146 lines
3.2 KiB
C
146 lines
3.2 KiB
C
/*
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* MMU context allocation for 64-bit kernels.
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*
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* Copyright (C) 2004 Anton Blanchard, IBM Corp. <anton@samba.org>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/spinlock.h>
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#include <linux/idr.h>
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#include <linux/export.h>
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#include <linux/gfp.h>
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#include <linux/slab.h>
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#include <asm/mmu_context.h>
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#include <asm/pgalloc.h>
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#include "icswx.h"
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static DEFINE_SPINLOCK(mmu_context_lock);
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static DEFINE_IDA(mmu_context_ida);
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int __init_new_context(void)
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{
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int index;
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int err;
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again:
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if (!ida_pre_get(&mmu_context_ida, GFP_KERNEL))
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return -ENOMEM;
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spin_lock(&mmu_context_lock);
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err = ida_get_new_above(&mmu_context_ida, 1, &index);
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spin_unlock(&mmu_context_lock);
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if (err == -EAGAIN)
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goto again;
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else if (err)
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return err;
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if (index > MAX_USER_CONTEXT) {
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spin_lock(&mmu_context_lock);
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ida_remove(&mmu_context_ida, index);
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spin_unlock(&mmu_context_lock);
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return -ENOMEM;
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}
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return index;
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}
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EXPORT_SYMBOL_GPL(__init_new_context);
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int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
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{
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int index;
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index = __init_new_context();
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if (index < 0)
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return index;
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/* The old code would re-promote on fork, we don't do that
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* when using slices as it could cause problem promoting slices
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* that have been forced down to 4K
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*/
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if (slice_mm_new_context(mm))
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slice_set_user_psize(mm, mmu_virtual_psize);
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subpage_prot_init_new_context(mm);
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mm->context.id = index;
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#ifdef CONFIG_PPC_ICSWX
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mm->context.cop_lockp = kmalloc(sizeof(spinlock_t), GFP_KERNEL);
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if (!mm->context.cop_lockp) {
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__destroy_context(index);
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subpage_prot_free(mm);
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mm->context.id = MMU_NO_CONTEXT;
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return -ENOMEM;
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}
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spin_lock_init(mm->context.cop_lockp);
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#endif /* CONFIG_PPC_ICSWX */
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#ifdef CONFIG_PPC_64K_PAGES
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mm->context.pte_frag = NULL;
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#endif
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return 0;
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}
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void __destroy_context(int context_id)
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{
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spin_lock(&mmu_context_lock);
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ida_remove(&mmu_context_ida, context_id);
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spin_unlock(&mmu_context_lock);
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}
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EXPORT_SYMBOL_GPL(__destroy_context);
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#ifdef CONFIG_PPC_64K_PAGES
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static void destroy_pagetable_page(struct mm_struct *mm)
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{
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int count;
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void *pte_frag;
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struct page *page;
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pte_frag = mm->context.pte_frag;
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if (!pte_frag)
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return;
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page = virt_to_page(pte_frag);
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/* drop all the pending references */
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count = ((unsigned long)pte_frag & ~PAGE_MASK) >> PTE_FRAG_SIZE_SHIFT;
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/* We allow PTE_FRAG_NR fragments from a PTE page */
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count = atomic_sub_return(PTE_FRAG_NR - count, &page->_count);
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if (!count) {
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pgtable_page_dtor(page);
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free_hot_cold_page(page, 0);
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}
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}
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#else
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static inline void destroy_pagetable_page(struct mm_struct *mm)
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{
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return;
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}
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#endif
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void destroy_context(struct mm_struct *mm)
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{
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#ifdef CONFIG_PPC_ICSWX
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drop_cop(mm->context.acop, mm);
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kfree(mm->context.cop_lockp);
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mm->context.cop_lockp = NULL;
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#endif /* CONFIG_PPC_ICSWX */
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destroy_pagetable_page(mm);
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__destroy_context(mm->context.id);
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subpage_prot_free(mm);
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mm->context.id = MMU_NO_CONTEXT;
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}
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