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/*
* Based on arch/arm/include/asm/cmpxchg.h
*
* Copyright (C) 2012 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ASM_CMPXCHG_H
#define __ASM_CMPXCHG_H
#include <linux/build_bug.h>
#include <linux/compiler.h>
#include <asm/atomic.h>
#include <asm/barrier.h>
#include <asm/lse.h>
/*
* We need separate acquire parameters for ll/sc and lse, since the full
* barrier case is generated as release+dmb for the former and
* acquire+release for the latter.
*/
#define __XCHG_CASE(w, sfx, name, sz, mb, nop_lse, acq, acq_lse, rel, cl) \
static inline u##sz __xchg_case_##name##sz(u##sz x, volatile void *ptr) \
{ \
u##sz ret; \
unsigned long tmp; \
\
asm volatile(ARM64_LSE_ATOMIC_INSN( \
/* LL/SC */ \
" prfm pstl1strm, %2\n" \
"1: ld" #acq "xr" #sfx "\t%" #w "0, %2\n" \
" st" #rel "xr" #sfx "\t%w1, %" #w "3, %2\n" \
" cbnz %w1, 1b\n" \
" " #mb, \
/* LSE atomics */ \
" swp" #acq_lse #rel #sfx "\t%" #w "3, %" #w "0, %2\n" \
__nops(3) \
" " #nop_lse) \
: "=&r" (ret), "=&r" (tmp), "+Q" (*(u##sz *)ptr) \
: "r" (x) \
: cl); \
\
return ret; \
}
__XCHG_CASE(w, b, , 8, , , , , , )
__XCHG_CASE(w, h, , 16, , , , , , )
__XCHG_CASE(w, , , 32, , , , , , )
__XCHG_CASE( , , , 64, , , , , , )
__XCHG_CASE(w, b, acq_, 8, , , a, a, , "memory")
__XCHG_CASE(w, h, acq_, 16, , , a, a, , "memory")
__XCHG_CASE(w, , acq_, 32, , , a, a, , "memory")
__XCHG_CASE( , , acq_, 64, , , a, a, , "memory")
__XCHG_CASE(w, b, rel_, 8, , , , , l, "memory")
__XCHG_CASE(w, h, rel_, 16, , , , , l, "memory")
__XCHG_CASE(w, , rel_, 32, , , , , l, "memory")
__XCHG_CASE( , , rel_, 64, , , , , l, "memory")
__XCHG_CASE(w, b, mb_, 8, dmb ish, nop, , a, l, "memory")
__XCHG_CASE(w, h, mb_, 16, dmb ish, nop, , a, l, "memory")
__XCHG_CASE(w, , mb_, 32, dmb ish, nop, , a, l, "memory")
__XCHG_CASE( , , mb_, 64, dmb ish, nop, , a, l, "memory")
#undef __XCHG_CASE
#define __XCHG_GEN(sfx) \
static __always_inline unsigned long __xchg##sfx(unsigned long x, \
volatile void *ptr, \
int size) \
{ \
switch (size) { \
case 1: \
return __xchg_case##sfx##_8(x, ptr); \
case 2: \
return __xchg_case##sfx##_16(x, ptr); \
case 4: \
return __xchg_case##sfx##_32(x, ptr); \
case 8: \
return __xchg_case##sfx##_64(x, ptr); \
default: \
BUILD_BUG(); \
} \
\
unreachable(); \
}
__XCHG_GEN()
__XCHG_GEN(_acq)
__XCHG_GEN(_rel)
__XCHG_GEN(_mb)
#undef __XCHG_GEN
#define __xchg_wrapper(sfx, ptr, x) \
({ \
__typeof__(*(ptr)) __ret; \
__ret = (__typeof__(*(ptr))) \
__xchg##sfx((unsigned long)(x), (ptr), sizeof(*(ptr))); \
__ret; \
})
/* xchg */
#define xchg_relaxed(...) __xchg_wrapper( , __VA_ARGS__)
#define xchg_acquire(...) __xchg_wrapper(_acq, __VA_ARGS__)
#define xchg_release(...) __xchg_wrapper(_rel, __VA_ARGS__)
#define xchg(...) __xchg_wrapper( _mb, __VA_ARGS__)
#define __CMPXCHG_GEN(sfx) \
static __always_inline unsigned long __cmpxchg##sfx(volatile void *ptr, \
unsigned long old, \
unsigned long new, \
int size) \
{ \
switch (size) { \
case 1: \
return __cmpxchg_case##sfx##_8(ptr, (u8)old, new); \
case 2: \
return __cmpxchg_case##sfx##_16(ptr, (u16)old, new); \
case 4: \
return __cmpxchg_case##sfx##_32(ptr, old, new); \
case 8: \
return __cmpxchg_case##sfx##_64(ptr, old, new); \
default: \
BUILD_BUG(); \
} \
\
unreachable(); \
}
__CMPXCHG_GEN()
__CMPXCHG_GEN(_acq)
__CMPXCHG_GEN(_rel)
__CMPXCHG_GEN(_mb)
#undef __CMPXCHG_GEN
#define __cmpxchg_wrapper(sfx, ptr, o, n) \
({ \
__typeof__(*(ptr)) __ret; \
__ret = (__typeof__(*(ptr))) \
__cmpxchg##sfx((ptr), (unsigned long)(o), \
(unsigned long)(n), sizeof(*(ptr))); \
__ret; \
})
/* cmpxchg */
#define cmpxchg_relaxed(...) __cmpxchg_wrapper( , __VA_ARGS__)
#define cmpxchg_acquire(...) __cmpxchg_wrapper(_acq, __VA_ARGS__)
#define cmpxchg_release(...) __cmpxchg_wrapper(_rel, __VA_ARGS__)
#define cmpxchg(...) __cmpxchg_wrapper( _mb, __VA_ARGS__)
#define cmpxchg_local cmpxchg_relaxed
/* cmpxchg64 */
#define cmpxchg64_relaxed cmpxchg_relaxed
#define cmpxchg64_acquire cmpxchg_acquire
#define cmpxchg64_release cmpxchg_release
#define cmpxchg64 cmpxchg
#define cmpxchg64_local cmpxchg_local
/* cmpxchg_double */
#define system_has_cmpxchg_double() 1
#define __cmpxchg_double_check(ptr1, ptr2) \
({ \
if (sizeof(*(ptr1)) != 8) \
BUILD_BUG(); \
VM_BUG_ON((unsigned long *)(ptr2) - (unsigned long *)(ptr1) != 1); \
})
#define cmpxchg_double(ptr1, ptr2, o1, o2, n1, n2) \
({\
int __ret;\
__cmpxchg_double_check(ptr1, ptr2); \
__ret = !__cmpxchg_double_mb((unsigned long)(o1), (unsigned long)(o2), \
(unsigned long)(n1), (unsigned long)(n2), \
ptr1); \
__ret; \
})
#define cmpxchg_double_local(ptr1, ptr2, o1, o2, n1, n2) \
({\
int __ret;\
__cmpxchg_double_check(ptr1, ptr2); \
__ret = !__cmpxchg_double((unsigned long)(o1), (unsigned long)(o2), \
(unsigned long)(n1), (unsigned long)(n2), \
ptr1); \
__ret; \
})
#define __CMPWAIT_CASE(w, sfx, sz) \
static inline void __cmpwait_case_##sz(volatile void *ptr, \
unsigned long val) \
{ \
unsigned long tmp; \
\
asm volatile( \
" sevl\n" \
" wfe\n" \
" ldxr" #sfx "\t%" #w "[tmp], %[v]\n" \
" eor %" #w "[tmp], %" #w "[tmp], %" #w "[val]\n" \
" cbnz %" #w "[tmp], 1f\n" \
" wfe\n" \
"1:" \
: [tmp] "=&r" (tmp), [v] "+Q" (*(unsigned long *)ptr) \
: [val] "r" (val)); \
}
__CMPWAIT_CASE(w, b, 8);
__CMPWAIT_CASE(w, h, 16);
__CMPWAIT_CASE(w, , 32);
__CMPWAIT_CASE( , , 64);
#undef __CMPWAIT_CASE
#define __CMPWAIT_GEN(sfx) \
static __always_inline void __cmpwait##sfx(volatile void *ptr, \
unsigned long val, \
int size) \
{ \
switch (size) { \
case 1: \
return __cmpwait_case##sfx##_8(ptr, (u8)val); \
case 2: \
return __cmpwait_case##sfx##_16(ptr, (u16)val); \
case 4: \
return __cmpwait_case##sfx##_32(ptr, val); \
case 8: \
return __cmpwait_case##sfx##_64(ptr, val); \
default: \
BUILD_BUG(); \
} \
\
unreachable(); \
}
__CMPWAIT_GEN()
#undef __CMPWAIT_GEN
#define __cmpwait_relaxed(ptr, val) \
__cmpwait((ptr), (unsigned long)(val), sizeof(*(ptr)))
#endif /* __ASM_CMPXCHG_H */
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