From d6ee09a2a0865f5640592e73ca5da4b06404b200 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 30 Jan 2008 13:33:59 +0100 Subject: [PATCH] x86: simplify pageattr_64.c simplify pageattr_64.c. Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/mm/pageattr_64.c | 168 +++++++++++++------------------------- 1 file changed, 55 insertions(+), 113 deletions(-) diff --git a/arch/x86/mm/pageattr_64.c b/arch/x86/mm/pageattr_64.c index 7b734ee5b7fd..8493c469f877 100644 --- a/arch/x86/mm/pageattr_64.c +++ b/arch/x86/mm/pageattr_64.c @@ -9,6 +9,14 @@ #include #include +void clflush_cache_range(void *addr, int size) +{ + int i; + + for (i = 0; i < size; i += boot_cpu_data.x86_clflush_size) + clflush(addr+i); +} + #include #include #include @@ -47,12 +55,6 @@ split_large_page(unsigned long address, pgprot_t prot, pgprot_t ref_prot) base = alloc_pages(GFP_KERNEL, 0); if (!base) return NULL; - /* - * page_private is used to track the number of entries in - * the page table page have non standard attributes. - */ - SetPagePrivate(base); - page_private(base) = 0; address = __pa(address); addr = address & LARGE_PAGE_MASK; @@ -64,80 +66,13 @@ split_large_page(unsigned long address, pgprot_t prot, pgprot_t ref_prot) return base; } -void clflush_cache_range(void *addr, int size) -{ - int i; - - for (i = 0; i < size; i += boot_cpu_data.x86_clflush_size) - clflush(addr+i); -} - -static void flush_kernel_map(void *arg) -{ - struct list_head *l = (struct list_head *)arg; - struct page *pg; - - __flush_tlb_all(); - - /* When clflush is available always use it because it is - much cheaper than WBINVD. */ - /* clflush is still broken. Disable for now. */ - if (1 || !cpu_has_clflush) { - wbinvd(); - } else { - list_for_each_entry(pg, l, lru) { - void *addr = page_address(pg); - - clflush_cache_range(addr, PAGE_SIZE); - } - } -} - -static inline void flush_map(struct list_head *l) -{ - on_each_cpu(flush_kernel_map, l, 1, 1); -} - -static LIST_HEAD(deferred_pages); /* protected by init_mm.mmap_sem */ - -static inline void save_page(struct page *fpage) -{ - if (!test_and_set_bit(PG_arch_1, &fpage->flags)) - list_add(&fpage->lru, &deferred_pages); -} - -/* - * No more special protections in this 2/4MB area - revert to a - * large page again. - */ -static void revert_page(unsigned long address, pgprot_t ref_prot) -{ - unsigned long pfn; - pgd_t *pgd; - pud_t *pud; - pmd_t *pmd; - pte_t large_pte; - - pgd = pgd_offset_k(address); - BUG_ON(pgd_none(*pgd)); - pud = pud_offset(pgd, address); - BUG_ON(pud_none(*pud)); - pmd = pmd_offset(pud, address); - BUG_ON(pmd_val(*pmd) & _PAGE_PSE); - pfn = (__pa(address) & LARGE_PAGE_MASK) >> PAGE_SHIFT; - large_pte = pfn_pte(pfn, ref_prot); - large_pte = pte_mkhuge(large_pte); - - set_pte((pte_t *)pmd, large_pte); -} - static int __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot, pgprot_t ref_prot) { struct page *kpte_page; - pgprot_t ref_prot2; pte_t *kpte; + pgprot_t ref_prot2, oldprot; int level; kpte = lookup_address(address, &level); @@ -145,8 +80,12 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot, return 0; kpte_page = virt_to_page(kpte); + oldprot = pte_pgprot(*kpte); BUG_ON(PageLRU(kpte_page)); BUG_ON(PageCompound(kpte_page)); + ref_prot = canon_pgprot(ref_prot); + prot = canon_pgprot(prot); + if (pgprot_val(prot) != pgprot_val(ref_prot)) { if (level == 4) { set_pte(kpte, pfn_pte(pfn, prot)); @@ -165,38 +104,29 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot, set_pte(kpte, mk_pte(split, ref_prot2)); kpte_page = split; } - page_private(kpte_page)++; } else { if (level == 4) { set_pte(kpte, pfn_pte(pfn, ref_prot)); - BUG_ON(page_private(kpte_page) == 0); - page_private(kpte_page)--; } else BUG(); } - /* on x86-64 the direct mapping set at boot is not using 4k pages */ - BUG_ON(PageReserved(kpte_page)); - - save_page(kpte_page); - if (page_private(kpte_page) == 0) - revert_page(address, ref_prot); return 0; } -/* - * Change the page attributes of an page in the linear mapping. - * - * This should be used when a page is mapped with a different caching policy - * than write-back somewhere - some CPUs do not like it when mappings with - * different caching policies exist. This changes the page attributes of the - * in kernel linear mapping too. +/** + * change_page_attr_addr - Change page table attributes in linear mapping + * @address: Virtual address in linear mapping. + * @numpages: Number of pages to change + * @prot: New page table attribute (PAGE_*) * - * The caller needs to ensure that there are no conflicting mappings elsewhere. - * This function only deals with the kernel linear map. + * Change page attributes of a page in the direct mapping. This is a variant + * of change_page_attr() that also works on memory holes that do not have + * mem_map entry (pfn_valid() is false). * - * Caller must call global_flush_tlb() after this. + * See change_page_attr() documentation for more details. */ + int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot) { int err = 0, kernel_map = 0, i; @@ -236,7 +166,26 @@ int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot) return err; } -/* Don't call this for MMIO areas that may not have a mem_map entry */ +/** + * change_page_attr - Change page table attributes in the linear mapping. + * @page: First page to change + * @numpages: Number of pages to change + * @prot: New protection/caching type (PAGE_*) + * + * Returns 0 on success, otherwise a negated errno. + * + * This should be used when a page is mapped with a different caching policy + * than write-back somewhere - some CPUs do not like it when mappings with + * different caching policies exist. This changes the page attributes of the + * in kernel linear mapping too. + * + * Caller must call global_flush_tlb() later to make the changes active. + * + * The caller needs to ensure that there are no conflicting mappings elsewhere + * (e.g. in user space) * This function only deals with the kernel linear map. + * + * For MMIO areas without mem_map use change_page_attr_addr() instead. + */ int change_page_attr(struct page *page, int numpages, pgprot_t prot) { unsigned long addr = (unsigned long)page_address(page); @@ -245,29 +194,22 @@ int change_page_attr(struct page *page, int numpages, pgprot_t prot) } EXPORT_SYMBOL(change_page_attr); -void global_flush_tlb(void) +static void flush_kernel_map(void *arg) { - struct page *pg, *next; - struct list_head l; - /* - * Write-protect the semaphore, to exclude two contexts - * doing a list_replace_init() call in parallel and to - * exclude new additions to the deferred_pages list: + * Flush all to work around Errata in early athlons regarding + * large page flushing. */ - down_write(&init_mm.mmap_sem); - list_replace_init(&deferred_pages, &l); - up_write(&init_mm.mmap_sem); + __flush_tlb_all(); - flush_map(&l); + if (boot_cpu_data.x86_model >= 4) + wbinvd(); +} - list_for_each_entry_safe(pg, next, &l, lru) { - list_del(&pg->lru); - clear_bit(PG_arch_1, &pg->flags); - if (page_private(pg) != 0) - continue; - ClearPagePrivate(pg); - __free_page(pg); - } +void global_flush_tlb(void) +{ + BUG_ON(irqs_disabled()); + + on_each_cpu(flush_kernel_map, NULL, 1, 1); } EXPORT_SYMBOL(global_flush_tlb); -- 2.20.1