1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited 4 */ 5 #ifndef _ASM_FUTEX_H 6 #define _ASM_FUTEX_H 7 8 #include <linux/futex.h> 9 #include <linux/uaccess.h> 10 #include <asm/asm-extable.h> 11 #include <asm/barrier.h> 12 #include <asm/errno.h> 13 14 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \ 15 { \ 16 __asm__ __volatile__( \ 17 "1: ll.w %1, %4 # __futex_atomic_op\n" \ 18 " " insn " \n" \ 19 "2: sc.w $t0, %2 \n" \ 20 " beqz $t0, 1b \n" \ 21 "3: \n" \ 22 _ASM_EXTABLE_UACCESS_ERR(1b, 3b, %0) \ 23 _ASM_EXTABLE_UACCESS_ERR(2b, 3b, %0) \ 24 : "=r" (ret), "=&r" (oldval), \ 25 "=ZC" (*uaddr) \ 26 : "0" (0), "ZC" (*uaddr), "Jr" (oparg) \ 27 : "memory", "t0"); \ 28 } 29 30 static inline int 31 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr) 32 { 33 int oldval = 0, ret = 0; 34 35 pagefault_disable(); 36 37 switch (op) { 38 case FUTEX_OP_SET: 39 __futex_atomic_op("move $t0, %z5", ret, oldval, uaddr, oparg); 40 break; 41 case FUTEX_OP_ADD: 42 __futex_atomic_op("add.w $t0, %1, %z5", ret, oldval, uaddr, oparg); 43 break; 44 case FUTEX_OP_OR: 45 __futex_atomic_op("or $t0, %1, %z5", ret, oldval, uaddr, oparg); 46 break; 47 case FUTEX_OP_ANDN: 48 __futex_atomic_op("and $t0, %1, %z5", ret, oldval, uaddr, ~oparg); 49 break; 50 case FUTEX_OP_XOR: 51 __futex_atomic_op("xor $t0, %1, %z5", ret, oldval, uaddr, oparg); 52 break; 53 default: 54 ret = -ENOSYS; 55 } 56 57 pagefault_enable(); 58 59 if (!ret) 60 *oval = oldval; 61 62 return ret; 63 } 64 65 static inline int 66 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval) 67 { 68 int ret = 0; 69 u32 val = 0; 70 71 if (!access_ok(uaddr, sizeof(u32))) 72 return -EFAULT; 73 74 __asm__ __volatile__( 75 "# futex_atomic_cmpxchg_inatomic \n" 76 "1: ll.w %1, %3 \n" 77 " bne %1, %z4, 3f \n" 78 " move $t0, %z5 \n" 79 "2: sc.w $t0, %2 \n" 80 " beqz $t0, 1b \n" 81 "3: \n" 82 __WEAK_LLSC_MB 83 _ASM_EXTABLE_UACCESS_ERR(1b, 3b, %0) 84 _ASM_EXTABLE_UACCESS_ERR(2b, 3b, %0) 85 : "+r" (ret), "=&r" (val), "=ZC" (*uaddr) 86 : "ZC" (*uaddr), "Jr" (oldval), "Jr" (newval) 87 : "memory", "t0"); 88 89 *uval = val; 90 91 return ret; 92 } 93 94 #endif /* _ASM_FUTEX_H */ 95