| David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 2 | /* |
| 3 | * Copyright (c) 2006 Ralf Baechle (ralf@linux-mips.org) |
| 4 | * Copyright (c) 2018 Jim Wilson (jimw@sifive.com) |
| 5 | */ |
| 6 | |
| 7 | #ifndef _ASM_FUTEX_H |
| 8 | #define _ASM_FUTEX_H |
| 9 | |
| 10 | #include <linux/futex.h> |
| 11 | #include <linux/uaccess.h> |
| 12 | #include <linux/errno.h> |
| 13 | #include <asm/asm.h> |
| 14 | |
| 15 | #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \ |
| 16 | { \ |
| 17 | uintptr_t tmp; \ |
| 18 | __enable_user_access(); \ |
| 19 | __asm__ __volatile__ ( \ |
| 20 | "1: " insn " \n" \ |
| 21 | "2: \n" \ |
| 22 | " .section .fixup,\"ax\" \n" \ |
| 23 | " .balign 4 \n" \ |
| 24 | "3: li %[r],%[e] \n" \ |
| 25 | " jump 2b,%[t] \n" \ |
| 26 | " .previous \n" \ |
| 27 | " .section __ex_table,\"a\" \n" \ |
| 28 | " .balign " RISCV_SZPTR " \n" \ |
| 29 | " " RISCV_PTR " 1b, 3b \n" \ |
| 30 | " .previous \n" \ |
| 31 | : [r] "+r" (ret), [ov] "=&r" (oldval), \ |
| 32 | [u] "+m" (*uaddr), [t] "=&r" (tmp) \ |
| 33 | : [op] "Jr" (oparg), [e] "i" (-EFAULT) \ |
| 34 | : "memory"); \ |
| 35 | __disable_user_access(); \ |
| 36 | } |
| 37 | |
| 38 | static inline int |
| 39 | arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr) |
| 40 | { |
| 41 | int oldval = 0, ret = 0; |
| 42 | |
| 43 | pagefault_disable(); |
| 44 | |
| 45 | switch (op) { |
| 46 | case FUTEX_OP_SET: |
| 47 | __futex_atomic_op("amoswap.w.aqrl %[ov],%z[op],%[u]", |
| 48 | ret, oldval, uaddr, oparg); |
| 49 | break; |
| 50 | case FUTEX_OP_ADD: |
| 51 | __futex_atomic_op("amoadd.w.aqrl %[ov],%z[op],%[u]", |
| 52 | ret, oldval, uaddr, oparg); |
| 53 | break; |
| 54 | case FUTEX_OP_OR: |
| 55 | __futex_atomic_op("amoor.w.aqrl %[ov],%z[op],%[u]", |
| 56 | ret, oldval, uaddr, oparg); |
| 57 | break; |
| 58 | case FUTEX_OP_ANDN: |
| 59 | __futex_atomic_op("amoand.w.aqrl %[ov],%z[op],%[u]", |
| 60 | ret, oldval, uaddr, ~oparg); |
| 61 | break; |
| 62 | case FUTEX_OP_XOR: |
| 63 | __futex_atomic_op("amoxor.w.aqrl %[ov],%z[op],%[u]", |
| 64 | ret, oldval, uaddr, oparg); |
| 65 | break; |
| 66 | default: |
| 67 | ret = -ENOSYS; |
| 68 | } |
| 69 | |
| 70 | pagefault_enable(); |
| 71 | |
| 72 | if (!ret) |
| 73 | *oval = oldval; |
| 74 | |
| 75 | return ret; |
| 76 | } |
| 77 | |
| 78 | static inline int |
| 79 | futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, |
| 80 | u32 oldval, u32 newval) |
| 81 | { |
| 82 | int ret = 0; |
| 83 | u32 val; |
| 84 | uintptr_t tmp; |
| 85 | |
| 86 | if (!access_ok(uaddr, sizeof(u32))) |
| 87 | return -EFAULT; |
| 88 | |
| 89 | __enable_user_access(); |
| 90 | __asm__ __volatile__ ( |
| 91 | "1: lr.w.aqrl %[v],%[u] \n" |
| 92 | " bne %[v],%z[ov],3f \n" |
| 93 | "2: sc.w.aqrl %[t],%z[nv],%[u] \n" |
| 94 | " bnez %[t],1b \n" |
| 95 | "3: \n" |
| 96 | " .section .fixup,\"ax\" \n" |
| 97 | " .balign 4 \n" |
| 98 | "4: li %[r],%[e] \n" |
| 99 | " jump 3b,%[t] \n" |
| 100 | " .previous \n" |
| 101 | " .section __ex_table,\"a\" \n" |
| 102 | " .balign " RISCV_SZPTR " \n" |
| 103 | " " RISCV_PTR " 1b, 4b \n" |
| 104 | " " RISCV_PTR " 2b, 4b \n" |
| 105 | " .previous \n" |
| 106 | : [r] "+r" (ret), [v] "=&r" (val), [u] "+m" (*uaddr), [t] "=&r" (tmp) |
| 107 | : [ov] "Jr" (oldval), [nv] "Jr" (newval), [e] "i" (-EFAULT) |
| 108 | : "memory"); |
| 109 | __disable_user_access(); |
| 110 | |
| 111 | *uval = val; |
| 112 | return ret; |
| 113 | } |
| 114 | |
| 115 | #endif /* _ASM_FUTEX_H */ |