mirror of
https://github.com/torvalds/linux.git
synced 2024-12-28 05:41:55 +00:00
c60ac5693c
This patch change the kernel VSID range so that we limit VSID_BITS to 37. This enables us to support 64TB with 65 bit VA (37+28). Without this patch we have boot hangs on platforms that only support 65 bit VA. With this patch we now have proto vsid generated as below: We first generate a 37-bit "proto-VSID". Proto-VSIDs are generated from mmu context id and effective segment id of the address. For user processes max context id is limited to ((1ul << 19) - 5) for kernel space, we use the top 4 context ids to map address as below 0x7fffc - [ 0xc000000000000000 - 0xc0003fffffffffff ] 0x7fffd - [ 0xd000000000000000 - 0xd0003fffffffffff ] 0x7fffe - [ 0xe000000000000000 - 0xe0003fffffffffff ] 0x7ffff - [ 0xf000000000000000 - 0xf0003fffffffffff ] Acked-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Tested-by: Geoff Levand <geoff@infradead.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> CC: <stable@vger.kernel.org> [v3.8]
110 lines
2.5 KiB
C
110 lines
2.5 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/export.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/slab.h>
|
|
|
|
#include <asm/mmu_context.h>
|
|
|
|
#include "icswx.h"
|
|
|
|
static DEFINE_SPINLOCK(mmu_context_lock);
|
|
static DEFINE_IDA(mmu_context_ida);
|
|
|
|
int __init_new_context(void)
|
|
{
|
|
int index;
|
|
int err;
|
|
|
|
again:
|
|
if (!ida_pre_get(&mmu_context_ida, GFP_KERNEL))
|
|
return -ENOMEM;
|
|
|
|
spin_lock(&mmu_context_lock);
|
|
err = ida_get_new_above(&mmu_context_ida, 1, &index);
|
|
spin_unlock(&mmu_context_lock);
|
|
|
|
if (err == -EAGAIN)
|
|
goto again;
|
|
else if (err)
|
|
return err;
|
|
|
|
if (index > MAX_USER_CONTEXT) {
|
|
spin_lock(&mmu_context_lock);
|
|
ida_remove(&mmu_context_ida, 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);
|
|
subpage_prot_init_new_context(mm);
|
|
mm->context.id = index;
|
|
#ifdef CONFIG_PPC_ICSWX
|
|
mm->context.cop_lockp = kmalloc(sizeof(spinlock_t), GFP_KERNEL);
|
|
if (!mm->context.cop_lockp) {
|
|
__destroy_context(index);
|
|
subpage_prot_free(mm);
|
|
mm->context.id = MMU_NO_CONTEXT;
|
|
return -ENOMEM;
|
|
}
|
|
spin_lock_init(mm->context.cop_lockp);
|
|
#endif /* CONFIG_PPC_ICSWX */
|
|
|
|
return 0;
|
|
}
|
|
|
|
void __destroy_context(int context_id)
|
|
{
|
|
spin_lock(&mmu_context_lock);
|
|
ida_remove(&mmu_context_ida, context_id);
|
|
spin_unlock(&mmu_context_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__destroy_context);
|
|
|
|
void destroy_context(struct mm_struct *mm)
|
|
{
|
|
#ifdef CONFIG_PPC_ICSWX
|
|
drop_cop(mm->context.acop, mm);
|
|
kfree(mm->context.cop_lockp);
|
|
mm->context.cop_lockp = NULL;
|
|
#endif /* CONFIG_PPC_ICSWX */
|
|
__destroy_context(mm->context.id);
|
|
subpage_prot_free(mm);
|
|
mm->context.id = MMU_NO_CONTEXT;
|
|
}
|