/arch/i386/mm/pgtable.c

  1/*
  2 *  linux/arch/i386/mm/pgtable.c
  3 */
  4
  5#include <linux/config.h>
  6#include <linux/sched.h>
  7#include <linux/kernel.h>
  8#include <linux/errno.h>
  9#include <linux/mm.h>
 10#include <linux/swap.h>
 11#include <linux/smp.h>
 12#include <linux/highmem.h>
 13#include <linux/slab.h>
 14#include <linux/pagemap.h>
 15#include <linux/spinlock.h>
 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
 25void 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;
 33
 34	printk("Mem-info:\n");
 35	show_free_areas();
 36	printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
 37	for_each_pgdat(pgdat) {
 38		for (i = 0; i < pgdat->node_spanned_pages; ++i) {
 39			page = pgdat->node_mem_map + i;
 40			total++;
 41			if (PageHighMem(page))
 42				highmem++;
 43			if (PageReserved(page))
 44				reserved++;
 45			else if (PageSwapCache(page))
 46				cached++;
 47			else if (page_count(page))
 48				shared += page_count(page) - 1;
 49		}
 50	}
 51	printk("%d pages of RAM\n", total);
 52	printk("%d pages of HIGHMEM\n",highmem);
 53	printk("%d reserved pages\n",reserved);
 54	printk("%d pages shared\n",shared);
 55	printk("%d pages swap cached\n",cached);
 56}
 57
 58/*
 59 * Associate a virtual page frame with a given physical page frame 
 60 * and protection flags for that frame.
 61 */ 
 62static void set_pte_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
 63{
 64	pgd_t *pgd;
 65	pud_t *pud;
 66	pmd_t *pmd;
 67	pte_t *pte;
 68
 69	pgd = swapper_pg_dir + pgd_index(vaddr);
 70	if (pgd_none(*pgd)) {
 71		BUG();
 72		return;
 73	}
 74	pud = pud_offset(pgd, vaddr);
 75	if (pud_none(*pud)) {
 76		BUG();
 77		return;
 78	}
 79	pmd = pmd_offset(pud, vaddr);
 80	if (pmd_none(*pmd)) {
 81		BUG();
 82		return;
 83	}
 84	pte = pte_offset_kernel(pmd, vaddr);
 85	/* <pfn,flags> stored as-is, to permit clearing entries */
 86	set_pte(pte, pfn_pte(pfn, flags));
 87
 88	/*
 89	 * It's enough to flush this one mapping.
 90	 * (PGE mappings get flushed as well)
 91	 */
 92	__flush_tlb_one(vaddr);
 93}
 94
 95/*
 96 * Associate a large virtual page frame with a given physical page frame 
 97 * and protection flags for that frame. pfn is for the base of the page,
 98 * vaddr is what the page gets mapped to - both must be properly aligned. 
 99 * The pmd must already be instantiated. Assumes PAE mode.
100 */ 
101void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
102{
103	pgd_t *pgd;
104	pud_t *pud;
105	pmd_t *pmd;
106
107	if (vaddr & (PMD_SIZE-1)) {		/* vaddr is misaligned */
108		printk ("set_pmd_pfn: vaddr misaligned\n");
109		return; /* BUG(); */
110	}
111	if (pfn & (PTRS_PER_PTE-1)) {		/* pfn is misaligned */
112		printk ("set_pmd_pfn: pfn misaligned\n");
113		return; /* BUG(); */
114	}
115	pgd = swapper_pg_dir + pgd_index(vaddr);
116	if (pgd_none(*pgd)) {
117		printk ("set_pmd_pfn: pgd_none\n");
118		return; /* BUG(); */
119	}
120	pud = pud_offset(pgd, vaddr);
121	pmd = pmd_offset(pud, vaddr);
122	set_pmd(pmd, pfn_pmd(pfn, flags));
123	/*
124	 * It's enough to flush this one mapping.
125	 * (PGE mappings get flushed as well)
126	 */
127	__flush_tlb_one(vaddr);
128}
129
130void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
131{
132	unsigned long address = __fix_to_virt(idx);
133
134	if (idx >= __end_of_fixed_addresses) {
135		BUG();
136		return;
137	}
138	set_pte_pfn(address, phys >> PAGE_SHIFT, flags);
139}
140
141pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
142{
143	return (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
144}
145
146struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
147{
148	struct page *pte;
149
150#ifdef CONFIG_HIGHPTE
151	pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT|__GFP_ZERO, 0);
152#else
153	pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
154#endif
155	return pte;
156}
157
158void pmd_ctor(void *pmd, kmem_cache_t *cache, unsigned long flags)
159{
160	memset(pmd, 0, PTRS_PER_PMD*sizeof(pmd_t));
161}
162
163/*
164 * List of all pgd's needed for non-PAE so it can invalidate entries
165 * in both cached and uncached pgd's; not needed for PAE since the
166 * kernel pmd is shared. If PAE were not to share the pmd a similar
167 * tactic would be needed. This is essentially codepath-based locking
168 * against pageattr.c; it is the unique case in which a valid change
169 * of kernel pagetables can't be lazily synchronized by vmalloc faults.
170 * vmalloc faults work because attached pagetables are never freed.
171 * The locking scheme was chosen on the basis of manfred's
172 * recommendations and having no core impact whatsoever.
173 * -- wli
174 */
175DEFINE_SPINLOCK(pgd_lock);
176struct page *pgd_list;
177
178static inline void pgd_list_add(pgd_t *pgd)
179{
180	struct page *page = virt_to_page(pgd);
181	page->index = (unsigned long)pgd_list;
182	if (pgd_list)
183		pgd_list->private = (unsigned long)&page->index;
184	pgd_list = page;
185	page->private = (unsigned long)&pgd_list;
186}
187
188static inline void pgd_list_del(pgd_t *pgd)
189{
190	struct page *next, **pprev, *page = virt_to_page(pgd);
191	next = (struct page *)page->index;
192	pprev = (struct page **)page->private;
193	*pprev = next;
194	if (next)
195		next->private = (unsigned long)pprev;
196}
197
198void pgd_ctor(void *pgd, kmem_cache_t *cache, unsigned long unused)
199{
200	unsigned long flags;
201
202	if (PTRS_PER_PMD == 1)
203		spin_lock_irqsave(&pgd_lock, flags);
204
205	memcpy((pgd_t *)pgd + USER_PTRS_PER_PGD,
206			swapper_pg_dir + USER_PTRS_PER_PGD,
207			(PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
208
209	if (PTRS_PER_PMD > 1)
210		return;
211
212	pgd_list_add(pgd);
213	spin_unlock_irqrestore(&pgd_lock, flags);
214	memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
215}
216
217/* never called when PTRS_PER_PMD > 1 */
218void pgd_dtor(void *pgd, kmem_cache_t *cache, unsigned long unused)
219{
220	unsigned long flags; /* can be called from interrupt context */
221
222	spin_lock_irqsave(&pgd_lock, flags);
223	pgd_list_del(pgd);
224	spin_unlock_irqrestore(&pgd_lock, flags);
225}
226
227pgd_t *pgd_alloc(struct mm_struct *mm)
228{
229	int i;
230	pgd_t *pgd = kmem_cache_alloc(pgd_cache, GFP_KERNEL);
231
232	if (PTRS_PER_PMD == 1 || !pgd)
233		return pgd;
234
235	for (i = 0; i < USER_PTRS_PER_PGD; ++i) {
236		pmd_t *pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);
237		if (!pmd)
238			goto out_oom;
239		set_pgd(&pgd[i], __pgd(1 + __pa(pmd)));
240	}
241	return pgd;
242
243out_oom:
244	for (i--; i >= 0; i--)
245		kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i])-1));
246	kmem_cache_free(pgd_cache, pgd);
247	return NULL;
248}
249
250void pgd_free(pgd_t *pgd)
251{
252	int i;
253
254	/* in the PAE case user pgd entries are overwritten before usage */
255	if (PTRS_PER_PMD > 1)
256		for (i = 0; i < USER_PTRS_PER_PGD; ++i)
257			kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i])-1));
258	/* in the non-PAE case, clear_page_range() clears user pgd entries */
259	kmem_cache_free(pgd_cache, pgd);
260}