/*
* 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/mm_types.h>
#include <linux/smp.h>
#include <linux/slab.h>
#include <asm/barrier.h>
#include <asm/cacheflush.h>
#include <asm/dsemul.h>
#include <asm/ginvt.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);
extern char tlbmiss_handler_setup_pgd_end[];
/* 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*/
/*
* The ginvt instruction will invalidate wired entries when its type field
* targets anything other than the entire TLB. That means that if we were to
* allow the kernel to create wired entries with the MMID of current->active_mm
* then those wired entries could be invalidated when we later use ginvt to
* invalidate TLB entries with that MMID.
*
* In order to prevent ginvt from trashing wired entries, we reserve one MMID
* for use by the kernel when creating wired entries. This MMID will never be
* assigned to a struct mm, and we'll never target it with a ginvt instruction.
*/
#define MMID_KERNEL_WIRED 0
/*
* All unused by hardware upper bits will be considered
* as a software asid extension.
*/
static inline u64 asid_version_mask(unsigned int cpu)
{
unsigned long asid_mask = cpu_asid_mask(&cpu_data[cpu]);
return ~(u64)(asid_mask | (asid_mask - 1));
}
static inline u64 asid_first_version(unsigned int cpu)
{
return ~asid_version_mask(cpu) + 1;
}
static inline u64 cpu_context(unsigned int cpu, const struct mm_struct *mm)
{
if (cpu_has_mmid)
return atomic64_read(&mm->context.mmid);
return mm->context.asid[cpu];
}
static inline void set_cpu_context(unsigned int cpu,
struct mm_struct *mm, u64 ctx)
{
if (cpu_has_mmid)
atomic64_set(&mm->context.mmid, ctx);
else
mm->context.asid[cpu] = ctx;
}
#define asid_cache(cpu) (cpu_data[cpu].asid_cache)
#define cpu_asid(cpu, mm) \
(cpu_context((cpu), (mm)) & cpu_asid_mask(&cpu_data[cpu]))
extern void get_new_mmu_context(struct mm_struct *mm);
extern void check_mmu_context(struct mm_struct *mm);
extern void check_switch_mmu_context(struct mm_struct *mm);
/*
* Initialize the context related info for a new mm_struct
* instance.
*/
#define init_new_context init_new_context
static inline int
init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
int i;
if (cpu_has_mmid) {
set_cpu_context(0, mm, 0);
} else {
for_each_possible_cpu(i)
set_cpu_context(i, mm, 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_switch_mmu_context(next);
/*
* 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.
*/
#define destroy_context destroy_context
static inline void destroy_context(struct mm_struct *mm)
{
dsemul_mm_cleanup(mm);
}
static inline void
drop_mmu_context(struct mm_struct *mm)
{
unsigned long flags;
unsigned int cpu;
u32 old_mmid;
u64 ctx;
local_irq_save(flags);
cpu = smp_processor_id();
ctx = cpu_context(cpu, mm);
if (!ctx) {
/* no-op */
} else if (cpu_has_mmid) {
/*
* Globally invalidating TLB entries associated with the MMID
* is pretty cheap using the GINVT instruction, so we'll do
* that rather than incur the overhead of allocating a new
* MMID. The latter would be especially difficult since MMIDs
* are global & other CPUs may be actively using ctx.
*/
htw_stop();
old_mmid = read_c0_memorymapid();
write_c0_memorymapid(ctx & cpu_asid_mask(&cpu_data[cpu]));
mtc0_tlbw_hazard();
ginvt_mmid();
sync_ginv();
write_c0_memorymapid(old_mmid);
instruction_hazard();
htw_start();
} else if (cpumask_test_cpu(cpu, mm_cpumask(mm))) {
/*
* mm is currently active, so we can't really drop it.
* Instead we bump the ASID.
*/
htw_stop();
get_new_mmu_context(mm);
write_c0_entryhi(cpu_asid(cpu, mm));
htw_start();
} else {
/* will get a new context next time */
set_cpu_context(cpu, mm, 0);
}
local_irq_restore(flags);
}
#include <asm-generic/mmu_context.h>
#endif /* _ASM_MMU_CONTEXT_H */