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x86: 64-bit, add the new split_large_page() function

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Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Ingo Molnar 2008-01-30 13:34:03 +01:00
parent 44136717e0
commit 6faa4c53b2
1 changed files with 75 additions and 28 deletions
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103
arch/x86/mm/pageattr_64.c
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@ -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)
{
unsigned long addr;
struct page *base;
pte_t *pbase;
int i;
/* change init_mm */
set_pte_atomic(kpte, pte);
#ifdef CONFIG_X86_32
if (SHARED_KERNEL_PMD)
return;
{
struct page *page;
base = alloc_pages(GFP_KERNEL, 0);
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;
int i, level;
#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);
for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE)
pbase[i] = pfn_pte(addr >> PAGE_SHIFT, ref_prot);
#ifdef CONFIG_X86_32
paravirt_alloc_pt(&init_mm, page_to_pfn(base));
#endif
return base;
for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE)
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 0;
}
static int
__change_page_attr(unsigned long address, struct page *page, pgprot_t prot)
{
struct page *kpte_page;
pte_t *kpte;
pgprot_t ref_prot2, oldprot;
int level;
struct page *kpte_page;
int level, err = 0;
pte_t *kpte;
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;
}
/**