arch/um/kernel/mem.c - linux - Git at Google

 /*
  * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
  * Licensed under the GPL
  */

 #include "linux/stddef.h"
 #include "linux/kernel.h"
 #include "linux/mm.h"
 #include "linux/bootmem.h"
 #include "linux/swap.h"
 #include "linux/highmem.h"
 #include "linux/gfp.h"
 #include "asm/page.h"
 #include "asm/fixmap.h"
 #include "asm/pgalloc.h"
 #include "kern_util.h"
 #include "as-layout.h"
 #include "kern.h"
 #include "mem_user.h"
 #include "uml_uaccess.h"
 #include "os.h"
 #include "linux/types.h"
 #include "linux/string.h"
 #include "init.h"
 #include "kern_constants.h"

 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
 unsigned long *empty_zero_page = NULL;
 /* allocated in paging_init and unchanged thereafter */
 unsigned long *empty_bad_page = NULL;
 pgd_t swapper_pg_dir[PTRS_PER_PGD];
 unsigned long long highmem;
 int kmalloc_ok = 0;

 static unsigned long brk_end;

 void unmap_physmem(void)
 {
 	os_unmap_memory((void *) brk_end, uml_reserved - brk_end);
 }

 static void map_cb(void *unused)
 {
 	map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
 }

 #ifdef CONFIG_HIGHMEM
 static void setup_highmem(unsigned long highmem_start,
 			  unsigned long highmem_len)
 {
 	struct page *page;
 	unsigned long highmem_pfn;
 	int i;

 	highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
 	for(i = 0; i < highmem_len >> PAGE_SHIFT; i++){
 		page = &mem_map[highmem_pfn + i];
 		ClearPageReserved(page);
 		init_page_count(page);
 		__free_page(page);
 	}
 }
 #endif

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

 	/* Map in the area just after the brk now that kmalloc is about
 	 * to be turned on.
 	 */
 	brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
 	map_cb(NULL);
 	initial_thread_cb(map_cb, NULL);
 	free_bootmem(__pa(brk_end), uml_reserved - brk_end);
 	uml_reserved = brk_end;

 	/* this will put all low memory onto the freelists */
 	totalram_pages = free_all_bootmem();
 	max_low_pfn = totalram_pages;
 #ifdef CONFIG_HIGHMEM
 	totalhigh_pages = highmem >> PAGE_SHIFT;
 	totalram_pages += totalhigh_pages;
 #endif
 	num_physpages = totalram_pages;
 	max_pfn = totalram_pages;
 	printk(KERN_INFO "Memory: %luk available\n",
 	       (unsigned long) nr_free_pages() << (PAGE_SHIFT-10));
 	kmalloc_ok = 1;

 #ifdef CONFIG_HIGHMEM
 	setup_highmem(end_iomem, highmem);
 #endif
 }

 /*
  * Create a page table and place a pointer to it in a middle page
  * directory entry.
  */
 static void __init one_page_table_init(pmd_t *pmd)
 {
 	if (pmd_none(*pmd)) {
 		pte_t *pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 		set_pmd(pmd, __pmd(_KERNPG_TABLE +
 					   (unsigned long) __pa(pte)));
 		if (pte != pte_offset_kernel(pmd, 0))
 			BUG();
 	}
 }

 static void __init one_md_table_init(pud_t *pud)
 {
 #ifdef CONFIG_3_LEVEL_PGTABLES
 	pmd_t *pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 	set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
 	if (pmd_table != pmd_offset(pud, 0))
 		BUG();
 #endif
 }

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

 	vaddr = start;
 	i = pgd_index(vaddr);
 	j = pmd_index(vaddr);
 	pgd = pgd_base + i;

 	for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
 		pud = pud_offset(pgd, vaddr);
 		if (pud_none(*pud))
 			one_md_table_init(pud);
 		pmd = pmd_offset(pud, vaddr);
 		for (; (j < PTRS_PER_PMD) && (vaddr != end); pmd++, j++) {
 			one_page_table_init(pmd);
 			vaddr += PMD_SIZE;
 		}
 		j = 0;
 	}
 }

 #ifdef CONFIG_HIGHMEM
 pte_t *kmap_pte;
 pgprot_t kmap_prot;

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

 static 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;
 }

 static void init_highmem(void)
 {
 	pgd_t *pgd;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
 	unsigned long vaddr;

 	/*
 	 * Permanent kmaps:
 	 */
 	vaddr = PKMAP_BASE;
 	fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);

 	pgd = swapper_pg_dir + pgd_index(vaddr);
 	pud = pud_offset(pgd, vaddr);
 	pmd = pmd_offset(pud, vaddr);
 	pte = pte_offset_kernel(pmd, vaddr);
 	pkmap_page_table = pte;

 	kmap_init();
 }
 #endif /* CONFIG_HIGHMEM */

 static void __init fixaddr_user_init( void)
 {
 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
 	long size = FIXADDR_USER_END - FIXADDR_USER_START;
 	pgd_t *pgd;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
 	unsigned long paddr, vaddr = FIXADDR_USER_START;

 	if (  ! size )
 		return;

 	fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
 	paddr = (unsigned long)alloc_bootmem_low_pages( size);
 	memcpy( (void *)paddr, (void *)FIXADDR_USER_START, size);
 	paddr = __pa(paddr);
 	for ( ; size > 0; size-=PAGE_SIZE, vaddr+=PAGE_SIZE, paddr+=PAGE_SIZE){
 		pgd = swapper_pg_dir + pgd_index(vaddr);
 		pud = pud_offset(pgd, vaddr);
 		pmd = pmd_offset(pud, vaddr);
 		pte = pte_offset_kernel(pmd, vaddr);
 		pte_set_val( (*pte), paddr, PAGE_READONLY);
 	}
 #endif
 }

 void paging_init(void)
 {
 	unsigned long zones_size[MAX_NR_ZONES], vaddr;
 	int i;

 	empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 	empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 	for(i = 0; i < ARRAY_SIZE(zones_size); i++)
 		zones_size[i] = 0;

 	zones_size[ZONE_NORMAL] = (end_iomem >> PAGE_SHIFT) -
 		(uml_physmem >> PAGE_SHIFT);
 #ifdef CONFIG_HIGHMEM
 	zones_size[ZONE_HIGHMEM] = highmem >> PAGE_SHIFT;
 #endif
 	free_area_init(zones_size);

 	/*
 	 * 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, FIXADDR_TOP, swapper_pg_dir);

 	fixaddr_user_init();

 #ifdef CONFIG_HIGHMEM
 	init_highmem();
 #endif
 }

 struct page *arch_validate(struct page *page, gfp_t mask, int order)
 {
 	unsigned long addr, zero = 0;
 	int i;

  again:
 	if(page == NULL)
 		return page;
 	if(PageHighMem(page))
 		return page;

 	addr = (unsigned long) page_address(page);
 	for(i = 0; i < (1 << order); i++){
 		current->thread.fault_addr = (void *) addr;
 		if(__do_copy_to_user((void __user *) addr, &zero,
 				     sizeof(zero),
 				     &current->thread.fault_addr,
 				     &current->thread.fault_catcher)){
 			if(!(mask & __GFP_WAIT))
 				return NULL;
 			else break;
 		}
 		addr += PAGE_SIZE;
 	}

 	if(i == (1 << order))
 		return page;
 	page = alloc_pages(mask, order);
 	goto again;
 }

 /* This can't do anything because nothing in the kernel image can be freed
  * since it's not in kernel physical memory.
  */

 void free_initmem(void)
 {
 }

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

 void show_mem(void)
 {
 	int pfn, total = 0, reserved = 0;
 	int shared = 0, cached = 0;
 	int highmem = 0;
 	struct page *page;

 	printk("Mem-info:\n");
 	show_free_areas();
 	printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
 	pfn = max_mapnr;
 	while(pfn-- > 0) {
 		page = pfn_to_page(pfn);
 		total++;
 		if(PageHighMem(page))
 			highmem++;
 		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 pages of HIGHMEM\n", highmem);
 	printk("%d reserved pages\n", reserved);
 	printk("%d pages shared\n", shared);
 	printk("%d pages swap cached\n", cached);
 }

 /*
  * Allocate and free page tables.
  */

 pgd_t *pgd_alloc(struct mm_struct *mm)
 {
 	pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);

 	if (pgd) {
 		memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
 		memcpy(pgd + USER_PTRS_PER_PGD,
 		       swapper_pg_dir + USER_PTRS_PER_PGD,
 		       (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 	}
 	return pgd;
 }

 void pgd_free(pgd_t *pgd)
 {
 	free_page((unsigned long) pgd);
 }

 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 {
 	pte_t *pte;

 	pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 	return pte;
 }

 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 {
 	struct page *pte;

 	pte = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 	return pte;
 }
	/*
	* Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
	* Licensed under the GPL
	*/

	#include "linux/stddef.h"
	#include "linux/kernel.h"
	#include "linux/mm.h"
	#include "linux/bootmem.h"
	#include "linux/swap.h"
	#include "linux/highmem.h"
	#include "linux/gfp.h"
	#include "asm/page.h"
	#include "asm/fixmap.h"
	#include "asm/pgalloc.h"
	#include "kern_util.h"
	#include "as-layout.h"
	#include "kern.h"
	#include "mem_user.h"
	#include "uml_uaccess.h"
	#include "os.h"
	#include "linux/types.h"
	#include "linux/string.h"
	#include "init.h"
	#include "kern_constants.h"

	/* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
	unsigned long *empty_zero_page = NULL;
	/* allocated in paging_init and unchanged thereafter */
	unsigned long *empty_bad_page = NULL;
	pgd_t swapper_pg_dir[PTRS_PER_PGD];
	unsigned long long highmem;
	int kmalloc_ok = 0;

	static unsigned long brk_end;

	void unmap_physmem(void)
	{
	os_unmap_memory((void *) brk_end, uml_reserved - brk_end);
	}

	static void map_cb(void *unused)
	{
	map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
	}

	#ifdef CONFIG_HIGHMEM
	static void setup_highmem(unsigned long highmem_start,
	unsigned long highmem_len)
	{
	struct page *page;
	unsigned long highmem_pfn;
	int i;

	highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
	for(i = 0; i < highmem_len >> PAGE_SHIFT; i++){
	page = &mem_map[highmem_pfn + i];
	ClearPageReserved(page);
	init_page_count(page);
	__free_page(page);
	}
	}
	#endif

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

	/* Map in the area just after the brk now that kmalloc is about
	* to be turned on.
	*/
	brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
	map_cb(NULL);
	initial_thread_cb(map_cb, NULL);
	free_bootmem(__pa(brk_end), uml_reserved - brk_end);
	uml_reserved = brk_end;

	/* this will put all low memory onto the freelists */
	totalram_pages = free_all_bootmem();
	max_low_pfn = totalram_pages;
	#ifdef CONFIG_HIGHMEM
	totalhigh_pages = highmem >> PAGE_SHIFT;
	totalram_pages += totalhigh_pages;
	#endif
	num_physpages = totalram_pages;
	max_pfn = totalram_pages;
	printk(KERN_INFO "Memory: %luk available\n",
	(unsigned long) nr_free_pages() << (PAGE_SHIFT-10));
	kmalloc_ok = 1;

	#ifdef CONFIG_HIGHMEM
	setup_highmem(end_iomem, highmem);
	#endif
	}

	/*
	* Create a page table and place a pointer to it in a middle page
	* directory entry.
	*/
	static void __init one_page_table_init(pmd_t *pmd)
	{
	if (pmd_none(*pmd)) {
	pte_t pte = (pte_t ) alloc_bootmem_low_pages(PAGE_SIZE);
	set_pmd(pmd, __pmd(_KERNPG_TABLE +
	(unsigned long) __pa(pte)));
	if (pte != pte_offset_kernel(pmd, 0))
	BUG();
	}
	}

	static void __init one_md_table_init(pud_t *pud)
	{
	#ifdef CONFIG_3_LEVEL_PGTABLES
	pmd_t pmd_table = (pmd_t ) alloc_bootmem_low_pages(PAGE_SIZE);
	set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
	if (pmd_table != pmd_offset(pud, 0))
	BUG();
	#endif
	}

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

	vaddr = start;
	i = pgd_index(vaddr);
	j = pmd_index(vaddr);
	pgd = pgd_base + i;

	for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
	pud = pud_offset(pgd, vaddr);
	if (pud_none(*pud))
	one_md_table_init(pud);
	pmd = pmd_offset(pud, vaddr);
	for (; (j < PTRS_PER_PMD) && (vaddr != end); pmd++, j++) {
	one_page_table_init(pmd);
	vaddr += PMD_SIZE;
	}
	j = 0;
	}
	}

	#ifdef CONFIG_HIGHMEM
	pte_t *kmap_pte;
	pgprot_t kmap_prot;

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

	static 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;
	}

	static void init_highmem(void)
	{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;
	unsigned long vaddr;

	/*
	* Permanent kmaps:
	*/
	vaddr = PKMAP_BASE;
	fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);

	pgd = swapper_pg_dir + pgd_index(vaddr);
	pud = pud_offset(pgd, vaddr);
	pmd = pmd_offset(pud, vaddr);
	pte = pte_offset_kernel(pmd, vaddr);
	pkmap_page_table = pte;

	kmap_init();
	}
	#endif /* CONFIG_HIGHMEM */

	static void __init fixaddr_user_init( void)
	{
	#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
	long size = FIXADDR_USER_END - FIXADDR_USER_START;
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;
	unsigned long paddr, vaddr = FIXADDR_USER_START;

	if ( ! size )
	return;

	fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
	paddr = (unsigned long)alloc_bootmem_low_pages( size);
	memcpy( (void )paddr, (void )FIXADDR_USER_START, size);
	paddr = __pa(paddr);
	for ( ; size > 0; size-=PAGE_SIZE, vaddr+=PAGE_SIZE, paddr+=PAGE_SIZE){
	pgd = swapper_pg_dir + pgd_index(vaddr);
	pud = pud_offset(pgd, vaddr);
	pmd = pmd_offset(pud, vaddr);
	pte = pte_offset_kernel(pmd, vaddr);
	pte_set_val( (*pte), paddr, PAGE_READONLY);
	}
	#endif
	}

	void paging_init(void)
	{
	unsigned long zones_size[MAX_NR_ZONES], vaddr;
	int i;

	empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
	empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
	for(i = 0; i < ARRAY_SIZE(zones_size); i++)
	zones_size[i] = 0;

	zones_size[ZONE_NORMAL] = (end_iomem >> PAGE_SHIFT) -
	(uml_physmem >> PAGE_SHIFT);
	#ifdef CONFIG_HIGHMEM
	zones_size[ZONE_HIGHMEM] = highmem >> PAGE_SHIFT;
	#endif
	free_area_init(zones_size);

	/*
	* 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, FIXADDR_TOP, swapper_pg_dir);

	fixaddr_user_init();

	#ifdef CONFIG_HIGHMEM
	init_highmem();
	#endif
	}

	struct page arch_validate(struct page page, gfp_t mask, int order)
	{
	unsigned long addr, zero = 0;
	int i;

	again:
	if(page == NULL)
	return page;
	if(PageHighMem(page))
	return page;

	addr = (unsigned long) page_address(page);
	for(i = 0; i < (1 << order); i++){
	current->thread.fault_addr = (void *) addr;
	if(__do_copy_to_user((void __user *) addr, &zero,
	sizeof(zero),
	&current->thread.fault_addr,
	&current->thread.fault_catcher)){
	if(!(mask & __GFP_WAIT))
	return NULL;
	else break;
	}
	addr += PAGE_SIZE;
	}

	if(i == (1 << order))
	return page;
	page = alloc_pages(mask, order);
	goto again;
	}

	/* This can't do anything because nothing in the kernel image can be freed
	* since it's not in kernel physical memory.
	*/

	void free_initmem(void)
	{
	}

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

	void show_mem(void)
	{
	int pfn, total = 0, reserved = 0;
	int shared = 0, cached = 0;
	int highmem = 0;
	struct page *page;

	printk("Mem-info:\n");
	show_free_areas();
	printk("Free swap: %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
	pfn = max_mapnr;
	while(pfn-- > 0) {
	page = pfn_to_page(pfn);
	total++;
	if(PageHighMem(page))
	highmem++;
	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 pages of HIGHMEM\n", highmem);
	printk("%d reserved pages\n", reserved);
	printk("%d pages shared\n", shared);
	printk("%d pages swap cached\n", cached);
	}

	/*
	* Allocate and free page tables.
	*/

	pgd_t pgd_alloc(struct mm_struct mm)
	{
	pgd_t pgd = (pgd_t )__get_free_page(GFP_KERNEL);

	if (pgd) {
	memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
	memcpy(pgd + USER_PTRS_PER_PGD,
	swapper_pg_dir + USER_PTRS_PER_PGD,
	(PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
	}
	return pgd;
	}

	void pgd_free(pgd_t *pgd)
	{
	free_page((unsigned long) pgd);
	}

	pte_t pte_alloc_one_kernel(struct mm_struct mm, unsigned long address)
	{
	pte_t *pte;

	pte = (pte_t *)__get_free_page(GFP_KERNEL\|__GFP_REPEAT\|__GFP_ZERO);
	return pte;
	}

	struct page pte_alloc_one(struct mm_struct mm, unsigned long address)
	{
	struct page *pte;

	pte = alloc_page(GFP_KERNEL\|__GFP_REPEAT\|__GFP_ZERO);
	return pte;
	}