1 #ifndef _ASM_ARM_FUTEX_H 2 #define _ASM_ARM_FUTEX_H 3 4 #ifdef __KERNEL__ 5 6 #include <linux/futex.h> 7 #include <linux/uaccess.h> 8 #include <asm/errno.h> 9 10 #define __futex_atomic_ex_table(err_reg) \ 11 "3:\n" \ 12 " .pushsection __ex_table,\"a\"\n" \ 13 " .align 3\n" \ 14 " .long 1b, 4f, 2b, 4f\n" \ 15 " .popsection\n" \ 16 " .pushsection .text.fixup,\"ax\"\n" \ 17 " .align 2\n" \ 18 "4: mov %0, " err_reg "\n" \ 19 " b 3b\n" \ 20 " .popsection" 21 22 #ifdef CONFIG_SMP 23 24 #define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \ 25 smp_mb(); \ 26 prefetchw(uaddr); \ 27 __asm__ __volatile__( \ 28 "1: ldrex %1, [%3]\n" \ 29 " " insn "\n" \ 30 "2: strex %2, %0, [%3]\n" \ 31 " teq %2, #0\n" \ 32 " bne 1b\n" \ 33 " mov %0, #0\n" \ 34 __futex_atomic_ex_table("%5") \ 35 : "=&r" (ret), "=&r" (oldval), "=&r" (tmp) \ 36 : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \ 37 : "cc", "memory") 38 39 static inline int 40 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 41 u32 oldval, u32 newval) 42 { 43 int ret; 44 u32 val; 45 46 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) 47 return -EFAULT; 48 49 smp_mb(); 50 /* Prefetching cannot fault */ 51 prefetchw(uaddr); 52 __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" 53 "1: ldrex %1, [%4]\n" 54 " teq %1, %2\n" 55 " ite eq @ explicit IT needed for the 2b label\n" 56 "2: strexeq %0, %3, [%4]\n" 57 " movne %0, #0\n" 58 " teq %0, #0\n" 59 " bne 1b\n" 60 __futex_atomic_ex_table("%5") 61 : "=&r" (ret), "=&r" (val) 62 : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) 63 : "cc", "memory"); 64 smp_mb(); 65 66 *uval = val; 67 return ret; 68 } 69 70 #else /* !SMP, we can work around lack of atomic ops by disabling preemption */ 71 72 #include <linux/preempt.h> 73 #include <asm/domain.h> 74 75 #define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \ 76 __asm__ __volatile__( \ 77 "1: " TUSER(ldr) " %1, [%3]\n" \ 78 " " insn "\n" \ 79 "2: " TUSER(str) " %0, [%3]\n" \ 80 " mov %0, #0\n" \ 81 __futex_atomic_ex_table("%5") \ 82 : "=&r" (ret), "=&r" (oldval), "=&r" (tmp) \ 83 : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \ 84 : "cc", "memory") 85 86 static inline int 87 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 88 u32 oldval, u32 newval) 89 { 90 int ret = 0; 91 u32 val; 92 93 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) 94 return -EFAULT; 95 96 preempt_disable(); 97 __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" 98 "1: " TUSER(ldr) " %1, [%4]\n" 99 " teq %1, %2\n" 100 " it eq @ explicit IT needed for the 2b label\n" 101 "2: " TUSER(streq) " %3, [%4]\n" 102 __futex_atomic_ex_table("%5") 103 : "+r" (ret), "=&r" (val) 104 : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) 105 : "cc", "memory"); 106 107 *uval = val; 108 preempt_enable(); 109 110 return ret; 111 } 112 113 #endif /* !SMP */ 114 115 static inline int 116 futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr) 117 { 118 int op = (encoded_op >> 28) & 7; 119 int cmp = (encoded_op >> 24) & 15; 120 int oparg = (encoded_op << 8) >> 20; 121 int cmparg = (encoded_op << 20) >> 20; 122 int oldval = 0, ret, tmp; 123 124 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) 125 oparg = 1 << oparg; 126 127 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) 128 return -EFAULT; 129 130 #ifndef CONFIG_SMP 131 preempt_disable(); 132 #endif 133 pagefault_disable(); 134 135 switch (op) { 136 case FUTEX_OP_SET: 137 __futex_atomic_op("mov %0, %4", ret, oldval, tmp, uaddr, oparg); 138 break; 139 case FUTEX_OP_ADD: 140 __futex_atomic_op("add %0, %1, %4", ret, oldval, tmp, uaddr, oparg); 141 break; 142 case FUTEX_OP_OR: 143 __futex_atomic_op("orr %0, %1, %4", ret, oldval, tmp, uaddr, oparg); 144 break; 145 case FUTEX_OP_ANDN: 146 __futex_atomic_op("and %0, %1, %4", ret, oldval, tmp, uaddr, ~oparg); 147 break; 148 case FUTEX_OP_XOR: 149 __futex_atomic_op("eor %0, %1, %4", ret, oldval, tmp, uaddr, oparg); 150 break; 151 default: 152 ret = -ENOSYS; 153 } 154 155 pagefault_enable(); 156 #ifndef CONFIG_SMP 157 preempt_enable(); 158 #endif 159 160 if (!ret) { 161 switch (cmp) { 162 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; 163 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; 164 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; 165 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; 166 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; 167 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; 168 default: ret = -ENOSYS; 169 } 170 } 171 return ret; 172 } 173 174 #endif /* __KERNEL__ */ 175 #endif /* _ASM_ARM_FUTEX_H */ 176