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 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, 48 u32 __user *uaddr) 49 { 50 int oldval = 0, ret; 51 52 #if !XCHAL_HAVE_S32C1I 53 return -ENOSYS; 54 #endif 55 56 pagefault_disable(); 57 58 switch (op) { 59 case FUTEX_OP_SET: 60 __futex_atomic_op("mov %1, %4", ret, oldval, uaddr, oparg); 61 break; 62 case FUTEX_OP_ADD: 63 __futex_atomic_op("add %1, %0, %4", ret, oldval, uaddr, 64 oparg); 65 break; 66 case FUTEX_OP_OR: 67 __futex_atomic_op("or %1, %0, %4", ret, oldval, uaddr, 68 oparg); 69 break; 70 case FUTEX_OP_ANDN: 71 __futex_atomic_op("and %1, %0, %4", ret, oldval, uaddr, 72 ~oparg); 73 break; 74 case FUTEX_OP_XOR: 75 __futex_atomic_op("xor %1, %0, %4", ret, oldval, uaddr, 76 oparg); 77 break; 78 default: 79 ret = -ENOSYS; 80 } 81 82 pagefault_enable(); 83 84 if (!ret) 85 *oval = oldval; 86 87 return ret; 88 } 89 90 static inline int 91 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 92 u32 oldval, u32 newval) 93 { 94 int ret = 0; 95 96 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) 97 return -EFAULT; 98 99 #if !XCHAL_HAVE_S32C1I 100 return -ENOSYS; 101 #endif 102 103 __asm__ __volatile__ ( 104 " # futex_atomic_cmpxchg_inatomic\n" 105 " wsr %5, scompare1\n" 106 "1: s32c1i %1, %4, 0\n" 107 " s32i %1, %6, 0\n" 108 "2:\n" 109 " .section .fixup,\"ax\"\n" 110 " .align 4\n" 111 "3: .long 2b\n" 112 "4: l32r %1, 3b\n" 113 " movi %0, %7\n" 114 " jx %1\n" 115 " .previous\n" 116 " .section __ex_table,\"a\"\n" 117 " .long 1b,4b\n" 118 " .previous\n" 119 : "+r" (ret), "+r" (newval), "+m" (*uaddr), "+m" (*uval) 120 : "r" (uaddr), "r" (oldval), "r" (uval), "I" (-EFAULT) 121 : "memory"); 122 123 return ret; 124 } 125 126 #endif /* __KERNEL__ */ 127 #endif /* _ASM_XTENSA_FUTEX_H */ 128