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