diff options
Diffstat (limited to 'arch/parisc/include/asm/futex.h')
| -rw-r--r-- | arch/parisc/include/asm/futex.h | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/arch/parisc/include/asm/futex.h b/arch/parisc/include/asm/futex.h new file mode 100644 index 000000000..49df14805 --- /dev/null +++ b/arch/parisc/include/asm/futex.h @@ -0,0 +1,154 @@ +#ifndef _ASM_PARISC_FUTEX_H +#define _ASM_PARISC_FUTEX_H + +#ifdef __KERNEL__ + +#include <linux/futex.h> +#include <linux/uaccess.h> +#include <asm/atomic.h> +#include <asm/errno.h> + +/* The following has to match the LWS code in syscall.S. We have + sixteen four-word locks. */ + +static inline void +_futex_spin_lock_irqsave(u32 __user *uaddr, unsigned long int *flags) +{ + extern u32 lws_lock_start[]; + long index = ((long)uaddr & 0xf0) >> 2; + arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index]; + local_irq_save(*flags); + arch_spin_lock(s); +} + +static inline void +_futex_spin_unlock_irqrestore(u32 __user *uaddr, unsigned long int *flags) +{ + extern u32 lws_lock_start[]; + long index = ((long)uaddr & 0xf0) >> 2; + arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index]; + arch_spin_unlock(s); + local_irq_restore(*flags); +} + +static inline int +futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr) +{ + unsigned long int flags; + u32 val; + int op = (encoded_op >> 28) & 7; + int cmp = (encoded_op >> 24) & 15; + int oparg = (encoded_op << 8) >> 20; + int cmparg = (encoded_op << 20) >> 20; + int oldval = 0, ret; + if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) + oparg = 1 << oparg; + + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(*uaddr))) + return -EFAULT; + + pagefault_disable(); + + _futex_spin_lock_irqsave(uaddr, &flags); + + switch (op) { + case FUTEX_OP_SET: + /* *(int *)UADDR2 = OPARG; */ + ret = get_user(oldval, uaddr); + if (!ret) + ret = put_user(oparg, uaddr); + break; + case FUTEX_OP_ADD: + /* *(int *)UADDR2 += OPARG; */ + ret = get_user(oldval, uaddr); + if (!ret) { + val = oldval + oparg; + ret = put_user(val, uaddr); + } + break; + case FUTEX_OP_OR: + /* *(int *)UADDR2 |= OPARG; */ + ret = get_user(oldval, uaddr); + if (!ret) { + val = oldval | oparg; + ret = put_user(val, uaddr); + } + break; + case FUTEX_OP_ANDN: + /* *(int *)UADDR2 &= ~OPARG; */ + ret = get_user(oldval, uaddr); + if (!ret) { + val = oldval & ~oparg; + ret = put_user(val, uaddr); + } + break; + case FUTEX_OP_XOR: + /* *(int *)UADDR2 ^= OPARG; */ + ret = get_user(oldval, uaddr); + if (!ret) { + val = oldval ^ oparg; + ret = put_user(val, uaddr); + } + break; + default: + ret = -ENOSYS; + } + + _futex_spin_unlock_irqrestore(uaddr, &flags); + + pagefault_enable(); + + if (!ret) { + switch (cmp) { + case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; + case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; + case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; + case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; + case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; + case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; + default: ret = -ENOSYS; + } + } + return ret; +} + +/* Non-atomic version */ +static inline int +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, + u32 oldval, u32 newval) +{ + int ret; + u32 val; + unsigned long flags; + + /* futex.c wants to do a cmpxchg_inatomic on kernel NULL, which is + * our gateway page, and causes no end of trouble... + */ + if (segment_eq(KERNEL_DS, get_fs()) && !uaddr) + return -EFAULT; + + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) + return -EFAULT; + + /* HPPA has no cmpxchg in hardware and therefore the + * best we can do here is use an array of locks. The + * lock selected is based on a hash of the userspace + * address. This should scale to a couple of CPUs. + */ + + _futex_spin_lock_irqsave(uaddr, &flags); + + ret = get_user(val, uaddr); + + if (!ret && val == oldval) + ret = put_user(newval, uaddr); + + *uval = val; + + _futex_spin_unlock_irqrestore(uaddr, &flags); + + return ret; +} + +#endif /*__KERNEL__*/ +#endif /*_ASM_PARISC_FUTEX_H*/ |