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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (c) 2006 Ralf Baechle (ralf@linux-mips.org)
* Copyright (c) 2018 Jim Wilson (jimw@sifive.com)
*/
#ifndef _ASM_RISCV_FUTEX_H
#define _ASM_RISCV_FUTEX_H
#include <linux/futex.h>
#include <linux/uaccess.h>
#include <linux/errno.h>
#include <asm/asm.h>
/* We don't even really need the extable code, but for now keep it simple */
#ifndef CONFIG_MMU
#define __enable_user_access() do { } while (0)
#define __disable_user_access() do { } while (0)
#endif
#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
{ \
uintptr_t tmp; \
__enable_user_access(); \
__asm__ __volatile__ ( \
"1: " insn " \n" \
"2: \n" \
" .section .fixup,\"ax\" \n" \
" .balign 4 \n" \
"3: li %[r],%[e] \n" \
" jump 2b,%[t] \n" \
" .previous \n" \
" .section __ex_table,\"a\" \n" \
" .balign " RISCV_SZPTR " \n" \
" " RISCV_PTR " 1b, 3b \n" \
" .previous \n" \
: [r] "+r" (ret), [ov] "=&r" (oldval), \
[u] "+m" (*uaddr), [t] "=&r" (tmp) \
: [op] "Jr" (oparg), [e] "i" (-EFAULT) \
: "memory"); \
__disable_user_access(); \
}
static inline int
arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
{
int oldval = 0, ret = 0;
if (!access_ok(uaddr, sizeof(u32)))
return -EFAULT;
switch (op) {
case FUTEX_OP_SET:
__futex_atomic_op("amoswap.w.aqrl %[ov],%z[op],%[u]",
ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ADD:
__futex_atomic_op("amoadd.w.aqrl %[ov],%z[op],%[u]",
ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_OR:
__futex_atomic_op("amoor.w.aqrl %[ov],%z[op],%[u]",
ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ANDN:
__futex_atomic_op("amoand.w.aqrl %[ov],%z[op],%[u]",
ret, oldval, uaddr, ~oparg);
break;
case FUTEX_OP_XOR:
__futex_atomic_op("amoxor.w.aqrl %[ov],%z[op],%[u]",
ret, oldval, uaddr, oparg);
break;
default:
ret = -ENOSYS;
}
if (!ret)
*oval = oldval;
return ret;
}
static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
int ret = 0;
u32 val;
uintptr_t tmp;
if (!access_ok(uaddr, sizeof(u32)))
return -EFAULT;
__enable_user_access();
__asm__ __volatile__ (
"1: lr.w.aqrl %[v],%[u] \n"
" bne %[v],%z[ov],3f \n"
"2: sc.w.aqrl %[t],%z[nv],%[u] \n"
" bnez %[t],1b \n"
"3: \n"
" .section .fixup,\"ax\" \n"
" .balign 4 \n"
"4: li %[r],%[e] \n"
" jump 3b,%[t] \n"
" .previous \n"
" .section __ex_table,\"a\" \n"
" .balign " RISCV_SZPTR " \n"
" " RISCV_PTR " 1b, 4b \n"
" " RISCV_PTR " 2b, 4b \n"
" .previous \n"
: [r] "+r" (ret), [v] "=&r" (val), [u] "+m" (*uaddr), [t] "=&r" (tmp)
: [ov] "Jr" (oldval), [nv] "Jr" (newval), [e] "i" (-EFAULT)
: "memory");
__disable_user_access();
*uval = val;
return ret;
}
#endif /* _ASM_RISCV_FUTEX_H */
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