- 根目录:
- arch
- frv
- kernel
- futex.c
/* futex.c: futex operations
*
* Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/futex.h>
#include <linux/uaccess.h>
#include <asm/futex.h>
#include <asm/errno.h>
/*
* the various futex operations; MMU fault checking is ignored under no-MMU
* conditions
*/
static inline int atomic_futex_op_xchg_set(int oparg, u32 __user *uaddr, int *_oldval)
{
int oldval, ret;
asm("0: \n"
" orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
" ckeq icc3,cc7 \n"
"1: ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
" orcr cc7,cc7,cc3 \n" /* set CC3 to true */
"2: cst.p %3,%M0 ,cc3,#1 \n"
" corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
" beq icc3,#0,0b \n"
" setlos 0,%2 \n"
"3: \n"
".subsection 2 \n"
"4: setlos %5,%2 \n"
" bra 3b \n"
".previous \n"
".section __ex_table,\"a\" \n"
" .balign 8 \n"
" .long 1b,4b \n"
" .long 2b,4b \n"
".previous"
: "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
: "3"(oparg), "i"(-EFAULT)
: "memory", "cc7", "cc3", "icc3"
);
*_oldval = oldval;
return ret;
}
static inline int atomic_futex_op_xchg_add(int oparg, u32 __user *uaddr, int *_oldval)
{
int oldval, ret;
asm("0: \n"
" orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
" ckeq icc3,cc7 \n"
"1: ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
" orcr cc7,cc7,cc3 \n" /* set CC3 to true */
" add %1,%3,%3 \n"
"2: cst.p %3,%M0 ,cc3,#1 \n"
" corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
" beq icc3,#0,0b \n"
" setlos 0,%2 \n"
"3: \n"
".subsection 2 \n"
"4: setlos %5,%2 \n"
" bra 3b \n"
".previous \n"
".section __ex_table,\"a\" \n"
" .balign 8 \n"
" .long 1b,4b \n"
" .long 2b,4b \n"
".previous"
: "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
: "3"(oparg), "i"(-EFAULT)
: "memory", "cc7", "cc3", "icc3"
);
*_oldval = oldval;
return ret;
}
static inline int atomic_futex_op_xchg_or(int oparg, u32 __user *uaddr, int *_oldval)
{
int oldval, ret;
asm("0: \n"
" orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
" ckeq icc3,cc7 \n"
"1: ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
" orcr cc7,cc7,cc3 \n" /* set CC3 to true */
" or %1,%3,%3 \n"
"2: cst.p %3,%M0 ,cc3,#1 \n"
" corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
" beq icc3,#0,0b \n"
" setlos 0,%2 \n"
"3: \n"
".subsection 2 \n"
"4: setlos %5,%2 \n"
" bra 3b \n"
".previous \n"
".section __ex_table,\"a\" \n"
" .balign 8 \n"
" .long 1b,4b \n"
" .long 2b,4b \n"
".previous"
: "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
: "3"(oparg), "i"(-EFAULT)
: "memory", "cc7", "cc3", "icc3"
);
*_oldval = oldval;
return ret;
}
static inline int atomic_futex_op_xchg_and(int oparg, u32 __user *uaddr, int *_oldval)
{
int oldval, ret;
asm("0: \n"
" orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
" ckeq icc3,cc7 \n"
"1: ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
" orcr cc7,cc7,cc3 \n" /* set CC3 to true */
" and %1,%3,%3 \n"
"2: cst.p %3,%M0 ,cc3,#1 \n"
" corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
" beq icc3,#0,0b \n"
" setlos 0,%2 \n"
"3: \n"
".subsection 2 \n"
"4: setlos %5,%2 \n"
" bra 3b \n"
".previous \n"
".section __ex_table,\"a\" \n"
" .balign 8 \n"
" .long 1b,4b \n"
" .long 2b,4b \n"
".previous"
: "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
: "3"(oparg), "i"(-EFAULT)
: "memory", "cc7", "cc3", "icc3"
);
*_oldval = oldval;
return ret;
}
static inline int atomic_futex_op_xchg_xor(int oparg, u32 __user *uaddr, int *_oldval)
{
int oldval, ret;
asm("0: \n"
" orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
" ckeq icc3,cc7 \n"
"1: ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
" orcr cc7,cc7,cc3 \n" /* set CC3 to true */
" xor %1,%3,%3 \n"
"2: cst.p %3,%M0 ,cc3,#1 \n"
" corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
" beq icc3,#0,0b \n"
" setlos 0,%2 \n"
"3: \n"
".subsection 2 \n"
"4: setlos %5,%2 \n"
" bra 3b \n"
".previous \n"
".section __ex_table,\"a\" \n"
" .balign 8 \n"
" .long 1b,4b \n"
" .long 2b,4b \n"
".previous"
: "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
: "3"(oparg), "i"(-EFAULT)
: "memory", "cc7", "cc3", "icc3"
);
*_oldval = oldval;
return ret;
}
/*****************************************************************************/
/*
* do the futex operations
*/
int futex_atomic_op_inuser(int encoded_op, u32 __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(u32)))
return -EFAULT;
pagefault_disable();
switch (op) {
case FUTEX_OP_SET:
ret = atomic_futex_op_xchg_set(oparg, uaddr, &oldval);
break;
case FUTEX_OP_ADD:
ret = atomic_futex_op_xchg_add(oparg, uaddr, &oldval);
break;
case FUTEX_OP_OR:
ret = atomic_futex_op_xchg_or(oparg, uaddr, &oldval);
break;
case FUTEX_OP_ANDN:
ret = atomic_futex_op_xchg_and(~oparg, uaddr, &oldval);
break;
case FUTEX_OP_XOR:
ret = atomic_futex_op_xchg_xor(oparg, uaddr, &oldval);
break;
default:
ret = -ENOSYS;
break;
}
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; break;
}
}
return ret;
} /* end futex_atomic_op_inuser() */