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 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \ 23 __asm__ __volatile( \ 24 "1: l32i %0, %2, 0\n" \ 25 insn "\n" \ 26 " wsr %0, scompare1\n" \ 27 "2: s32c1i %1, %2, 0\n" \ 28 " bne %1, %0, 1b\n" \ 29 " movi %1, 0\n" \ 30 "3:\n" \ 31 " .section .fixup,\"ax\"\n" \ 32 " .align 4\n" \ 33 " .literal_position\n" \ 34 "5: movi %0, 3b\n" \ 35 " movi %1, %3\n" \ 36 " jx %0\n" \ 37 " .previous\n" \ 38 " .section __ex_table,\"a\"\n" \ 39 " .long 1b,5b,2b,5b\n" \ 40 " .previous\n" \ 41 : "=&r" (oldval), "=&r" (ret) \ 42 : "r" (uaddr), "I" (-EFAULT), "r" (oparg) \ 43 : "memory") 44 45 static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval, 46 u32 __user *uaddr) 47 { 48 int oldval = 0, ret; 49 50 #if !XCHAL_HAVE_S32C1I 51 return -ENOSYS; 52 #endif 53 54 pagefault_disable(); 55 56 switch (op) { 57 case FUTEX_OP_SET: 58 __futex_atomic_op("mov %1, %4", ret, oldval, uaddr, oparg); 59 break; 60 case FUTEX_OP_ADD: 61 __futex_atomic_op("add %1, %0, %4", ret, oldval, uaddr, 62 oparg); 63 break; 64 case FUTEX_OP_OR: 65 __futex_atomic_op("or %1, %0, %4", ret, oldval, uaddr, 66 oparg); 67 break; 68 case FUTEX_OP_ANDN: 69 __futex_atomic_op("and %1, %0, %4", ret, oldval, uaddr, 70 ~oparg); 71 break; 72 case FUTEX_OP_XOR: 73 __futex_atomic_op("xor %1, %0, %4", ret, oldval, uaddr, 74 oparg); 75 break; 76 default: 77 ret = -ENOSYS; 78 } 79 80 pagefault_enable(); 81 82 if (!ret) 83 *oval = oldval; 84 85 return ret; 86 } 87 88 static inline int 89 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 90 u32 oldval, u32 newval) 91 { 92 int ret = 0; 93 94 if (!access_ok(uaddr, sizeof(u32))) 95 return -EFAULT; 96 97 #if !XCHAL_HAVE_S32C1I 98 return -ENOSYS; 99 #endif 100 101 __asm__ __volatile__ ( 102 " # futex_atomic_cmpxchg_inatomic\n" 103 " wsr %5, scompare1\n" 104 "1: s32c1i %1, %4, 0\n" 105 " s32i %1, %6, 0\n" 106 "2:\n" 107 " .section .fixup,\"ax\"\n" 108 " .align 4\n" 109 " .literal_position\n" 110 "4: movi %1, 2b\n" 111 " movi %0, %7\n" 112 " jx %1\n" 113 " .previous\n" 114 " .section __ex_table,\"a\"\n" 115 " .long 1b,4b\n" 116 " .previous\n" 117 : "+r" (ret), "+r" (newval), "+m" (*uaddr), "+m" (*uval) 118 : "r" (uaddr), "r" (oldval), "r" (uval), "I" (-EFAULT) 119 : "memory"); 120 121 return ret; 122 } 123 124 #endif /* _ASM_XTENSA_FUTEX_H */ 125