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linux-next/arch/avr32/mm/tlb.c
Russell King 4b3073e1c5 MM: Pass a PTE pointer to update_mmu_cache() rather than the PTE itself 
On VIVT ARM, when we have multiple shared mappings of the same file
in the same MM, we need to ensure that we have coherency across all
copies.  We do this via make_coherent() by making the pages
uncacheable.

This used to work fine, until we allowed highmem with highpte - we
now have a page table which is mapped as required, and is not available
for modification via update_mmu_cache().

Ralf Beache suggested getting rid of the PTE value passed to
update_mmu_cache():

  On MIPS update_mmu_cache() calls __update_tlb() which walks pagetables
  to construct a pointer to the pte again.  Passing a pte_t * is much
  more elegant.  Maybe we might even replace the pte argument with the
  pte_t?

Ben Herrenschmidt would also like the pte pointer for PowerPC:

  Passing the ptep in there is exactly what I want.  I want that
  -instead- of the PTE value, because I have issue on some ppc cases,
  for I$/D$ coherency, where set_pte_at() may decide to mask out the
  _PAGE_EXEC.

So, pass in the mapped page table pointer into update_mmu_cache(), and
remove the PTE value, updating all implementations and call sites to
suit.

Includes a fix from Stephen Rothwell:

  sparc: fix fallout from update_mmu_cache API change

  Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-02-20 16:41:46 +00:00

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/*
* AVR32 TLB operations
*
* Copyright (C) 2004-2006 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/mm.h>
#include <asm/mmu_context.h>
/* TODO: Get the correct number from the CONFIG1 system register */
#define NR_TLB_ENTRIES 32
static void show_dtlb_entry(unsigned int index)
{
u32 tlbehi, tlbehi_save, tlbelo, mmucr, mmucr_save;
unsigned long flags;
local_irq_save(flags);
mmucr_save = sysreg_read(MMUCR);
tlbehi_save = sysreg_read(TLBEHI);
mmucr = SYSREG_BFINS(DRP, index, mmucr_save);
sysreg_write(MMUCR, mmucr);
__builtin_tlbr();
cpu_sync_pipeline();
tlbehi = sysreg_read(TLBEHI);
tlbelo = sysreg_read(TLBELO);
printk("%2u: %c %c %02x %05x %05x %o %o %c %c %c %c\n",
index,
SYSREG_BFEXT(TLBEHI_V, tlbehi) ? '1' : '0',
SYSREG_BFEXT(G, tlbelo) ? '1' : '0',
SYSREG_BFEXT(ASID, tlbehi),
SYSREG_BFEXT(VPN, tlbehi) >> 2,
SYSREG_BFEXT(PFN, tlbelo) >> 2,
SYSREG_BFEXT(AP, tlbelo),
SYSREG_BFEXT(SZ, tlbelo),
SYSREG_BFEXT(TLBELO_C, tlbelo) ? 'C' : ' ',
SYSREG_BFEXT(B, tlbelo) ? 'B' : ' ',
SYSREG_BFEXT(W, tlbelo) ? 'W' : ' ',
SYSREG_BFEXT(TLBELO_D, tlbelo) ? 'D' : ' ');
sysreg_write(MMUCR, mmucr_save);
sysreg_write(TLBEHI, tlbehi_save);
cpu_sync_pipeline();
local_irq_restore(flags);
}
void dump_dtlb(void)
{
unsigned int i;
printk("ID V G ASID VPN PFN AP SZ C B W D\n");
for (i = 0; i < NR_TLB_ENTRIES; i++)
show_dtlb_entry(i);
}
static void update_dtlb(unsigned long address, pte_t pte)
{
u32 tlbehi;
u32 mmucr;
/*
* We're not changing the ASID here, so no need to flush the
* pipeline.
*/
tlbehi = sysreg_read(TLBEHI);
tlbehi = SYSREG_BF(ASID, SYSREG_BFEXT(ASID, tlbehi));
tlbehi |= address & MMU_VPN_MASK;
tlbehi |= SYSREG_BIT(TLBEHI_V);
sysreg_write(TLBEHI, tlbehi);
/* Does this mapping already exist? */
__builtin_tlbs();
mmucr = sysreg_read(MMUCR);
if (mmucr & SYSREG_BIT(MMUCR_N)) {
/* Not found -- pick a not-recently-accessed entry */
unsigned int rp;
u32 tlbar = sysreg_read(TLBARLO);
rp = 32 - fls(tlbar);
if (rp == 32) {
rp = 0;
sysreg_write(TLBARLO, -1L);
}
mmucr = SYSREG_BFINS(DRP, rp, mmucr);
sysreg_write(MMUCR, mmucr);
}
sysreg_write(TLBELO, pte_val(pte) & _PAGE_FLAGS_HARDWARE_MASK);
/* Let's go */
__builtin_tlbw();
}
void update_mmu_cache(struct vm_area_struct *vma,
unsigned long address, pte_t *ptep)
{
unsigned long flags;
/* ptrace may call this routine */
if (vma && current->active_mm != vma->vm_mm)
return;
local_irq_save(flags);
update_dtlb(address, *ptep);
local_irq_restore(flags);
}
static void __flush_tlb_page(unsigned long asid, unsigned long page)
{
u32 mmucr, tlbehi;
/*
* Caller is responsible for masking out non-PFN bits in page
* and changing the current ASID if necessary. This means that
* we don't need to flush the pipeline after writing TLBEHI.
*/
tlbehi = page | asid;
sysreg_write(TLBEHI, tlbehi);
__builtin_tlbs();
mmucr = sysreg_read(MMUCR);
if (!(mmucr & SYSREG_BIT(MMUCR_N))) {
unsigned int entry;
u32 tlbarlo;
/* Clear the "valid" bit */
sysreg_write(TLBEHI, tlbehi);
/* mark the entry as "not accessed" */
entry = SYSREG_BFEXT(DRP, mmucr);
tlbarlo = sysreg_read(TLBARLO);
tlbarlo |= (0x80000000UL >> entry);
sysreg_write(TLBARLO, tlbarlo);
/* update the entry with valid bit clear */
__builtin_tlbw();
}
}
void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
if (vma->vm_mm && vma->vm_mm->context != NO_CONTEXT) {
unsigned long flags, asid;
unsigned long saved_asid = MMU_NO_ASID;
asid = vma->vm_mm->context & MMU_CONTEXT_ASID_MASK;
page &= PAGE_MASK;
local_irq_save(flags);
if (vma->vm_mm != current->mm) {
saved_asid = get_asid();
set_asid(asid);
}
__flush_tlb_page(asid, page);
if (saved_asid != MMU_NO_ASID)
set_asid(saved_asid);
local_irq_restore(flags);
}
}
void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end)
{
struct mm_struct *mm = vma->vm_mm;
if (mm->context != NO_CONTEXT) {
unsigned long flags;
int size;
local_irq_save(flags);
size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
if (size > (MMU_DTLB_ENTRIES / 4)) { /* Too many entries to flush */
mm->context = NO_CONTEXT;
if (mm == current->mm)
activate_context(mm);
} else {
unsigned long asid;
unsigned long saved_asid;
asid = mm->context & MMU_CONTEXT_ASID_MASK;
saved_asid = MMU_NO_ASID;
start &= PAGE_MASK;
end += (PAGE_SIZE - 1);
end &= PAGE_MASK;
if (mm != current->mm) {
saved_asid = get_asid();
set_asid(asid);
}
while (start < end) {
__flush_tlb_page(asid, start);
start += PAGE_SIZE;
}
if (saved_asid != MMU_NO_ASID)
set_asid(saved_asid);
}
local_irq_restore(flags);
}
}
/*
* This function depends on the pages to be flushed having the G
* (global) bit set in their pte. This is true for all
* PAGE_KERNEL(_RO) pages.
*/
void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
unsigned long flags;
int size;
size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
if (size > (MMU_DTLB_ENTRIES / 4)) { /* Too many entries to flush */
flush_tlb_all();
} else {
unsigned long asid;
local_irq_save(flags);
asid = get_asid();
start &= PAGE_MASK;
end += (PAGE_SIZE - 1);
end &= PAGE_MASK;
while (start < end) {
__flush_tlb_page(asid, start);
start += PAGE_SIZE;
}
local_irq_restore(flags);
}
}
void flush_tlb_mm(struct mm_struct *mm)
{
/* Invalidate all TLB entries of this process by getting a new ASID */
if (mm->context != NO_CONTEXT) {
unsigned long flags;
local_irq_save(flags);
mm->context = NO_CONTEXT;
if (mm == current->mm)
activate_context(mm);
local_irq_restore(flags);
}
}
void flush_tlb_all(void)
{
unsigned long flags;
local_irq_save(flags);
sysreg_write(MMUCR, sysreg_read(MMUCR) | SYSREG_BIT(MMUCR_I));
local_irq_restore(flags);
}
#ifdef CONFIG_PROC_FS
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
static void *tlb_start(struct seq_file *tlb, loff_t *pos)
{
static unsigned long tlb_index;
if (*pos >= NR_TLB_ENTRIES)
return NULL;
tlb_index = 0;
return &tlb_index;
}
static void *tlb_next(struct seq_file *tlb, void *v, loff_t *pos)
{
unsigned long *index = v;
if (*index >= NR_TLB_ENTRIES - 1)
return NULL;
++*pos;
++*index;
return index;
}
static void tlb_stop(struct seq_file *tlb, void *v)
{
}
static int tlb_show(struct seq_file *tlb, void *v)
{
unsigned int tlbehi, tlbehi_save, tlbelo, mmucr, mmucr_save;
unsigned long flags;
unsigned long *index = v;
if (*index == 0)
seq_puts(tlb, "ID V G ASID VPN PFN AP SZ C B W D\n");
BUG_ON(*index >= NR_TLB_ENTRIES);
local_irq_save(flags);
mmucr_save = sysreg_read(MMUCR);
tlbehi_save = sysreg_read(TLBEHI);
mmucr = SYSREG_BFINS(DRP, *index, mmucr_save);
sysreg_write(MMUCR, mmucr);
/* TLBR might change the ASID */
__builtin_tlbr();
cpu_sync_pipeline();
tlbehi = sysreg_read(TLBEHI);
tlbelo = sysreg_read(TLBELO);
sysreg_write(MMUCR, mmucr_save);
sysreg_write(TLBEHI, tlbehi_save);
cpu_sync_pipeline();
local_irq_restore(flags);
seq_printf(tlb, "%2lu: %c %c %02x %05x %05x %o %o %c %c %c %c\n",
*index,
SYSREG_BFEXT(TLBEHI_V, tlbehi) ? '1' : '0',
SYSREG_BFEXT(G, tlbelo) ? '1' : '0',
SYSREG_BFEXT(ASID, tlbehi),
SYSREG_BFEXT(VPN, tlbehi) >> 2,
SYSREG_BFEXT(PFN, tlbelo) >> 2,
SYSREG_BFEXT(AP, tlbelo),
SYSREG_BFEXT(SZ, tlbelo),
SYSREG_BFEXT(TLBELO_C, tlbelo) ? '1' : '0',
SYSREG_BFEXT(B, tlbelo) ? '1' : '0',
SYSREG_BFEXT(W, tlbelo) ? '1' : '0',
SYSREG_BFEXT(TLBELO_D, tlbelo) ? '1' : '0');
return 0;
}
static const struct seq_operations tlb_ops = {
.start = tlb_start,
.next = tlb_next,
.stop = tlb_stop,
.show = tlb_show,
};
static int tlb_open(struct inode *inode, struct file *file)
{
return seq_open(file, &tlb_ops);
}
static const struct file_operations proc_tlb_operations = {
.open = tlb_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int __init proctlb_init(void)
{
proc_create("tlb", 0, NULL, &proc_tlb_operations);
return 0;
}
late_initcall(proctlb_init);
#endif /* CONFIG_PROC_FS */
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