1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_X86_FUTEX_H 3 #define _ASM_X86_FUTEX_H 4 5 #ifdef __KERNEL__ 6 7 #include <linux/futex.h> 8 #include <linux/uaccess.h> 9 10 #include <asm/asm.h> 11 #include <asm/errno.h> 12 #include <asm/processor.h> 13 #include <asm/smap.h> 14 15 #define unsafe_atomic_op1(insn, oval, uaddr, oparg, label) \ 16 do { \ 17 int oldval = 0, ret; \ 18 asm volatile("1:\t" insn "\n" \ 19 "2:\n" \ 20 "\t.section .fixup,\"ax\"\n" \ 21 "3:\tmov\t%3, %1\n" \ 22 "\tjmp\t2b\n" \ 23 "\t.previous\n" \ 24 _ASM_EXTABLE_UA(1b, 3b) \ 25 : "=r" (oldval), "=r" (ret), "+m" (*uaddr) \ 26 : "i" (-EFAULT), "0" (oparg), "1" (0)); \ 27 if (ret) \ 28 goto label; \ 29 *oval = oldval; \ 30 } while(0) 31 32 33 #define unsafe_atomic_op2(insn, oval, uaddr, oparg, label) \ 34 do { \ 35 int oldval = 0, ret, tem; \ 36 asm volatile("1:\tmovl %2, %0\n" \ 37 "2:\tmovl\t%0, %3\n" \ 38 "\t" insn "\n" \ 39 "3:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" \ 40 "\tjnz\t2b\n" \ 41 "4:\n" \ 42 "\t.section .fixup,\"ax\"\n" \ 43 "5:\tmov\t%5, %1\n" \ 44 "\tjmp\t4b\n" \ 45 "\t.previous\n" \ 46 _ASM_EXTABLE_UA(1b, 5b) \ 47 _ASM_EXTABLE_UA(3b, 5b) \ 48 : "=&a" (oldval), "=&r" (ret), \ 49 "+m" (*uaddr), "=&r" (tem) \ 50 : "r" (oparg), "i" (-EFAULT), "1" (0)); \ 51 if (ret) \ 52 goto label; \ 53 *oval = oldval; \ 54 } while(0) 55 56 static __always_inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval, 57 u32 __user *uaddr) 58 { 59 if (!user_access_begin(uaddr, sizeof(u32))) 60 return -EFAULT; 61 62 switch (op) { 63 case FUTEX_OP_SET: 64 unsafe_atomic_op1("xchgl %0, %2", oval, uaddr, oparg, Efault); 65 break; 66 case FUTEX_OP_ADD: 67 unsafe_atomic_op1(LOCK_PREFIX "xaddl %0, %2", oval, 68 uaddr, oparg, Efault); 69 break; 70 case FUTEX_OP_OR: 71 unsafe_atomic_op2("orl %4, %3", oval, uaddr, oparg, Efault); 72 break; 73 case FUTEX_OP_ANDN: 74 unsafe_atomic_op2("andl %4, %3", oval, uaddr, ~oparg, Efault); 75 break; 76 case FUTEX_OP_XOR: 77 unsafe_atomic_op2("xorl %4, %3", oval, uaddr, oparg, Efault); 78 break; 79 default: 80 user_access_end(); 81 return -ENOSYS; 82 } 83 user_access_end(); 84 return 0; 85 Efault: 86 user_access_end(); 87 return -EFAULT; 88 } 89 90 static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 91 u32 oldval, u32 newval) 92 { 93 int ret = 0; 94 95 if (!user_access_begin(uaddr, sizeof(u32))) 96 return -EFAULT; 97 asm volatile("\n" 98 "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n" 99 "2:\n" 100 "\t.section .fixup, \"ax\"\n" 101 "3:\tmov %3, %0\n" 102 "\tjmp 2b\n" 103 "\t.previous\n" 104 _ASM_EXTABLE_UA(1b, 3b) 105 : "+r" (ret), "=a" (oldval), "+m" (*uaddr) 106 : "i" (-EFAULT), "r" (newval), "1" (oldval) 107 : "memory" 108 ); 109 user_access_end(); 110 *uval = oldval; 111 return ret; 112 } 113 114 #endif 115 #endif /* _ASM_X86_FUTEX_H */ 116