* [PATCH 4.9 052/241] x86/boot/32: Defer resyncing initial_page_table until per-cpu is set up
[not found] <20180319180751.172155436@linuxfoundation.org>
@ 2018-03-19 18:05 ` Greg Kroah-Hartman
2018-03-19 18:07 ` [PATCH 4.9 211/241] x86/boot/32: Fix UP boot on Quark and possibly other platforms Greg Kroah-Hartman
1 sibling, 0 replies; 2+ messages in thread
From: Greg Kroah-Hartman @ 2018-03-19 18:05 UTC (permalink / raw)
To: linux-kernel
Cc: Greg Kroah-Hartman, stable, Andy Lutomirski, Ard Biesheuvel,
Boris Ostrovsky, Borislav Petkov, Brian Gerst, Denys Vlasenko,
H. Peter Anvin, Josh Poimboeuf, Juergen Gross, Linus Torvalds,
Matt Fleming, Peter Zijlstra, Thomas Garnier, Thomas Gleixner,
linux-efi, Ingo Molnar, Sasha Levin
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Andy Lutomirski <luto@kernel.org>
[ 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 <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.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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
}
^ permalink raw reply [flat|nested] 2+ messages in thread* [PATCH 4.9 211/241] x86/boot/32: Fix UP boot on Quark and possibly other platforms
[not found] <20180319180751.172155436@linuxfoundation.org>
2018-03-19 18:05 ` [PATCH 4.9 052/241] x86/boot/32: Defer resyncing initial_page_table until per-cpu is set up Greg Kroah-Hartman
@ 2018-03-19 18:07 ` Greg Kroah-Hartman
1 sibling, 0 replies; 2+ messages in thread
From: Greg Kroah-Hartman @ 2018-03-19 18:07 UTC (permalink / raw)
To: linux-kernel
Cc: Greg Kroah-Hartman, stable, Jan Kiszka, Andy Lutomirski,
Andy Shevchenko, Ard Biesheuvel, Boris Ostrovsky, Borislav Petkov,
Brian Gerst, Denys Vlasenko, Josh Poimboeuf, Juergen Gross,
Linus Torvalds, Matt Fleming, Peter Zijlstra, Thomas Garnier,
Thomas Gleixner, linux-efi, Ingo Molnar
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Andy Lutomirski <luto@kernel.org>
commit d2b6dc61a8dd3c429609b993778cb54e75a5c5f0 upstream.
This partially reverts commit:
23b2a4ddebdd17f ("x86/boot/32: Defer resyncing initial_page_table until per-cpu is set up")
That commit had one definite bug and one potential bug. The
definite bug is that setup_per_cpu_areas() uses a differnet generic
implementation on UP kernels, so initial_page_table never got
resynced. This was fine for access to percpu data (it's in the
identity map on UP), but it breaks other users of
initial_page_table. The potential bug is that helpers like
efi_init() would be called before the tables were synced.
Avoid both problems by just syncing the page tables in setup_arch()
*and* setup_per_cpu_areas().
Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
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: 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
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/setup.c | 15 +++++++++++++++
arch/x86/kernel/setup_percpu.c | 10 +++++-----
2 files changed, 20 insertions(+), 5 deletions(-)
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1200,6 +1200,21 @@ 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
@@ -290,11 +290,11 @@ void __init setup_per_cpu_areas(void)
#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.
+ * Sync back kernel address range again. We already did this in
+ * setup_arch(), but percpu data also needs to be 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,
^ permalink raw reply [flat|nested] 2+ messages in thread