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alpha: futex implementation 

Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Richard Henderson <rth@twiddle.net
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ivan Kokshaysky 2009-04-30 15:08:48 -07:00 committed by Linus Torvalds
parent 08a42e86bc
commit 77b4cf5cb0
2 changed files with 116 additions and 4 deletions
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2
arch/alpha/include/asm/barrier.h
View File

@ -16,11 +16,13 @@ __asm__ __volatile__("wmb": : :"memory")
__asm__ __volatile__("mb": : :"memory")
#ifdef CONFIG_SMP
#define __ASM_SMP_MB "\tmb\n"
#define smp_mb() mb()
#define smp_rmb() rmb()
#define smp_wmb() wmb()
#define smp_read_barrier_depends() read_barrier_depends()
#else
#define __ASM_SMP_MB
#define smp_mb() barrier()
#define smp_rmb() barrier()
#define smp_wmb() barrier()

118
arch/alpha/include/asm/futex.h
View File

@ -1,6 +1,116 @@
#ifndef _ASM_FUTEX_H
#define _ASM_FUTEX_H
#ifndef _ASM_ALPHA_FUTEX_H
#define _ASM_ALPHA_FUTEX_H
#include <asm-generic/futex.h>
#ifdef __KERNEL__
#endif
#include <linux/futex.h>
#include <linux/uaccess.h>
#include <asm/errno.h>
#include <asm/barrier.h>
#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
__asm__ __volatile__( \
__ASM_SMP_MB \
"1: ldl_l %0,0(%2)\n" \
insn \
"2: stl_c %1,0(%2)\n" \
" beq %1,4f\n" \
" mov $31,%1\n" \
"3: .subsection 2\n" \
"4: br 1b\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .long 1b-.\n" \
" lda $31,3b-1b(%1)\n" \
" .long 2b-.\n" \
" lda $31,3b-2b(%1)\n" \
" .previous\n" \
: "=&r" (oldval), "=&r"(ret) \
: "r" (uaddr), "r"(oparg) \
: "memory")
static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
{
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(int)))
return -EFAULT;
pagefault_disable();
switch (op) {
case FUTEX_OP_SET:
__futex_atomic_op("mov %3,%1\n", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ADD:
__futex_atomic_op("addl %0,%3,%1\n", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_OR:
__futex_atomic_op("or %0,%3,%1\n", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ANDN:
__futex_atomic_op("andnot %0,%3,%1\n", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_XOR:
__futex_atomic_op("xor %0,%3,%1\n", ret, oldval, uaddr, oparg);
break;
default:
ret = -ENOSYS;
}
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;
}
static inline int
futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
{
int prev, cmp;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
__asm__ __volatile__ (
__ASM_SMP_MB
"1: ldl_l %0,0(%2)\n"
" cmpeq %0,%3,%1\n"
" beq %1,3f\n"
" mov %4,%1\n"
"2: stl_c %1,0(%2)\n"
" beq %1,4f\n"
"3: .subsection 2\n"
"4: br 1b\n"
" .previous\n"
" .section __ex_table,\"a\"\n"
" .long 1b-.\n"
" lda $31,3b-1b(%0)\n"
" .long 2b-.\n"
" lda $31,3b-2b(%0)\n"
" .previous\n"
: "=&r"(prev), "=&r"(cmp)
: "r"(uaddr), "r"((long)oldval), "r"(newval)
: "memory");
return prev;
}
#endif /* __KERNEL__ */
#endif /* _ASM_ALPHA_FUTEX_H */