/*
* Low level TLB handling.
*
* Copyright (C) 2000-2003, Axis Communications AB.
*
* Authors: Bjorn Wesen <bjornw@axis.com>
* Tobias Anderberg <tobiasa@axis.com>, CRISv32 port.
*/
#include <asm/tlb.h>
#include <asm/mmu_context.h>
#include <arch/hwregs/asm/mmu_defs_asm.h>
#include <arch/hwregs/supp_reg.h>
#define UPDATE_TLB_SEL_IDX(val) \
do { \
unsigned long tlb_sel; \
\
tlb_sel = REG_FIELD(mmu, rw_mm_tlb_sel, idx, val); \
SUPP_REG_WR(RW_MM_TLB_SEL, tlb_sel); \
} while(0)
#define UPDATE_TLB_HILO(tlb_hi, tlb_lo) \
do { \
SUPP_REG_WR(RW_MM_TLB_HI, tlb_hi); \
SUPP_REG_WR(RW_MM_TLB_LO, tlb_lo); \
} while(0)
/*
* The TLB can host up to 256 different mm contexts at the same time. The running
* context is found in the PID register. Each TLB entry contains a page_id that
* has to match the PID register to give a hit. page_id_map keeps track of which
* mm's is assigned to which page_id's, making sure it's known when to
* invalidate TLB entries.
*
* The last page_id is never running, it is used as an invalid page_id so that
* it's possible to make TLB entries that will nerver match.
*
* Note; the flushes needs to be atomic otherwise an interrupt hander that uses
* vmalloc'ed memory might cause a TLB load in the middle of a flush.
*/
/* Flush all TLB entries. */
void
__flush_tlb_all(void)
{
int i;
int mmu;
unsigned long flags;
unsigned long mmu_tlb_hi;
unsigned long mmu_tlb_sel;
/*
* Mask with 0xf so similar TLB entries aren't written in the same 4-way
* entry group.
*/
local_irq_save(flags);
for (mmu = 1; mmu <= 2; mmu++) {
SUPP_BANK_SEL(mmu); /* Select the MMU */
for (i = 0; i < NUM_TLB_ENTRIES; i++) {
/* Store invalid entry */
mmu_tlb_sel = REG_FIELD(mmu, rw_mm_tlb_sel, idx, i);
mmu_tlb_hi = (REG_FIELD(mmu, rw_mm_tlb_hi, pid, INVALID_PAGEID)
| REG_FIELD(mmu, rw_mm_tlb_hi, vpn, i & 0xf));
SUPP_REG_WR(RW_MM_TLB_SEL, mmu_tlb_sel);
SUPP_REG_WR(RW_MM_TLB_HI, mmu_tlb_hi);
SUPP_REG_WR(RW_MM_TLB_LO, 0);
}
}
local_irq_restore(flags);
}
/* Flush an entire user address space. */
void
__flush_tlb_mm(struct mm_struct *mm)
{
int i;
int mmu;
unsigned long flags;
unsigned long page_id;
unsigned long tlb_hi;
unsigned long mmu_tlb_hi;
page_id = mm->context.page_id;
if (page_id == NO_CONTEXT)
return;
/* Mark the TLB entries that match the page_id as invalid. */
local_irq_save(flags);
for (mmu = 1; mmu <= 2; mmu++) {
SUPP_BANK_SEL(mmu);
for (i = 0; i < NUM_TLB_ENTRIES; i++) {
UPDATE_TLB_SEL_IDX(i);
/* Get the page_id */
SUPP_REG_RD(RW_MM_TLB_HI, tlb_hi);
/* Check if the page_id match. */
if ((tlb_hi & 0xff) == page_id) {
mmu_tlb_hi = (REG_FIELD(mmu, rw_mm_tlb_hi, pid,
INVALID_PAGEID)
| REG_FIELD(mmu, rw_mm_tlb_hi, vpn,
i & 0xf));
UPDATE_TLB_HILO(mmu_tlb_hi, 0);
}
}
}
local_irq_restore(flags);
}
/* Invalidate a single page. */
void
__flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
{
int i;
int mmu;
unsigned long page_id;
unsigned long flags;
unsigned long tlb_hi;
unsigned long mmu_tlb_hi;
page_id = vma->vm_mm->context.page_id;
if (page_id == NO_CONTEXT)
return;
addr &= PAGE_MASK;
/*
* Invalidate those TLB entries that match both the mm context and the
* requested virtual address.
*/
local_irq_save(flags);
for (mmu = 1; mmu <= 2; mmu++) {
SUPP_BANK_SEL(mmu);
for (i = 0; i < NUM_TLB_ENTRIES; i++) {
UPDATE_TLB_SEL_IDX(i);
SUPP_REG_RD(RW_MM_TLB_HI, tlb_hi);
/* Check if page_id and address matches */
if (((tlb_hi & 0xff) == page_id) &&
((tlb_hi & PAGE_MASK) == addr)) {
mmu_tlb_hi = REG_FIELD(mmu, rw_mm_tlb_hi, pid,
INVALID_PAGEID) | addr;
UPDATE_TLB_HILO(mmu_tlb_hi, 0);
}
}
}
local_irq_restore(flags);
}
/*
* Initialize the context related info for a new mm_struct
* instance.
*/
int
init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
mm->context.page_id = NO_CONTEXT;
return 0;
}
static DEFINE_SPINLOCK(mmu_context_lock);
/* Called in schedule() just before actually doing the switch_to. */
void
switch_mm(struct mm_struct *prev, struct mm_struct *next,
struct task_struct *tsk)
{
if (prev != next) {
int cpu = smp_processor_id();
/* Make sure there is a MMU context. */
spin_lock(&mmu_context_lock);
get_mmu_context(next);
cpumask_set_cpu(cpu, mm_cpumask(next));
spin_unlock(&mmu_context_lock);
/*
* Remember the pgd for the fault handlers. Keep a separate
* copy of it because current and active_mm might be invalid
* at points where * there's still a need to derefer the pgd.
*/
per_cpu(current_pgd, cpu) = next->pgd;
/* Switch context in the MMU. */
if (tsk && task_thread_info(tsk)) {
SPEC_REG_WR(SPEC_REG_PID, next->context.page_id |
task_thread_info(tsk)->tls);
} else {
SPEC_REG_WR(SPEC_REG_PID, next->context.page_id);
}
}
}
