm-i386/rwlock.h b/include/asm-i386/rwlock.h
index 94f0019..96b0bef 100644
--- a/include/asm-i386/rwlock.h
+++ b/include/asm-i386/rwlock.h
@@ -37,7 +37,7 @@
"popl %%eax\n\t" \
"1:\n", \
"subl $1,%0\n\t", \
- "=m" (*(volatile int *)rw) : : "memory")
+ "+m" (*(volatile int *)rw) : : "memory")
#define __build_read_lock(rw, helper) do { \
if (__builtin_constant_p(rw)) \
@@ -63,7 +63,7 @@
"popl %%eax\n\t" \
"1:\n", \
"subl $" RW_LOCK_BIAS_STR ",%0\n\t", \
- "=m" (*(volatile int *)rw) : : "memory")
+ "+m" (*(volatile int *)rw) : : "memory")
#define __build_write_lock(rw, helper) do { \
if (__builtin_constant_p(rw)) \
diff --git a/include/asm-i386/rwsem.h b/include/asm-i386/rwsem.h
index 2f07601..43113f5 100644
--- a/include/asm-i386/rwsem.h
+++ b/include/asm-i386/rwsem.h
@@ -111,8 +111,8 @@
" jmp 1b\n"
LOCK_SECTION_END
"# ending down_read\n\t"
- : "=m"(sem->count)
- : "a"(sem), "m"(sem->count)
+ : "+m" (sem->count)
+ : "a" (sem)
: "memory", "cc");
}
@@ -133,8 +133,8 @@
" jnz 1b\n\t"
"2:\n\t"
"# ending __down_read_trylock\n\t"
- : "+m"(sem->count), "=&a"(result), "=&r"(tmp)
- : "i"(RWSEM_ACTIVE_READ_BIAS)
+ : "+m" (sem->count), "=&a" (result), "=&r" (tmp)
+ : "i" (RWSEM_ACTIVE_READ_BIAS)
: "memory", "cc");
return result>=0 ? 1 : 0;
}
@@ -161,8 +161,8 @@
" jmp 1b\n"
LOCK_SECTION_END
"# ending down_write"
- : "=m"(sem->count), "=d"(tmp)
- : "a"(sem), "1"(tmp), "m"(sem->count)
+ : "+m" (sem->count), "=d" (tmp)
+ : "a" (sem), "1" (tmp)
: "memory", "cc");
}
@@ -205,8 +205,8 @@
" jmp 1b\n"
LOCK_SECTION_END
"# ending __up_read\n"
- : "=m"(sem->count), "=d"(tmp)
- : "a"(sem), "1"(tmp), "m"(sem->count)
+ : "+m" (sem->count), "=d" (tmp)
+ : "a" (sem), "1" (tmp)
: "memory", "cc");
}
@@ -231,8 +231,8 @@
" jmp 1b\n"
LOCK_SECTION_END
"# ending __up_write\n"
- : "=m"(sem->count)
- : "a"(sem), "i"(-RWSEM_ACTIVE_WRITE_BIAS), "m"(sem->count)
+ : "+m" (sem->count)
+ : "a" (sem), "i" (-RWSEM_ACTIVE_WRITE_BIAS)
: "memory", "cc", "edx");
}
@@ -256,8 +256,8 @@
" jmp 1b\n"
LOCK_SECTION_END
"# ending __downgrade_write\n"
- : "=m"(sem->count)
- : "a"(sem), "i"(-RWSEM_WAITING_BIAS), "m"(sem->count)
+ : "+m" (sem->count)
+ : "a" (sem), "i" (-RWSEM_WAITING_BIAS)
: "memory", "cc");
}
@@ -268,8 +268,8 @@
{
__asm__ __volatile__(
LOCK_PREFIX "addl %1,%0"
- : "=m"(sem->count)
- : "ir"(delta), "m"(sem->count));
+ : "+m" (sem->count)
+ : "ir" (delta));
}
/*
@@ -280,10 +280,9 @@
int tmp = delta;
__asm__ __volatile__(
-LOCK_PREFIX "xadd %0,(%2)"
- : "+r"(tmp), "=m"(sem->count)
- : "r"(sem), "m"(sem->count)
- : "memory");
+LOCK_PREFIX "xadd %0,%1"
+ : "+r" (tmp), "+m" (sem->count)
+ : : "memory");
return tmp+delta;
}
diff --git a/include/asm-i386/semaphore.h b/include/asm-i386/semaphore.h
index f7a0f31..d51e800 100644
--- a/include/asm-i386/semaphore.h
+++ b/include/asm-i386/semaphore.h
@@ -107,7 +107,7 @@
"call __down_failed\n\t"
"jmp 1b\n"
LOCK_SECTION_END
- :"=m" (sem->count)
+ :"+m" (sem->count)
:
:"memory","ax");
}
@@ -132,7 +132,7 @@
"call __down_failed_interruptible\n\t"
"jmp 1b\n"
LOCK_SECTION_END
- :"=a" (result), "=m" (sem->count)
+ :"=a" (result), "+m" (sem->count)
:
:"memory");
return result;
@@ -157,7 +157,7 @@
"call __down_failed_trylock\n\t"
"jmp 1b\n"
LOCK_SECTION_END
- :"=a" (result), "=m" (sem->count)
+ :"=a" (result), "+m" (sem->count)
:
:"memory");
return result;
@@ -182,7 +182,7 @@
"jmp 1b\n"
LOCK_SECTION_END
".subsection 0\n"
- :"=m" (sem->count)
+ :"+m" (sem->count)
:
:"memory","ax");
}
diff --git a/include/asm-i386/spinlock.h b/include/asm-i386/spinlock.h
index 87c40f8..d816c62 100644
--- a/include/asm-i386/spinlock.h
+++ b/include/asm-i386/spinlock.h
@@ -65,7 +65,7 @@
alternative_smp(
__raw_spin_lock_string,
__raw_spin_lock_string_up,
- "=m" (lock->slock) : : "memory");
+ "+m" (lock->slock) : : "memory");
}
/*
@@ -79,7 +79,7 @@
alternative_smp(
__raw_spin_lock_string_flags,
__raw_spin_lock_string_up,
- "=m" (lock->slock) : "r" (flags) : "memory");
+ "+m" (lock->slock) : "r" (flags) : "memory");
}
#endif
@@ -88,7 +88,7 @@
char oldval;
__asm__ __volatile__(
"xchgb %b0,%1"
- :"=q" (oldval), "=m" (lock->slock)
+ :"=q" (oldval), "+m" (lock->slock)
:"0" (0) : "memory");
return oldval > 0;
}
@@ -104,7 +104,7 @@
#define __raw_spin_unlock_string \
"movb $1,%0" \
- :"=m" (lock->slock) : : "memory"
+ :"+m" (lock->slock) : : "memory"
static inline void __raw_spin_unlock(raw_spinlock_t *lock)
@@ -118,7 +118,7 @@
#define __raw_spin_unlock_string \
"xchgb %b0, %1" \
- :"=q" (oldval), "=m" (lock->slock) \
+ :"=q" (oldval), "+m" (lock->slock) \
:"0" (oldval) : "memory"
static inline void __raw_spin_unlock(raw_spinlock_t *lock)
@@ -199,13 +199,13 @@
static inline void __raw_read_unlock(raw_rwlock_t *rw)
{
- asm volatile(LOCK_PREFIX "incl %0" :"=m" (rw->lock) : : "memory");
+ asm volatile(LOCK_PREFIX "incl %0" :"+m" (rw->lock) : : "memory");
}
static inline void __raw_write_unlock(raw_rwlock_t *rw)
{
asm volatile(LOCK_PREFIX "addl $" RW_LOCK_BIAS_STR ", %0"
- : "=m" (rw->lock) : : "memory");
+ : "+m" (rw->lock) : : "memory");
}
#endif /* __ASM_SPINLOCK_H */
