/*
* 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/bug.h>
#include <linux/mmdebug.h>
#include <asm/barrier.h>
static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
{
unsigned long ret, tmp;
switch (size) {
case 1:
asm volatile("// __xchg1\n"
"1: ldxrb %w0, %2\n"
" stlxrb %w1, %w3, %2\n"
" cbnz %w1, 1b\n"
: "=&r" (ret), "=&r" (tmp), "+Q" (*(u8 *)ptr)
: "r" (x)
: "memory");
break;
case 2:
asm volatile("// __xchg2\n"
"1: ldxrh %w0, %2\n"
" stlxrh %w1, %w3, %2\n"
" cbnz %w1, 1b\n"
: "=&r" (ret), "=&r" (tmp), "+Q" (*(u16 *)ptr)
: "r" (x)
: "memory");
break;
case 4:
asm volatile("// __xchg4\n"
"1: ldxr %w0, %2\n"
" stlxr %w1, %w3, %2\n"
" cbnz %w1, 1b\n"
: "=&r" (ret), "=&r" (tmp), "+Q" (*(u32 *)ptr)
: "r" (x)
: "memory");
break;
case 8:
asm volatile("// __xchg8\n"
"1: ldxr %0, %2\n"
" stlxr %w1, %3, %2\n"
" cbnz %w1, 1b\n"
: "=&r" (ret), "=&r" (tmp), "+Q" (*(u64 *)ptr)
: "r" (x)
: "memory");
break;
default:
BUILD_BUG();
}
smp_mb();
return ret;
}
#define xchg(ptr,x) \
({ \
__typeof__(*(ptr)) __ret; \
__ret = (__typeof__(*(ptr))) \
__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))); \
__ret; \
})
static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
unsigned long new, int size)
{
unsigned long oldval = 0, res;
switch (size) {
case 1:
do {
asm volatile("// __cmpxchg1\n"
" ldxrb %w1, %2\n"
" mov %w0, #0\n"
" cmp %w1, %w3\n"
" b.ne 1f\n"
" stxrb %w0, %w4, %2\n"
"1:\n"
: "=&r" (res), "=&r" (oldval), "+Q" (*(u8 *)ptr)
: "Ir" (old), "r" (new)
: "cc");
} while (res);
break;
case 2:
do {
asm volatile("// __cmpxchg2\n"
" ldxrh %w1, %2\n"
" mov %w0, #0\n"
" cmp %w1, %w3\n"
" b.ne 1f\n"
" stxrh %w0, %w4, %2\n"
"1:\n"
: "=&r" (res), "=&r" (oldval), "+Q" (*(u16 *)ptr)
: "Ir" (old), "r" (new)
: "cc");
} while (res);
break;
case 4:
do {
asm volatile("// __cmpxchg4\n"
" ldxr %w1, %2\n"
" mov %w0, #0\n"
" cmp %w1, %w3\n"
" b.ne 1f\n"
" stxr %w0, %w4, %2\n"
"1:\n"
: "=&r" (res), "=&r" (oldval), "+Q" (*(u32 *)ptr)
: "Ir" (old), "r" (new)
: "cc");
} while (res);
break;
case 8:
do {
asm volatile("// __cmpxchg8\n"
" ldxr %1, %2\n"
" mov %w0, #0\n"
" cmp %1, %3\n"
" b.ne 1f\n"
" stxr %w0, %4, %2\n"
"1:\n"
: "=&r" (res), "=&r" (oldval), "+Q" (*(u64 *)ptr)
: "Ir" (old), "r" (new)
: "cc");
} while (res);
break;
default:
BUILD_BUG();
}
return oldval;
}
#define system_has_cmpxchg_double() 1
static inline int __cmpxchg_double(volatile void *ptr1, volatile void *ptr2,
unsigned long old1, unsigned long old2,
unsigned long new1, unsigned long new2, int size)
{
unsigned long loop, lost;
switch (size) {
case 8:
VM_BUG_ON((unsigned long *)ptr2 - (unsigned long *)ptr1 != 1);
do {
asm volatile("// __cmpxchg_double8\n"
" ldxp %0, %1, %2\n"
" eor %0, %0, %3\n"
" eor %1, %1, %4\n"
" orr %1, %0, %1\n"
" mov %w0, #0\n"
" cbnz %1, 1f\n"
" stxp %w0, %5, %6, %2\n"
"1:\n"
: "=&r"(loop), "=&r"(lost), "+Q" (*(u64 *)ptr1)
: "r" (old1), "r"(old2), "r"(new1), "r"(new2));
} while (loop);
break;
default:
BUILD_BUG();
}
return !lost;
}
static inline int __cmpxchg_double_mb(volatile void *ptr1, volatile void *ptr2,
unsigned long old1, unsigned long old2,
unsigned long new1, unsigned long new2, int size)
{
int ret;
smp_mb();
ret = __cmpxchg_double(ptr1, ptr2, old1, old2, new1, new2, size);
smp_mb();
return ret;
}
static inline unsigned long __cmpxchg_mb(volatile void *ptr, unsigned long old,
unsigned long new, int size)
{
unsigned long ret;
smp_mb();
ret = __cmpxchg(ptr, old, new, size);
smp_mb();
return ret;
}
#define cmpxchg(ptr, o, n) \
({ \
__typeof__(*(ptr)) __ret; \
__ret = (__typeof__(*(ptr))) \
__cmpxchg_mb((ptr), (unsigned long)(o), (unsigned long)(n), \
sizeof(*(ptr))); \
__ret; \
})
#define cmpxchg_local(ptr, o, n) \
({ \
__typeof__(*(ptr)) __ret; \
__ret = (__typeof__(*(ptr))) \
__cmpxchg((ptr), (unsigned long)(o), \
(unsigned long)(n), sizeof(*(ptr))); \
__ret; \
})
#define cmpxchg_double(ptr1, ptr2, o1, o2, n1, n2) \
({\
int __ret;\
__ret = __cmpxchg_double_mb((ptr1), (ptr2), (unsigned long)(o1), \
(unsigned long)(o2), (unsigned long)(n1), \
(unsigned long)(n2), sizeof(*(ptr1)));\
__ret; \
})
#define cmpxchg_double_local(ptr1, ptr2, o1, o2, n1, n2) \
({\
int __ret;\
__ret = __cmpxchg_double((ptr1), (ptr2), (unsigned long)(o1), \
(unsigned long)(o2), (unsigned long)(n1), \
(unsigned long)(n2), sizeof(*(ptr1)));\
__ret; \
})
#define _protect_cmpxchg_local(pcp, o, n) \
({ \
typeof(*raw_cpu_ptr(&(pcp))) __ret; \
preempt_disable(); \
__ret = cmpxchg_local(raw_cpu_ptr(&(pcp)), o, n); \
preempt_enable(); \
__ret; \
})
#define this_cpu_cmpxchg_1(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
#define this_cpu_cmpxchg_2(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
#define this_cpu_cmpxchg_4(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
#define this_cpu_cmpxchg_8(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
#define this_cpu_cmpxchg_double_8(ptr1, ptr2, o1, o2, n1, n2) \
({ \
int __ret; \
preempt_disable(); \
__ret = cmpxchg_double_local( raw_cpu_ptr(&(ptr1)), \
raw_cpu_ptr(&(ptr2)), \
o1, o2, n1, n2); \
preempt_enable(); \
__ret; \
})
#define cmpxchg64(ptr,o,n) cmpxchg((ptr),(o),(n))
#define cmpxchg64_local(ptr,o,n) cmpxchg_local((ptr),(o),(n))
#define cmpxchg64_relaxed(ptr,o,n) cmpxchg_local((ptr),(o),(n))
#endif /* __ASM_CMPXCHG_H */
