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authorAndrea Arcangeli <aarcange@redhat.com>2013-04-10 15:28:25 +0200
committerIngo Molnar <mingo@kernel.org>2013-04-11 10:34:42 +0200
commitf76cfa3c2496c462b5bc01bd0c9340c2715b73ca (patch)
tree90752856da4872450c37b0e2ebf0b3ca62d341eb
parent511ba86e1d386f671084b5d0e6f110bb30b8eeb2 (diff)
x86/mm/cpa: Convert noop to functional fix
Commit: a8aed3e0752b ("x86/mm/pageattr: Prevent PSE and GLOABL leftovers to confuse pmd/pte_present and pmd_huge") introduced a valid fix but one location that didn't trigger the bug that lead to finding those (small) problems, wasn't updated using the right variable. The wrong variable was also initialized for no good reason, that may have been the source of the confusion. Remove the noop initialization accordingly. Commit a8aed3e0752b also erroneously removed one canon_pgprot pass meant to clear pmd bitflags not supported in hardware by older CPUs, that automatically gets corrected by this patch too by applying it to the right variable in the new location. Reported-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Borislav Petkov <bp@alien8.de> Cc: Andy Whitcroft <apw@canonical.com> Cc: Mel Gorman <mgorman@suse.de> Link: http://lkml.kernel.org/r/1365600505-19314-1-git-send-email-aarcange@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--arch/x86/mm/pageattr.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 091934e1d0d9..7896f7190fda 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -467,7 +467,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
* We are safe now. Check whether the new pgprot is the same:
*/
old_pte = *kpte;
- old_prot = new_prot = req_prot = pte_pgprot(old_pte);
+ old_prot = req_prot = pte_pgprot(old_pte);
pgprot_val(req_prot) &= ~pgprot_val(cpa->mask_clr);
pgprot_val(req_prot) |= pgprot_val(cpa->mask_set);
@@ -478,12 +478,12 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
* a non present pmd. The canon_pgprot will clear _PAGE_GLOBAL
* for the ancient hardware that doesn't support it.
*/
- if (pgprot_val(new_prot) & _PAGE_PRESENT)
- pgprot_val(new_prot) |= _PAGE_PSE | _PAGE_GLOBAL;
+ if (pgprot_val(req_prot) & _PAGE_PRESENT)
+ pgprot_val(req_prot) |= _PAGE_PSE | _PAGE_GLOBAL;
else
- pgprot_val(new_prot) &= ~(_PAGE_PSE | _PAGE_GLOBAL);
+ pgprot_val(req_prot) &= ~(_PAGE_PSE | _PAGE_GLOBAL);
- new_prot = canon_pgprot(new_prot);
+ req_prot = canon_pgprot(req_prot);
/*
* old_pte points to the large page base address. So we need