From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:45216 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754718AbeCRQHp (ORCPT ); Sun, 18 Mar 2018 12:07:45 -0400 Subject: Patch "x86/boot/32: Defer resyncing initial_page_table until per-cpu is set up" has been added to the 4.9-stable tree To: luto@kernel.org, alexander.levin@microsoft.com, ard.biesheuvel@linaro.org, boris.ostrovsky@oracle.com, bp@alien8.de, brgerst@gmail.com, dvlasenk@redhat.com, gregkh@linuxfoundation.org, hpa@zytor.com, jgross@suse.com, jpoimboe@redhat.com, matt@codeblueprint.co.uk, mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de, thgarnie@google.com, torvalds@linux-foundation.org Cc: , From: Date: Sun, 18 Mar 2018 17:06:00 +0100 Message-ID: <1521389160109134@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled x86/boot/32: Defer resyncing initial_page_table until per-cpu is set up to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-boot-32-defer-resyncing-initial_page_table-until-per-cpu-is-set-up.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Sun Mar 18 16:55:33 CET 2018 From: Andy Lutomirski Date: Wed, 22 Mar 2017 14:32:32 -0700 Subject: x86/boot/32: Defer resyncing initial_page_table until per-cpu is set up From: Andy Lutomirski [ Upstream commit 23b2a4ddebdd17fad265b4bb77256c2e4ec37dee ] 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: Andy Lutomirski Cc: Ard Biesheuvel Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Matt Fleming Cc: Peter Zijlstra Cc: Thomas Garnier Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/a553264a5972c6a86f9b5caac237470a0c74a720.1490218061.git.luto@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/setup.c | 15 --------------- arch/x86/kernel/setup_percpu.c | 21 +++++++++++++++++++++ 2 files changed, 21 insertions(+), 15 deletions(-) --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1200,21 +1200,6 @@ void __init setup_arch(char **cmdline_p) kasan_init(); -#ifdef CONFIG_X86_32 - /* sync back kernel address range */ - clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY, - swapper_pg_dir + KERNEL_PGD_BOUNDARY, - KERNEL_PGD_PTRS); - - /* - * sync back low identity map too. It is used for example - * in the 32-bit EFI stub. - */ - clone_pgd_range(initial_page_table, - swapper_pg_dir + KERNEL_PGD_BOUNDARY, - min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY)); -#endif - tboot_probe(); map_vsyscall(); --- a/arch/x86/kernel/setup_percpu.c +++ b/arch/x86/kernel/setup_percpu.c @@ -287,4 +287,25 @@ void __init setup_per_cpu_areas(void) /* Setup cpu initialized, callin, callout masks */ setup_cpu_local_masks(); + +#ifdef CONFIG_X86_32 + /* + * Sync back kernel address range. We want to make sure that + * all kernel mappings, including percpu mappings, are available + * in the smpboot asm. We can't reliably pick up percpu + * mappings using vmalloc_fault(), because exception dispatch + * needs percpu data. + */ + clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY, + swapper_pg_dir + KERNEL_PGD_BOUNDARY, + KERNEL_PGD_PTRS); + + /* + * sync back low identity map too. It is used for example + * in the 32-bit EFI stub. + */ + clone_pgd_range(initial_page_table, + swapper_pg_dir + KERNEL_PGD_BOUNDARY, + min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY)); +#endif } Patches currently in stable-queue which might be from luto@kernel.org are queue-4.9/perf-tools-make-perf_event__synthesize_mmap_events-scale.patch queue-4.9/x86-mm-make-mmap-map_32bit-work-correctly.patch queue-4.9/x86-boot-32-defer-resyncing-initial_page_table-until-per-cpu-is-set-up.patch