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authorMatt Fleming <matt@codeblueprint.co.uk>2016-03-14 11:33:01 +0100
committerIngo Molnar <mingo@kernel.org>2016-03-16 09:00:49 +0100
commitd367cef0a7f0c6ee86e997c0cb455b21b3c6b9ba (patch)
tree751ba107592ea31382d387730f625ebc552f53b7 /Documentation/x86
parentx86/efi: Only map kernel text for EFI mixed mode (diff)
downloadlinux-d367cef0a7f0c6ee86e997c0cb455b21b3c6b9ba.tar.xz
linux-d367cef0a7f0c6ee86e997c0cb455b21b3c6b9ba.zip
x86/mm/pat: Fix boot crash when 1GB pages are not supported by the CPU
Scott reports that with the new separate EFI page tables he's seeing the following error on boot, caused by setting reserved bits in the page table structures (fault code is PF_RSVD | PF_PROT), swapper/0: Corrupted page table at address 17b102020 PGD 17b0e5063 PUD 1400000e3 Bad pagetable: 0009 [#1] SMP On first inspection the PUD is using a 1GB page size (_PAGE_PSE) and looks fine but that's only true if support for 1GB PUD pages ("pdpe1gb") is present in the CPU. Scott's Intel Celeron N2820 does not have that feature and so the _PAGE_PSE bit is reserved. Fix this issue by making the 1GB mapping code in conditional on "cpu_has_gbpages". This issue didn't come up in the past because the required mapping for the faulting address (0x17b102020) will already have been setup by the kernel in early boot before we got to efi_map_regions(), but we no longer use the standard kernel page tables during EFI calls. Reported-by: Scott Ashcroft <scott.ashcroft@talk21.com> Tested-by: Scott Ashcroft <scott.ashcroft@talk21.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Acked-by: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Ben Hutchings <ben@decadent.org.uk> 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: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Raphael Hertzog <hertzog@debian.org> Cc: Roger Shimizu <rogershimizu@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/1457951581-27353-2-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
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