diff options
| author | Matt Fleming <matt@codeblueprint.co.uk> | 2016-04-25 20:06:35 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-04-28 09:33:48 (GMT) |
| commit | 7fc8442f2a8a77f40565b42c41e4f2d48b179a56 (patch) | |
| tree | d9316292a12f75156616c6bd1d08c9c4122c655d /arch/x86/mm/pageattr.c | |
| parent | 14c43be60166981f0b1f034ad9c59252c6f99e0d (diff) | |
| download | linux-7fc8442f2a8a77f40565b42c41e4f2d48b179a56.tar.xz | |
x86/mm/pat: Document the (currently) EFI-only code path
It's not at all obvious that populate_pgd() and friends are only
executed when mapping EFI virtual memory regions or that no other
pageattr callers pass a ->pgd value.
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-4-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm/pageattr.c')
| -rw-r--r-- | arch/x86/mm/pageattr.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 01be9ec..a1f0e1d 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -1125,8 +1125,14 @@ static int populate_pgd(struct cpa_data *cpa, unsigned long addr) static int __cpa_process_fault(struct cpa_data *cpa, unsigned long vaddr, int primary) { - if (cpa->pgd) + if (cpa->pgd) { + /* + * Right now, we only execute this code path when mapping + * the EFI virtual memory map regions, no other users + * provide a ->pgd value. This may change in the future. + */ return populate_pgd(cpa, vaddr); + } /* * Ignore all non primary paths. |