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