+++ /dev/null
-/*
- * Copyright 2002 Andi Kleen, SuSE Labs.
- * Thanks to Ben LaHaise for precious feedback.
- */
-
-#include <linux/config.h>
-#include <linux/mm.h>
-#include <linux/sched.h>
-#include <linux/highmem.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <asm/uaccess.h>
-#include <asm/processor.h>
-#include <asm/tlbflush.h>
-
-static DEFINE_SPINLOCK(cpa_lock);
-static struct list_head df_list = LIST_HEAD_INIT(df_list);
-
-
-pte_t *lookup_address(unsigned long address)
-{
- pgd_t *pgd = pgd_offset_k(address);
- pud_t *pud;
- pmd_t *pmd;
- if (pgd_none(*pgd))
- return NULL;
- pud = pud_offset(pgd, address);
- if (pud_none(*pud))
- return NULL;
- pmd = pmd_offset(pud, address);
- if (pmd_none(*pmd))
- return NULL;
- if (pmd_large(*pmd))
- return (pte_t *)pmd;
- return pte_offset_kernel(pmd, address);
-}
-
-static struct page *split_large_page(unsigned long address, pgprot_t prot)
-{
- int i;
- unsigned long addr;
- struct page *base;
- pte_t *pbase;
-
- spin_unlock_irq(&cpa_lock);
- base = alloc_pages(GFP_KERNEL, 0);
- spin_lock_irq(&cpa_lock);
- if (!base)
- return NULL;
-
- address = __pa(address);
- addr = address & LARGE_PAGE_MASK;
- pbase = (pte_t *)page_address(base);
- for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE) {
- pbase[i] = pfn_pte(addr >> PAGE_SHIFT,
- addr == address ? prot : PAGE_KERNEL);
- }
- return base;
-}
-
-static void flush_kernel_map(void *dummy)
-{
- /* Could use CLFLUSH here if the CPU supports it (Hammer,P4) */
- if (boot_cpu_data.x86_model >= 4)
- wbinvd();
- /* Flush all to work around Errata in early athlons regarding
- * large page flushing.
- */
- __flush_tlb_all();
-}
-
-static void set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
-{
- struct page *page;
- unsigned long flags;
-
- set_pte_atomic(kpte, pte); /* change init_mm */
- if (PTRS_PER_PMD > 1)
- return;
-
- spin_lock_irqsave(&pgd_lock, flags);
- for (page = pgd_list; page; page = (struct page *)page->index) {
- pgd_t *pgd;
- pud_t *pud;
- pmd_t *pmd;
- pgd = (pgd_t *)page_address(page) + pgd_index(address);
- pud = pud_offset(pgd, address);
- pmd = pmd_offset(pud, address);
- set_pte_atomic((pte_t *)pmd, pte);
- }
- spin_unlock_irqrestore(&pgd_lock, flags);
-}
-
-/*
- * No more special protections in this 2/4MB area - revert to a
- * large page again.
- */
-static inline void revert_page(struct page *kpte_page, unsigned long address)
-{
- pte_t *linear = (pte_t *)
- pmd_offset(pud_offset(pgd_offset_k(address), address), address);
- set_pmd_pte(linear, address,
- pfn_pte((__pa(address) & LARGE_PAGE_MASK) >> PAGE_SHIFT,
- PAGE_KERNEL_LARGE));
-}
-
-static int
-__change_page_attr(struct page *page, pgprot_t prot)
-{
- pte_t *kpte;
- unsigned long address;
- struct page *kpte_page;
-
- BUG_ON(PageHighMem(page));
- address = (unsigned long)page_address(page);
-
- kpte = lookup_address(address);
- if (!kpte)
- return -EINVAL;
- kpte_page = virt_to_page(kpte);
- if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL)) {
- if ((pte_val(*kpte) & _PAGE_PSE) == 0) {
- set_pte_batched(kpte, mk_pte(page, prot));
- } else {
- struct page *split = split_large_page(address, prot);
- if (!split)
- return -ENOMEM;
- set_pmd_pte(kpte,address,mk_pte(split, PAGE_KERNEL));
- kpte_page = split;
- }
- get_page(kpte_page);
- } else if ((pte_val(*kpte) & _PAGE_PSE) == 0) {
- set_pte_batched(kpte, mk_pte(page, PAGE_KERNEL));
- __put_page(kpte_page);
- } else
- BUG();
-
- /*
- * If the pte was reserved, it means it was created at boot
- * time (not via split_large_page) and in turn we must not
- * replace it with a largepage.
- */
- if (!PageReserved(kpte_page)) {
- /* memleak and potential failed 2M page regeneration */
- BUG_ON(!page_count(kpte_page));
-
- if (cpu_has_pse && (page_count(kpte_page) == 1)) {
- list_add(&kpte_page->lru, &df_list);
- revert_page(kpte_page, address);
- }
- }
- return 0;
-}
-
-static inline void flush_map(void)
-{
- on_each_cpu(flush_kernel_map, NULL, 1, 1);
-}
-
-/*
- * 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.
- *
- * The caller needs to ensure that there are no conflicting mappings elsewhere.
- * This function only deals with the kernel linear map.
- *
- * Caller must call global_flush_tlb() after this.
- */
-int change_page_attr(struct page *page, int numpages, pgprot_t prot)
-{
- int err = 0;
- int i;
- unsigned long flags;
-
- spin_lock_irqsave(&cpa_lock, flags);
- for (i = 0; i < numpages; i++, page++) {
- err = __change_page_attr(page, prot);
- if (err)
- break;
- }
- flush_page_update_queue();
- spin_unlock_irqrestore(&cpa_lock, flags);
- return err;
-}
-
-void global_flush_tlb(void)
-{
- LIST_HEAD(l);
- struct list_head* n;
-
- BUG_ON(irqs_disabled());
-
- spin_lock_irq(&cpa_lock);
- list_splice_init(&df_list, &l);
- spin_unlock_irq(&cpa_lock);
- flush_map();
- n = l.next;
- while (n != &l) {
- struct page *pg = list_entry(n, struct page, lru);
- n = n->next;
- __free_page(pg);
- }
-}
-
-#ifdef CONFIG_DEBUG_PAGEALLOC
-void kernel_map_pages(struct page *page, int numpages, int enable)
-{
- if (PageHighMem(page))
- return;
- /* the return value is ignored - the calls cannot fail,
- * large pages are disabled at boot time.
- */
- change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
- /* we should perform an IPI and flush all tlbs,
- * but that can deadlock->flush only current cpu.
- */
- __flush_tlb_all();
-}
-#endif
-
-EXPORT_SYMBOL(change_page_attr);
-EXPORT_SYMBOL(global_flush_tlb);
projects / xen.git / commitdiff