diff options
| author | Matt Fleming <[email protected]> | 2016-04-25 21:06:35 +0100 |
|---|---|---|
| committer | Ingo Molnar <[email protected]> | 2016-04-28 11:33:48 +0200 |
| commit | 7fc8442f2a8a77f40565b42c41e4f2d48b179a56 (patch) | |
| tree | d9316292a12f75156616c6bd1d08c9c4122c655d | |
| parent | 14c43be60166981f0b1f034ad9c59252c6f99e0d (diff) | |
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 <[email protected]>
Signed-off-by: Matt Fleming <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Sai Praneeth Prakhya <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
| -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 01be9ec3bf79..a1f0e1d0ddc2 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. |