Commit-ID: 5ad9a697fa957e61d50ef969179c18348968cd9f Gitweb: https://git.kernel.org/tip/5ad9a697fa957e61d50ef969179c18348968cd9f Author: Jiri Kosina <jkosina@xxxxxxx> AuthorDate: Fri, 5 Jan 2018 22:35:41 +0100 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Sat, 6 Jan 2018 11:43:44 +0100 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@xxxxxxx> Signed-off-by: Jiri Kosina <jkosina@xxxxxxx> Acked-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: linux-efi@xxxxxxxxxxxxxxx Link: http://lkml.kernel.org/r/nycvar.YFH.7.76.1801052215460.11852@xxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/platform/efi/efi_64.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index 39c4b35..61975b6 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(); -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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