kernel/arch/parisc/include/asm/futex.h

   1 #ifndef _ASM_PARISC_FUTEX_H
   2 #define _ASM_PARISC_FUTEX_H
   3
   4 #ifdef __KERNEL__
   5
   6 #include <linux/futex.h>
   7 #include <linux/uaccess.h>
   8 #include <asm/atomic.h>
   9 #include <asm/errno.h>
  10
  11 /* The following has to match the LWS code in syscall.S.  We have
  12    sixteen four-word locks. */
  13
  14 static inline void
  15 _futex_spin_lock_irqsave(u32 __user *uaddr, unsigned long int *flags)
  16 {
  17         extern u32 lws_lock_start[];
  18         long index = ((long)uaddr & 0xf0) >> 2;
  19         arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
  20         local_irq_save(*flags);
  21         arch_spin_lock(s);
  22 }
  23
  24 static inline void
  25 _futex_spin_unlock_irqrestore(u32 __user *uaddr, unsigned long int *flags)
  26 {
  27         extern u32 lws_lock_start[];
  28         long index = ((long)uaddr & 0xf0) >> 2;
  29         arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
  30         arch_spin_unlock(s);
  31         local_irq_restore(*flags);
  32 }
  33
  34 static inline int
  35 futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
  36 {
  37         unsigned long int flags;
  38         u32 val;
  39         int op = (encoded_op >> 28) & 7;
  40         int cmp = (encoded_op >> 24) & 15;
  41         int oparg = (encoded_op << 8) >> 20;
  42         int cmparg = (encoded_op << 20) >> 20;
  43         int oldval = 0, ret;
  44         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
  45                 oparg = 1 << oparg;
  46
  47         if (!access_ok(VERIFY_WRITE, uaddr, sizeof(*uaddr)))
  48                 return -EFAULT;
  49
  50         pagefault_disable();
  51
  52         _futex_spin_lock_irqsave(uaddr, &flags);
  53
  54         switch (op) {
  55         case FUTEX_OP_SET:
  56                 /* *(int *)UADDR2 = OPARG; */
  57                 ret = get_user(oldval, uaddr);
  58                 if (!ret)
  59                         ret = put_user(oparg, uaddr);
  60                 break;
  61         case FUTEX_OP_ADD:
  62                 /* *(int *)UADDR2 += OPARG; */
  63                 ret = get_user(oldval, uaddr);
  64                 if (!ret) {
  65                         val = oldval + oparg;
  66                         ret = put_user(val, uaddr);
  67                 }
  68                 break;
  69         case FUTEX_OP_OR:
  70                 /* *(int *)UADDR2 |= OPARG; */
  71                 ret = get_user(oldval, uaddr);
  72                 if (!ret) {
  73                         val = oldval | oparg;
  74                         ret = put_user(val, uaddr);
  75                 }
  76                 break;
  77         case FUTEX_OP_ANDN:
  78                 /* *(int *)UADDR2 &= ~OPARG; */
  79                 ret = get_user(oldval, uaddr);
  80                 if (!ret) {
  81                         val = oldval & ~oparg;
  82                         ret = put_user(val, uaddr);
  83                 }
  84                 break;
  85         case FUTEX_OP_XOR:
  86                 /* *(int *)UADDR2 ^= OPARG; */
  87                 ret = get_user(oldval, uaddr);
  88                 if (!ret) {
  89                         val = oldval ^ oparg;
  90                         ret = put_user(val, uaddr);
  91                 }
  92                 break;
  93         default:
  94                 ret = -ENOSYS;
  95         }
  96
  97         _futex_spin_unlock_irqrestore(uaddr, &flags);
  98
  99         pagefault_enable();
 100
 101         if (!ret) {
 102                 switch (cmp) {
 103                 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
 104                 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
 105                 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
 106                 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
 107                 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
 108                 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
 109                 default: ret = -ENOSYS;
 110                 }
 111         }
 112         return ret;
 113 }
 114
 115 /* Non-atomic version */
 116 static inline int
 117 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
 118                               u32 oldval, u32 newval)
 119 {
 120         int ret;
 121         u32 val;
 122         unsigned long flags;
 123
 124         /* futex.c wants to do a cmpxchg_inatomic on kernel NULL, which is
 125          * our gateway page, and causes no end of trouble...
 126          */
 127         if (segment_eq(KERNEL_DS, get_fs()) && !uaddr)
 128                 return -EFAULT;
 129
 130         if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
 131                 return -EFAULT;
 132
 133         /* HPPA has no cmpxchg in hardware and therefore the
 134          * best we can do here is use an array of locks. The
 135          * lock selected is based on a hash of the userspace
 136          * address. This should scale to a couple of CPUs.
 137          */
 138
 139         _futex_spin_lock_irqsave(uaddr, &flags);
 140
 141         ret = get_user(val, uaddr);
 142
 143         if (!ret && val == oldval)
 144                 ret = put_user(newval, uaddr);
 145
 146         *uval = val;
 147
 148         _futex_spin_unlock_irqrestore(uaddr, &flags);
 149
 150         return ret;
 151 }
 152
 153 #endif /*__KERNEL__*/
 154 #endif /*_ASM_PARISC_FUTEX_H*/