android_kernel_xiaomi_sm8350/arch/avr32/mm/init.c
Haavard Skinnemoen cfd23e93a0 avr32: Store virtual addresses in the PGD
Instead of storing physical addresses along with page flags in the
PGD, store virtual addresses and use NULL to indicate a not present
second-level page table. A non-page-aligned page table indicates a bad
PMD.

This simplifies the TLB miss handler since it no longer has to check
the Present bit and no longer has to convert the PGD entry from
physical to virtual address. Instead, it has to check for a NULL
entry, which is slightly cheaper than either.

Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
2008-07-02 11:01:28 +02:00

224 lines
5.3 KiB
C

/*
* 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/kernel.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/init.h>
#include <linux/mmzone.h>
#include <linux/module.h>
#include <linux/bootmem.h>
#include <linux/pagemap.h>
#include <linux/nodemask.h>
#include <asm/page.h>
#include <asm/mmu_context.h>
#include <asm/tlb.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <asm/setup.h>
#include <asm/sections.h>
#define __page_aligned __attribute__((section(".data.page_aligned")))
DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned;
struct page *empty_zero_page;
EXPORT_SYMBOL(empty_zero_page);
/*
* Cache of MMU context last used.
*/
unsigned long mmu_context_cache = NO_CONTEXT;
void show_mem(void)
{
int total = 0, reserved = 0, cached = 0;
int slab = 0, free = 0, shared = 0;
pg_data_t *pgdat;
printk("Mem-info:\n");
show_free_areas();
for_each_online_pgdat(pgdat) {
struct page *page, *end;
page = pgdat->node_mem_map;
end = page + pgdat->node_spanned_pages;
do {
total++;
if (PageReserved(page))
reserved++;
else if (PageSwapCache(page))
cached++;
else if (PageSlab(page))
slab++;
else if (!page_count(page))
free++;
else
shared += page_count(page) - 1;
page++;
} while (page < end);
}
printk ("%d pages of RAM\n", total);
printk ("%d free pages\n", free);
printk ("%d reserved pages\n", reserved);
printk ("%d slab pages\n", slab);
printk ("%d pages shared\n", shared);
printk ("%d pages swap cached\n", cached);
}
/*
* paging_init() sets up the page tables
*
* This routine also unmaps the page at virtual kernel address 0, so
* that we can trap those pesky NULL-reference errors in the kernel.
*/
void __init paging_init(void)
{
extern unsigned long _evba;
void *zero_page;
int nid;
/*
* Make sure we can handle exceptions before enabling
* paging. Not that we should ever _get_ any exceptions this
* early, but you never know...
*/
printk("Exception vectors start at %p\n", &_evba);
sysreg_write(EVBA, (unsigned long)&_evba);
/*
* Since we are ready to handle exceptions now, we should let
* the CPU generate them...
*/
__asm__ __volatile__ ("csrf %0" : : "i"(SR_EM_BIT));
/*
* Allocate the zero page. The allocator will panic if it
* can't satisfy the request, so no need to check.
*/
zero_page = alloc_bootmem_low_pages_node(NODE_DATA(0),
PAGE_SIZE);
sysreg_write(PTBR, (unsigned long)swapper_pg_dir);
enable_mmu();
printk ("CPU: Paging enabled\n");
for_each_online_node(nid) {
pg_data_t *pgdat = NODE_DATA(nid);
unsigned long zones_size[MAX_NR_ZONES];
unsigned long low, start_pfn;
start_pfn = pgdat->bdata->node_boot_start;
start_pfn >>= PAGE_SHIFT;
low = pgdat->bdata->node_low_pfn;
memset(zones_size, 0, sizeof(zones_size));
zones_size[ZONE_NORMAL] = low - start_pfn;
printk("Node %u: start_pfn = 0x%lx, low = 0x%lx\n",
nid, start_pfn, low);
free_area_init_node(nid, pgdat, zones_size, start_pfn, NULL);
printk("Node %u: mem_map starts at %p\n",
pgdat->node_id, pgdat->node_mem_map);
}
mem_map = NODE_DATA(0)->node_mem_map;
memset(zero_page, 0, PAGE_SIZE);
empty_zero_page = virt_to_page(zero_page);
flush_dcache_page(empty_zero_page);
}
void __init mem_init(void)
{
int codesize, reservedpages, datasize, initsize;
int nid, i;
reservedpages = 0;
high_memory = NULL;
/* this will put all low memory onto the freelists */
for_each_online_node(nid) {
pg_data_t *pgdat = NODE_DATA(nid);
unsigned long node_pages = 0;
void *node_high_memory;
num_physpages += pgdat->node_present_pages;
if (pgdat->node_spanned_pages != 0)
node_pages = free_all_bootmem_node(pgdat);
totalram_pages += node_pages;
for (i = 0; i < node_pages; i++)
if (PageReserved(pgdat->node_mem_map + i))
reservedpages++;
node_high_memory = (void *)((pgdat->node_start_pfn
+ pgdat->node_spanned_pages)
<< PAGE_SHIFT);
if (node_high_memory > high_memory)
high_memory = node_high_memory;
}
max_mapnr = MAP_NR(high_memory);
codesize = (unsigned long)_etext - (unsigned long)_text;
datasize = (unsigned long)_edata - (unsigned long)_data;
initsize = (unsigned long)__init_end - (unsigned long)__init_begin;
printk ("Memory: %luk/%luk available (%dk kernel code, "
"%dk reserved, %dk data, %dk init)\n",
(unsigned long)nr_free_pages() << (PAGE_SHIFT - 10),
totalram_pages << (PAGE_SHIFT - 10),
codesize >> 10,
reservedpages << (PAGE_SHIFT - 10),
datasize >> 10,
initsize >> 10);
}
static inline void free_area(unsigned long addr, unsigned long end, char *s)
{
unsigned int size = (end - addr) >> 10;
for (; addr < end; addr += PAGE_SIZE) {
struct page *page = virt_to_page(addr);
ClearPageReserved(page);
init_page_count(page);
free_page(addr);
totalram_pages++;
}
if (size && s)
printk(KERN_INFO "Freeing %s memory: %dK (%lx - %lx)\n",
s, size, end - (size << 10), end);
}
void free_initmem(void)
{
free_area((unsigned long)__init_begin, (unsigned long)__init_end,
"init");
}
#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
free_area(start, end, "initrd");
}
#endif