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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ALPHA_CMPXCHG_H
#error Do not include xchg.h directly!
#else
/*
* xchg/xchg_local and cmpxchg/cmpxchg_local share the same code
* except that local version do not have the expensive memory barrier.
* So this file is included twice from asm/cmpxchg.h.
*/
/*
* Atomic exchange.
* Since it can be used to implement critical sections
* it must clobber "memory" (also for interrupts in UP).
*/
static inline unsigned long
____xchg(_u8, volatile char *m, unsigned long val)
{
unsigned long ret, tmp, addr64;
__asm__ __volatile__(
" andnot %4,7,%3\n"
" insbl %1,%4,%1\n"
"1: ldq_l %2,0(%3)\n"
" extbl %2,%4,%0\n"
" mskbl %2,%4,%2\n"
" or %1,%2,%2\n"
" stq_c %2,0(%3)\n"
" beq %2,2f\n"
__ASM__MB
".subsection 2\n"
"2: br 1b\n"
".previous"
: "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64)
: "r" ((long)m), "1" (val) : "memory");
return ret;
}
static inline unsigned long
____xchg(_u16, volatile short *m, unsigned long val)
{
unsigned long ret, tmp, addr64;
__asm__ __volatile__(
" andnot %4,7,%3\n"
" inswl %1,%4,%1\n"
"1: ldq_l %2,0(%3)\n"
" extwl %2,%4,%0\n"
" mskwl %2,%4,%2\n"
" or %1,%2,%2\n"
" stq_c %2,0(%3)\n"
" beq %2,2f\n"
__ASM__MB
".subsection 2\n"
"2: br 1b\n"
".previous"
: "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64)
: "r" ((long)m), "1" (val) : "memory");
return ret;
}
static inline unsigned long
____xchg(_u32, volatile int *m, unsigned long val)
{
unsigned long dummy;
__asm__ __volatile__(
"1: ldl_l %0,%4\n"
" bis $31,%3,%1\n"
" stl_c %1,%2\n"
" beq %1,2f\n"
__ASM__MB
".subsection 2\n"
"2: br 1b\n"
".previous"
: "=&r" (val), "=&r" (dummy), "=m" (*m)
: "rI" (val), "m" (*m) : "memory");
return val;
}
static inline unsigned long
____xchg(_u64, volatile long *m, unsigned long val)
{
unsigned long dummy;
__asm__ __volatile__(
"1: ldq_l %0,%4\n"
" bis $31,%3,%1\n"
" stq_c %1,%2\n"
" beq %1,2f\n"
__ASM__MB
".subsection 2\n"
"2: br 1b\n"
".previous"
: "=&r" (val), "=&r" (dummy), "=m" (*m)
: "rI" (val), "m" (*m) : "memory");
return val;
}
/* This function doesn't exist, so you'll get a linker error
if something tries to do an invalid xchg(). */
extern void __xchg_called_with_bad_pointer(void);
static __always_inline unsigned long
____xchg(, volatile void *ptr, unsigned long x, int size)
{
switch (size) {
case 1:
return ____xchg(_u8, ptr, x);
case 2:
return ____xchg(_u16, ptr, x);
case 4:
return ____xchg(_u32, ptr, x);
case 8:
return ____xchg(_u64, ptr, x);
}
__xchg_called_with_bad_pointer();
return x;
}
/*
* Atomic compare and exchange. Compare OLD with MEM, if identical,
* store NEW in MEM. Return the initial value in MEM. Success is
* indicated by comparing RETURN with OLD.
*
* The memory barrier should be placed in SMP only when we actually
* make the change. If we don't change anything (so if the returned
* prev is equal to old) then we aren't acquiring anything new and
* we don't need any memory barrier as far I can tell.
*/
static inline unsigned long
____cmpxchg(_u8, volatile char *m, unsigned char old, unsigned char new)
{
unsigned long prev, tmp, cmp, addr64;
__asm__ __volatile__(
" andnot %5,7,%4\n"
" insbl %1,%5,%1\n"
"1: ldq_l %2,0(%4)\n"
" extbl %2,%5,%0\n"
" cmpeq %0,%6,%3\n"
" beq %3,2f\n"
" mskbl %2,%5,%2\n"
" or %1,%2,%2\n"
" stq_c %2,0(%4)\n"
" beq %2,3f\n"
__ASM__MB
"2:\n"
".subsection 2\n"
"3: br 1b\n"
".previous"
: "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64)
: "r" ((long)m), "Ir" (old), "1" (new) : "memory");
return prev;
}
static inline unsigned long
____cmpxchg(_u16, volatile short *m, unsigned short old, unsigned short new)
{
unsigned long prev, tmp, cmp, addr64;
__asm__ __volatile__(
" andnot %5,7,%4\n"
" inswl %1,%5,%1\n"
"1: ldq_l %2,0(%4)\n"
" extwl %2,%5,%0\n"
" cmpeq %0,%6,%3\n"
" beq %3,2f\n"
" mskwl %2,%5,%2\n"
" or %1,%2,%2\n"
" stq_c %2,0(%4)\n"
" beq %2,3f\n"
__ASM__MB
"2:\n"
".subsection 2\n"
"3: br 1b\n"
".previous"
: "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64)
: "r" ((long)m), "Ir" (old), "1" (new) : "memory");
return prev;
}
static inline unsigned long
____cmpxchg(_u32, volatile int *m, int old, int new)
{
unsigned long prev, cmp;
__asm__ __volatile__(
"1: ldl_l %0,%5\n"
" cmpeq %0,%3,%1\n"
" beq %1,2f\n"
" mov %4,%1\n"
" stl_c %1,%2\n"
" beq %1,3f\n"
__ASM__MB
"2:\n"
".subsection 2\n"
"3: br 1b\n"
".previous"
: "=&r"(prev), "=&r"(cmp), "=m"(*m)
: "r"((long) old), "r"(new), "m"(*m) : "memory");
return prev;
}
static inline unsigned long
____cmpxchg(_u64, volatile long *m, unsigned long old, unsigned long new)
{
unsigned long prev, cmp;
__asm__ __volatile__(
"1: ldq_l %0,%5\n"
" cmpeq %0,%3,%1\n"
" beq %1,2f\n"
" mov %4,%1\n"
" stq_c %1,%2\n"
" beq %1,3f\n"
__ASM__MB
"2:\n"
".subsection 2\n"
"3: br 1b\n"
".previous"
: "=&r"(prev), "=&r"(cmp), "=m"(*m)
: "r"((long) old), "r"(new), "m"(*m) : "memory");
return prev;
}
/* This function doesn't exist, so you'll get a linker error
if something tries to do an invalid cmpxchg(). */
extern void __cmpxchg_called_with_bad_pointer(void);
static __always_inline unsigned long
____cmpxchg(, volatile void *ptr, unsigned long old, unsigned long new,
int size)
{
switch (size) {
case 1:
return ____cmpxchg(_u8, ptr, old, new);
case 2:
return ____cmpxchg(_u16, ptr, old, new);
case 4:
return ____cmpxchg(_u32, ptr, old, new);
case 8:
return ____cmpxchg(_u64, ptr, old, new);
}
__cmpxchg_called_with_bad_pointer();
return old;
}
#endif
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