1 /* 2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * Vineetg: August 2010: From Android kernel work 9 */ 10 11 #ifndef _ASM_FUTEX_H 12 #define _ASM_FUTEX_H 13 14 #include <linux/futex.h> 15 #include <linux/preempt.h> 16 #include <linux/uaccess.h> 17 #include <asm/errno.h> 18 19 #ifdef CONFIG_ARC_HAS_LLSC 20 21 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\ 22 \ 23 smp_mb(); \ 24 __asm__ __volatile__( \ 25 "1: llock %1, [%2] \n" \ 26 insn "\n" \ 27 "2: scond %0, [%2] \n" \ 28 " bnz 1b \n" \ 29 " mov %0, 0 \n" \ 30 "3: \n" \ 31 " .section .fixup,\"ax\" \n" \ 32 " .align 4 \n" \ 33 "4: mov %0, %4 \n" \ 34 " b 3b \n" \ 35 " .previous \n" \ 36 " .section __ex_table,\"a\" \n" \ 37 " .align 4 \n" \ 38 " .word 1b, 4b \n" \ 39 " .word 2b, 4b \n" \ 40 " .previous \n" \ 41 \ 42 : "=&r" (ret), "=&r" (oldval) \ 43 : "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \ 44 : "cc", "memory"); \ 45 smp_mb() \ 46 47 #else /* !CONFIG_ARC_HAS_LLSC */ 48 49 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\ 50 \ 51 smp_mb(); \ 52 __asm__ __volatile__( \ 53 "1: ld %1, [%2] \n" \ 54 insn "\n" \ 55 "2: st %0, [%2] \n" \ 56 " mov %0, 0 \n" \ 57 "3: \n" \ 58 " .section .fixup,\"ax\" \n" \ 59 " .align 4 \n" \ 60 "4: mov %0, %4 \n" \ 61 " b 3b \n" \ 62 " .previous \n" \ 63 " .section __ex_table,\"a\" \n" \ 64 " .align 4 \n" \ 65 " .word 1b, 4b \n" \ 66 " .word 2b, 4b \n" \ 67 " .previous \n" \ 68 \ 69 : "=&r" (ret), "=&r" (oldval) \ 70 : "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \ 71 : "cc", "memory"); \ 72 smp_mb() \ 73 74 #endif 75 76 static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) 77 { 78 int op = (encoded_op >> 28) & 7; 79 int cmp = (encoded_op >> 24) & 15; 80 int oparg = (encoded_op << 8) >> 20; 81 int cmparg = (encoded_op << 20) >> 20; 82 int oldval = 0, ret; 83 84 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) 85 oparg = 1 << oparg; 86 87 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) 88 return -EFAULT; 89 90 pagefault_disable(); 91 92 switch (op) { 93 case FUTEX_OP_SET: 94 __futex_atomic_op("mov %0, %3", ret, oldval, uaddr, oparg); 95 break; 96 case FUTEX_OP_ADD: 97 /* oldval = *uaddr; *uaddr += oparg ; ret = *uaddr */ 98 __futex_atomic_op("add %0, %1, %3", ret, oldval, uaddr, oparg); 99 break; 100 case FUTEX_OP_OR: 101 __futex_atomic_op("or %0, %1, %3", ret, oldval, uaddr, oparg); 102 break; 103 case FUTEX_OP_ANDN: 104 __futex_atomic_op("bic %0, %1, %3", ret, oldval, uaddr, oparg); 105 break; 106 case FUTEX_OP_XOR: 107 __futex_atomic_op("xor %0, %1, %3", ret, oldval, uaddr, oparg); 108 break; 109 default: 110 ret = -ENOSYS; 111 } 112 113 pagefault_enable(); 114 115 if (!ret) { 116 switch (cmp) { 117 case FUTEX_OP_CMP_EQ: 118 ret = (oldval == cmparg); 119 break; 120 case FUTEX_OP_CMP_NE: 121 ret = (oldval != cmparg); 122 break; 123 case FUTEX_OP_CMP_LT: 124 ret = (oldval < cmparg); 125 break; 126 case FUTEX_OP_CMP_GE: 127 ret = (oldval >= cmparg); 128 break; 129 case FUTEX_OP_CMP_LE: 130 ret = (oldval <= cmparg); 131 break; 132 case FUTEX_OP_CMP_GT: 133 ret = (oldval > cmparg); 134 break; 135 default: 136 ret = -ENOSYS; 137 } 138 } 139 return ret; 140 } 141 142 /* 143 * cmpxchg of futex (pagefaults disabled by caller) 144 * Return 0 for success, -EFAULT otherwise 145 */ 146 static inline int 147 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 expval, 148 u32 newval) 149 { 150 int ret = 0; 151 u32 existval; 152 153 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) 154 return -EFAULT; 155 156 smp_mb(); 157 158 __asm__ __volatile__( 159 #ifdef CONFIG_ARC_HAS_LLSC 160 "1: llock %1, [%4] \n" 161 " brne %1, %2, 3f \n" 162 "2: scond %3, [%4] \n" 163 " bnz 1b \n" 164 #else 165 "1: ld %1, [%4] \n" 166 " brne %1, %2, 3f \n" 167 "2: st %3, [%4] \n" 168 #endif 169 "3: \n" 170 " .section .fixup,\"ax\" \n" 171 "4: mov %0, %5 \n" 172 " b 3b \n" 173 " .previous \n" 174 " .section __ex_table,\"a\" \n" 175 " .align 4 \n" 176 " .word 1b, 4b \n" 177 " .word 2b, 4b \n" 178 " .previous\n" 179 : "+&r"(ret), "=&r"(existval) 180 : "r"(expval), "r"(newval), "r"(uaddr), "ir"(-EFAULT) 181 : "cc", "memory"); 182 183 smp_mb(); 184 185 *uval = existval; 186 return ret; 187 } 188 189 #endif 190