linux_dsm_epyc7002/arch/x86/platform
Baoquan He 94133e46a0 x86/efi: Correct EFI identity mapping under 'efi=old_map' when KASLR is enabled
For EFI with the 'efi=old_map' kernel option specified, the kernel will panic
when KASLR is enabled:

  BUG: unable to handle kernel paging request at 000000007febd57e
  IP: 0x7febd57e
  PGD 1025a067
  PUD 0

  Oops: 0010 [#1] SMP
  Call Trace:
   efi_enter_virtual_mode()
   start_kernel()
   x86_64_start_reservations()
   x86_64_start_kernel()
   start_cpu()

The root cause is that the identity mapping is not built correctly
in the 'efi=old_map' case.

On 'nokaslr' kernels, PAGE_OFFSET is 0xffff880000000000 which is PGDIR_SIZE
aligned. We can borrow the PUD table from the direct mappings safely. Given a
physical address X, we have pud_index(X) == pud_index(__va(X)).

However, on KASLR kernels, PAGE_OFFSET is PUD_SIZE aligned. For a given physical
address X, pud_index(X) != pud_index(__va(X)). We can't just copy the PGD entry
from direct mapping to build identity mapping, instead we need to copy the
PUD entries one by one from the direct mapping.

Fix it.

Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Young <dyoung@redhat.com>
Cc: Frank Ramsay <frank.ramsay@hpe.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <rja@sgi.com>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170526113652.21339-5-matt@codeblueprint.co.uk
[ Fixed and reworded the changelog and code comments to be more readable. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-28 11:06:16 +02:00
..
atom arch/x86/platform/atom: Move pmc_atom to drivers/platform/x86 2017-01-26 16:21:27 -08:00
ce4100 x86/init: Remove i8042_detect() from platform ops 2016-12-19 11:34:15 +01:00
efi x86/efi: Correct EFI identity mapping under 'efi=old_map' when KASLR is enabled 2017-05-28 11:06:16 +02:00
geode x86/platform: Make platform/geode/net5501.c explicitly non-modular 2016-02-16 09:11:09 +01:00
goldfish x86/platform/goldfish: Prevent unconditional loading 2017-02-15 08:49:58 -08:00
intel x86/platform/intel/iosf_mbi: Add a PMIC bus access notifier 2017-03-02 15:46:25 +01:00
intel-mid Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-05-01 23:05:12 -07:00
intel-quark x86/platform/intel/quark: Add printf attribute to imr_self_test_result() 2016-12-20 09:37:24 +01:00
iris x86: platform: iris: drop owner assignment from platform_drivers 2014-10-20 16:20:15 +02:00
olpc x86/platform/olpc: Fix resume handler build warning 2016-11-28 07:46:03 +01:00
scx200 X86: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
sfi x86: Cleanup irq_domain ops 2015-04-24 15:36:55 +02:00
ts5500 x86/platform: Delete extraneous MODULE_* tags fromm ts5500 2016-07-16 22:41:00 +02:00
uv Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-05-01 23:05:12 -07:00
Makefile platform/x86: mlx-platform: Move module from arch/x86 2016-12-16 23:30:24 +02:00