• Andy Lutomirski's avatar
    x86/boot/32: Defer resyncing initial_page_table until per-cpu is set up · 23b2a4dd
    Andy Lutomirski authored
    The x86 smpboot trampoline expects initial_page_table to have the
    GDT mapped.  If the GDT ends up in a virtually mapped per-cpu page,
    then it won't be in the page tables at all until perc-pu areas are
    set up.  The result will be a triple fault the first time that the
    CPU attempts to access the GDT after LGDT loads the perc-pu GDT.
    
    This appears to be an old bug, but somehow the GDT fixmap rework
    is triggering it.  This seems to have something to do with the
    memory layout.
    Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
    Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
    Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
    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: Josh Poimboeuf <jpoimboe@redhat.com>
    Cc: Juergen Gross <jgross@suse.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Matt Fleming <matt@codeblueprint.co.uk>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Garnier <thgarnie@google.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: linux-efi@vger.kernel.org
    Link: http://lkml.kernel.org/r/a553264a5972c6a86f9b5caac237470a0c74a720.1490218061.git.luto@kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    23b2a4dd
setup_percpu.c 8.73 KB