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_RISCV_FUTEX_H 8 #define _ASM_RISCV_FUTEX_H 9 10 #include <linux/futex.h> 11 #include <linux/uaccess.h> 12 #include <linux/errno.h> 13 #include <asm/asm.h> 14 #include <asm/asm-extable.h> 15 16 /* We don't even really need the extable code, but for now keep it simple */ 17 #ifndef CONFIG_MMU 18 #define __enable_user_access() do { } while (0) 19 #define __disable_user_access() do { } while (0) 20 #endif 21 22 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \ 23 { \ 24 __enable_user_access(); \ 25 __asm__ __volatile__ ( \ 26 "1: " insn " \n" \ 27 "2: \n" \ 28 _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %[r]) \ 29 : [r] "+r" (ret), [ov] "=&r" (oldval), \ 30 [u] "+m" (*uaddr) \ 31 : [op] "Jr" (oparg) \ 32 : "memory"); \ 33 __disable_user_access(); \ 34 } 35 36 static inline int 37 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr) 38 { 39 int oldval = 0, ret = 0; 40 41 if (!access_ok(uaddr, sizeof(u32))) 42 return -EFAULT; 43 44 switch (op) { 45 case FUTEX_OP_SET: 46 __futex_atomic_op("amoswap.w.aqrl %[ov],%z[op],%[u]", 47 ret, oldval, uaddr, oparg); 48 break; 49 case FUTEX_OP_ADD: 50 __futex_atomic_op("amoadd.w.aqrl %[ov],%z[op],%[u]", 51 ret, oldval, uaddr, oparg); 52 break; 53 case FUTEX_OP_OR: 54 __futex_atomic_op("amoor.w.aqrl %[ov],%z[op],%[u]", 55 ret, oldval, uaddr, oparg); 56 break; 57 case FUTEX_OP_ANDN: 58 __futex_atomic_op("amoand.w.aqrl %[ov],%z[op],%[u]", 59 ret, oldval, uaddr, ~oparg); 60 break; 61 case FUTEX_OP_XOR: 62 __futex_atomic_op("amoxor.w.aqrl %[ov],%z[op],%[u]", 63 ret, oldval, uaddr, oparg); 64 break; 65 default: 66 ret = -ENOSYS; 67 } 68 69 if (!ret) 70 *oval = oldval; 71 72 return ret; 73 } 74 75 static inline int 76 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 77 u32 oldval, u32 newval) 78 { 79 int ret = 0; 80 u32 val; 81 uintptr_t tmp; 82 83 if (!access_ok(uaddr, sizeof(u32))) 84 return -EFAULT; 85 86 __enable_user_access(); 87 __asm__ __volatile__ ( 88 "1: lr.w.aqrl %[v],%[u] \n" 89 " bne %[v],%z[ov],3f \n" 90 "2: sc.w.aqrl %[t],%z[nv],%[u] \n" 91 " bnez %[t],1b \n" 92 "3: \n" 93 _ASM_EXTABLE_UACCESS_ERR(1b, 3b, %[r]) \ 94 _ASM_EXTABLE_UACCESS_ERR(2b, 3b, %[r]) \ 95 : [r] "+r" (ret), [v] "=&r" (val), [u] "+m" (*uaddr), [t] "=&r" (tmp) 96 : [ov] "Jr" (oldval), [nv] "Jr" (newval) 97 : "memory"); 98 __disable_user_access(); 99 100 *uval = val; 101 return ret; 102 } 103 104 #endif /* _ASM_RISCV_FUTEX_H */ 105