path: root/arch/x86/mm/init_64.c

/*
 *  linux/arch/x86_64/mm/init.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 *  Copyright (C) 2000  Pavel Machek <pavel@ucw.cz>
 *  Copyright (C) 2002,2003 Andi Kleen <ak@suse.de>
 */

#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/initrd.h>
#include <linux/pagemap.h>
#include <linux/memblock.h>
#include <linux/proc_fs.h>
#include <linux/pci.h>
#include <linux/pfn.h>
#include <linux/poison.h>
#include <linux/dma-mapping.h>
#include <linux/memory.h>
#include <linux/memory_hotplug.h>
#include <linux/memremap.h>
#include <linux/nmi.h>
#include <linux/gfp.h>
#include <linux/kcore.h>

#include <asm/processor.h>
#include <asm/bios_ebda.h>
#include <linux/uaccess.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/dma.h>
#include <asm/fixmap.h>
#include <asm/e820/api.h>
#include <asm/apic.h>
#include <asm/tlb.h>
#include <asm/mmu_context.h>
#include <asm/proto.h>
#include <asm/smp.h>
#include <asm/sections.h>
#include <asm/kdebug.h>
#include <asm/numa.h>
#include <asm/set_memory.h>
#include <asm/init.h>
#include <asm/uv/uv.h>
#include <asm/setup.h>

#include "mm_internal.h"

#include "ident_map.c"

/*
 * 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.
 */

/* Bits supported by the hardware: */
pteval_t __supported_pte_mask __read_mostly = ~0;
/* Bits allowed in normal kernel mappings: */
pteval_t __default_kernel_pte_mask __read_mostly = ~0;
EXPORT_SYMBOL_GPL(__supported_pte_mask);
/* Used in PAGE_KERNEL_* macros which are reasonably used out-of-tree: */
EXPORT_SYMBOL(__default_kernel_pte_mask);

int force_personality32;

/*
 * noexec32=on|off
 * Control non executable heap for 32bit processes.
 * To control the stack too use noexec=off
 *
 * on	PROT_READ does not imply PROT_EXEC for 32-bit processes (default)
 * off	PROT_READ implies PROT_EXEC
 */
static int __init nonx32_setup(char *str)
{
	if (!strcmp(str, "on"))
		force_personality32 &= ~READ_IMPLIES_EXEC;
	else if (!strcmp(str, "off"))
		force_personality32 |= READ_IMPLIES_EXEC;
	return 1;
}
__setup("noexec32=", nonx32_setup);

static void sync_global_pgds_l5(unsigned long start, unsigned long end)
{
	unsigned long addr;

	for (addr = start; addr <= end; addr = ALIGN(addr + 1, PGDIR_SIZE)) {
		const pgd_t *pgd_ref = pgd_offset_k(addr);
		struct page *page;

		/* Check for overflow */
		if (addr < start)
			break;

		if (pgd_none(*pgd_ref))
			continue;

		spin_lock(&pgd_lock);
		list_for_each_entry(page, &pgd_list, lru) {
			pgd_t *pgd;
			spinlock_t *pgt_lock;

			pgd = (pgd_t *)page_address(page) + pgd_index(addr);
			/* the pgt_lock only for Xen */
			pgt_lock = &pgd_page_get_mm(page)->page_table_lock;
			spin_lock(pgt_lock);

			if (!pgd_none(*pgd_ref) && !pgd_none(*pgd))
				BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));

			if (pgd_none(*pgd))
				set_pgd(pgd, *pgd_ref);

			spin_unlock(pgt_lock);
		}
		spin_unlock(&pgd_lock);
	}
}

static void sync_global_pgds_l4(unsigned long start, unsigned long end)
{
	unsigned long addr;

	for (addr = start; addr <= end; addr = ALIGN(addr + 1, PGDIR_SIZE)) {
		pgd_t *pgd_ref = pgd_offset_k(addr);
		const p4d_t *p4d_ref;
		struct page *page;

		/*
		 * With folded p4d, pgd_none() is always false, we need to
		 * handle synchonization on p4d level.
		 */
		MAYBE_BUILD_BUG_ON(pgd_none(*pgd_ref));
		p4d_ref = p4d_offset(pgd_ref, addr);

		if (p4d_none(*p4d_ref))
			continue;

		spin_lock(&pgd_lock);
		list_for_each_entry(page, &pgd_list, lru) {
			pgd_t *pgd;
			p4d_t *p4d;
			spinlock_t *pgt_lock;

			pgd = (pgd_t *)page_address(page) + pgd_index(addr);
			p4d = p4d_offset(pgd, addr);
			/* the pgt_lock only for Xen */
			pgt_lock = &pgd_page_get_mm(page)->page_table_lock;
			spin_lock(pgt_lock);

			if (!p4d_none(*p4d_ref) && !p4d_none(*p4d))
				BUG_ON(p4d_page_vaddr(*p4d)
				       != p4d_page_vaddr(*p4d_ref));

			if (p4d_none(*p4d))
				set_p4d(p4d, *p4d_ref);

			spin_unlock(pgt_lock);
		}
		spin_unlock(&pgd_lock);
	}
}

/*
 * When memory was added make sure all the processes MM have
 * suitable PGD entries in the local PGD level page.
 */
void sync_global_pgds(unsigned long start, unsigned long end)
{
	if (pgtable_l5_enabled())
		sync_global_pgds_l5(start, end);
	else
		sync_global_pgds_l4(start, end);
}

/*
 * NOTE: This function is marked __ref because it calls __init function
 * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
 */
static __ref void *spp_getpage(void)
{
	void *ptr;

	if (after_bootmem)
		ptr = (void *) get_zeroed_page(GFP_ATOMIC);
	else
		ptr = memblock_alloc(PAGE_SIZE, PAGE_SIZE);

	if (!ptr || ((unsigned long)ptr & ~PAGE_MASK)) {
		panic("set_pte_phys: cannot allocate page data %s\n",
			after_bootmem ? "after bootmem" : "");
	}

	pr_debug("spp_getpage %p\n", ptr);

	return ptr;
}

static p4d_t *fill_p4d(pgd_t *pgd, unsigned long vaddr)
{
	if (pgd_none(*pgd)) {
		p4d_t *p4d = (p4d_t *)spp_getpage();
		pgd_populate(&init_mm, pgd, p4d);
		if (p4d != p4d_offset(pgd, 0))
			printk(KERN_ERR "PAGETABLE BUG #00! %p <-> %p\n",
			       p4d, p4d_offset(pgd, 0));
	}
	return p4d_offset(pgd, vaddr);
}

static pud_t *fill_pud(p4d_t *p4d, unsigned long vaddr)
{
	if (p4d_none(*p4d)) {
		pud_t *pud = (pud_t *)spp_getpage();
		p4d_populate(&init_mm, p4d, pud);
		if (pud != pud_offset(p4d, 0))
			printk(KERN_ERR "PAGETABLE BUG #01! %p <-> %p\n",
			       pud, pud_offset(p4d, 0));
	}
	return pud_offset(p4d, vaddr);
}

static pmd_t *fill_pmd(pud_t *pud, unsigned long vaddr)
{
	if (pud_none(*pud)) {
		pmd_t *pmd = (pmd_t *) spp_getpage();
		pud_populate(&init_mm, pud, pmd);
		if (pmd != pmd_offset(pud, 0))
			printk(KERN_ERR "PAGETABLE BUG #02! %p <-> %p\n",
			       pmd, pmd_offset(pud, 0));
	}
	return pmd_offset(pud, vaddr);
}

static pte_t *fill_pte(pmd_t *pmd, unsigned long vaddr)
{
	if (pmd_none(*pmd)) {
		pte_t *pte = (pte_t *) spp_getpage();
		pmd_populate_kernel(&init_mm, pmd,