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/* $Id: mmu_context.h,v 1.4 2000/02/23 00:41:38 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>
#include <linux/slab.h>
#include <asm/pgalloc.h>
#include <asm/processor.h>
/*
* For the fast tlb miss handlers, we currently keep a per cpu array
* of pointers to the current pgd for each processor. Also, the proc.
* id is stuffed into the context register. This should be changed to
* use the processor id via current->processor, where current is stored
* in watchhi/lo. The context register should be used to contiguously
* map the page tables.
*/
#define TLBMISS_HANDLER_SETUP_PGD(pgd) \
pgd_current[smp_processor_id()] = (unsigned long)(pgd)
#define TLBMISS_HANDLER_SETUP() \
set_context((unsigned long) smp_processor_id() << (23 + 3)); \
TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir)
extern unsigned long pgd_current[];
#ifndef CONFIG_SMP
#define CPU_CONTEXT(cpu, mm) (mm)->context
#else
#define CPU_CONTEXT(cpu, mm) (*((unsigned long *)((mm)->context) + cpu))
#endif
#define ASID_CACHE(cpu) cpu_data[cpu].asid_cache
#define ASID_INC 0x1
#define ASID_MASK 0xff
static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk, unsigned cpu)
{
}
/*
* 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_cpu_mmu_context(struct mm_struct *mm, unsigned long cpu)
{
unsigned long asid = ASID_CACHE(cpu);
if (! ((asid += ASID_INC) & ASID_MASK) ) {
_flush_tlb_all(); /* start new asid cycle */
if (!asid) /* fix version if needed */
asid = ASID_FIRST_VERSION;
}
CPU_CONTEXT(cpu, mm) = ASID_CACHE(cpu) = asid;
}
/*
* Initialize the context related info for a new mm_struct
* instance.
*/
extern inline int
init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
#ifndef CONFIG_SMP
mm->context = 0;
#else
mm->context = (unsigned long)kmalloc(smp_num_cpus *
sizeof(unsigned long), GFP_KERNEL);
/*
* Init the "context" values so that a tlbpid allocation
* happens on the first switch.
*/
if (mm->context == 0)
return -ENOMEM;
memset((void *)mm->context, 0, smp_num_cpus * sizeof(unsigned long));
#endif
return 0;
}
extern inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
struct task_struct *tsk, unsigned cpu)
{
/* Check if our ASID is of an older version and thus invalid */
if ((CPU_CONTEXT(cpu, next) ^ ASID_CACHE(cpu)) & ASID_VERSION_MASK)
get_new_cpu_mmu_context(next, cpu);
set_entryhi(CPU_CONTEXT(cpu, next) & 0xff);
TLBMISS_HANDLER_SETUP_PGD(next->pgd);
}
/*
* 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)
{
#ifdef CONFIG_SMP
if (mm->context)
kfree((void *)mm->context);
#endif
}
/*
* 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_cpu_mmu_context(next, smp_processor_id());
set_entryhi(CPU_CONTEXT(smp_processor_id(), next) & 0xff);
TLBMISS_HANDLER_SETUP_PGD(next->pgd);
}
#endif /* _ASM_MMU_CONTEXT_H */
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