1/* pgalloc.c: page directory & page table allocation 2 * 3 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells (dhowells@redhat.com) 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 */ 11 12#include <linux/sched.h> 13#include <linux/gfp.h> 14#include <linux/mm.h> 15#include <linux/highmem.h> 16#include <linux/quicklist.h> 17#include <asm/pgalloc.h> 18#include <asm/page.h> 19#include <asm/cacheflush.h> 20 21pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((aligned(PAGE_SIZE))); 22 23pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address) 24{ 25 pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT); 26 if (pte) 27 clear_page(pte); 28 return pte; 29} 30 31pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address) 32{ 33 struct page *page; 34 35#ifdef CONFIG_HIGHPTE 36 page = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT, 0); 37#else 38 page = alloc_pages(GFP_KERNEL|__GFP_REPEAT, 0); 39#endif 40 if (!page) 41 return NULL; 42 43 clear_highpage(page); 44 if (!pgtable_page_ctor(page)) { 45 __free_page(page); 46 return NULL; 47 } 48 flush_dcache_page(page); 49 return page; 50} 51 52void __set_pmd(pmd_t *pmdptr, unsigned long pmd) 53{ 54 unsigned long *__ste_p = pmdptr->ste; 55 int loop; 56 57 if (!pmd) { 58 memset(__ste_p, 0, PME_SIZE); 59 } 60 else { 61 BUG_ON(pmd & (0x3f00 | xAMPRx_SS | 0xe)); 62 63 for (loop = PME_SIZE; loop > 0; loop -= 4) { 64 *__ste_p++ = pmd; 65 pmd += __frv_PT_SIZE; 66 } 67 } 68 69 frv_dcache_writeback((unsigned long) pmdptr, (unsigned long) (pmdptr + 1)); 70} 71 72/* 73 * List of all pgd's needed for non-PAE so it can invalidate entries 74 * in both cached and uncached pgd's; not needed for PAE since the 75 * kernel pmd is shared. If PAE were not to share the pmd a similar 76 * tactic would be needed. This is essentially codepath-based locking 77 * against pageattr.c; it is the unique case in which a valid change 78 * of kernel pagetables can't be lazily synchronized by vmalloc faults. 79 * vmalloc faults work because attached pagetables are never freed. 80 * If the locking proves to be non-performant, a ticketing scheme with 81 * checks at dup_mmap(), exec(), and other mmlist addition points 82 * could be used. The locking scheme was chosen on the basis of 83 * manfred's recommendations and having no core impact whatsoever. 84 * -- nyc 85 */ 86DEFINE_SPINLOCK(pgd_lock); 87struct page *pgd_list; 88 89static inline void pgd_list_add(pgd_t *pgd) 90{ 91 struct page *page = virt_to_page(pgd); 92 page->index = (unsigned long) pgd_list; 93 if (pgd_list) 94 set_page_private(pgd_list, (unsigned long) &page->index); 95 pgd_list = page; 96 set_page_private(page, (unsigned long)&pgd_list); 97} 98 99static inline void pgd_list_del(pgd_t *pgd) 100{ 101 struct page *next, **pprev, *page = virt_to_page(pgd); 102 next = (struct page *) page->index; 103 pprev = (struct page **) page_private(page); 104 *pprev = next; 105 if (next) 106 set_page_private(next, (unsigned long) pprev); 107} 108 109void pgd_ctor(void *pgd) 110{ 111 unsigned long flags; 112 113 if (PTRS_PER_PMD == 1) 114 spin_lock_irqsave(&pgd_lock, flags); 115 116 memcpy((pgd_t *) pgd + USER_PGDS_IN_LAST_PML4, 117 swapper_pg_dir + USER_PGDS_IN_LAST_PML4, 118 (PTRS_PER_PGD - USER_PGDS_IN_LAST_PML4) * sizeof(pgd_t)); 119 120 if (PTRS_PER_PMD > 1) 121 return; 122 123 pgd_list_add(pgd); 124 spin_unlock_irqrestore(&pgd_lock, flags); 125 memset(pgd, 0, USER_PGDS_IN_LAST_PML4 * sizeof(pgd_t)); 126} 127 128/* never called when PTRS_PER_PMD > 1 */ 129void pgd_dtor(void *pgd) 130{ 131 unsigned long flags; /* can be called from interrupt context */ 132 133 spin_lock_irqsave(&pgd_lock, flags); 134 pgd_list_del(pgd); 135 spin_unlock_irqrestore(&pgd_lock, flags); 136} 137 138pgd_t *pgd_alloc(struct mm_struct *mm) 139{ 140 return quicklist_alloc(0, GFP_KERNEL, pgd_ctor); 141} 142 143void pgd_free(struct mm_struct *mm, pgd_t *pgd) 144{ 145 /* in the non-PAE case, clear_page_tables() clears user pgd entries */ 146 quicklist_free(0, pgd_dtor, pgd); 147} 148 149void __init pgtable_cache_init(void) 150{ 151} 152 153void check_pgt_cache(void) 154{ 155 quicklist_trim(0, pgd_dtor, 25, 16); 156} 157 158