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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
#ifdef __KERNEL__
#include <linux/futex.h>
#include <linux/uaccess.h>
#include <linux/errno.h>
#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
__asm__ __volatile( \
"1: l32i %0, %2, 0
" \
insn "
" \
" wsr %0, scompare1
" \
"2: s32c1i %1, %2, 0
" \
" bne %1, %0, 1b
" \
" movi %1, 0
" \
"3:
" \
" .section .fixup,\"ax\"
" \
" .align 4
" \
"4: .long 3b
" \
"5: l32r %0, 4b
" \
" movi %1, %3
" \
" jx %0
" \
" .previous
" \
" .section __ex_table,\"a\"
" \
" .long 1b,5b,2b,5b
" \
" .previous
" \
: "=&r" (oldval), "=&r" (ret) \
: "r" (uaddr), "I" (-EFAULT), "r" (oparg) \
: "memory")
static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
{
int op = (encoded_op >> 28) & 7;
int cmp = (encoded_op >> 24) & 15;
int oparg = (encoded_op << 8) >> 20;
int cmparg = (encoded_op << 20) >> 20;
int oldval = 0, ret;
if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
oparg = 1 << oparg;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
return -EFAULT;
#if !XCHAL_HAVE_S32C1I
return -ENOSYS;
#endif
pagefault_disable();
switch (op) {
case FUTEX_OP_SET:
__futex_atomic_op("mov %1, %4", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ADD:
__futex_atomic_op("add %1, %0, %4", ret, oldval, uaddr,
oparg);
break;
case FUTEX_OP_OR:
__futex_atomic_op("or %1, %0, %4", ret, oldval, uaddr,
oparg);
break;
case FUTEX_OP_ANDN:
__futex_atomic_op("and %1, %0, %4", ret, oldval, uaddr,
~oparg);
break;
case FUTEX_OP_XOR:
__futex_atomic_op("xor %1, %0, %4", ret, oldval, uaddr,
oparg);
break;
default:
ret = -ENOSYS;
}
pagefault_enable();
if (ret)
return ret;
switch (cmp) {
case FUTEX_OP_CMP_EQ: return (oldval == cmparg);
case FUTEX_OP_CMP_NE: return (oldval != cmparg);
case FUTEX_OP_CMP_LT: return (oldval < cmparg);
case FUTEX_OP_CMP_GE: return (oldval >= cmparg);
case FUTEX_OP_CMP_LE: return (oldval <= cmparg);
case FUTEX_OP_CMP_GT: return (oldval > cmparg);
}
return -ENOSYS;
}
static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
int ret = 0;
u32 prev;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
return -EFAULT;
#if !XCHAL_HAVE_S32C1I
return -ENOSYS;
#endif
__asm__ __volatile__ (
" # futex_atomic_cmpxchg_inatomic
"
"1: l32i %1, %3, 0
"
" mov %0, %5
"
" wsr %1, scompare1
"
"2: s32c1i %0, %3, 0
"
"3:
"
" .section .fixup,\"ax\"
"
" .align 4
"
"4: .long 3b
"
"5: l32r %1, 4b
"
" movi %0, %6
"
" jx %1
"
" .previous
"
" .section __ex_table,\"a\"
"
" .long 1b,5b,2b,5b
"
" .previous
"
: "+r" (ret), "=&r" (prev), "+m" (*uaddr)
: "r" (uaddr), "r" (oldval), "r" (newval), "I" (-EFAULT)
: "memory");
*uval = prev;
return ret;
}
#endif /* __KERNEL__ */
#endif /* _ASM_XTENSA_FUTEX_H */
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