init.c

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/*
 *  linux/arch/i386/mm/init.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 *
 *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
 */

#include <linux/config.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
#ifdef CONFIG_BLK_DEV_INITRD
#include <linux/blk.h>
#endif
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/slab.h>

#include <asm/processor.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/dma.h>
#include <asm/fixmap.h>
#include <asm/e820.h>
#include <asm/apic.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>

mmu_gather_t mmu_gathers[NR_CPUS];
unsigned long highstart_pfn, highend_pfn;
static unsigned long totalram_pages;
static unsigned long totalhigh_pages;

/*
 * NOTE: pagetable_init alloc all the fixmap pagetables contiguous on the
 * physical space so we can cache the place of the first one and move
 * around without checking the pgd every time.
 */

#if CONFIG_HIGHMEM
pte_t *kmap_pte;
pgprot_t kmap_prot;

#define kmap_get_fixmap_pte(vaddr)					\
	pte_offset_kernel(pmd_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr))

void __init kmap_init(void)
{
	unsigned long kmap_vstart;

	/* cache the first kmap pte */
	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
	kmap_pte = kmap_get_fixmap_pte(kmap_vstart);

	kmap_prot = PAGE_KERNEL;
}
#endif /* CONFIG_HIGHMEM */

void show_mem(void)
{
	int i, total = 0, reserved = 0;
	int shared = 0, cached = 0;
	int highmem = 0;

	printk("Mem-info:\n");
	show_free_areas();
	printk("Free swap:       %6dkB\n",nr_swap_pages<<(PAGE_SHIFT-10));
	i = max_mapnr;
	while (i-- > 0) {
		total++;
		if (PageHighMem(mem_map+i))
			highmem++;
		if (PageReserved(mem_map+i))
			reserved++;
		else if (PageSwapCache(mem_map+i))
			cached++;
		else if (page_count(mem_map+i))
			shared += page_count(mem_map+i) - 1;
	}
	printk("%d pages of RAM\n", total);
	printk("%d pages of HIGHMEM\n",highmem);
	printk("%d reserved pages\n",reserved);
	printk("%d pages shared\n",shared);
	printk("%d pages swap cached\n",cached);
	show_buffers();
}

/* References to section boundaries */

extern char _text, _etext, _edata, __bss_start, _end;
extern char __init_begin, __init_end;

static inline void set_pte_phys (unsigned long vaddr,
			unsigned long phys, pgprot_t flags)
{
	pgd_t *pgd;
	pmd_t *pmd;
	pte_t *pte;

	pgd = swapper_pg_dir + __pgd_offset(vaddr);
	if (pgd_none(*pgd)) {
		printk("PAE BUG #00!\n");
		return;
	}
	pmd = pmd_offset(pgd, vaddr);
	if (pmd_none(*pmd)) {
		printk("PAE BUG #01!\n");
		return;
	}
	pte = pte_offset_kernel(pmd, vaddr);
	/* <phys,flags> stored as-is, to permit clearing entries */
	set_pte(pte, mk_pte_phys(phys, flags));

	/*
	 * It's enough to flush this one mapping.
	 * (PGE mappings get flushed as well)
	 */
	__flush_tlb_one(vaddr);
}

void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
{
	unsigned long address = __fix_to_virt(idx);

	if (idx >= __end_of_fixed_addresses) {
		printk("Invalid __set_fixmap\n");
		return;
	}
	set_pte_phys(address, phys, flags);
}

static void __init fixrange_init (unsigned long start, unsigned long end, pgd_t *pgd_base)
{
	pgd_t *pgd;
	pmd_t *pmd;
	pte_t *pte;
	int i, j;
	unsigned long vaddr;

	vaddr = start;
	i = __pgd_offset(vaddr);
	j = __pmd_offset(vaddr);
	pgd = pgd_base + i;

	for ( ; (i < PTRS_PER_PGD) && (vaddr != end); pgd++, i++) {
#if CONFIG_X86_PAE
		if (pgd_none(*pgd)) {
			pmd = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
			set_pgd(pgd, __pgd(__pa(pmd) + 0x1));
			if (pmd != pmd_offset(pgd, 0))
				printk("PAE BUG #02!\n");
		}
		pmd = pmd_offset(pgd, vaddr);
#else
		pmd = (pmd_t *)pgd;
#endif
		for (; (j < PTRS_PER_PMD) && (vaddr != end); pmd++, j++) {
			if (pmd_none(*pmd)) {
				pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
				set_pmd(pmd, __pmd(_KERNPG_TABLE + __pa(pte)));
				if (pte != pte_offset_kernel(pmd, 0))
					BUG();
			}
			vaddr += PMD_SIZE;
		}
		j = 0;
	}
}

static void __init pagetable_init (void)
{
	unsigned long vaddr, end;
	pgd_t *pgd, *pgd_base;
	int i, j, k;
	pmd_t *pmd;
	pte_t *pte, *pte_base;

	/*
	 * This can be zero as well - no problem, in that case we exit
	 * the loops anyway due to the PTRS_PER_* conditions.
	 */
	end = (unsigned long)__va(max_low_pfn*PAGE_SIZE);

	pgd_base = swapper_pg_dir;
#if CONFIG_X86_PAE
	for (i = 0; i < PTRS_PER_PGD; i++)
		set_pgd(pgd_base + i, __pgd(1 + __pa(empty_zero_page)));
#endif
	i = __pgd_offset(PAGE_OFFSET);
	pgd = pgd_base + i;

	for (; i < PTRS_PER_PGD; pgd++, i++) {
		vaddr = i*PGDIR_SIZE;
		if (end && (vaddr >= end))
			break;
#if CONFIG_X86_PAE
		pmd = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
		set_pgd(pgd, __pgd(__pa(pmd) + 0x1));
#else
		pmd = (pmd_t *)pgd;
#endif
		if (pmd != pmd_offset(pgd, 0))
			BUG();
		for (j = 0; j < PTRS_PER_PMD; pmd++, j++) {
			vaddr = i*PGDIR_SIZE + j*PMD_SIZE;
			if (end && (vaddr >= end))
				break;
			if (cpu_has_pse) {
				unsigned long __pe;

				set_in_cr4(X86_CR4_PSE);
				boot_cpu_data.wp_works_ok = 1;
				__pe = _KERNPG_TABLE + _PAGE_PSE + __pa(vaddr);
				/* Make it "global" too if supported */
				if (cpu_has_pge) {
					set_in_cr4(X86_CR4_PGE);
					__pe += _PAGE_GLOBAL;
				}
				set_pmd(pmd, __pmd(__pe));
				continue;
			}

			pte_base = pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);

			for (k = 0; k < PTRS_PER_PTE; pte++, k++) {
				vaddr = i*PGDIR_SIZE + j*PMD_SIZE + k*PAGE_SIZE;
				if (end && (vaddr >= end))
					break;
				*pte = mk_pte_phys(__pa(vaddr), PAGE_KERNEL);
			}
			set_pmd(pmd, __pmd(_KERNPG_TABLE + __pa(pte_base)));
			if (pte_base != pte_offset_kernel(pmd, 0))
				BUG();

		}
	}

	/*
	 * Fixed mappings, only the page table structure has to be
	 * created - mappings will be set by set_fixmap():
	 */
	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
	fixrange_init(vaddr, 0, pgd_base);

#if CONFIG_HIGHMEM
	/*
	 * Permanent kmaps:
	 */
	vaddr = PKMAP_BASE;
	fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);

	pgd = swapper_pg_dir + __pgd_offset(vaddr);
	pmd = pmd_offset(pgd, vaddr);
	pte = pte_offset_kernel(pmd, vaddr);
	pkmap_page_table = pte;
#endif

#if CONFIG_X86_PAE
	/*
	 * Add low memory identity-mappings - SMP needs it when
	 * starting up on an AP from real-mode. In the non-PAE
	 * case we already have these mappings through head.S.
	 * All user-space mappings are explicitly cleared after
	 * SMP startup.
	 */
	pgd_base[0] = pgd_base[USER_PTRS_PER_PGD];
#endif
}

void __init zap_low_mappings (void)
{
	int i;
	/*
	 * Zap initial low-memory mappings.
	 *
	 * Note that "pgd_clear()" doesn't do it for
	 * us, because pgd_clear() is a no-op on i386.
	 */
	for (i = 0; i < USER_PTRS_PER_PGD; i++)
#if CONFIG_X86_PAE
		set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
#else
		set_pgd(swapper_pg_dir+i, __pgd(0));
#endif
	flush_tlb_all();
}

/*
 * paging_init() sets up the page tables - note that the first 8MB are
 * already mapped by head.S.
 *
 * This routines 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)
{
	pagetable_init();

	__asm__( "movl %0,%%cr3\n" ::"r"(__pa(swapper_pg_dir)));

#if CONFIG_X86_PAE
	/*
	 * We will bail out later - printk doesnt work right now so
	 * the user would just see a hanging kernel.
	 */
	if (cpu_has_pae)
		set_in_cr4(X86_CR4_PAE);
#endif

	__flush_tlb_all();

#ifdef CONFIG_HIGHMEM
	kmap_init();
#endif
	{
		unsigned long zones_size[MAX_NR_ZONES] = {0, 0, 0};
		unsigned int max_dma, high, low;

		max_dma = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
		low = max_low_pfn;
		high = highend_pfn;

		if (low < max_dma)
			zones_size[ZONE_DMA] = low;
		else {
			zones_size[ZONE_DMA] = max_dma;
			zones_size[ZONE_NORMAL] = low - max_dma;
#ifdef CONFIG_HIGHMEM