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| author |   Jiri Kosina <jkosina@suse.cz> | 2018-01-05 22:35:41 +0100 |
|---|---|---|
| committer |   Thomas Gleixner <tglx@linutronix.de> | 2018-01-06 21:38:16 +0100 |
| commit | de53c3786a3ce162a1c815d0c04c766c23ec9c0a (patch) | |
| tree | 467308e283d86cfa5fe99e0dc7fc6654675bb323 /arch/x86 | |
| parent | x86/pti: Rename BUG_CPU_INSECURE to BUG_CPU_MELTDOWN (diff) | |
| download | linux-dev-de53c3786a3ce162a1c815d0c04c766c23ec9c0a.tar.xz linux-dev-de53c3786a3ce162a1c815d0c04c766c23ec9c0a.zip | |
x86/pti: Unbreak EFI old_memmap
EFI_OLD_MEMMAP's efi_call_phys_prolog() calls set_pgd() with swapper PGD that
has PAGE_USER set, which makes PTI set NX on it, and therefore EFI can't
execute it's code.
Fix that by forcefully clearing _PAGE_NX from the PGD (this can't be done
by the pgprot API).
_PAGE_NX will be automatically reintroduced in efi_call_phys_epilog(), as
_set_pgd() will again notice that this is _PAGE_USER, and set _PAGE_NX on
it.
Tested-by: Dimitri Sivanich <sivanich@hpe.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/nycvar.YFH.7.76.1801052215460.11852@cbobk.fhfr.pm
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/platform/efi/efi_64.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index 39c4b35ac7a4..61975b6bcb1a 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -134,7 +134,9 @@ pgd_t * __init efi_call_phys_prolog(void) pud[j] = *pud_offset(p4d_k, vaddr); } } + pgd_offset_k(pgd * PGDIR_SIZE)->pgd &= ~_PAGE_NX; } + out: __flush_tlb_all(); |