| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame^] | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
| 2 | /* |
| 3 | * Copyright (C) 2012 ARM Ltd. |
| 4 | */ |
| 5 | #ifndef __ASM_FUTEX_H |
| 6 | #define __ASM_FUTEX_H |
| 7 | |
| 8 | #include <linux/futex.h> |
| 9 | #include <linux/uaccess.h> |
| 10 | |
| 11 | #include <asm/errno.h> |
| 12 | |
| 13 | #define FUTEX_MAX_LOOPS 128 /* What's the largest number you can think of? */ |
| 14 | |
| 15 | #define __futex_atomic_op(insn, ret, oldval, uaddr, tmp, oparg) \ |
| 16 | do { \ |
| 17 | unsigned int loops = FUTEX_MAX_LOOPS; \ |
| 18 | \ |
| 19 | uaccess_enable(); \ |
| 20 | asm volatile( \ |
| 21 | " prfm pstl1strm, %2\n" \ |
| 22 | "1: ldxr %w1, %2\n" \ |
| 23 | insn "\n" \ |
| 24 | "2: stlxr %w0, %w3, %2\n" \ |
| 25 | " cbz %w0, 3f\n" \ |
| 26 | " sub %w4, %w4, %w0\n" \ |
| 27 | " cbnz %w4, 1b\n" \ |
| 28 | " mov %w0, %w7\n" \ |
| 29 | "3:\n" \ |
| 30 | " dmb ish\n" \ |
| 31 | " .pushsection .fixup,\"ax\"\n" \ |
| 32 | " .align 2\n" \ |
| 33 | "4: mov %w0, %w6\n" \ |
| 34 | " b 3b\n" \ |
| 35 | " .popsection\n" \ |
| 36 | _ASM_EXTABLE(1b, 4b) \ |
| 37 | _ASM_EXTABLE(2b, 4b) \ |
| 38 | : "=&r" (ret), "=&r" (oldval), "+Q" (*uaddr), "=&r" (tmp), \ |
| 39 | "+r" (loops) \ |
| 40 | : "r" (oparg), "Ir" (-EFAULT), "Ir" (-EAGAIN) \ |
| 41 | : "memory"); \ |
| 42 | uaccess_disable(); \ |
| 43 | } while (0) |
| 44 | |
| 45 | static inline int |
| 46 | arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *_uaddr) |
| 47 | { |
| 48 | int oldval = 0, ret, tmp; |
| 49 | u32 __user *uaddr = __uaccess_mask_ptr(_uaddr); |
| 50 | |
| 51 | pagefault_disable(); |
| 52 | |
| 53 | switch (op) { |
| 54 | case FUTEX_OP_SET: |
| 55 | __futex_atomic_op("mov %w3, %w5", |
| 56 | ret, oldval, uaddr, tmp, oparg); |
| 57 | break; |
| 58 | case FUTEX_OP_ADD: |
| 59 | __futex_atomic_op("add %w3, %w1, %w5", |
| 60 | ret, oldval, uaddr, tmp, oparg); |
| 61 | break; |
| 62 | case FUTEX_OP_OR: |
| 63 | __futex_atomic_op("orr %w3, %w1, %w5", |
| 64 | ret, oldval, uaddr, tmp, oparg); |
| 65 | break; |
| 66 | case FUTEX_OP_ANDN: |
| 67 | __futex_atomic_op("and %w3, %w1, %w5", |
| 68 | ret, oldval, uaddr, tmp, ~oparg); |
| 69 | break; |
| 70 | case FUTEX_OP_XOR: |
| 71 | __futex_atomic_op("eor %w3, %w1, %w5", |
| 72 | ret, oldval, uaddr, tmp, oparg); |
| 73 | break; |
| 74 | default: |
| 75 | ret = -ENOSYS; |
| 76 | } |
| 77 | |
| 78 | pagefault_enable(); |
| 79 | |
| 80 | if (!ret) |
| 81 | *oval = oldval; |
| 82 | |
| 83 | return ret; |
| 84 | } |
| 85 | |
| 86 | static inline int |
| 87 | futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *_uaddr, |
| 88 | u32 oldval, u32 newval) |
| 89 | { |
| 90 | int ret = 0; |
| 91 | unsigned int loops = FUTEX_MAX_LOOPS; |
| 92 | u32 val, tmp; |
| 93 | u32 __user *uaddr; |
| 94 | |
| 95 | if (!access_ok(_uaddr, sizeof(u32))) |
| 96 | return -EFAULT; |
| 97 | |
| 98 | uaddr = __uaccess_mask_ptr(_uaddr); |
| 99 | uaccess_enable(); |
| 100 | asm volatile("// futex_atomic_cmpxchg_inatomic\n" |
| 101 | " prfm pstl1strm, %2\n" |
| 102 | "1: ldxr %w1, %2\n" |
| 103 | " sub %w3, %w1, %w5\n" |
| 104 | " cbnz %w3, 4f\n" |
| 105 | "2: stlxr %w3, %w6, %2\n" |
| 106 | " cbz %w3, 3f\n" |
| 107 | " sub %w4, %w4, %w3\n" |
| 108 | " cbnz %w4, 1b\n" |
| 109 | " mov %w0, %w8\n" |
| 110 | "3:\n" |
| 111 | " dmb ish\n" |
| 112 | "4:\n" |
| 113 | " .pushsection .fixup,\"ax\"\n" |
| 114 | "5: mov %w0, %w7\n" |
| 115 | " b 4b\n" |
| 116 | " .popsection\n" |
| 117 | _ASM_EXTABLE(1b, 5b) |
| 118 | _ASM_EXTABLE(2b, 5b) |
| 119 | : "+r" (ret), "=&r" (val), "+Q" (*uaddr), "=&r" (tmp), "+r" (loops) |
| 120 | : "r" (oldval), "r" (newval), "Ir" (-EFAULT), "Ir" (-EAGAIN) |
| 121 | : "memory"); |
| 122 | uaccess_disable(); |
| 123 | |
| 124 | if (!ret) |
| 125 | *uval = val; |
| 126 | |
| 127 | return ret; |
| 128 | } |
| 129 | |
| 130 | #endif /* __ASM_FUTEX_H */ |