init.c

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/*
 *  linux/arch/x86_64/mm/init.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 *  Copyright (C) 2000  Pavel Machek <[e-mail]>
 *  Copyright (C) 2002,2003 Andi Kleen <[e-mail]>
 */

#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>
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/proc_fs.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/mmu_context.h>
#include <asm/proto.h>
#include <asm/smp.h>

#ifndef Dprintk
#define Dprintk(x...)
#endif

extern char _stext[];

DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

/*
 * 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.
 */

void show_mem(void)
{
	int i, total = 0, reserved = 0;
	int shared = 0, cached = 0;
	pg_data_t *pgdat;
	struct page *page;

	printk("Mem-info:\n");
	show_free_areas();
	printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));

	for_each_pgdat(pgdat) {
               for (i = 0; i < pgdat->node_spanned_pages; ++i) {
                       page = pgdat->node_mem_map + i;
		total++;
                       if (PageReserved(page))
			reserved++;
                       else if (PageSwapCache(page))
			cached++;
                       else if (page_count(page))
                               shared += page_count(page) - 1;
               }
	}
	printk("%d pages of RAM\n", total);
	printk("%d reserved pages\n",reserved);
	printk("%d pages shared\n",shared);
	printk("%d pages swap cached\n",cached);
}

/* References to section boundaries */

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

int after_bootmem;

static void *spp_getpage(void)
{ 
	void *ptr;
	if (after_bootmem)
		ptr = (void *) get_zeroed_page(GFP_ATOMIC); 
	else
		ptr = alloc_bootmem_pages(PAGE_SIZE);
	if (!ptr || ((unsigned long)ptr & ~PAGE_MASK))
		panic("set_pte_phys: cannot allocate page data %s\n", after_bootmem?"after bootmem":"");

	Dprintk("spp_getpage %p\n", ptr);
	return ptr;
} 

static void set_pte_phys(unsigned long vaddr,
			 unsigned long phys, pgprot_t prot)
{
	pml4_t *level4;
	pgd_t *pgd;
	pmd_t *pmd;
	pte_t *pte, new_pte;

	Dprintk("set_pte_phys %lx to %lx\n", vaddr, phys);

	level4 = pml4_offset_k(vaddr);
	if (pml4_none(*level4)) {
		printk("PML4 FIXMAP MISSING, it should be setup in head.S!\n");
		return;
	}
	pgd = level3_offset_k(level4, vaddr);
	if (pgd_none(*pgd)) {
		pmd = (pmd_t *) spp_getpage(); 
		set_pgd(pgd, __pgd(__pa(pmd) | _KERNPG_TABLE | _PAGE_USER));
		if (pmd != pmd_offset(pgd, 0)) {
			printk("PAGETABLE BUG #01! %p <-> %p\n", pmd, pmd_offset(pgd,0));
			return;
		}
	}
	pmd = pmd_offset(pgd, vaddr);
	if (pmd_none(*pmd)) {
		pte = (pte_t *) spp_getpage();
		set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE | _PAGE_USER));
		if (pte != pte_offset_kernel(pmd, 0)) {
			printk("PAGETABLE BUG #02!\n");
			return;
		}
	}
	new_pte = pfn_pte(phys >> PAGE_SHIFT, prot);

	pte = pte_offset_kernel(pmd, vaddr);
	if (!pte_none(*pte) &&
	    pte_val(*pte) != (pte_val(new_pte) & __supported_pte_mask))
		pte_ERROR(*pte);
	set_pte(pte, new_pte);

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

/* NOTE: this is meant to be run only at boot */
void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t prot)
{
	unsigned long address = __fix_to_virt(idx);

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

unsigned long __initdata table_start, table_end; 

extern pmd_t temp_boot_pmds[]; 

static  struct temp_map { 
	pmd_t *pmd;
	void  *address; 
	int    allocated; 
} temp_mappings[] __initdata = { 
	{ &temp_boot_pmds[0], (void *)(40UL * 1024 * 1024) },
	{ &temp_boot_pmds[1], (void *)(42UL * 1024 * 1024) }, 
	{}
}; 

static __init void *alloc_low_page(int *index, unsigned long *phys) 
{ 
	struct temp_map *ti;
	int i; 
	unsigned long pfn = table_end++, paddr; 
	void *adr;

	if (pfn >= end_pfn) 
		panic("alloc_low_page: ran out of memory"); 
	for (i = 0; temp_mappings[i].allocated; i++) {
		if (!temp_mappings[i].pmd) 
			panic("alloc_low_page: ran out of temp mappings"); 
	} 
	ti = &temp_mappings[i];
	paddr = (pfn << PAGE_SHIFT) & PMD_MASK; 
	set_pmd(ti->pmd, __pmd(paddr | _KERNPG_TABLE | _PAGE_PSE)); 
	ti->allocated = 1; 
	__flush_tlb(); 	       
	adr = ti->address + ((pfn << PAGE_SHIFT) & ~PMD_MASK); 
	*index = i; 
	*phys  = pfn * PAGE_SIZE;  
	return adr; 
} 

static __init void unmap_low_page(int i)
{ 
	struct temp_map *ti = &temp_mappings[i];
	set_pmd(ti->pmd, __pmd(0));
	ti->allocated = 0; 
} 

static void __init phys_pgd_init(pgd_t *pgd, unsigned long address, unsigned long end)
{ 
	long i, j; 

	i = pgd_index(address);
	pgd = pgd + i;
	for (; i < PTRS_PER_PGD; pgd++, i++) {
		int map; 
		unsigned long paddr, pmd_phys;
		pmd_t *pmd;

		paddr = (address & PML4_MASK) + i*PGDIR_SIZE;
		if (paddr >= end) { 
			for (; i < PTRS_PER_PGD; i++, pgd++) 
				set_pgd(pgd, __pgd(0)); 
			break;
		} 

		if (!e820_mapped(paddr, paddr+PGDIR_SIZE, 0)) { 
			set_pgd(pgd, __pgd(0)); 
			continue;
		} 

		pmd = alloc_low_page(&map, &pmd_phys);
		set_pgd(pgd, __pgd(pmd_phys | _KERNPG_TABLE));
		for (j = 0; j < PTRS_PER_PMD; pmd++, j++, paddr += PMD_SIZE) {
			unsigned long pe;

			if (paddr >= end) { 
				for (; j < PTRS_PER_PMD; j++, pmd++)
					set_pmd(pmd,  __pmd(0)); 
				break;
		}
			pe = _PAGE_NX|_PAGE_PSE | _KERNPG_TABLE | _PAGE_GLOBAL | paddr;
			pe &= __supported_pte_mask;
			set_pmd(pmd, __pmd(pe));
		}
		unmap_low_page(map);
	}
	__flush_tlb();
} 

/* Setup the direct mapping of the physical memory at PAGE_OFFSET.
   This runs before bootmem is initialized and gets pages directly from the 
   physical memory. To access them they are temporarily mapped. */
void __init init_memory_mapping(void) 
{ 
	unsigned long adr;	       
	unsigned long end;
	unsigned long next; 
	unsigned long pgds, pmds, tables; 

	Dprintk("init_memory_mapping\n");

	end = end_pfn_map << PAGE_SHIFT;

	/* 
	 * Find space for the kernel direct mapping tables.
	 * Later we should allocate these tables in the local node of the memory
	 * mapped.  Unfortunately this is done currently before the nodes are 
	 * discovered.
	 */

	pgds = (end + PGDIR_SIZE - 1) >> PGDIR_SHIFT;
	pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT; 
	tables = round_up(pgds*8, PAGE_SIZE) + round_up(pmds * 8, PAGE_SIZE); 

	table_start = find_e820_area(0x8000, __pa_symbol(&_text), tables); 
	if (table_start == -1UL) 
		panic("Cannot find space for the kernel page tables"); 

	table_start >>= PAGE_SHIFT; 
	table_end = table_start;
       
	end += __PAGE_OFFSET; /* turn virtual */  	

	for (adr = PAGE_OFFSET; adr < end; adr = next) { 
		int map;
		unsigned long pgd_phys; 
		pgd_t *pgd = alloc_low_page(&map, &pgd_phys);
		next = adr + PML4_SIZE;
		if (next > end) 
			next = end; 
		phys_pgd_init(pgd, adr-PAGE_OFFSET, next-PAGE_OFFSET); 
		set_pml4(init_level4_pgt + pml4_index(adr), mk_kernel_pml4(pgd_phys));
		unmap_low_page(map);   
	} 
	asm volatile("movq %%cr4,%0" : "=r" (mmu_cr4_features));
	__flush_tlb_all();
	early_printk("kernel direct mapping tables upto %lx @ %lx-%lx\n", end, 
	       table_start<<PAGE_SHIFT, 
	       table_end<<PAGE_SHIFT);
}

extern struct x8664_pda cpu_pda[NR_CPUS];