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Groups > linux.kernel > #1651326 > unrolled thread
| Started by | Matt Fleming <matt@codeblueprint.co.uk> |
|---|---|
| First post | 2017-05-26 13:40 +0200 |
| Last post | 2017-05-28 12:00 +0200 |
| Articles | 2 — 2 participants |
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[PATCH 3/5] x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map Matt Fleming <matt@codeblueprint.co.uk> - 2017-05-26 13:40 +0200
[tip:efi/urgent] x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map tip-bot for Sai Praneeth <tipbot@zytor.com> - 2017-05-28 12:00 +0200
| From | Matt Fleming <matt@codeblueprint.co.uk> |
|---|---|
| Date | 2017-05-26 13:40 +0200 |
| Subject | [PATCH 3/5] x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map |
| Message-ID | <tLlL3-5kc-5@gated-at.bofh.it> |
From: Sai Praneeth <sai.praneeth.prakhya@intel.com>
Booting kexec kernel with "efi=old_map" in kernel command line hits
kernel panic as shown below.
BUG: unable to handle kernel paging request at ffff88007fe78070
IP: virt_efi_set_variable.part.7+0x63/0x1b0
PGD 7ea28067
PUD 7ea2b067
PMD 7ea2d067
PTE 0
[...]
Call Trace:
virt_efi_set_variable+0x5d/0x70
efi_delete_dummy_variable+0x7a/0x80
efi_enter_virtual_mode+0x3f6/0x4a7
start_kernel+0x375/0x400
x86_64_start_reservations+0x2a/0x2c
x86_64_start_kernel+0x168/0x176
start_cpu+0x14/0x14
[ efi=old_map was never intended to work with kexec. The problem with
using efi=old_map is that the virtual addresses are assigned from the
memory region used by other kernel mappings; vmalloc() space.
Potentially there could be collisions when booting kexec if something
else is mapped at the virtual address we allocated for runtime service
regions in the initial boot - Matt Fleming ]
Since kexec was never intended to work with efi=old_map, disable
runtime services in kexec if booted with efi=old_map, so that we don't
panic.
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Tested-by: Lee Chun-Yi <jlee@suse.com>
Acked-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
---
arch/x86/platform/efi/efi.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 7e76a4d8304b..43b96f5f78ba 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -828,9 +828,11 @@ static void __init kexec_enter_virtual_mode(void)
/*
* We don't do virtual mode, since we don't do runtime services, on
- * non-native EFI
+ * non-native EFI. With efi=old_map, we don't do runtime services in
+ * kexec kernel because in the initial boot something else might
+ * have been mapped at these virtual addresses.
*/
- if (!efi_is_native()) {
+ if (!efi_is_native() || efi_enabled(EFI_OLD_MEMMAP)) {
efi_memmap_unmap();
clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
return;
--
2.12.2
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| From | tip-bot for Sai Praneeth <tipbot@zytor.com> |
|---|---|
| Date | 2017-05-28 12:00 +0200 |
| Subject | [tip:efi/urgent] x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map |
| Message-ID | <tM39o-f6-9@gated-at.bofh.it> |
| In reply to | #1651326 |
Commit-ID: 4e52797d2efefac3271abdc54439a3435abd77b9
Gitweb: http://git.kernel.org/tip/4e52797d2efefac3271abdc54439a3435abd77b9
Author: Sai Praneeth <sai.praneeth.prakhya@intel.com>
AuthorDate: Fri, 26 May 2017 12:36:49 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Sun, 28 May 2017 11:06:16 +0200
x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map
Booting kexec kernel with "efi=old_map" in kernel command line hits
kernel panic as shown below.
BUG: unable to handle kernel paging request at ffff88007fe78070
IP: virt_efi_set_variable.part.7+0x63/0x1b0
PGD 7ea28067
PUD 7ea2b067
PMD 7ea2d067
PTE 0
[...]
Call Trace:
virt_efi_set_variable()
efi_delete_dummy_variable()
efi_enter_virtual_mode()
start_kernel()
x86_64_start_reservations()
x86_64_start_kernel()
start_cpu()
[ efi=old_map was never intended to work with kexec. The problem with
using efi=old_map is that the virtual addresses are assigned from the
memory region used by other kernel mappings; vmalloc() space.
Potentially there could be collisions when booting kexec if something
else is mapped at the virtual address we allocated for runtime service
regions in the initial boot - Matt Fleming ]
Since kexec was never intended to work with efi=old_map, disable
runtime services in kexec if booted with efi=old_map, so that we don't
panic.
Tested-by: Lee Chun-Yi <jlee@suse.com>
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170526113652.21339-4-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/platform/efi/efi.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 7e76a4d..43b96f5 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -828,9 +828,11 @@ static void __init kexec_enter_virtual_mode(void)
/*
* We don't do virtual mode, since we don't do runtime services, on
- * non-native EFI
+ * non-native EFI. With efi=old_map, we don't do runtime services in
+ * kexec kernel because in the initial boot something else might
+ * have been mapped at these virtual addresses.
*/
- if (!efi_is_native()) {
+ if (!efi_is_native() || efi_enabled(EFI_OLD_MEMMAP)) {
efi_memmap_unmap();
clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
return;
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