arch/i386/mm/pgtable.c - third_party/linux - Git at Google

 /*
  *  linux/arch/i386/mm/pgtable.c
  */

 #include <linux/config.h>
 #include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/mm.h>
 #include <linux/swap.h>
 #include <linux/smp.h>
 #include <linux/highmem.h>
 #include <linux/slab.h>
 #include <linux/pagemap.h>
 #include <linux/spinlock.h>

 #include <asm/system.h>
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
 #include <asm/fixmap.h>
 #include <asm/e820.h>
 #include <asm/tlb.h>
 #include <asm/tlbflush.h>

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

 	printk(KERN_INFO "Mem-info:\n");
 	show_free_areas();
 	printk(KERN_INFO "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_page_nr(pgdat, i);
 			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(KERN_INFO "%d pages of RAM\n", total);
 	printk(KERN_INFO "%d pages of HIGHMEM\n", highmem);
 	printk(KERN_INFO "%d reserved pages\n", reserved);
 	printk(KERN_INFO "%d pages shared\n", shared);
 	printk(KERN_INFO "%d pages swap cached\n", cached);

 	get_page_state(&ps);
 	printk(KERN_INFO "%lu pages dirty\n", ps.nr_dirty);
 	printk(KERN_INFO "%lu pages writeback\n", ps.nr_writeback);
 	printk(KERN_INFO "%lu pages mapped\n", ps.nr_mapped);
 	printk(KERN_INFO "%lu pages slab\n", ps.nr_slab);
 	printk(KERN_INFO "%lu pages pagetables\n", ps.nr_page_table_pages);
 }

 /*
  * Associate a virtual page frame with a given physical page frame
  * and protection flags for that frame.
  */
 static void set_pte_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
 {
 	pgd_t *pgd;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;

 	pgd = swapper_pg_dir + pgd_index(vaddr);
 	if (pgd_none(*pgd)) {
 		BUG();
 		return;
 	}
 	pud = pud_offset(pgd, vaddr);
 	if (pud_none(*pud)) {
 		BUG();
 		return;
 	}
 	pmd = pmd_offset(pud, vaddr);
 	if (pmd_none(*pmd)) {
 		BUG();
 		return;
 	}
 	pte = pte_offset_kernel(pmd, vaddr);
 	/* <pfn,flags> stored as-is, to permit clearing entries */
 	set_pte(pte, pfn_pte(pfn, flags));

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

 /*
  * Associate a large virtual page frame with a given physical page frame
  * and protection flags for that frame. pfn is for the base of the page,
  * vaddr is what the page gets mapped to - both must be properly aligned.
  * The pmd must already be instantiated. Assumes PAE mode.
  */
 void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
 {
 	pgd_t *pgd;
 	pud_t *pud;
 	pmd_t *pmd;

 	if (vaddr & (PMD_SIZE-1)) {		/* vaddr is misaligned */
 		printk(KERN_WARNING "set_pmd_pfn: vaddr misaligned\n");
 		return; /* BUG(); */
 	}
 	if (pfn & (PTRS_PER_PTE-1)) {		/* pfn is misaligned */
 		printk(KERN_WARNING "set_pmd_pfn: pfn misaligned\n");
 		return; /* BUG(); */
 	}
 	pgd = swapper_pg_dir + pgd_index(vaddr);
 	if (pgd_none(*pgd)) {
 		printk(KERN_WARNING "set_pmd_pfn: pgd_none\n");
 		return; /* BUG(); */
 	}
 	pud = pud_offset(pgd, vaddr);
 	pmd = pmd_offset(pud, vaddr);
 	set_pmd(pmd, pfn_pmd(pfn, 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) {
 		BUG();
 		return;
 	}
 	set_pte_pfn(address, phys >> PAGE_SHIFT, flags);
 }

 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 {
 	return (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 }

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

 #ifdef CONFIG_HIGHPTE
 	pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT|__GFP_ZERO, 0);
 #else
 	pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
 #endif
 	return pte;
 }

 void pmd_ctor(void *pmd, kmem_cache_t *cache, unsigned long flags)
 {
 	memset(pmd, 0, PTRS_PER_PMD*sizeof(pmd_t));
 }

 /*
  * List of all pgd's needed for non-PAE so it can invalidate entries
  * in both cached and uncached pgd's; not needed for PAE since the
  * kernel pmd is shared. If PAE were not to share the pmd a similar
  * tactic would be needed. This is essentially codepath-based locking
  * against pageattr.c; it is the unique case in which a valid change
  * of kernel pagetables can't be lazily synchronized by vmalloc faults.
  * vmalloc faults work because attached pagetables are never freed.
  * The locking scheme was chosen on the basis of manfred's
  * recommendations and having no core impact whatsoever.
  * -- wli
  */
 DEFINE_SPINLOCK(pgd_lock);
 struct page *pgd_list;

 static inline void pgd_list_add(pgd_t *pgd)
 {
 	struct page *page = virt_to_page(pgd);
 	page->index = (unsigned long)pgd_list;
 	if (pgd_list)
 		pgd_list->private = (unsigned long)&page->index;
 	pgd_list = page;
 	page->private = (unsigned long)&pgd_list;
 }

 static inline void pgd_list_del(pgd_t *pgd)
 {
 	struct page *next, **pprev, *page = virt_to_page(pgd);
 	next = (struct page *)page->index;
 	pprev = (struct page **)page->private;
 	*pprev = next;
 	if (next)
 		next->private = (unsigned long)pprev;
 }

 void pgd_ctor(void *pgd, kmem_cache_t *cache, unsigned long unused)
 {
 	unsigned long flags;

 	if (PTRS_PER_PMD == 1) {
 		memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
 		spin_lock_irqsave(&pgd_lock, flags);
 	}

 	clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD,
 			swapper_pg_dir + USER_PTRS_PER_PGD,
 			KERNEL_PGD_PTRS);
 	if (PTRS_PER_PMD > 1)
 		return;

 	pgd_list_add(pgd);
 	spin_unlock_irqrestore(&pgd_lock, flags);
 }

 /* never called when PTRS_PER_PMD > 1 */
 void pgd_dtor(void *pgd, kmem_cache_t *cache, unsigned long unused)
 {
 	unsigned long flags; /* can be called from interrupt context */

 	spin_lock_irqsave(&pgd_lock, flags);
 	pgd_list_del(pgd);
 	spin_unlock_irqrestore(&pgd_lock, flags);
 }

 pgd_t *pgd_alloc(struct mm_struct *mm)
 {
 	int i;
 	pgd_t *pgd = kmem_cache_alloc(pgd_cache, GFP_KERNEL);

 	if (PTRS_PER_PMD == 1 || !pgd)
 		return pgd;

 	for (i = 0; i < USER_PTRS_PER_PGD; ++i) {
 		pmd_t *pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);
 		if (!pmd)
 			goto out_oom;
 		set_pgd(&pgd[i], __pgd(1 + __pa(pmd)));
 	}
 	return pgd;

 out_oom:
 	for (i--; i >= 0; i--)
 		kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i])-1));
 	kmem_cache_free(pgd_cache, pgd);
 	return NULL;
 }

 void pgd_free(pgd_t *pgd)
 {
 	int i;

 	/* in the PAE case user pgd entries are overwritten before usage */
 	if (PTRS_PER_PMD > 1)
 		for (i = 0; i < USER_PTRS_PER_PGD; ++i)
 			kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i])-1));
 	/* in the non-PAE case, free_pgtables() clears user pgd entries */
 	kmem_cache_free(pgd_cache, pgd);
 }
	/*
	* linux/arch/i386/mm/pgtable.c
	*/

	#include <linux/config.h>
	#include <linux/sched.h>
	#include <linux/kernel.h>
	#include <linux/errno.h>
	#include <linux/mm.h>
	#include <linux/swap.h>
	#include <linux/smp.h>
	#include <linux/highmem.h>
	#include <linux/slab.h>
	#include <linux/pagemap.h>
	#include <linux/spinlock.h>

	#include <asm/system.h>
	#include <asm/pgtable.h>
	#include <asm/pgalloc.h>
	#include <asm/fixmap.h>
	#include <asm/e820.h>
	#include <asm/tlb.h>
	#include <asm/tlbflush.h>

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

	printk(KERN_INFO "Mem-info:\n");
	show_free_areas();
	printk(KERN_INFO "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_page_nr(pgdat, i);
	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(KERN_INFO "%d pages of RAM\n", total);
	printk(KERN_INFO "%d pages of HIGHMEM\n", highmem);
	printk(KERN_INFO "%d reserved pages\n", reserved);
	printk(KERN_INFO "%d pages shared\n", shared);
	printk(KERN_INFO "%d pages swap cached\n", cached);

	get_page_state(&ps);
	printk(KERN_INFO "%lu pages dirty\n", ps.nr_dirty);
	printk(KERN_INFO "%lu pages writeback\n", ps.nr_writeback);
	printk(KERN_INFO "%lu pages mapped\n", ps.nr_mapped);
	printk(KERN_INFO "%lu pages slab\n", ps.nr_slab);
	printk(KERN_INFO "%lu pages pagetables\n", ps.nr_page_table_pages);
	}

	/*
	* Associate a virtual page frame with a given physical page frame
	* and protection flags for that frame.
	*/
	static void set_pte_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
	{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;

	pgd = swapper_pg_dir + pgd_index(vaddr);
	if (pgd_none(*pgd)) {
	BUG();
	return;
	}
	pud = pud_offset(pgd, vaddr);
	if (pud_none(*pud)) {
	BUG();
	return;
	}
	pmd = pmd_offset(pud, vaddr);
	if (pmd_none(*pmd)) {
	BUG();
	return;
	}
	pte = pte_offset_kernel(pmd, vaddr);
	/* <pfn,flags> stored as-is, to permit clearing entries */
	set_pte(pte, pfn_pte(pfn, flags));

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

	/*
	* Associate a large virtual page frame with a given physical page frame
	* and protection flags for that frame. pfn is for the base of the page,
	* vaddr is what the page gets mapped to - both must be properly aligned.
	* The pmd must already be instantiated. Assumes PAE mode.
	*/
	void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
	{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;

	if (vaddr & (PMD_SIZE-1)) { /* vaddr is misaligned */
	printk(KERN_WARNING "set_pmd_pfn: vaddr misaligned\n");
	return; /* BUG(); */
	}
	if (pfn & (PTRS_PER_PTE-1)) { /* pfn is misaligned */
	printk(KERN_WARNING "set_pmd_pfn: pfn misaligned\n");
	return; /* BUG(); */
	}
	pgd = swapper_pg_dir + pgd_index(vaddr);
	if (pgd_none(*pgd)) {
	printk(KERN_WARNING "set_pmd_pfn: pgd_none\n");
	return; /* BUG(); */
	}
	pud = pud_offset(pgd, vaddr);
	pmd = pmd_offset(pud, vaddr);
	set_pmd(pmd, pfn_pmd(pfn, 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) {
	BUG();
	return;
	}
	set_pte_pfn(address, phys >> PAGE_SHIFT, flags);
	}

	pte_t pte_alloc_one_kernel(struct mm_struct mm, unsigned long address)
	{
	return (pte_t *)__get_free_page(GFP_KERNEL\|__GFP_REPEAT\|__GFP_ZERO);
	}

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

	#ifdef CONFIG_HIGHPTE
	pte = alloc_pages(GFP_KERNEL\|__GFP_HIGHMEM\|__GFP_REPEAT\|__GFP_ZERO, 0);
	#else
	pte = alloc_pages(GFP_KERNEL\|__GFP_REPEAT\|__GFP_ZERO, 0);
	#endif
	return pte;
	}

	void pmd_ctor(void pmd, kmem_cache_t cache, unsigned long flags)
	{
	memset(pmd, 0, PTRS_PER_PMD*sizeof(pmd_t));
	}

	/*
	* List of all pgd's needed for non-PAE so it can invalidate entries
	* in both cached and uncached pgd's; not needed for PAE since the
	* kernel pmd is shared. If PAE were not to share the pmd a similar
	* tactic would be needed. This is essentially codepath-based locking
	* against pageattr.c; it is the unique case in which a valid change
	* of kernel pagetables can't be lazily synchronized by vmalloc faults.
	* vmalloc faults work because attached pagetables are never freed.
	* The locking scheme was chosen on the basis of manfred's
	* recommendations and having no core impact whatsoever.
	* -- wli
	*/
	DEFINE_SPINLOCK(pgd_lock);
	struct page *pgd_list;

	static inline void pgd_list_add(pgd_t *pgd)
	{
	struct page *page = virt_to_page(pgd);
	page->index = (unsigned long)pgd_list;
	if (pgd_list)
	pgd_list->private = (unsigned long)&page->index;
	pgd_list = page;
	page->private = (unsigned long)&pgd_list;
	}

	static inline void pgd_list_del(pgd_t *pgd)
	{
	struct page next, pprev, page = virt_to_page(pgd);
	next = (struct page *)page->index;
	pprev = (struct page **)page->private;
	*pprev = next;
	if (next)
	next->private = (unsigned long)pprev;
	}

	void pgd_ctor(void pgd, kmem_cache_t cache, unsigned long unused)
	{
	unsigned long flags;

	if (PTRS_PER_PMD == 1) {
	memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
	spin_lock_irqsave(&pgd_lock, flags);
	}

	clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD,
	swapper_pg_dir + USER_PTRS_PER_PGD,
	KERNEL_PGD_PTRS);
	if (PTRS_PER_PMD > 1)
	return;

	pgd_list_add(pgd);
	spin_unlock_irqrestore(&pgd_lock, flags);
	}

	/* never called when PTRS_PER_PMD > 1 */
	void pgd_dtor(void pgd, kmem_cache_t cache, unsigned long unused)
	{
	unsigned long flags; /* can be called from interrupt context */

	spin_lock_irqsave(&pgd_lock, flags);
	pgd_list_del(pgd);
	spin_unlock_irqrestore(&pgd_lock, flags);
	}

	pgd_t pgd_alloc(struct mm_struct mm)
	{
	int i;
	pgd_t *pgd = kmem_cache_alloc(pgd_cache, GFP_KERNEL);

	if (PTRS_PER_PMD == 1 \|\| !pgd)
	return pgd;

	for (i = 0; i < USER_PTRS_PER_PGD; ++i) {
	pmd_t *pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);
	if (!pmd)
	goto out_oom;
	set_pgd(&pgd[i], __pgd(1 + __pa(pmd)));
	}
	return pgd;

	out_oom:
	for (i--; i >= 0; i--)
	kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i])-1));
	kmem_cache_free(pgd_cache, pgd);
	return NULL;
	}

	void pgd_free(pgd_t *pgd)
	{
	int i;

	/* in the PAE case user pgd entries are overwritten before usage */
	if (PTRS_PER_PMD > 1)
	for (i = 0; i < USER_PTRS_PER_PGD; ++i)
	kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i])-1));
	/* in the non-PAE case, free_pgtables() clears user pgd entries */
	kmem_cache_free(pgd_cache, pgd);
	}