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authorIngo Molnar <mingo@elte.hu>2008-01-30 13:34:03 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-30 13:34:03 +0100
commit6faa4c53b2f06fd271060761ce27f4f53289175c (patch)
treea10304d5ed232f9ad862dee6350cdfea5f4c9076
parent44136717e06b888c2d3129a80abf9ac79233f1eb (diff)
x86: 64-bit, add the new split_large_page() function
Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--arch/x86/mm/pageattr_64.c95
1 files changed, 71 insertions, 24 deletions
diff --git a/arch/x86/mm/pageattr_64.c b/arch/x86/mm/pageattr_64.c
index 190d4d37bc2..139795029fb 100644
--- a/arch/x86/mm/pageattr_64.c
+++ b/arch/x86/mm/pageattr_64.c
@@ -45,34 +45,91 @@ pte_t *lookup_address(unsigned long address, int *level)
return pte_offset_kernel(pmd, address);
}
-static struct page *
-split_large_page(unsigned long address, pgprot_t ref_prot)
+static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
{
+ /* change init_mm */
+ set_pte_atomic(kpte, pte);
+#ifdef CONFIG_X86_32
+ if (SHARED_KERNEL_PMD)
+ return;
+ {
+ struct page *page;
+
+ 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);
+ }
+ }
+#endif
+}
+
+static int split_large_page(pte_t *kpte, unsigned long address)
+{
+ pgprot_t ref_prot = pte_pgprot(pte_clrhuge(*kpte));
+ gfp_t gfp_flags = GFP_KERNEL;
+ unsigned long flags;
unsigned long addr;
+ pte_t *pbase, *tmp;
struct page *base;
- pte_t *pbase;
- int i;
+ int i, level;
+
- base = alloc_pages(GFP_KERNEL, 0);
+#ifdef CONFIG_DEBUG_PAGEALLOC
+ gfp_flags = GFP_ATOMIC;
+#endif
+ base = alloc_pages(gfp_flags, 0);
if (!base)
- return NULL;
+ return -ENOMEM;
+
+ spin_lock_irqsave(&pgd_lock, flags);
+ /*
+ * Check for races, another CPU might have split this page
+ * up for us already:
+ */
+ tmp = lookup_address(address, &level);
+ if (tmp != kpte) {
+ WARN_ON_ONCE(1);
+ goto out_unlock;
+ }
address = __pa(address);
addr = address & LARGE_PAGE_MASK;
pbase = (pte_t *)page_address(base);
+#ifdef CONFIG_X86_32
+ paravirt_alloc_pt(&init_mm, page_to_pfn(base));
+#endif
+
for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE)
- pbase[i] = pfn_pte(addr >> PAGE_SHIFT, ref_prot);
+ set_pte(&pbase[i], pfn_pte(addr >> PAGE_SHIFT, ref_prot));
+
+ /*
+ * Install the new, split up pagetable:
+ */
+ __set_pmd_pte(kpte, address, mk_pte(base, ref_prot));
+ base = NULL;
+
+out_unlock:
+ spin_unlock_irqrestore(&pgd_lock, flags);
+
+ if (base)
+ __free_pages(base, 0);
- return base;
+ return 0;
}
static int
__change_page_attr(unsigned long address, struct page *page, pgprot_t prot)
{
+ pgprot_t ref_prot2, oldprot;
struct page *kpte_page;
+ int level, err = 0;
pte_t *kpte;
- pgprot_t ref_prot2, oldprot;
- int level;
repeat:
kpte = lookup_address(address, &level);
@@ -88,22 +145,12 @@ repeat:
if (level == 4) {
set_pte_atomic(kpte, mk_pte(page, prot));
} else {
- /*
- * split_large_page will take the reference for this
- * change_page_attr on the split page.
- */
- struct page *split;
-
- ref_prot2 = pte_pgprot(pte_clrhuge(*kpte));
- split = split_large_page(address, ref_prot2);
- if (!split)
- return -ENOMEM;
- pgprot_val(ref_prot2) &= ~_PAGE_NX;
- set_pte_atomic(kpte, mk_pte(split, ref_prot2));
- goto repeat;
+ err = split_large_page(kpte, address);
+ if (!err)
+ goto repeat;
}
- return 0;
+ return err;
}
/**