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120 lines
2.8 KiB
120 lines
2.8 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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/* |
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* Copyright (c) 2006 Ralf Baechle ([email protected]) |
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* Copyright (c) 2018 Jim Wilson ([email protected]) |
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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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