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