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/*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) IBM Corporation, 2011
*
* Authors: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
* Anton Blanchard <anton@au.ibm.com>
*/
#include <linux/uaccess.h>
#include <linux/hardirq.h>
#include <asm/switch_to.h>
int enter_vmx_usercopy(void)
{
if (in_interrupt())
return 0;
/* This acts as preempt_disable() as well and will make
* enable_kernel_altivec(). We need to disable page faults
* as they can call schedule and thus make us lose the VMX
* context. So on page faults, we just fail which will cause
* a fallback to the normal non-vmx copy.
*/
pagefault_disable();
enable_kernel_altivec();
return 1;
}
/*
* This function must return 0 because we tail call optimise when calling
* from __copy_tofrom_user_power7 which returns 0 on success.
*/
int exit_vmx_usercopy(void)
{
pagefault_enable();
return 0;
}
int enter_vmx_copy(void)
{
if (in_interrupt())
return 0;
preempt_disable();
enable_kernel_altivec();
return 1;
}
/*
* All calls to this function will be optimised into tail calls. We are
* passed a pointer to the destination which we return as required by a
* memcpy implementation.
*/
void *exit_vmx_copy(void *dest)
{
preempt_enable();
return dest;
}
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