init.c

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

#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

#ifdef CONFIG_GART_IOMMU
extern int swiotlb;
#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 = pfn_to_page(pgdat->node_start_pfn + 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)
{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte, new_pte;

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

	pgd = pgd_offset_k(vaddr);
	if (pgd_none(*pgd)) {
		printk("PGD FIXMAP MISSING, it should be setup in head.S!\n");
		return;
	}
	pud = pud_offset(pgd, vaddr);
	if (pud_none(*pud)) {
		pmd = (pmd_t *) spp_getpage(); 
		set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE | _PAGE_USER));
		if (pmd != pmd_offset(pud, 0)) {
			printk("PAGETABLE BUG #01! %p <-> %p\n", pmd, pmd_offset(pud,0));
			return;
		}
	}
	pmd = pmd_offset(pud, 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_pud_init(pud_t *pud, unsigned long address, unsigned long end)
{ 
	long i, j; 

	i = pud_index(address);
	pud = pud + i;
	for (; i < PTRS_PER_PUD; pud++, i++) {
		int map; 
		unsigned long paddr, pmd_phys;
		pmd_t *pmd;

		paddr = address + i*PUD_SIZE;
		if (paddr >= end) { 
			for (; i < PTRS_PER_PUD; i++, pud++) 
				set_pud(pud, __pud(0)); 
			break;
		} 

		if (!e820_mapped(paddr, paddr+PUD_SIZE, 0)) { 
			set_pud(pud, __pud(0)); 
			continue;
		} 

		pmd = alloc_low_page(&map, &pmd_phys);
		set_pud(pud, __pud(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();
} 

static void __init find_early_table_space(unsigned long end)
{
	unsigned long puds, pmds, tables;

	puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
	pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
	tables = round_up(puds * sizeof(pud_t), PAGE_SIZE) +
		 round_up(pmds * sizeof(pmd_t), 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;
}

/* 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(unsigned long start, unsigned long end)
{ 
	unsigned long next; 

	Dprintk("init_memory_mapping\n");

	/* 
	 * 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.
	 */
	find_early_table_space(end);

	start = (unsigned long)__va(start);
	end = (unsigned long)__va(end);

	for (; start < end; start = next) {
		int map;
		unsigned long pud_phys; 
		pud_t *pud = alloc_low_page(&map, &pud_phys);
		next = start + PGDIR_SIZE;
		if (next > end) 
			next = end; 
		phys_pud_init(pud, __pa(start), __pa(next));
		set_pgd(pgd_offset_k(start), mk_kernel_pgd(pud_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];

/* Assumes all CPUs still execute in init_mm */
void zap_low_mappings(void)
{
	pgd_t *pgd = pgd_offset_k(0UL);
	pgd_clear(pgd);
	flush_tlb_all();
}

#ifndef CONFIG_DISCONTIGMEM
void __init paging_init(void)
{
	{
		unsigned long zones_size[MAX_NR_ZONES] = {0, 0, 0};
		unsigned int max_dma;

		max_dma = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;

		if (end_pfn < max_dma)
			zones_size[ZONE_DMA] = end_pfn;
		else {
			zones_size[ZONE_DMA] = max_dma;
			zones_size[ZONE_NORMAL] = end_pfn - max_dma;
		}
		free_area_init(zones_size);
	}
	return;
}
#endif

/* Unmap a kernel mapping if it exists. This is useful to avoid prefetches
   from the CPU leading to inconsistent cache lines. address and size
   must be aligned to 2MB boundaries. 
   Does nothing when the mapping doesn't exist. */
void __init clear_kernel_mapping(unsigned long address, unsigned long size) 
{
	unsigned long end = address + size;

	BUG_ON(address & ~LARGE_PAGE_MASK);
	BUG_ON(size & ~LARGE_PAGE_MASK); 
	
	for (; address < end; address += LARGE_PAGE_SIZE) { 
		pgd_t *pgd = pgd_offset_k(address);
		pud_t *pud;
		pmd_t *pmd;
		if (pgd_none(*pgd))
			continue;
		pud = pud_offset(pgd, address);
		if (pud_none(*pud))
			continue; 
		pmd = pmd_offset(pud, address);
		if (!pmd || pmd_none(*pmd))
			continue; 
		if (0 == (pmd_val(*pmd) & _PAGE_PSE)) { 
			/* Could handle this, but it should not happen currently. */
			printk(KERN_ERR 
	       "clear_kernel_mapping: mapping has been split. will leak memory\n"); 
			pmd_ERROR(*pmd); 
		}
		set_pmd(pmd, __pmd(0)); 		
	}
	__flush_tlb_all();
} 

static inline int page_is_ram (unsigned long pagenr)
{
	int i;

	for (i = 0; i < e820.nr_map; i++) {
		unsigned long addr, end;

		if (e820.map[i].type != E820_RAM)	/* not usable memory */
			continue;
		/*
		 *	!!!FIXME!!! Some BIOSen report areas as RAM that
		 *	are not. Notably the 640->1Mb area. We need a sanity
		 *	check here.
		 */
		addr = (e820.map[i].addr+PAGE_SIZE-1) >> PAGE_SHIFT;
		end = (e820.map[i].addr+e820.map[i].size) >> PAGE_SHIFT;
		if  ((pagenr >= addr) && (pagenr < end))
			return 1;
	}
	return 0;
}

extern int swiotlb_force;

static struct kcore_list kcore_mem, kcore_vmalloc, kcore_kernel, kcore_modules,
			 kcore_vsyscall;

void __init mem_init(void)
{
	int codesize, reservedpages, datasize, initsize;
	int tmp;

#ifdef CONFIG_SWIOTLB
	if (swiotlb_force)
		swiotlb = 1;
	if (!iommu_aperture &&
	    (end_pfn >= 0xffffffff>>PAGE_SHIFT || force_iommu))
	       swiotlb = 1;
	if (swiotlb)
		swiotlb_init();	
#endif

	/* How many end-of-memory variables you have, grandma! */
	max_low_pfn = end_pfn;
	max_pfn = end_pfn;
	num_physpages = end_pfn;
	high_memory = (void *) __va(end_pfn * PAGE_SIZE);

	/* clear the zero-page */
	memset(empty_zero_page, 0, PAGE_SIZE);

	reservedpages = 0;

	/* this will put all low memory onto the freelists */
#ifdef CONFIG_DISCONTIGMEM
	totalram_pages += numa_free_all_bootmem();
	tmp = 0;
	/* should count reserved pages here for all nodes */ 
#else
	max_mapnr = end_pfn;
	if (!mem_map) BUG();

	totalram_pages += free_all_bootmem();

	for (tmp = 0; tmp < end_pfn; tmp++)
		/*
		 * Only count reserved RAM pages
		 */
		if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
			reservedpages++;
#endif

	after_bootmem = 1;

	codesize =  (unsigned long) &_etext - (unsigned long) &_text;
	datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
	initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;

	/* Register memory areas for /proc/kcore */
	kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT); 
	kclist_add(&kcore_vmalloc, (void *)VMALLOC_START, 
		   VMALLOC_END-VMALLOC_START);
	kclist_add(&kcore_kernel, &_stext, _end - _stext);
	kclist_add(&kcore_modules, (void *)MODULES_VADDR, MODULES_LEN);
	kclist_add(&kcore_vsyscall, (void *)VSYSCALL_START, 
				 VSYSCALL_END - VSYSCALL_START);

	printk("Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init)\n",
		(unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
		end_pfn << (PAGE_SHIFT-10),
		codesize >> 10,
		reservedpages << (PAGE_SHIFT-10),
		datasize >> 10,
		initsize >> 10);

	/*
	 * Subtle. SMP is doing its boot stuff late (because it has to
	 * fork idle threads) - but it also needs low mappings for the
	 * protected-mode entry to work. We zap these entries only after
	 * the WP-bit has been tested.
	 */
#ifndef CONFIG_SMP
	zap_low_mappings();
#endif
}

extern char __initdata_begin[], __initdata_end[];

void free_initmem(void)
{
	unsigned long addr;

	addr = (unsigned long)(&__init_begin);
	for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
		ClearPageReserved(virt_to_page(addr));
		set_page_count(virt_to_page(addr), 1);
		memset((void *)(addr & ~(PAGE_SIZE-1)), 0xcc, PAGE_SIZE); 
		free_page(addr);
		totalram_pages++;
	}
	memset(__initdata_begin, 0xba, __initdata_end - __initdata_begin);
	printk ("Freeing unused kernel memory: %luk freed\n", (&__init_end - &__init_begin) >> 10);
}

#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
	if (start < (unsigned long)&_end)
		return;
	printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
	for (; start < end; start += PAGE_SIZE) {
		ClearPageReserved(virt_to_page(start));
		set_page_count(virt_to_page(start), 1);
		free_page(start);
		totalram_pages++;
	}
}
#endif

void __init reserve_bootmem_generic(unsigned long phys, unsigned len) 
{ 
	/* Should check here against the e820 map to avoid double free */ 
#ifdef CONFIG_DISCONTIGMEM
	int nid = phys_to_nid(phys);
  	reserve_bootmem_node(NODE_DATA(nid), phys, len);
#else       		
	reserve_bootmem(phys, len);    
#endif
}

int kern_addr_valid(unsigned long addr) 
{ 
	unsigned long above = ((long)addr) >> __VIRTUAL_MASK_SHIFT;
       pgd_t *pgd;
       pud_t *pud;
       pmd_t *pmd;
       pte_t *pte;

	if (above != 0 && above != -1UL)
		return 0; 
	
	pgd = pgd_offset_k(addr);
	if (pgd_none(*pgd))
		return 0;

	pud = pud_offset(pgd, addr);
	if (pud_none(*pud))
		return 0; 

	pmd = pmd_offset(pud, addr);
	if (pmd_none(*pmd))
		return 0;
	if (pmd_large(*pmd))
		return pfn_valid(pmd_pfn(*pmd));

	pte = pte_offset_kernel(pmd, addr);
	if (pte_none(*pte))
		return 0;
	return pfn_valid(pte_pfn(*pte));
}

#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>

extern int exception_trace, page_fault_trace;

static ctl_table debug_table2[] = {
	{ 99, "exception-trace", &exception_trace, sizeof(int), 0644, NULL,
	  proc_dointvec },
#ifdef CONFIG_CHECKING
	{ 100, "page-fault-trace", &page_fault_trace, sizeof(int), 0644, NULL,
	  proc_dointvec },
#endif
	{ 0, }
}; 

static ctl_table debug_root_table2[] = { 
	{ .ctl_name = CTL_DEBUG, .procname = "debug", .mode = 0555, 
	   .child = debug_table2 }, 
	{ 0 }, 
}; 

static __init int x8664_sysctl_init(void)
{ 
	register_sysctl_table(debug_root_table2, 1);
	return 0;
}
__initcall(x8664_sysctl_init);
#endif

/* Pseudo VMAs to allow ptrace access for the vsyscall pages.  x86-64 has two
   different ones: one for 32bit and one for 64bit. Use the appropiate
   for the target task. */

static struct vm_area_struct gate_vma = {
	.vm_start = VSYSCALL_START,
	.vm_end = VSYSCALL_END,
	.vm_page_prot = PAGE_READONLY
};

static struct vm_area_struct gate32_vma = {
	.vm_start = VSYSCALL32_BASE,
	.vm_end = VSYSCALL32_END,
	.vm_page_prot = PAGE_READONLY
};

struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
{
#ifdef CONFIG_IA32_EMULATION
	if (test_tsk_thread_flag(tsk, TIF_IA32)) {
		/* lookup code assumes the pages are present. set them up
		   now */
		if (__map_syscall32(tsk->mm, VSYSCALL32_BASE) < 0)
			return NULL;
		return &gate32_vma;
	}
#endif
	return &gate_vma;
}

int in_gate_area(struct task_struct *task, unsigned long addr)
{
	struct vm_area_struct *vma = get_gate_vma(task);
	return (addr >= vma->vm_start) && (addr < vma->vm_end);
}

/* Use this when you have no reliable task/vma, typically from interrupt
 * context.  It is less reliable than using the task's vma and may give
 * false positives.
 */
int in_gate_area_no_task(unsigned long addr)
{
	return (((addr >= VSYSCALL_START) && (addr < VSYSCALL_END)) ||
		((addr >= VSYSCALL32_BASE) && (addr < VSYSCALL32_END)));
}