97 lines
2.2 KiB
C
97 lines
2.2 KiB
C
/*
|
|
* 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 <linux/module.h>
|
|
|
|
#include <asm/mmu_context.h>
|
|
|
|
static DEFINE_SPINLOCK(mmu_context_lock);
|
|
static DEFINE_IDR(mmu_context_idr);
|
|
|
|
/*
|
|
* The proto-VSID space has 2^35 - 1 segments available for user mappings.
|
|
* Each segment contains 2^28 bytes. Each context maps 2^44 bytes,
|
|
* so we can support 2^19-1 contexts (19 == 35 + 28 - 44).
|
|
*/
|
|
#define NO_CONTEXT 0
|
|
#define MAX_CONTEXT ((1UL << 19) - 1)
|
|
|
|
int __init_new_context(void)
|
|
{
|
|
int index;
|
|
int err;
|
|
|
|
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;
|
|
}
|
|
|
|
return index;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__init_new_context);
|
|
|
|
int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
|
|
{
|
|
int index;
|
|
|
|
index = __init_new_context();
|
|
if (index < 0)
|
|
return index;
|
|
|
|
/* 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 (slice_mm_new_context(mm))
|
|
slice_set_user_psize(mm, mmu_virtual_psize);
|
|
mm->context.id = index;
|
|
|
|
return 0;
|
|
}
|
|
|
|
void __destroy_context(int context_id)
|
|
{
|
|
spin_lock(&mmu_context_lock);
|
|
idr_remove(&mmu_context_idr, context_id);
|
|
spin_unlock(&mmu_context_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__destroy_context);
|
|
|
|
void destroy_context(struct mm_struct *mm)
|
|
{
|
|
__destroy_context(mm->context.id);
|
|
mm->context.id = NO_CONTEXT;
|
|
}
|