Commit-ID: d551aaa2f7e1387fa66093ce9914c2e91f283a50
Gitweb: http://git.kernel.org/tip/d551aaa2f7e1387fa66093ce9914c2e91f283a50
Author: Toshi Kani <toshi.kani@xxxxxxx>
AuthorDate: Thu, 17 Sep 2015 12:24:23 -0600
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 22 Sep 2015 21:27:33 +0200
x86/mm: Fix __split_large_page() to handle large PAT bit
__split_large_page() is called from __change_page_attr() to change
the mapping attribute by splitting a given large page into smaller
pages. This function uses pte_pfn() and pte_pgprot() for PUD/PMD,
which do not handle the large PAT bit properly.
Fix __split_large_page() by using the corresponding pud/pmd pfn/
pgprot interfaces.
Also remove '#ifdef CONFIG_X86_64', which is not necessary.
Signed-off-by: Toshi Kani <toshi.kani@xxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Konrad Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Robert Elliot <elliott@xxxxxxx>
Cc: linux-mm@xxxxxxxxx
Link: http://lkml.kernel.org/r/1442514264-12475-11-git-send-email-toshi.kani@xxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/mm/pageattr.c | 31 +++++++++++++++++++------------
1 file changed, 19 insertions(+), 12 deletions(-)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 3f61271..ab9465b 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -605,7 +605,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
struct page *base)
{
pte_t *pbase = (pte_t *)page_address(base);
- unsigned long pfn, pfninc = 1;
+ unsigned long ref_pfn, pfn, pfninc = 1;
unsigned int i, level;
pte_t *tmp;
pgprot_t ref_prot;
@@ -622,26 +622,33 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
}
paravirt_alloc_pte(&init_mm, page_to_pfn(base));
- ref_prot = pte_pgprot(pte_clrhuge(*kpte));
- /* promote PAT bit to correct position */
- if (level == PG_LEVEL_2M)
+ switch (level) {
+ case PG_LEVEL_2M:
+ ref_prot = pmd_pgprot(*(pmd_t *)kpte);
+ /* clear PSE and promote PAT bit to correct position */
ref_prot = pgprot_large_2_4k(ref_prot);
+ ref_pfn = pmd_pfn(*(pmd_t *)kpte);
+ break;
-#ifdef CONFIG_X86_64
- if (level == PG_LEVEL_1G) {
+ case PG_LEVEL_1G:
+ ref_prot = pud_pgprot(*(pud_t *)kpte);
+ ref_pfn = pud_pfn(*(pud_t *)kpte);
pfninc = PMD_PAGE_SIZE >> PAGE_SHIFT;
+
/*
- * Set the PSE flags only if the PRESENT flag is set
+ * Clear the PSE flags if the PRESENT flag is not set
* otherwise pmd_present/pmd_huge will return true
* even on a non present pmd.
*/
- if (pgprot_val(ref_prot) & _PAGE_PRESENT)
- pgprot_val(ref_prot) |= _PAGE_PSE;
- else
+ if (!(pgprot_val(ref_prot) & _PAGE_PRESENT))
pgprot_val(ref_prot) &= ~_PAGE_PSE;
+ break;
+
+ default:
+ spin_unlock(&pgd_lock);
+ return 1;
}
-#endif
/*
* Set the GLOBAL flags only if the PRESENT flag is set
@@ -657,7 +664,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
/*
* Get the target pfn from the original entry:
*/
- pfn = pte_pfn(*kpte);
+ pfn = ref_pfn;
for (i = 0; i < PTRS_PER_PTE; i++, pfn += pfninc)
set_pte(&pbase[i], pfn_pte(pfn, canon_pgprot(ref_prot)));
--
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