[deliverable/linux.git] / arch / i386 / mm / pgtable.c

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

#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 <linux/module.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;
	unsigned long flags;

	printk(KERN_INFO "Mem-info:\n");
	show_free_areas();
	printk(KERN_INFO "Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
	for_each_online_pgdat(pgdat) {
		pgdat_resize_lock(pgdat, &flags);
		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;
		}
		pgdat_resize_unlock(pgdat, &flags);
	}
	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);

	printk(KERN_INFO "%lu pages dirty\n", global_page_state(NR_FILE_DIRTY));
	printk(KERN_INFO "%lu pages writeback\n",
					global_page_state(NR_WRITEBACK));
	printk(KERN_INFO "%lu pages mapped\n", global_page_state(NR_FILE_MAPPED));
	printk(KERN_INFO "%lu pages slab\n",
		global_page_state(NR_SLAB_RECLAIMABLE) +
		global_page_state(NR_SLAB_UNRECLAIMABLE));
	printk(KERN_INFO "%lu pages pagetables\n",
					global_page_state(NR_PAGETABLE));
}

/*
 * 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);
	if (pgprot_val(flags))
		/* <pfn,flags> stored as-is, to permit clearing entries */
		set_pte(pte, pfn_pte(pfn, flags));
	else
		pte_clear(&init_mm, vaddr, pte);

	/*
	 * 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);
}

static int fixmaps;
unsigned long __FIXADDR_TOP = 0xfffff000;
EXPORT_SYMBOL(__FIXADDR_TOP);

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);
	fixmaps++;
}

/**
 * reserve_top_address - reserves a hole in the top of kernel address space
 * @reserve - size of hole to reserve
 *
 * Can be used to relocate the fixmap area and poke a hole in the top
 * of kernel address space to make room for a hypervisor.
 */
void reserve_top_address(unsigned long reserve)
{
	BUG_ON(fixmaps > 0);
	printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
	       (int)-reserve);
	__FIXADDR_TOP = -reserve - PAGE_SIZE;
	__VMALLOC_RESERVE += reserve;
}

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, struct kmem_cache *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)
		set_page_private(pgd_list, (unsigned long)&page->index);
	pgd_list = page;
	set_page_private(page, (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(page);
	*pprev = next;
	if (next)
		set_page_private(next, (unsigned long)pprev);
}

#if (PTRS_PER_PMD == 1)
/* Non-PAE pgd constructor */
void pgd_ctor(void *pgd, struct kmem_cache *cache, unsigned long unused)
{
	unsigned long flags;

	/* !PAE, no pagetable sharing */
	memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));

	spin_lock_irqsave(&pgd_lock, flags);

	/* must happen under lock */
	clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD,
			swapper_pg_dir + USER_PTRS_PER_PGD,
			KERNEL_PGD_PTRS);
	paravirt_alloc_pd_clone(__pa(pgd) >> PAGE_SHIFT,
				__pa(swapper_pg_dir) >> PAGE_SHIFT,
				USER_PTRS_PER_PGD,
				KERNEL_PGD_PTRS);
	pgd_list_add(pgd);
	spin_unlock_irqrestore(&pgd_lock, flags);
}
#else  /* PTRS_PER_PMD > 1 */
/* PAE pgd constructor */
void pgd_ctor(void *pgd, struct kmem_cache *cache, unsigned long unused)
{
	/* PAE, kernel PMD may be shared */

	if (SHARED_KERNEL_PMD) {
		clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD,
				swapper_pg_dir + USER_PTRS_PER_PGD,
				KERNEL_PGD_PTRS);
	} else {
		unsigned long flags;

		memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
		spin_lock_irqsave(&pgd_lock, flags);
		pgd_list_add(pgd);
		spin_unlock_irqrestore(&pgd_lock, flags);
	}
}
#endif	/* PTRS_PER_PMD */

void pgd_dtor(void *pgd, struct kmem_cache *cache, unsigned long unused)
{
	unsigned long flags; /* can be called from interrupt context */

	BUG_ON(SHARED_KERNEL_PMD);

	paravirt_release_pd(__pa(pgd) >> PAGE_SHIFT);
	spin_lock_irqsave(&pgd_lock, flags);
	pgd_list_del(pgd);
	spin_unlock_irqrestore(&pgd_lock, flags);
}

#define UNSHARED_PTRS_PER_PGD				\
	(SHARED_KERNEL_PMD ? USER_PTRS_PER_PGD : PTRS_PER_PGD)

/* If we allocate a pmd for part of the kernel address space, then
   make sure its initialized with the appropriate kernel mappings.
   Otherwise use a cached zeroed pmd.  */
static pmd_t *pmd_cache_alloc(int idx)
{
	pmd_t *pmd;

	if (idx >= USER_PTRS_PER_PGD) {
		pmd = (pmd_t *)__get_free_page(GFP_KERNEL);

		if (pmd)
			memcpy(pmd,
			       (void *)pgd_page_vaddr(swapper_pg_dir[idx]),
			       sizeof(pmd_t) * PTRS_PER_PMD);
	} else
		pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);

	return pmd;
}

static void pmd_cache_free(pmd_t *pmd, int idx)
{
	if (idx >= USER_PTRS_PER_PGD)
		free_page((unsigned long)pmd);
	else
		kmem_cache_free(pmd_cache, pmd);
}

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 < UNSHARED_PTRS_PER_PGD; ++i) {
		pmd_t *pmd = pmd_cache_alloc(i);

		if (!pmd)
			goto out_oom;

		paravirt_alloc_pd(__pa(pmd) >> PAGE_SHIFT);
		set_pgd(&pgd[i], __pgd(1 + __pa(pmd)));
	}
	return pgd;

out_oom:
	for (i--; i >= 0; i--) {
		pgd_t pgdent = pgd[i];
		void* pmd = (void *)__va(pgd_val(pgdent)-1);
		paravirt_release_pd(__pa(pmd) >> PAGE_SHIFT);
		pmd_cache_free(pmd, i);
	}
	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 < UNSHARED_PTRS_PER_PGD; ++i) {
			pgd_t pgdent = pgd[i];
			void* pmd = (void *)__va(pgd_val(pgdent)-1);
			paravirt_release_pd(__pa(pmd) >> PAGE_SHIFT);
			pmd_cache_free(pmd, i);
		}
	/* in the non-PAE case, free_pgtables() clears user pgd entries */
	kmem_cache_free(pgd_cache, pgd);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/i386/mm/pgtable.c
	3	*/
	4
1da177e4 LT	5	#include <linux/sched.h>
	6	#include <linux/kernel.h>
	7	#include <linux/errno.h>
	8	#include <linux/mm.h>
	9	#include <linux/swap.h>
	10	#include <linux/smp.h>
	11	#include <linux/highmem.h>
	12	#include <linux/slab.h>
	13	#include <linux/pagemap.h>
	14	#include <linux/spinlock.h>
052e7994	15	#include <linux/module.h>
1da177e4 LT	16
	17	#include <asm/system.h>
	18	#include <asm/pgtable.h>
	19	#include <asm/pgalloc.h>
	20	#include <asm/fixmap.h>
	21	#include <asm/e820.h>
	22	#include <asm/tlb.h>
	23	#include <asm/tlbflush.h>
	24
	25	void show_mem(void)
	26	{
	27	int total = 0, reserved = 0;
	28	int shared = 0, cached = 0;
	29	int highmem = 0;
	30	struct page *page;
	31	pg_data_t *pgdat;
	32	unsigned long i;
208d54e5	33	unsigned long flags;
1da177e4	34
f90e7185	35	printk(KERN_INFO "Mem-info:\n");
1da177e4	36	show_free_areas();
f90e7185	37	printk(KERN_INFO "Free swap: %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
ec936fc5	38	for_each_online_pgdat(pgdat) {
208d54e5	39	pgdat_resize_lock(pgdat, &flags);
1da177e4	40	for (i = 0; i < pgdat->node_spanned_pages; ++i) {
408fde81	41	page = pgdat_page_nr(pgdat, i);
1da177e4 LT	42	total++;
	43	if (PageHighMem(page))
	44	highmem++;
	45	if (PageReserved(page))
	46	reserved++;
	47	else if (PageSwapCache(page))
	48	cached++;
	49	else if (page_count(page))
	50	shared += page_count(page) - 1;
	51	}
208d54e5	52	pgdat_resize_unlock(pgdat, &flags);
1da177e4	53	}
f90e7185 CL	54	printk(KERN_INFO "%d pages of RAM\n", total);
	55	printk(KERN_INFO "%d pages of HIGHMEM\n", highmem);
	56	printk(KERN_INFO "%d reserved pages\n", reserved);
	57	printk(KERN_INFO "%d pages shared\n", shared);
	58	printk(KERN_INFO "%d pages swap cached\n", cached);
6f4e1e50	59
b1e7a8fd	60	printk(KERN_INFO "%lu pages dirty\n", global_page_state(NR_FILE_DIRTY));
ce866b34 CL	61	printk(KERN_INFO "%lu pages writeback\n",
ce866b34 CL	62	global_page_state(NR_WRITEBACK));
65ba55f5	63	printk(KERN_INFO "%lu pages mapped\n", global_page_state(NR_FILE_MAPPED));
972d1a7b CL	64	printk(KERN_INFO "%lu pages slab\n",
	65	global_page_state(NR_SLAB_RECLAIMABLE) +
	66	global_page_state(NR_SLAB_UNRECLAIMABLE));
df849a15 CL	67	printk(KERN_INFO "%lu pages pagetables\n",
df849a15 CL	68	global_page_state(NR_PAGETABLE));
1da177e4 LT	69	}
	70
	71	/*
	72	* Associate a virtual page frame with a given physical page frame
	73	* and protection flags for that frame.
	74	*/
	75	static void set_pte_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
	76	{
	77	pgd_t *pgd;
	78	pud_t *pud;
	79	pmd_t *pmd;
	80	pte_t *pte;
	81
	82	pgd = swapper_pg_dir + pgd_index(vaddr);
	83	if (pgd_none(*pgd)) {
	84	BUG();
	85	return;
	86	}
	87	pud = pud_offset(pgd, vaddr);
	88	if (pud_none(*pud)) {
	89	BUG();
	90	return;
	91	}
	92	pmd = pmd_offset(pud, vaddr);
	93	if (pmd_none(*pmd)) {
	94	BUG();
	95	return;
	96	}
	97	pte = pte_offset_kernel(pmd, vaddr);
b0bfece4 JB	98	if (pgprot_val(flags))
	99	/* <pfn,flags> stored as-is, to permit clearing entries */
	100	set_pte(pte, pfn_pte(pfn, flags));
	101	else
	102	pte_clear(&init_mm, vaddr, pte);
1da177e4 LT	103
	104	/*
	105	* It's enough to flush this one mapping.
	106	* (PGE mappings get flushed as well)
	107	*/
	108	__flush_tlb_one(vaddr);
	109	}
	110
	111	/*
	112	* Associate a large virtual page frame with a given physical page frame
	113	* and protection flags for that frame. pfn is for the base of the page,
	114	* vaddr is what the page gets mapped to - both must be properly aligned.
	115	* The pmd must already be instantiated. Assumes PAE mode.
	116	*/
	117	void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
	118	{
	119	pgd_t *pgd;
	120	pud_t *pud;
	121	pmd_t *pmd;
	122
	123	if (vaddr & (PMD_SIZE-1)) { /* vaddr is misaligned */
f90e7185	124	printk(KERN_WARNING "set_pmd_pfn: vaddr misaligned\n");
1da177e4 LT	125	return; /* BUG(); */
	126	}
	127	if (pfn & (PTRS_PER_PTE-1)) { /* pfn is misaligned */
f90e7185	128	printk(KERN_WARNING "set_pmd_pfn: pfn misaligned\n");
1da177e4 LT	129	return; /* BUG(); */
	130	}
	131	pgd = swapper_pg_dir + pgd_index(vaddr);
	132	if (pgd_none(*pgd)) {
f90e7185	133	printk(KERN_WARNING "set_pmd_pfn: pgd_none\n");
1da177e4 LT	134	return; /* BUG(); */
	135	}
	136	pud = pud_offset(pgd, vaddr);
	137	pmd = pmd_offset(pud, vaddr);
	138	set_pmd(pmd, pfn_pmd(pfn, flags));
	139	/*
	140	* It's enough to flush this one mapping.
	141	* (PGE mappings get flushed as well)
	142	*/
	143	__flush_tlb_one(vaddr);
	144	}
	145
052e7994	146	static int fixmaps;
052e7994 JF	147	unsigned long __FIXADDR_TOP = 0xfffff000;
052e7994 JF	148	EXPORT_SYMBOL(__FIXADDR_TOP);
052e7994	149
1da177e4 LT	150	void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
	151	{
	152	unsigned long address = __fix_to_virt(idx);
	153
	154	if (idx >= __end_of_fixed_addresses) {
	155	BUG();
	156	return;
	157	}
	158	set_pte_pfn(address, phys >> PAGE_SHIFT, flags);
052e7994 JF	159	fixmaps++;
	160	}
	161
	162	/**
	163	* reserve_top_address - reserves a hole in the top of kernel address space
	164	* @reserve - size of hole to reserve
	165	*
	166	* Can be used to relocate the fixmap area and poke a hole in the top
	167	* of kernel address space to make room for a hypervisor.
	168	*/
	169	void reserve_top_address(unsigned long reserve)
	170	{
	171	BUG_ON(fixmaps > 0);
7ce0bcfd ZA	172	printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
7ce0bcfd ZA	173	(int)-reserve);
052e7994 JF	174	__FIXADDR_TOP = -reserve - PAGE_SIZE;
052e7994 JF	175	__VMALLOC_RESERVE += reserve;
1da177e4 LT	176	}
	177
	178	pte_t pte_alloc_one_kernel(struct mm_struct mm, unsigned long address)
	179	{
	180	return (pte_t *)__get_free_page(GFP_KERNEL\|__GFP_REPEAT\|__GFP_ZERO);
	181	}
	182
	183	struct page pte_alloc_one(struct mm_struct mm, unsigned long address)
	184	{
	185	struct page *pte;
	186
	187	#ifdef CONFIG_HIGHPTE
	188	pte = alloc_pages(GFP_KERNEL\|__GFP_HIGHMEM\|__GFP_REPEAT\|__GFP_ZERO, 0);
	189	#else
	190	pte = alloc_pages(GFP_KERNEL\|__GFP_REPEAT\|__GFP_ZERO, 0);
	191	#endif
	192	return pte;
	193	}
	194
e18b890b	195	void pmd_ctor(void pmd, struct kmem_cache cache, unsigned long flags)
1da177e4 LT	196	{
	197	memset(pmd, 0, PTRS_PER_PMD*sizeof(pmd_t));
	198	}
	199
	200	/*
	201	* List of all pgd's needed for non-PAE so it can invalidate entries
	202	* in both cached and uncached pgd's; not needed for PAE since the
	203	* kernel pmd is shared. If PAE were not to share the pmd a similar
	204	* tactic would be needed. This is essentially codepath-based locking
	205	* against pageattr.c; it is the unique case in which a valid change
	206	* of kernel pagetables can't be lazily synchronized by vmalloc faults.
	207	* vmalloc faults work because attached pagetables are never freed.
	208	* The locking scheme was chosen on the basis of manfred's
	209	* recommendations and having no core impact whatsoever.
	210	* -- wli
	211	*/
	212	DEFINE_SPINLOCK(pgd_lock);
	213	struct page *pgd_list;
	214
	215	static inline void pgd_list_add(pgd_t *pgd)
	216	{
	217	struct page *page = virt_to_page(pgd);
	218	page->index = (unsigned long)pgd_list;
	219	if (pgd_list)
4c21e2f2	220	set_page_private(pgd_list, (unsigned long)&page->index);
1da177e4	221	pgd_list = page;
4c21e2f2	222	set_page_private(page, (unsigned long)&pgd_list);
1da177e4 LT	223	}
	224
	225	static inline void pgd_list_del(pgd_t *pgd)
	226	{
	227	struct page next, pprev, page = virt_to_page(pgd);
	228	next = (struct page *)page->index;
4c21e2f2	229	pprev = (struct page **)page_private(page);
1da177e4 LT	230	*pprev = next;
1da177e4 LT	231	if (next)
4c21e2f2	232	set_page_private(next, (unsigned long)pprev);
1da177e4 LT	233	}
1da177e4 LT	234
5311ab62 JF	235	#if (PTRS_PER_PMD == 1)
5311ab62 JF	236	/* Non-PAE pgd constructor */
e18b890b	237	void pgd_ctor(void pgd, struct kmem_cache cache, unsigned long unused)
1da177e4 LT	238	{
	239	unsigned long flags;
	240
5311ab62 JF	241	/* !PAE, no pagetable sharing */
	242	memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
	243
	244	spin_lock_irqsave(&pgd_lock, flags);
1da177e4	245
5311ab62	246	/* must happen under lock */
d7271b14	247	clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD,
1da177e4	248	swapper_pg_dir + USER_PTRS_PER_PGD,
d7271b14	249	KERNEL_PGD_PTRS);
c119ecce	250	paravirt_alloc_pd_clone(__pa(pgd) >> PAGE_SHIFT,
5311ab62 JF	251	__pa(swapper_pg_dir) >> PAGE_SHIFT,
	252	USER_PTRS_PER_PGD,
	253	KERNEL_PGD_PTRS);
1da177e4 LT	254	pgd_list_add(pgd);
1da177e4 LT	255	spin_unlock_irqrestore(&pgd_lock, flags);
1da177e4	256	}
5311ab62 JF	257	#else /* PTRS_PER_PMD > 1 */
	258	/* PAE pgd constructor */
	259	void pgd_ctor(void pgd, struct kmem_cache cache, unsigned long unused)
	260	{
	261	/* PAE, kernel PMD may be shared */
	262
	263	if (SHARED_KERNEL_PMD) {
	264	clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD,
	265	swapper_pg_dir + USER_PTRS_PER_PGD,
	266	KERNEL_PGD_PTRS);
	267	} else {
	268	unsigned long flags;
	269
	270	memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
	271	spin_lock_irqsave(&pgd_lock, flags);
	272	pgd_list_add(pgd);
	273	spin_unlock_irqrestore(&pgd_lock, flags);
	274	}
	275	}
	276	#endif /* PTRS_PER_PMD */
1da177e4	277
e18b890b	278	void pgd_dtor(void pgd, struct kmem_cache cache, unsigned long unused)
1da177e4 LT	279	{
	280	unsigned long flags; /* can be called from interrupt context */
	281
5311ab62 JF	282	BUG_ON(SHARED_KERNEL_PMD);
5311ab62 JF	283
c119ecce	284	paravirt_release_pd(__pa(pgd) >> PAGE_SHIFT);
1da177e4 LT	285	spin_lock_irqsave(&pgd_lock, flags);
	286	pgd_list_del(pgd);
	287	spin_unlock_irqrestore(&pgd_lock, flags);
	288	}
	289
5311ab62 JF	290	#define UNSHARED_PTRS_PER_PGD \
	291	(SHARED_KERNEL_PMD ? USER_PTRS_PER_PGD : PTRS_PER_PGD)
	292
	293	/* If we allocate a pmd for part of the kernel address space, then
	294	make sure its initialized with the appropriate kernel mappings.
	295	Otherwise use a cached zeroed pmd. */
	296	static pmd_t *pmd_cache_alloc(int idx)
	297	{
	298	pmd_t *pmd;
	299
	300	if (idx >= USER_PTRS_PER_PGD) {
	301	pmd = (pmd_t *)__get_free_page(GFP_KERNEL);
	302
	303	if (pmd)
	304	memcpy(pmd,
	305	(void *)pgd_page_vaddr(swapper_pg_dir[idx]),
	306	sizeof(pmd_t) * PTRS_PER_PMD);
	307	} else
	308	pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);
	309
	310	return pmd;
	311	}
	312
	313	static void pmd_cache_free(pmd_t *pmd, int idx)
	314	{
	315	if (idx >= USER_PTRS_PER_PGD)
	316	free_page((unsigned long)pmd);
	317	else
	318	kmem_cache_free(pmd_cache, pmd);
	319	}
	320
1da177e4 LT	321	pgd_t pgd_alloc(struct mm_struct mm)
	322	{
	323	int i;
	324	pgd_t *pgd = kmem_cache_alloc(pgd_cache, GFP_KERNEL);
	325
	326	if (PTRS_PER_PMD == 1 \|\| !pgd)
	327	return pgd;
	328
5311ab62 JF	329	for (i = 0; i < UNSHARED_PTRS_PER_PGD; ++i) {
	330	pmd_t *pmd = pmd_cache_alloc(i);
	331
1da177e4 LT	332	if (!pmd)
1da177e4 LT	333	goto out_oom;
5311ab62	334
c119ecce	335	paravirt_alloc_pd(__pa(pmd) >> PAGE_SHIFT);
1da177e4 LT	336	set_pgd(&pgd[i], __pgd(1 + __pa(pmd)));
	337	}
	338	return pgd;
	339
	340	out_oom:
c119ecce ZA	341	for (i--; i >= 0; i--) {
	342	pgd_t pgdent = pgd[i];
	343	void* pmd = (void *)__va(pgd_val(pgdent)-1);
	344	paravirt_release_pd(__pa(pmd) >> PAGE_SHIFT);
5311ab62	345	pmd_cache_free(pmd, i);
c119ecce	346	}
1da177e4 LT	347	kmem_cache_free(pgd_cache, pgd);
	348	return NULL;
	349	}
	350
	351	void pgd_free(pgd_t *pgd)
	352	{
	353	int i;
	354
	355	/* in the PAE case user pgd entries are overwritten before usage */
	356	if (PTRS_PER_PMD > 1)
5311ab62	357	for (i = 0; i < UNSHARED_PTRS_PER_PGD; ++i) {
c119ecce ZA	358	pgd_t pgdent = pgd[i];
	359	void* pmd = (void *)__va(pgd_val(pgdent)-1);
	360	paravirt_release_pd(__pa(pmd) >> PAGE_SHIFT);
5311ab62	361	pmd_cache_free(pmd, i);
c119ecce	362	}
e0da382c	363	/* in the non-PAE case, free_pgtables() clears user pgd entries */
1da177e4 LT	364	kmem_cache_free(pgd_cache, pgd);
1da177e4 LT	365	}