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openwrt/target/linux/coldfire/files-2.6.31/arch/m68k/mm/cf-mmu.c

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/*
* linux/arch/m68k/mm/cf-mmu.c
*
* Based upon linux/arch/m68k/mm/sun3mmu.c
* Based upon linux/arch/ppc/mm/mmu_context.c
*
* Implementations of mm routines specific to the Coldfire MMU.
*
* Copyright (c) 2008 Freescale Semiconductor, Inc.
* Copyright Freescale Semiconductor, Inc. 2008-2009
* Jason Jin Jason.Jin@freescale.com
* Shrek Wu B16972@freescale.com
*/
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/init.h>
#ifdef CONFIG_BLK_DEV_RAM
#include <linux/blkdev.h>
#endif
#include <linux/bootmem.h>
#include <asm/setup.h>
#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/mmu_context.h>
#include <asm/cf_pgalloc.h>
#include <asm/coldfire.h>
#include <asm/tlbflush.h>
#define KMAPAREA(x) ((x >= VMALLOC_START) && (x < KMAP_END))
#undef DEBUG
#ifdef CONFIG_VDSO
unsigned long next_mmu_context;
#else
mm_context_t next_mmu_context;
#endif
unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1];
atomic_t nr_free_contexts;
struct mm_struct *context_mm[LAST_CONTEXT+1];
void steal_context(void);
#ifdef CONFIG_M5445X
void m68k_setup_node(int);
#endif
const char bad_pmd_string[] = "Bad pmd in pte_alloc: %08lx\n";
extern unsigned long empty_bad_page_table;
extern unsigned long empty_bad_page;
extern unsigned long num_pages;
#ifdef CONFIG_M5445X
extern unsigned long availmem;
#endif
extern char __init_begin, __init_end;
/*
* Free memory used for system initialization.
*/
void free_initmem(void)
{
#if 0
unsigned long addr;
unsigned long start = (unsigned long)&__init_begin;
unsigned long end = (unsigned long)&__init_end;
printk(KERN_INFO "free_initmem: __init_begin = 0x%lx __init_end = 0x%lx\n", start, end);
addr = (unsigned long)&__init_begin;
for (; addr < (unsigned long)&__init_end; addr += PAGE_SIZE) {
/* not currently used */
virt_to_page(addr)->flags &= ~(1 << PG_reserved);
init_page_count(virt_to_page(addr));
free_page(addr);
totalram_pages++;
}
#endif
}
/*
* Initialize the paging system.
*/
void __init paging_init(void)
{
pgd_t * pg_dir;
pte_t * pg_table;
int i;
unsigned long address;
unsigned long next_pgtable;
unsigned long zones_size[MAX_NR_ZONES];
unsigned long size;
enum zone_type zone;
/* allocate zero page */
empty_zero_page = (void *)alloc_bootmem_pages(PAGE_SIZE);
memset((void *)empty_zero_page, 0, PAGE_SIZE);
/* zero kernel page directory */
pg_dir = swapper_pg_dir;
memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir));
/*
* setup page tables for PHYSRAM
*/
/* starting loc in page directory */
pg_dir += PAGE_OFFSET >> PGDIR_SHIFT;
/* allocate page tables */
size = num_pages * sizeof(pte_t);
size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);
next_pgtable = (unsigned long)alloc_bootmem_pages(size);
address = PAGE_OFFSET;
while (address < (unsigned long)high_memory) {
/* setup page table in page directory */
pg_table = (pte_t *)next_pgtable;
next_pgtable += PTRS_PER_PTE * sizeof(pte_t);
pgd_val(*pg_dir) = (unsigned long)pg_table;
pg_dir++;
/* create PTEs in page table */
for (i=0; i<PTRS_PER_PTE; ++i, ++pg_table) {
pte_t pte = pfn_pte(virt_to_pfn(address), PAGE_INIT);
if (address >= (unsigned long)high_memory)
pte_val (pte) = 0;
set_pte(pg_table, pte);
address += PAGE_SIZE;
}
}
/*
* setup page tables for DMA area
*/
/* starting loc in page directory */
pg_dir = swapper_pg_dir;
pg_dir += CONFIG_DMA_BASE >> PGDIR_SHIFT;
/* allocate page tables */
size = (CONFIG_DMA_SIZE >> PAGE_SHIFT) * sizeof(pte_t);
size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);
next_pgtable = (unsigned long)alloc_bootmem_pages(size);
address = CONFIG_DMA_BASE;
while (address < (CONFIG_DMA_BASE + CONFIG_DMA_SIZE)) {
/* setup page table in page directory */
pg_table = (pte_t *)next_pgtable;
next_pgtable += PTRS_PER_PTE * sizeof(pte_t);
pgd_val(*pg_dir) = (unsigned long)pg_table;
pg_dir++;
/* create PTEs in page table */
for (i=0; i<PTRS_PER_PTE; ++i, ++pg_table) {
pte_t pte = pfn_pte(virt_to_pfn(address), PAGE_INIT);
if (address >= (CONFIG_DMA_BASE + CONFIG_DMA_SIZE))
pte_val (pte) = 0;
set_pte(pg_table, pte);
address += PAGE_SIZE;
}
}
/*
* setup zones
*/
current->mm = NULL;
/* clear zones */
for (zone = 0; zone < MAX_NR_ZONES; zone++)
zones_size[zone] = 0x0;
zones_size[ZONE_DMA] = CONFIG_DMA_SIZE >> PAGE_SHIFT;
zones_size[ZONE_NORMAL] = (((unsigned long)high_memory -
PAGE_OFFSET) >> PAGE_SHIFT) -
zones_size[ZONE_DMA];
free_area_init(zones_size);
}
/*
* Handle a missed TLB
*/
int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)
{
struct mm_struct *mm;
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
unsigned long mmuar;
int asid;
int flags;
local_save_flags(flags);
local_irq_disable();
mmuar = ( dtlb ) ? regs->mmuar
: regs->pc + (extension_word * sizeof(long));
mm = (!user_mode(regs) && KMAPAREA(mmuar)) ? &init_mm : current->mm;
if (!mm) {
local_irq_restore(flags);
return (-1);
}
pgd = pgd_offset(mm, mmuar);
if (pgd_none(*pgd)) {
local_irq_restore(flags);
return (-1);
}
pmd = pmd_offset(pgd, mmuar);
if (pmd_none(*pmd)) {
local_irq_restore(flags);
return (-1);
}
pte = (KMAPAREA(mmuar)) ? pte_offset_kernel(pmd, mmuar)
: pte_offset_map(pmd, mmuar);
if (pte_none(*pte) || !pte_present(*pte)) {
local_irq_restore(flags);
return (-1);
}
if (write) {
if (!pte_write(*pte)) {
local_irq_restore(flags);
return (-1);
}
set_pte(pte, pte_mkdirty(*pte));
}
set_pte(pte, pte_mkyoung(*pte));
asid = cpu_context(mm) & 0xff;
if (!pte_dirty(*pte) && !KMAPAREA(mmuar))
set_pte(pte, pte_wrprotect(*pte));
*MMUTR = (mmuar & PAGE_MASK) | (asid << CF_ASID_MMU_SHIFT)
| (((int)(pte->pte) & (int)CF_PAGE_MMUTR_MASK ) >> CF_PAGE_MMUTR_SHIFT)
| MMUTR_V;
*MMUDR = (pte_val(*pte) & PAGE_MASK)
| ((pte->pte) & CF_PAGE_MMUDR_MASK)
| MMUDR_SZ8K | MMUDR_X;
if ( dtlb )
*MMUOR = MMUOR_ACC | MMUOR_UAA;
else
*MMUOR = MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA;
asm("nop");
#ifdef DEBUG
printk("cf_tlb_miss: va=%lx, pa=%lx\n", (mmuar & PAGE_MASK),
(pte_val(*pte) & PAGE_MASK));
#endif
local_irq_restore(flags);
return (0);
}
/*
* Context Management
*
* Based on arch/ppc/mmu_context.c
*/
/*
* Initialize the context management system.
*/
void __init mmu_context_init(void)
{
/*
* Some processors have too few contexts to reserve one for
* init_mm, and require using context 0 for a normal task.
* Other processors reserve the use of context zero for the kernel.
* This code assumes FIRST_CONTEXT < 32.
*/
context_map[0] = (1 << FIRST_CONTEXT) - 1;
next_mmu_context = FIRST_CONTEXT;
atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1);
}
/*
* Steal a context from a task that has one at the moment.
* This is only used on 8xx and 4xx and we presently assume that
* they don't do SMP. If they do then thicfpgalloc.hs will have to check
* whether the MM we steal is in use.
* We also assume that this is only used on systems that don't
* use an MMU hash table - this is true for 8xx and 4xx.
* This isn't an LRU system, it just frees up each context in
* turn (sort-of pseudo-random replacement :). This would be the
* place to implement an LRU scheme if anyone was motivated to do it.
* -- paulus
*/
void steal_context(void)
{
struct mm_struct *mm;
/* free up context `next_mmu_context' */
/* if we shouldn't free context 0, don't... */
if (next_mmu_context < FIRST_CONTEXT)
next_mmu_context = FIRST_CONTEXT;
mm = context_mm[next_mmu_context];
flush_tlb_mm(mm);
destroy_context(mm);
}
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