2 * Copyright 2002 Andi Kleen, SuSE Labs.
3 * Thanks to Ben LaHaise for precious feedback.
6 #include <linux/highmem.h>
7 #include <linux/module.h>
8 #include <linux/sched.h>
9 #include <linux/slab.h>
12 #include <asm/processor.h>
13 #include <asm/tlbflush.h>
14 #include <asm/sections.h>
15 #include <asm/uaccess.h>
16 #include <asm/pgalloc.h>
18 pte_t *lookup_address(unsigned long address, int *level)
20 pgd_t *pgd = pgd_offset_k(address);
26 pud = pud_offset(pgd, address);
29 pmd = pmd_offset(pud, address);
37 return pte_offset_kernel(pmd, address);
41 split_large_page(unsigned long address, pgprot_t ref_prot)
48 base = alloc_pages(GFP_KERNEL, 0);
53 * page_private is used to track the number of entries in
54 * the page table page that have non standard attributes.
56 address = __pa(address);
57 addr = address & LARGE_PAGE_MASK;
58 pbase = (pte_t *)page_address(base);
59 paravirt_alloc_pt(&init_mm, page_to_pfn(base));
61 for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE)
62 set_pte(&pbase[i], pfn_pte(addr >> PAGE_SHIFT, ref_prot));
67 static void set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
73 set_pte_atomic(kpte, pte);
74 if (SHARED_KERNEL_PMD)
77 spin_lock_irqsave(&pgd_lock, flags);
78 for (page = pgd_list; page; page = (struct page *)page->index) {
83 pgd = (pgd_t *)page_address(page) + pgd_index(address);
84 pud = pud_offset(pgd, address);
85 pmd = pmd_offset(pud, address);
86 set_pte_atomic((pte_t *)pmd, pte);
88 spin_unlock_irqrestore(&pgd_lock, flags);
91 static int __change_page_attr(struct page *page, pgprot_t prot)
93 pgprot_t ref_prot = PAGE_KERNEL;
94 struct page *kpte_page;
95 unsigned long address;
100 BUG_ON(PageHighMem(page));
101 address = (unsigned long)page_address(page);
104 kpte = lookup_address(address, &level);
108 oldprot = pte_pgprot(*kpte);
109 kpte_page = virt_to_page(kpte);
110 BUG_ON(PageLRU(kpte_page));
111 BUG_ON(PageCompound(kpte_page));
114 * Better fail early if someone sets the kernel text to NX.
115 * Does not cover __inittext
117 BUG_ON(address >= (unsigned long)&_text &&
118 address < (unsigned long)&_etext &&
119 (pgprot_val(prot) & _PAGE_NX));
121 if ((address & LARGE_PAGE_MASK) < (unsigned long)&_etext)
122 ref_prot = PAGE_KERNEL_EXEC;
124 ref_prot = canon_pgprot(ref_prot);
125 prot = canon_pgprot(prot);
128 set_pte_atomic(kpte, mk_pte(page, prot));
132 split = split_large_page(address, ref_prot);
137 * There's a small window here to waste a bit of RAM:
139 set_pmd_pte(kpte, address, mk_pte(split, ref_prot));
146 * Change the page attributes of an page in the linear mapping.
148 * This should be used when a page is mapped with a different caching policy
149 * than write-back somewhere - some CPUs do not like it when mappings with
150 * different caching policies exist. This changes the page attributes of the
151 * in kernel linear mapping too.
153 * The caller needs to ensure that there are no conflicting mappings elsewhere.
154 * This function only deals with the kernel linear map.
156 * Caller must call global_flush_tlb() after this.
158 int change_page_attr(struct page *page, int numpages, pgprot_t prot)
162 for (i = 0; i < numpages; i++, page++) {
163 err = __change_page_attr(page, prot);
170 EXPORT_SYMBOL(change_page_attr);
172 int change_page_attr_addr(unsigned long addr, int numpages, pgprot_t prot)
175 unsigned long pfn = (addr >> PAGE_SHIFT);
177 for (i = 0; i < numpages; i++) {
178 if (!pfn_valid(pfn + i)) {
182 pte_t *pte = lookup_address(addr + i*PAGE_SIZE, &level);
183 BUG_ON(pte && !pte_none(*pte));
186 return change_page_attr(virt_to_page(addr), i, prot);
189 static void flush_kernel_map(void *arg)
192 * Flush all to work around Errata in early athlons regarding
193 * large page flushing.
197 if (boot_cpu_data.x86_model >= 4)
201 void global_flush_tlb(void)
203 BUG_ON(irqs_disabled());
205 on_each_cpu(flush_kernel_map, NULL, 1, 1);
207 EXPORT_SYMBOL(global_flush_tlb);
209 #ifdef CONFIG_DEBUG_PAGEALLOC
210 void kernel_map_pages(struct page *page, int numpages, int enable)
212 if (PageHighMem(page))
215 debug_check_no_locks_freed(page_address(page),
216 numpages * PAGE_SIZE);
220 * the return value is ignored - the calls cannot fail,
221 * large pages are disabled at boot time.
223 change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
226 * we should perform an IPI and flush all tlbs,
227 * but that can deadlock->flush only current cpu.