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x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page table mappings

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Since EFI page tables can be treated as kernel page tables they should
be global. All the other page mapping functions in pageattr.c set the
_PAGE_GLOBAL bit and we want to avoid inconsistencies when we map a page
in the EFI code paths, for example when that page is split in
__split_large_page(), etc. It also makes it easier to validate that the
EFI region mappings have the correct attributes because there are fewer
differences compared with regular kernel mappings.

Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1455712566-16727-4-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Sai Praneeth 2016-02-17 12:35:56 +00:00 committed by Ingo Molnar
parent fe3244945c
commit 3976301506
1 changed files with 14 additions and 0 deletions
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14
arch/x86/mm/pageattr.c
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@ -909,6 +909,20 @@ static void populate_pte(struct cpa_data *cpa,
pte = pte_offset_kernel(pmd, start);
/*
* Set the GLOBAL flags only if the PRESENT flag is
* set otherwise pte_present will return true even on
* a non present pte. The canon_pgprot will clear
* _PAGE_GLOBAL for the ancient hardware that doesn't
* support it.
*/
if (pgprot_val(pgprot) & _PAGE_PRESENT)
pgprot_val(pgprot) |= _PAGE_GLOBAL;
else
pgprot_val(pgprot) &= ~_PAGE_GLOBAL;
pgprot = canon_pgprot(pgprot);
while (num_pages-- && start < end) {
set_pte(pte, pfn_pte(cpa->pfn, pgprot));