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 _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %1) \ 21 : "=r" (oldval), "=r" (ret), "+m" (*uaddr) \ 22 : "0" (oparg), "1" (0)); \ 23 if (ret) \ 24 goto label; \ 25 *oval = oldval; \ 26 } while(0) 27 28 29 #define unsafe_atomic_op2(insn, oval, uaddr, oparg, label) \ 30 do { \ 31 int oldval = 0, ret, tem; \ 32 asm volatile("1:\tmovl %2, %0\n" \ 33 "2:\tmovl\t%0, %3\n" \ 34 "\t" insn "\n" \ 35 "3:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" \ 36 "\tjnz\t2b\n" \ 37 "4:\n" \ 38 _ASM_EXTABLE_TYPE_REG(1b, 4b, EX_TYPE_EFAULT_REG, %1) \ 39 _ASM_EXTABLE_TYPE_REG(3b, 4b, EX_TYPE_EFAULT_REG, %1) \ 40 : "=&a" (oldval), "=&r" (ret), \ 41 "+m" (*uaddr), "=&r" (tem) \ 42 : "r" (oparg), "1" (0)); \ 43 if (ret) \ 44 goto label; \ 45 *oval = oldval; \ 46 } while(0) 47 48 static __always_inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval, 49 u32 __user *uaddr) 50 { 51 if (!user_access_begin(uaddr, sizeof(u32))) 52 return -EFAULT; 53 54 switch (op) { 55 case FUTEX_OP_SET: 56 unsafe_atomic_op1("xchgl %0, %2", oval, uaddr, oparg, Efault); 57 break; 58 case FUTEX_OP_ADD: 59 unsafe_atomic_op1(LOCK_PREFIX "xaddl %0, %2", oval, 60 uaddr, oparg, Efault); 61 break; 62 case FUTEX_OP_OR: 63 unsafe_atomic_op2("orl %4, %3", oval, uaddr, oparg, Efault); 64 break; 65 case FUTEX_OP_ANDN: 66 unsafe_atomic_op2("andl %4, %3", oval, uaddr, ~oparg, Efault); 67 break; 68 case FUTEX_OP_XOR: 69 unsafe_atomic_op2("xorl %4, %3", oval, uaddr, oparg, Efault); 70 break; 71 default: 72 user_access_end(); 73 return -ENOSYS; 74 } 75 user_access_end(); 76 return 0; 77 Efault: 78 user_access_end(); 79 return -EFAULT; 80 } 81 82 static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 83 u32 oldval, u32 newval) 84 { 85 int ret = 0; 86 87 if (!user_access_begin(uaddr, sizeof(u32))) 88 return -EFAULT; 89 asm volatile("\n" 90 "1:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" 91 "2:\n" 92 _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %0) \ 93 : "+r" (ret), "=a" (oldval), "+m" (*uaddr) 94 : "r" (newval), "1" (oldval) 95 : "memory" 96 ); 97 user_access_end(); 98 *uval = oldval; 99 return ret; 100 } 101 102 #endif 103 #endif /* _ASM_X86_FUTEX_H */ 104