1 /* 2 * Atomic futex routines 3 * 4 * Based on the PowerPC implementataion 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * Copyright (C) 2013 TangoTec Ltd. 11 * 12 * Baruch Siach <baruch@tkos.co.il> 13 */ 14 15 #ifndef _ASM_XTENSA_FUTEX_H 16 #define _ASM_XTENSA_FUTEX_H 17 18 #ifdef __KERNEL__ 19 20 #include <linux/futex.h> 21 #include <linux/uaccess.h> 22 #include <linux/errno.h> 23 24 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \ 25 __asm__ __volatile( \ 26 "1: l32i %0, %2, 0\n" \ 27 insn "\n" \ 28 " wsr %0, scompare1\n" \ 29 "2: s32c1i %1, %2, 0\n" \ 30 " bne %1, %0, 1b\n" \ 31 " movi %1, 0\n" \ 32 "3:\n" \ 33 " .section .fixup,\"ax\"\n" \ 34 " .align 4\n" \ 35 "4: .long 3b\n" \ 36 "5: l32r %0, 4b\n" \ 37 " movi %1, %3\n" \ 38 " jx %0\n" \ 39 " .previous\n" \ 40 " .section __ex_table,\"a\"\n" \ 41 " .long 1b,5b,2b,5b\n" \ 42 " .previous\n" \ 43 : "=&r" (oldval), "=&r" (ret) \ 44 : "r" (uaddr), "I" (-EFAULT), "r" (oparg) \ 45 : "memory") 46 47 static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) 48 { 49 int op = (encoded_op >> 28) & 7; 50 int cmp = (encoded_op >> 24) & 15; 51 int oparg = (encoded_op << 8) >> 20; 52 int cmparg = (encoded_op << 20) >> 20; 53 int oldval = 0, ret; 54 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) 55 oparg = 1 << oparg; 56 57 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) 58 return -EFAULT; 59 60 #if !XCHAL_HAVE_S32C1I 61 return -ENOSYS; 62 #endif 63 64 pagefault_disable(); 65 66 switch (op) { 67 case FUTEX_OP_SET: 68 __futex_atomic_op("mov %1, %4", ret, oldval, uaddr, oparg); 69 break; 70 case FUTEX_OP_ADD: 71 __futex_atomic_op("add %1, %0, %4", ret, oldval, uaddr, 72 oparg); 73 break; 74 case FUTEX_OP_OR: 75 __futex_atomic_op("or %1, %0, %4", ret, oldval, uaddr, 76 oparg); 77 break; 78 case FUTEX_OP_ANDN: 79 __futex_atomic_op("and %1, %0, %4", ret, oldval, uaddr, 80 ~oparg); 81 break; 82 case FUTEX_OP_XOR: 83 __futex_atomic_op("xor %1, %0, %4", ret, oldval, uaddr, 84 oparg); 85 break; 86 default: 87 ret = -ENOSYS; 88 } 89 90 pagefault_enable(); 91 92 if (ret) 93 return ret; 94 95 switch (cmp) { 96 case FUTEX_OP_CMP_EQ: return (oldval == cmparg); 97 case FUTEX_OP_CMP_NE: return (oldval != cmparg); 98 case FUTEX_OP_CMP_LT: return (oldval < cmparg); 99 case FUTEX_OP_CMP_GE: return (oldval >= cmparg); 100 case FUTEX_OP_CMP_LE: return (oldval <= cmparg); 101 case FUTEX_OP_CMP_GT: return (oldval > cmparg); 102 } 103 104 return -ENOSYS; 105 } 106 107 static inline int 108 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 109 u32 oldval, u32 newval) 110 { 111 int ret = 0; 112 u32 prev; 113 114 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) 115 return -EFAULT; 116 117 #if !XCHAL_HAVE_S32C1I 118 return -ENOSYS; 119 #endif 120 121 __asm__ __volatile__ ( 122 " # futex_atomic_cmpxchg_inatomic\n" 123 "1: l32i %1, %3, 0\n" 124 " mov %0, %5\n" 125 " wsr %1, scompare1\n" 126 "2: s32c1i %0, %3, 0\n" 127 "3:\n" 128 " .section .fixup,\"ax\"\n" 129 " .align 4\n" 130 "4: .long 3b\n" 131 "5: l32r %1, 4b\n" 132 " movi %0, %6\n" 133 " jx %1\n" 134 " .previous\n" 135 " .section __ex_table,\"a\"\n" 136 " .long 1b,5b,2b,5b\n" 137 " .previous\n" 138 : "+r" (ret), "=&r" (prev), "+m" (*uaddr) 139 : "r" (uaddr), "r" (oldval), "r" (newval), "I" (-EFAULT) 140 : "memory"); 141 142 *uval = prev; 143 return ret; 144 } 145 146 #endif /* __KERNEL__ */ 147 #endif /* _ASM_XTENSA_FUTEX_H */ 148