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 #include <linux/futex.h> 19 #include <linux/uaccess.h> 20 #include <linux/errno.h> 21 22 #if XCHAL_HAVE_EXCLUSIVE 23 #define __futex_atomic_op(insn, ret, old, uaddr, arg) \ 24 __asm__ __volatile( \ 25 "1: l32ex %[oldval], %[addr]\n" \ 26 insn "\n" \ 27 "2: s32ex %[newval], %[addr]\n" \ 28 " getex %[newval]\n" \ 29 " beqz %[newval], 1b\n" \ 30 " movi %[newval], 0\n" \ 31 "3:\n" \ 32 " .section .fixup,\"ax\"\n" \ 33 " .align 4\n" \ 34 " .literal_position\n" \ 35 "5: movi %[oldval], 3b\n" \ 36 " movi %[newval], %[fault]\n" \ 37 " jx %[oldval]\n" \ 38 " .previous\n" \ 39 " .section __ex_table,\"a\"\n" \ 40 " .long 1b, 5b, 2b, 5b\n" \ 41 " .previous\n" \ 42 : [oldval] "=&r" (old), [newval] "=&r" (ret) \ 43 : [addr] "r" (uaddr), [oparg] "r" (arg), \ 44 [fault] "I" (-EFAULT) \ 45 : "memory") 46 #elif XCHAL_HAVE_S32C1I 47 #define __futex_atomic_op(insn, ret, old, uaddr, arg) \ 48 __asm__ __volatile( \ 49 "1: l32i %[oldval], %[addr], 0\n" \ 50 insn "\n" \ 51 " wsr %[oldval], scompare1\n" \ 52 "2: s32c1i %[newval], %[addr], 0\n" \ 53 " bne %[newval], %[oldval], 1b\n" \ 54 " movi %[newval], 0\n" \ 55 "3:\n" \ 56 " .section .fixup,\"ax\"\n" \ 57 " .align 4\n" \ 58 " .literal_position\n" \ 59 "5: movi %[oldval], 3b\n" \ 60 " movi %[newval], %[fault]\n" \ 61 " jx %[oldval]\n" \ 62 " .previous\n" \ 63 " .section __ex_table,\"a\"\n" \ 64 " .long 1b, 5b, 2b, 5b\n" \ 65 " .previous\n" \ 66 : [oldval] "=&r" (old), [newval] "=&r" (ret) \ 67 : [addr] "r" (uaddr), [oparg] "r" (arg), \ 68 [fault] "I" (-EFAULT) \ 69 : "memory") 70 #endif 71 72 static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval, 73 u32 __user *uaddr) 74 { 75 #if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE 76 int oldval = 0, ret; 77 78 pagefault_disable(); 79 80 switch (op) { 81 case FUTEX_OP_SET: 82 __futex_atomic_op("mov %[newval], %[oparg]", 83 ret, oldval, uaddr, oparg); 84 break; 85 case FUTEX_OP_ADD: 86 __futex_atomic_op("add %[newval], %[oldval], %[oparg]", 87 ret, oldval, uaddr, oparg); 88 break; 89 case FUTEX_OP_OR: 90 __futex_atomic_op("or %[newval], %[oldval], %[oparg]", 91 ret, oldval, uaddr, oparg); 92 break; 93 case FUTEX_OP_ANDN: 94 __futex_atomic_op("and %[newval], %[oldval], %[oparg]", 95 ret, oldval, uaddr, ~oparg); 96 break; 97 case FUTEX_OP_XOR: 98 __futex_atomic_op("xor %[newval], %[oldval], %[oparg]", 99 ret, oldval, uaddr, oparg); 100 break; 101 default: 102 ret = -ENOSYS; 103 } 104 105 pagefault_enable(); 106 107 if (!ret) 108 *oval = oldval; 109 110 return ret; 111 #else 112 return -ENOSYS; 113 #endif 114 } 115 116 static inline int 117 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 118 u32 oldval, u32 newval) 119 { 120 #if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE 121 unsigned long tmp; 122 int ret = 0; 123 124 if (!access_ok(uaddr, sizeof(u32))) 125 return -EFAULT; 126 127 __asm__ __volatile__ ( 128 " # futex_atomic_cmpxchg_inatomic\n" 129 #if XCHAL_HAVE_EXCLUSIVE 130 "1: l32ex %[tmp], %[addr]\n" 131 " s32i %[tmp], %[uval], 0\n" 132 " bne %[tmp], %[oldval], 2f\n" 133 " mov %[tmp], %[newval]\n" 134 "3: s32ex %[tmp], %[addr]\n" 135 " getex %[tmp]\n" 136 " beqz %[tmp], 1b\n" 137 #elif XCHAL_HAVE_S32C1I 138 " wsr %[oldval], scompare1\n" 139 "1: s32c1i %[newval], %[addr], 0\n" 140 " s32i %[newval], %[uval], 0\n" 141 #endif 142 "2:\n" 143 " .section .fixup,\"ax\"\n" 144 " .align 4\n" 145 " .literal_position\n" 146 "4: movi %[tmp], 2b\n" 147 " movi %[ret], %[fault]\n" 148 " jx %[tmp]\n" 149 " .previous\n" 150 " .section __ex_table,\"a\"\n" 151 " .long 1b, 4b\n" 152 #if XCHAL_HAVE_EXCLUSIVE 153 " .long 3b, 4b\n" 154 #endif 155 " .previous\n" 156 : [ret] "+r" (ret), [newval] "+r" (newval), [tmp] "=&r" (tmp) 157 : [addr] "r" (uaddr), [oldval] "r" (oldval), [uval] "r" (uval), 158 [fault] "I" (-EFAULT) 159 : "memory"); 160 161 return ret; 162 #else 163 return -ENOSYS; 164 #endif 165 } 166 167 #endif /* _ASM_XTENSA_FUTEX_H */ 168