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linux/include/asm-mips/mmu_context.h
Jeremy Fitzhardinge d6dd61c831 [PATCH] x86: PARAVIRT: add hooks to intercept mm creation and destruction 
Add hooks to allow a paravirt implementation to track the lifetime of
an mm.  Paravirtualization requires three hooks, but only two are
needed in common code.  They are:

arch_dup_mmap, which is called when a new mmap is created at fork

arch_exit_mmap, which is called when the last process reference to an
  mm is dropped, which typically happens on exit and exec.

The third hook is activate_mm, which is called from the arch-specific
activate_mm() macro/function, and so doesn't need stub versions for
other architectures.  It's called when an mm is first used.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: linux-arch@vger.kernel.org
Cc: James Bottomley <James.Bottomley@SteelEye.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
2007-05-02 19:27:14 +02:00

298 lines
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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/slab.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#ifdef CONFIG_MIPS_MT_SMTC
#include <asm/mipsmtregs.h>
#include <asm/smtc.h>
#endif /* SMTC */
#include <asm-generic/mm_hooks.h>
/*
* 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_SETUP_PGD(pgd) \
pgd_current[smp_processor_id()] = (unsigned long)(pgd)
#ifdef CONFIG_32BIT
#define TLBMISS_HANDLER_SETUP() \
write_c0_context((unsigned long) smp_processor_id() << 25); \
TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir)
#endif
#ifdef CONFIG_64BIT
#define TLBMISS_HANDLER_SETUP() \
write_c0_context((unsigned long) smp_processor_id() << 26); \
TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir)
#endif
#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
#define ASID_INC 0x40
#define ASID_MASK 0xfc0
#elif defined(CONFIG_CPU_R8000)
#define ASID_INC 0x10
#define ASID_MASK 0xff0
#elif defined(CONFIG_CPU_RM9000)
#define ASID_INC 0x1
#define ASID_MASK 0xfff
/* SMTC/34K debug hack - but maybe we'll keep it */
#elif defined(CONFIG_MIPS_MT_SMTC)
#define ASID_INC 0x1
extern unsigned long smtc_asid_mask;
#define ASID_MASK (smtc_asid_mask)
#define HW_ASID_MASK 0xff
/* End SMTC/34K debug hack */
#else /* FIXME: not correct for R6000 */
#define ASID_INC 0x1
#define ASID_MASK 0xff
#endif
#define cpu_context(cpu, mm) ((mm)->context[cpu])
#define cpu_asid(cpu, mm) (cpu_context((cpu), (mm)) & ASID_MASK)
#define asid_cache(cpu) (cpu_data[cpu].asid_cache)
static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
{
}
/*
* 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)
#ifndef CONFIG_MIPS_MT_SMTC
/* 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 += ASID_INC) & ASID_MASK) ) {
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_context(cpu, mm) = asid_cache(cpu) = asid;
}
#else /* CONFIG_MIPS_MT_SMTC */
#define get_new_mmu_context(mm,cpu) smtc_get_new_mmu_context((mm),(cpu))
#endif /* CONFIG_MIPS_MT_SMTC */
/*
* 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 (i = 0; i < num_online_cpus(); i++)
cpu_context(i, mm) = 0;
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;
#ifdef CONFIG_MIPS_MT_SMTC
unsigned long oldasid;
unsigned long mtflags;
int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
local_irq_save(flags);
mtflags = dvpe();
#else /* Not SMTC */
local_irq_save(flags);
#endif /* CONFIG_MIPS_MT_SMTC */
/* 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_mmu_context(next, cpu);
#ifdef CONFIG_MIPS_MT_SMTC
/*
* If the EntryHi ASID being replaced happens to be
* the value flagged at ASID recycling time as having
* an extended life, clear the bit showing it being
* in use by this "CPU", and if that's the last bit,
* free up the ASID value for use and flush any old
* instances of it from the TLB.
*/
oldasid = (read_c0_entryhi() & ASID_MASK);
if(smtc_live_asid[mytlb][oldasid]) {
smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
if(smtc_live_asid[mytlb][oldasid] == 0)
smtc_flush_tlb_asid(oldasid);
}
/*
* Tread softly on EntryHi, and so long as we support
* having ASID_MASK smaller than the hardware maximum,
* make sure no "soft" bits become "hard"...
*/
write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK)
| (cpu_context(cpu, next) & ASID_MASK));
ehb(); /* Make sure it propagates to TCStatus */
evpe(mtflags);
#else
write_c0_entryhi(cpu_context(cpu, next));
#endif /* CONFIG_MIPS_MT_SMTC */
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.
*/
cpu_clear(cpu, prev->cpu_vm_mask);
cpu_set(cpu, next->cpu_vm_mask);
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)
{
}
#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();
#ifdef CONFIG_MIPS_MT_SMTC
unsigned long oldasid;
unsigned long mtflags;
int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
#endif /* CONFIG_MIPS_MT_SMTC */
local_irq_save(flags);
/* Unconditionally get a new ASID. */
get_new_mmu_context(next, cpu);
#ifdef CONFIG_MIPS_MT_SMTC
/* See comments for similar code above */
mtflags = dvpe();
oldasid = read_c0_entryhi() & ASID_MASK;
if(smtc_live_asid[mytlb][oldasid]) {
smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
if(smtc_live_asid[mytlb][oldasid] == 0)
smtc_flush_tlb_asid(oldasid);
}
/* See comments for similar code above */
write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK) |
(cpu_context(cpu, next) & ASID_MASK));
ehb(); /* Make sure it propagates to TCStatus */
evpe(mtflags);
#else
write_c0_entryhi(cpu_context(cpu, next));
#endif /* CONFIG_MIPS_MT_SMTC */
TLBMISS_HANDLER_SETUP_PGD(next->pgd);
/* mark mmu ownership change */
cpu_clear(cpu, prev->cpu_vm_mask);
cpu_set(cpu, next->cpu_vm_mask);
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;
#ifdef CONFIG_MIPS_MT_SMTC
unsigned long oldasid;
/* Can't use spinlock because called from TLB flush within DVPE */
unsigned int prevvpe;
int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
#endif /* CONFIG_MIPS_MT_SMTC */
local_irq_save(flags);
if (cpu_isset(cpu, mm->cpu_vm_mask)) {
get_new_mmu_context(mm, cpu);
#ifdef CONFIG_MIPS_MT_SMTC
/* See comments for similar code above */
prevvpe = dvpe();
oldasid = (read_c0_entryhi() & ASID_MASK);
if (smtc_live_asid[mytlb][oldasid]) {
smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
if(smtc_live_asid[mytlb][oldasid] == 0)
smtc_flush_tlb_asid(oldasid);
}
/* See comments for similar code above */
write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK)
| cpu_asid(cpu, mm));
ehb(); /* Make sure it propagates to TCStatus */
evpe(prevvpe);
#else /* not CONFIG_MIPS_MT_SMTC */
write_c0_entryhi(cpu_asid(cpu, mm));
#endif /* CONFIG_MIPS_MT_SMTC */
} else {
/* will get a new context next time */
#ifndef CONFIG_MIPS_MT_SMTC
cpu_context(cpu, mm) = 0;
#else /* SMTC */
int i;
/* SMTC shares the TLB (and ASIDs) across VPEs */
for (i = 0; i < num_online_cpus(); i++) {
if((smtc_status & SMTC_TLB_SHARED)
|| (cpu_data[i].vpe_id == cpu_data[cpu].vpe_id))
cpu_context(i, mm) = 0;
}
#endif /* CONFIG_MIPS_MT_SMTC */
}
local_irq_restore(flags);
}
#endif /* _ASM_MMU_CONTEXT_H */
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