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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/powerpc/platforms/cell/spu_fault.c
10818 views
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/*

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 * SPU mm fault handler

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 *

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 * (C) Copyright IBM Deutschland Entwicklung GmbH 2007

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 *

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 * Author: Arnd Bergmann <[email protected]>

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 * Author: Jeremy Kerr <[email protected]>

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 *

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 * This program is free software; you can redistribute it and/or modify

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 * it under the terms of the GNU General Public License as published by

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 * the Free Software Foundation; either version 2, or (at your option)

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 * any later version.

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 *

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 * This program is distributed in the hope that it will be useful,

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 * but WITHOUT ANY WARRANTY; without even the implied warranty of

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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

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 * GNU General Public License for more details.

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 *

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 * You should have received a copy of the GNU General Public License

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 * along with this program; if not, write to the Free Software

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 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

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 */

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#include <linux/sched.h>

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#include <linux/mm.h>

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#include <linux/module.h>

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#include <asm/spu.h>

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#include <asm/spu_csa.h>

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/*

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 * This ought to be kept in sync with the powerpc specific do_page_fault

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 * function. Currently, there are a few corner cases that we haven't had

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 * to handle fortunately.

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 */

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int spu_handle_mm_fault(struct mm_struct *mm, unsigned long ea,

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		unsigned long dsisr, unsigned *flt)

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{

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	struct vm_area_struct *vma;

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	unsigned long is_write;

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	int ret;

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	if (mm == NULL)

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		return -EFAULT;

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	if (mm->pgd == NULL)

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		return -EFAULT;

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	down_read(&mm->mmap_sem);

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	ret = -EFAULT;

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	vma = find_vma(mm, ea);

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	if (!vma)

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		goto out_unlock;

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	if (ea < vma->vm_start) {

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		if (!(vma->vm_flags & VM_GROWSDOWN))

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			goto out_unlock;

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		if (expand_stack(vma, ea))

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			goto out_unlock;

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	}

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	is_write = dsisr & MFC_DSISR_ACCESS_PUT;

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	if (is_write) {

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		if (!(vma->vm_flags & VM_WRITE))

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			goto out_unlock;

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	} else {

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		if (dsisr & MFC_DSISR_ACCESS_DENIED)

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			goto out_unlock;

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		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))

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			goto out_unlock;

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	}

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	ret = 0;

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	*flt = handle_mm_fault(mm, vma, ea, is_write ? FAULT_FLAG_WRITE : 0);

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	if (unlikely(*flt & VM_FAULT_ERROR)) {

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		if (*flt & VM_FAULT_OOM) {

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			ret = -ENOMEM;

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			goto out_unlock;

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		} else if (*flt & VM_FAULT_SIGBUS) {

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			ret = -EFAULT;

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			goto out_unlock;

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		}

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		BUG();

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	}

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	if (*flt & VM_FAULT_MAJOR)

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		current->maj_flt++;

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	else

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		current->min_flt++;

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out_unlock:

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	up_read(&mm->mmap_sem);

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	return ret;

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}

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EXPORT_SYMBOL_GPL(spu_handle_mm_fault);

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