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/* $Id: mmu_context.h,v 1.3 1999/11/19 20:35:49 ralf Exp $
*
* Switch a MMU context.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1996, 1997, 1998, 1999 by Ralf Baechle
* Copyright (C) 1999 Silicon Graphics, Inc.
*/
#ifndef _ASM_MMU_CONTEXT_H
#define _ASM_MMU_CONTEXT_H
#include <linux/config.h>
/* Fuck. The f-word is here so you can grep for it :-) */
extern unsigned long asid_cache;
extern pgd_t *current_pgd;
#define ASID_INC 0x1
#define ASID_MASK 0xff
/*
* All unused by hardware upper bits will be considered
* as a software asid extension.
*/
#define ASID_VERSION_MASK ((unsigned long)~(ASID_MASK|(ASID_MASK-1)))
#define ASID_FIRST_VERSION ((unsigned long)(~ASID_VERSION_MASK) + 1)
extern inline void
get_new_mmu_context(struct mm_struct *mm, unsigned long asid)
{
if (! ((asid += ASID_INC) & ASID_MASK) ) {
flush_tlb_all(); /* start new asid cycle */
if (!asid) /* fix version if needed */
asid = ASID_FIRST_VERSION;
}
mm->context = asid_cache = asid;
}
/*
* Initialize the context related info for a new mm_struct
* instance.
*/
extern inline void
init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
mm->context = 0;
}
extern inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
struct task_struct *tsk, unsigned cpu)
{
unsigned long asid = asid_cache;
/* Check if our ASID is of an older version and thus invalid */
if ((next->context ^ asid) & ASID_VERSION_MASK)
get_new_mmu_context(next, asid);
current_pgd = next->pgd;
set_entryhi(next->context);
}
/*
* Destroy context related info for an mm_struct that is about
* to be put to rest.
*/
extern inline void destroy_context(struct mm_struct *mm)
{
/* Nothing to do. */
}
/*
* After we have set current->mm to a new value, this activates
* the context for the new mm so we see the new mappings.
*/
extern inline void
activate_mm(struct mm_struct *prev, struct mm_struct *next)
{
/* Unconditionally get a new ASID. */
get_new_mmu_context(next, asid_cache);
current_pgd = next->pgd;
set_entryhi(next->context);
}
#endif /* _ASM_MMU_CONTEXT_H */
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