/* pgalloc.c: page directory & page table allocation * * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <linux/sched.h> #include <linux/slab.h> #include <linux/mm.h> #include <linux/highmem.h> #include <linux/quicklist.h> #include <asm/pgalloc.h> #include <asm/page.h> #include <asm/cacheflush.h> pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((aligned(PAGE_SIZE))); pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address) { pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT); if (pte) clear_page(pte); return pte; } struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address) { struct page *page; #ifdef CONFIG_HIGHPTE page = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT, 0); #else page = alloc_pages(GFP_KERNEL|__GFP_REPEAT, 0); #endif if (page) clear_highpage(page); flush_dcache_page(page); return page; } void __set_pmd(pmd_t *pmdptr, unsigned long pmd) { unsigned long *__ste_p = pmdptr->ste; int loop; if (!pmd) { memset(__ste_p, 0, PME_SIZE); } else { BUG_ON(pmd & (0x3f00 | xAMPRx_SS | 0xe)); for (loop = PME_SIZE; loop > 0; loop -= 4) { *__ste_p++ = pmd; pmd += __frv_PT_SIZE; } } frv_dcache_writeback((unsigned long) pmdptr, (unsigned long) (pmdptr + 1)); } /* * 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. * If the locking proves to be non-performant, a ticketing scheme with * checks at dup_mmap(), exec(), and other mmlist addition points * could be used. 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); } void pgd_ctor(void *pgd) { unsigned long flags; if (PTRS_PER_PMD == 1) spin_lock_irqsave(&pgd_lock, flags); memcpy((pgd_t *) pgd + USER_PGDS_IN_LAST_PML4, swapper_pg_dir + USER_PGDS_IN_LAST_PML4, (PTRS_PER_PGD - USER_PGDS_IN_LAST_PML4) * sizeof(pgd_t)); if (PTRS_PER_PMD > 1) return; pgd_list_add(pgd); spin_unlock_irqrestore(&pgd_lock, flags); memset(pgd, 0, USER_PGDS_IN_LAST_PML4 * sizeof(pgd_t)); } /* never called when PTRS_PER_PMD > 1 */ void pgd_dtor(void *pgd) { 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) { pgd_t *pgd; pgd = quicklist_alloc(0, GFP_KERNEL, pgd_ctor); if (!pgd) return pgd; return pgd; } void pgd_free(pgd_t *pgd) { /* in the non-PAE case, clear_page_tables() clears user pgd entries */ quicklist_free(0, pgd_dtor, pgd); } void __init pgtable_cache_init(void) { } void check_pgt_cache(void) { quicklist_trim(0, pgd_dtor, 25, 16); }