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/*
* MMU context allocation for 64-bit kernels.
*
* Copyright (C) 2004 Anton Blanchard, IBM Corp. <anton@samba.org>
*
* 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/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
#include <linux/idr.h>
#include <asm/mmu_context.h>
static DEFINE_SPINLOCK(mmu_context_lock);
static DEFINE_IDR(mmu_context_idr);
int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
int index;
int err;
int new_context = (mm->context.id == 0);
again:
if (!idr_pre_get(&mmu_context_idr, GFP_KERNEL))
return -ENOMEM;
spin_lock(&mmu_context_lock);
err = idr_get_new_above(&mmu_context_idr, NULL, 1, &index);
spin_unlock(&mmu_context_lock);
if (err == -EAGAIN)
goto again;
else if (err)
return err;
if (index > MAX_CONTEXT) {
spin_lock(&mmu_context_lock);
idr_remove(&mmu_context_idr, index);
spin_unlock(&mmu_context_lock);
return -ENOMEM;
}
mm->context.id = index;
#ifdef CONFIG_PPC_MM_SLICES
/* The old code would re-promote on fork, we don't do that
* when using slices as it could cause problem promoting slices
* that have been forced down to 4K
*/
if (new_context)
slice_set_user_psize(mm, mmu_virtual_psize);
#else
mm->context.user_psize = mmu_virtual_psize;
mm->context.sllp = SLB_VSID_USER |
mmu_psize_defs[mmu_virtual_psize].sllp;
#endif
return 0;
}
void destroy_context(struct mm_struct *mm)
{
spin_lock(&mmu_context_lock);
idr_remove(&mmu_context_idr, mm->context.id);
spin_unlock(&mmu_context_lock);
mm->context.id = NO_CONTEXT;
}
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