59 lines
2.3 KiB
Diff
59 lines
2.3 KiB
Diff
From: Matt Fleming <matt@codeblueprint.co.uk>
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Date: Mon, 14 Mar 2016 10:33:01 +0000
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Subject: x86/mm/pat: Fix boot crash when 1GB pages are not supported by cpu
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Origin: http://mid.gmane.org/1457951581-27353-2-git-send-email-matt@codeblueprint.co.uk
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Scott reports that with the new separate EFI page tables he's seeing
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the following error on boot, caused by setting reserved bits in the
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page table structures (fault code is PF_RSVD | PF_PROT),
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swapper/0: Corrupted page table at address 17b102020
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PGD 17b0e5063 PUD 1400000e3
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Bad pagetable: 0009 [#1] SMP
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On first inspection the PUD is using a 1GB page size (_PAGE_PSE) and
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looks fine but that's only true if support for 1GB PUD pages
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("pdpe1gb") is present in the cpu.
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Scott's Intel Celeron N2820 does not have that feature and so the
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_PAGE_PSE bit is reserved. Fix this issue by making the 1GB mapping
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code in conditional on "cpu_has_gbpages".
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This issue didn't come up in the past because the required mapping for
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the faulting address (0x17b102020) will already have been setup by the
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kernel in early boot before we got to efi_map_regions(), but we no
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longer use the standard kernel page tables during EFI calls.
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Reported-by: Scott Ashcroft <scott.ashcroft@talk21.com>
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Tested-by: Scott Ashcroft <scott.ashcroft@talk21.com>
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Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
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Cc: Ben Hutchings <ben@decadent.org.uk>
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Cc: Borislav Petkov <bp@alien8.de>
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Cc: Brian Gerst <brgerst@gmail.com>
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Cc: Denys Vlasenko <dvlasenk@redhat.com>
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Cc: "H. Peter Anvin" <hpa@zytor.com>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
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Cc: Matthew Garrett <mjg59@srcf.ucam.org>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Raphael Hertzog <hertzog@debian.org>
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Cc: Roger Shimizu <rogershimizu@gmail.com>
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Cc: Thomas Gleixner <tglx@linutronix.de>
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Cc: linux-efi@vger.kernel.org
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Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
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---
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arch/x86/mm/pageattr.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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--- a/arch/x86/mm/pageattr.c
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+++ b/arch/x86/mm/pageattr.c
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@@ -1036,7 +1036,7 @@ static int populate_pud(struct cpa_data
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/*
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* Map everything starting from the Gb boundary, possibly with 1G pages
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*/
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- while (end - start >= PUD_SIZE) {
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+ while (cpu_has_gbpages && end - start >= PUD_SIZE) {
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set_pud(pud, __pud(cpa->pfn << PAGE_SHIFT | _PAGE_PSE |
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massage_pgprot(pud_pgprot)));
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