152 lines
3.5 KiB
C
152 lines
3.5 KiB
C
/*
|
|
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* Vineetg: August 2010: From Android kernel work
|
|
*/
|
|
|
|
#ifndef _ASM_FUTEX_H
|
|
#define _ASM_FUTEX_H
|
|
|
|
#include <linux/futex.h>
|
|
#include <linux/preempt.h>
|
|
#include <linux/uaccess.h>
|
|
#include <asm/errno.h>
|
|
|
|
#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\
|
|
\
|
|
__asm__ __volatile__( \
|
|
"1: ld %1, [%2] \n" \
|
|
insn "\n" \
|
|
"2: st %0, [%2] \n" \
|
|
" mov %0, 0 \n" \
|
|
"3: \n" \
|
|
" .section .fixup,\"ax\" \n" \
|
|
" .align 4 \n" \
|
|
"4: mov %0, %4 \n" \
|
|
" b 3b \n" \
|
|
" .previous \n" \
|
|
" .section __ex_table,\"a\" \n" \
|
|
" .align 4 \n" \
|
|
" .word 1b, 4b \n" \
|
|
" .word 2b, 4b \n" \
|
|
" .previous \n" \
|
|
\
|
|
: "=&r" (ret), "=&r" (oldval) \
|
|
: "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \
|
|
: "cc", "memory")
|
|
|
|
static inline 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(int)))
|
|
return -EFAULT;
|
|
|
|
pagefault_disable(); /* implies preempt_disable() */
|
|
|
|
switch (op) {
|
|
case FUTEX_OP_SET:
|
|
__futex_atomic_op("mov %0, %3", ret, oldval, uaddr, oparg);
|
|
break;
|
|
case FUTEX_OP_ADD:
|
|
__futex_atomic_op("add %0, %1, %3", ret, oldval, uaddr, oparg);
|
|
break;
|
|
case FUTEX_OP_OR:
|
|
__futex_atomic_op("or %0, %1, %3", ret, oldval, uaddr, oparg);
|
|
break;
|
|
case FUTEX_OP_ANDN:
|
|
__futex_atomic_op("bic %0, %1, %3", ret, oldval, uaddr, oparg);
|
|
break;
|
|
case FUTEX_OP_XOR:
|
|
__futex_atomic_op("xor %0, %1, %3", ret, oldval, uaddr, oparg);
|
|
break;
|
|
default:
|
|
ret = -ENOSYS;
|
|
}
|
|
|
|
pagefault_enable(); /* subsumes preempt_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;
|
|
}
|
|
|
|
/* Compare-xchg with preemption disabled.
|
|
* Notes:
|
|
* -Best-Effort: Exchg happens only if compare succeeds.
|
|
* If compare fails, returns; leaving retry/looping to upper layers
|
|
* -successful cmp-xchg: return orig value in @addr (same as cmp val)
|
|
* -Compare fails: return orig value in @addr
|
|
* -user access r/w fails: return -EFAULT
|
|
*/
|
|
static inline int
|
|
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval,
|
|
u32 newval)
|
|
{
|
|
u32 val;
|
|
|
|
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
|
|
return -EFAULT;
|
|
|
|
pagefault_disable(); /* implies preempt_disable() */
|
|
|
|
/* TBD : can use llock/scond */
|
|
__asm__ __volatile__(
|
|
"1: ld %0, [%3] \n"
|
|
" brne %0, %1, 3f \n"
|
|
"2: st %2, [%3] \n"
|
|
"3: \n"
|
|
" .section .fixup,\"ax\" \n"
|
|
"4: mov %0, %4 \n"
|
|
" b 3b \n"
|
|
" .previous \n"
|
|
" .section __ex_table,\"a\" \n"
|
|
" .align 4 \n"
|
|
" .word 1b, 4b \n"
|
|
" .word 2b, 4b \n"
|
|
" .previous\n"
|
|
: "=&r"(val)
|
|
: "r"(oldval), "r"(newval), "r"(uaddr), "ir"(-EFAULT)
|
|
: "cc", "memory");
|
|
|
|
pagefault_enable(); /* subsumes preempt_enable() */
|
|
|
|
*uval = val;
|
|
return val;
|
|
}
|
|
|
|
#endif
|