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/*
* Atomic futex routines
*
* Based on the PowerPC implementataion
*
* 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.
*
* Copyright (C) 2013 TangoTec Ltd.
*
* Baruch Siach <baruch@tkos.co.il>
*/
#ifndef _ASM_XTENSA_FUTEX_H
#define _ASM_XTENSA_FUTEX_H
#include <linux/futex.h>
#include <linux/uaccess.h>
#include <linux/errno.h>
#if XCHAL_HAVE_EXCLUSIVE
#define __futex_atomic_op(insn, ret, old, uaddr, arg) \
__asm__ __volatile( \
"1: l32ex %[oldval], %[addr]\n" \
insn "\n" \
"2: s32ex %[newval], %[addr]\n" \
" getex %[newval]\n" \
" beqz %[newval], 1b\n" \
" movi %[newval], 0\n" \
"3:\n" \
" .section .fixup,\"ax\"\n" \
" .align 4\n" \
" .literal_position\n" \
"5: movi %[oldval], 3b\n" \
" movi %[newval], %[fault]\n" \
" jx %[oldval]\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .long 1b, 5b, 2b, 5b\n" \
" .previous\n" \
: [oldval] "=&r" (old), [newval] "=&r" (ret) \
: [addr] "r" (uaddr), [oparg] "r" (arg), \
[fault] "I" (-EFAULT) \
: "memory")
#elif XCHAL_HAVE_S32C1I
#define __futex_atomic_op(insn, ret, old, uaddr, arg) \
__asm__ __volatile( \
"1: l32i %[oldval], %[addr], 0\n" \
insn "\n" \
" wsr %[oldval], scompare1\n" \
"2: s32c1i %[newval], %[addr], 0\n" \
" bne %[newval], %[oldval], 1b\n" \
" movi %[newval], 0\n" \
"3:\n" \
" .section .fixup,\"ax\"\n" \
" .align 4\n" \
" .literal_position\n" \
"5: movi %[oldval], 3b\n" \
" movi %[newval], %[fault]\n" \
" jx %[oldval]\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .long 1b, 5b, 2b, 5b\n" \
" .previous\n" \
: [oldval] "=&r" (old), [newval] "=&r" (ret) \
: [addr] "r" (uaddr), [oparg] "r" (arg), \
[fault] "I" (-EFAULT) \
: "memory")
#endif
static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
u32 __user *uaddr)
{
#if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE
int oldval = 0, ret;
pagefault_disable();
switch (op) {
case FUTEX_OP_SET:
__futex_atomic_op("mov %[newval], %[oparg]",
ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ADD:
__futex_atomic_op("add %[newval], %[oldval], %[oparg]",
ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_OR:
__futex_atomic_op("or %[newval], %[oldval], %[oparg]",
ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ANDN:
__futex_atomic_op("and %[newval], %[oldval], %[oparg]",
ret, oldval, uaddr, ~oparg);
break;
case FUTEX_OP_XOR:
__futex_atomic_op("xor %[newval], %[oldval], %[oparg]",
ret, oldval, uaddr, oparg);
break;
default:
ret = -ENOSYS;
}
pagefault_enable();
if (!ret)
*oval = oldval;
return ret;
#else
return -ENOSYS;
#endif
}
static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
#if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE
unsigned long tmp;
int ret = 0;
if (!access_ok(uaddr, sizeof(u32)))
return -EFAULT;
__asm__ __volatile__ (
" # futex_atomic_cmpxchg_inatomic\n"
#if XCHAL_HAVE_EXCLUSIVE
"1: l32ex %[tmp], %[addr]\n"
" s32i %[tmp], %[uval], 0\n"
" bne %[tmp], %[oldval], 2f\n"
" mov %[tmp], %[newval]\n"
"3: s32ex %[tmp], %[addr]\n"
" getex %[tmp]\n"
" beqz %[tmp], 1b\n"
#elif XCHAL_HAVE_S32C1I
" wsr %[oldval], scompare1\n"
"1: s32c1i %[newval], %[addr], 0\n"
" s32i %[newval], %[uval], 0\n"
#endif
"2:\n"
" .section .fixup,\"ax\"\n"
" .align 4\n"
" .literal_position\n"
"4: movi %[tmp], 2b\n"
" movi %[ret], %[fault]\n"
" jx %[tmp]\n"
" .previous\n"
" .section __ex_table,\"a\"\n"
" .long 1b, 4b\n"
#if XCHAL_HAVE_EXCLUSIVE
" .long 3b, 4b\n"
#endif
" .previous\n"
: [ret] "+r" (ret), [newval] "+r" (newval), [tmp] "=&r" (tmp)
: [addr] "r" (uaddr), [oldval] "r" (oldval), [uval] "r" (uval),
[fault] "I" (-EFAULT)
: "memory");
return ret;
#else
return -ENOSYS;
#endif
}
#endif /* _ASM_XTENSA_FUTEX_H */
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