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/*
* 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/errno.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/slab.h>
#include <asm/cacheflush.h>
#include <asm/dsemul.h>
#include <asm/hazards.h>
#include <asm/tlbflush.h>
#include <asm-generic/mm_hooks.h>
#define htw_set_pwbase(pgd) \
do { \
if (cpu_has_htw) { \
write_c0_pwbase(pgd); \
back_to_back_c0_hazard(); \
} \
} while (0)
extern void tlbmiss_handler_setup_pgd(unsigned long);
/* Note: This is also implemented with uasm in arch/mips/kvm/entry.c */
#define TLBMISS_HANDLER_SETUP_PGD(pgd) \
do { \
tlbmiss_handler_setup_pgd((unsigned long)(pgd)); \
htw_set_pwbase((unsigned long)pgd); \
} while (0)
#ifdef CONFIG_MIPS_PGD_C0_CONTEXT
#define TLBMISS_HANDLER_RESTORE() \
write_c0_xcontext((unsigned long) smp_processor_id() << \
SMP_CPUID_REGSHIFT)
#define TLBMISS_HANDLER_SETUP() \
do { \
TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir); \
TLBMISS_HANDLER_RESTORE(); \
} while (0)
#else /* !CONFIG_MIPS_PGD_C0_CONTEXT: using pgd_current*/
/*
* For the fast tlb miss handlers, we keep a per cpu array of pointers
* to the current pgd for each processor. Also, the proc. id is stuffed
* into the context register.
*/
extern unsigned long pgd_current[];
#define TLBMISS_HANDLER_RESTORE() \
write_c0_context((unsigned long) smp_processor_id() << \
SMP_CPUID_REGSHIFT)
#define TLBMISS_HANDLER_SETUP() \
TLBMISS_HANDLER_RESTORE(); \
back_to_back_c0_hazard(); \
TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir)
#endif /* CONFIG_MIPS_PGD_C0_CONTEXT*/
/*
* All unused by hardware upper bits will be considered
* as a software asid extension.
*/
static unsigned long asid_version_mask(unsigned int cpu)
{
unsigned long asid_mask = cpu_asid_mask(&cpu_data[cpu]);
return ~(asid_mask | (asid_mask - 1));
}
static unsigned long asid_first_version(unsigned int cpu)
{
return ~asid_version_mask(cpu) + 1;
}
#define cpu_context(cpu, mm) ((mm)->context.asid[cpu])
#define asid_cache(cpu) (cpu_data[cpu].asid_cache)
#define cpu_asid(cpu, mm) \
(cpu_context((cpu), (mm)) & cpu_asid_mask(&cpu_data[cpu]))
static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
{
}
/* Normal, classic MIPS get_new_mmu_context */
static inline void
get_new_mmu_context(struct mm_struct *mm, unsigned long cpu)
{
unsigned long asid = asid_cache(cpu);
if (!((asid += cpu_asid_inc()) & cpu_asid_mask(&cpu_data[cpu]))) {
if (cpu_has_vtag_icache)
flush_icache_all();
local_flush_tlb_all(); /* start new asid cycle */
if (!asid) /* fix version if needed */
asid = asid_first_version(cpu);
}
cpu_context(cpu, mm) = asid_cache(cpu) = asid;
}
/*
* Initialize the context related info for a new mm_struct
* instance.
*/
static inline int
init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
int i;
for_each_possible_cpu(i)
cpu_context(i, mm) = 0;
atomic_set(&mm->context.fp_mode_switching, 0);
mm->context.bd_emupage_allocmap = NULL;
spin_lock_init(&mm->context.bd_emupage_lock);
init_waitqueue_head(&mm->context.bd_emupage_queue);
return 0;
}
static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
struct task_struct *tsk)
{
unsigned int cpu = smp_processor_id();
unsigned long flags;
local_irq_save(flags);
htw_stop();
/* Check if our ASID is of an older version and thus invalid */
if ((cpu_context(cpu, next) ^ asid_cache(cpu)) & asid_version_mask(cpu))
get_new_mmu_context(next, cpu);
write_c0_entryhi(cpu_asid(cpu, next));
TLBMISS_HANDLER_SETUP_PGD(next->pgd);
/*
* Mark current->active_mm as not "active" anymore.
* We don't want to mislead possible IPI tlb flush routines.
*/
cpumask_clear_cpu(cpu, mm_cpumask(prev));
cpumask_set_cpu(cpu, mm_cpumask(next));
htw_start();
local_irq_restore(flags);
}
/*
* Destroy context related info for an mm_struct that is about
* to be put to rest.
*/
static inline void destroy_context(struct mm_struct *mm)
{
dsemul_mm_cleanup(mm);
}
#define deactivate_mm(tsk, mm) do { } while (0)
/*
* After we have set current->mm to a new value, this activates
* the context for the new mm so we see the new mappings.
*/
static inline void
activate_mm(struct mm_struct *prev, struct mm_struct *next)
{
unsigned long flags;
unsigned int cpu = smp_processor_id();
local_irq_save(flags);
htw_stop();
/* Unconditionally get a new ASID. */
get_new_mmu_context(next, cpu);
write_c0_entryhi(cpu_asid(cpu, next));
TLBMISS_HANDLER_SETUP_PGD(next->pgd);
/* mark mmu ownership change */
cpumask_clear_cpu(cpu, mm_cpumask(prev));
cpumask_set_cpu(cpu, mm_cpumask(next));
htw_start();
local_irq_restore(flags);
}
/*
* If mm is currently active_mm, we can't really drop it. Instead,
* we will get a new one for it.
*/
static inline void
drop_mmu_context(struct mm_struct *mm, unsigned cpu)
{
unsigned long flags;
local_irq_save(flags);
htw_stop();
if (cpumask_test_cpu(cpu, mm_cpumask(mm))) {
get_new_mmu_context(mm, cpu);
write_c0_entryhi(cpu_asid(cpu, mm));
} else {
/* will get a new context next time */
cpu_context(cpu, mm) = 0;
}
htw_start();
local_irq_restore(flags);
}
#endif /* _ASM_MMU_CONTEXT_H */
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