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 uaddr = untagged_addr(uaddr); 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 if (!ret) 71 *oval = oldval; 72 73 return ret; 74 } 75 76 static inline int 77 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 78 u32 oldval, u32 newval) 79 { 80 int ret = 0; 81 u32 val; 82 uintptr_t tmp; 83 84 if (!access_ok(uaddr, sizeof(u32))) 85 return -EFAULT; 86 uaddr = untagged_addr(uaddr); 87 88 __enable_user_access(); 89 __asm__ __volatile__ ( 90 "1: lr.w %[v],%[u] \n" 91 " bne %[v],%z[ov],3f \n" 92 "2: sc.w.aqrl %[t],%z[nv],%[u] \n" 93 " bnez %[t],1b \n" 94 "3: \n" 95 _ASM_EXTABLE_UACCESS_ERR(1b, 3b, %[r]) \ 96 _ASM_EXTABLE_UACCESS_ERR(2b, 3b, %[r]) \ 97 : [r] "+r" (ret), [v] "=&r" (val), [u] "+m" (*uaddr), [t] "=&r" (tmp) 98 : [ov] "Jr" ((long)(int)oldval), [nv] "Jr" (newval) 99 : "memory"); 100 __disable_user_access(); 101 102 *uval = val; 103 return ret; 104 } 105 106 #endif /* _ASM_RISCV_FUTEX_H */ 107