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-rw-r--r--arch/x86/mm/pageattr_32.c278
1 files changed, 278 insertions, 0 deletions
diff --git a/arch/x86/mm/pageattr_32.c b/arch/x86/mm/pageattr_32.c
new file mode 100644
index 00000000000..4241a74d16c
--- /dev/null
+++ b/arch/x86/mm/pageattr_32.c
@@ -0,0 +1,278 @@
+/*
+ * Copyright 2002 Andi Kleen, SuSE Labs.
+ * Thanks to Ben LaHaise for precious feedback.
+ */
+
+#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>
+#include <asm/pgalloc.h>
+#include <asm/sections.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,
+ pgprot_t ref_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;
+
+ /*
+ * page_private is used to track the number of entries in
+ * the page table page that have non standard attributes.
+ */
+ SetPagePrivate(base);
+ page_private(base) = 0;
+
+ address = __pa(address);
+ addr = address & LARGE_PAGE_MASK;
+ pbase = (pte_t *)page_address(base);
+ paravirt_alloc_pt(&init_mm, page_to_pfn(base));
+ for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE) {
+ set_pte(&pbase[i], pfn_pte(addr >> PAGE_SHIFT,
+ addr == address ? prot : ref_prot));
+ }
+ return base;
+}
+
+static void cache_flush_page(struct page *p)
+{
+ unsigned long adr = (unsigned long)page_address(p);
+ int i;
+ for (i = 0; i < PAGE_SIZE; i += boot_cpu_data.x86_clflush_size)
+ asm volatile("clflush (%0)" :: "r" (adr + i));
+}
+
+static void flush_kernel_map(void *arg)
+{
+ struct list_head *lh = (struct list_head *)arg;
+ struct page *p;
+
+ /* High level code is not ready for clflush yet */
+ if (0 && cpu_has_clflush) {
+ list_for_each_entry (p, lh, lru)
+ cache_flush_page(p);
+ } else 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 (SHARED_KERNEL_PMD)
+ 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)
+{
+ pgprot_t ref_prot;
+ pte_t *linear;
+
+ ref_prot =
+ ((address & LARGE_PAGE_MASK) < (unsigned long)&_etext)
+ ? PAGE_KERNEL_LARGE_EXEC : PAGE_KERNEL_LARGE;
+
+ 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,
+ ref_prot));
+}
+
+static inline void save_page(struct page *kpte_page)
+{
+ if (!test_and_set_bit(PG_arch_1, &kpte_page->flags))
+ list_add(&kpte_page->lru, &df_list);
+}
+
+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);
+ BUG_ON(PageLRU(kpte_page));
+ BUG_ON(PageCompound(kpte_page));
+
+ if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL)) {
+ if (!pte_huge(*kpte)) {
+ set_pte_atomic(kpte, mk_pte(page, prot));
+ } else {
+ pgprot_t ref_prot;
+ struct page *split;
+
+ ref_prot =
+ ((address & LARGE_PAGE_MASK) < (unsigned long)&_etext)
+ ? PAGE_KERNEL_EXEC : PAGE_KERNEL;
+ split = split_large_page(address, prot, ref_prot);
+ if (!split)
+ return -ENOMEM;
+ set_pmd_pte(kpte,address,mk_pte(split, ref_prot));
+ kpte_page = split;
+ }
+ page_private(kpte_page)++;
+ } else if (!pte_huge(*kpte)) {
+ set_pte_atomic(kpte, mk_pte(page, PAGE_KERNEL));
+ BUG_ON(page_private(kpte_page) == 0);
+ page_private(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.
+ */
+
+ save_page(kpte_page);
+ if (!PageReserved(kpte_page)) {
+ if (cpu_has_pse && (page_private(kpte_page) == 0)) {
+ paravirt_release_pt(page_to_pfn(kpte_page));
+ revert_page(kpte_page, address);
+ }
+ }
+ return 0;
+}
+
+static inline void flush_map(struct list_head *l)
+{
+ on_each_cpu(flush_kernel_map, l, 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;
+ }
+ spin_unlock_irqrestore(&cpa_lock, flags);
+ return err;
+}
+
+void global_flush_tlb(void)
+{
+ struct list_head l;
+ struct page *pg, *next;
+
+ BUG_ON(irqs_disabled());
+
+ spin_lock_irq(&cpa_lock);
+ list_replace_init(&df_list, &l);
+ spin_unlock_irq(&cpa_lock);
+ flush_map(&l);
+ list_for_each_entry_safe(pg, next, &l, lru) {
+ list_del(&pg->lru);
+ clear_bit(PG_arch_1, &pg->flags);
+ if (PageReserved(pg) || !cpu_has_pse || page_private(pg) != 0)
+ continue;
+ ClearPagePrivate(pg);
+ __free_page(pg);
+ }
+}
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
+void kernel_map_pages(struct page *page, int numpages, int enable)
+{
+ if (PageHighMem(page))
+ return;
+ if (!enable)
+ debug_check_no_locks_freed(page_address(page),
+ numpages * PAGE_SIZE);
+
+ /* 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);