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| author | Sai Praneeth <sai.praneeth.prakhya@intel.com> | 2015-10-17 01:20:27 +0200 |
|---|---|---|
| committer | Matt Fleming <matt@codeblueprint.co.uk> | 2015-10-25 11:22:25 +0100 |
| commit | 2c66e24d75d424919c42288b418d2e593fa818b1 (patch) | |
| tree | 97d12d3cdb2de8b7d17d0433e1d899cec965b271 /arch/x86/mm/pageattr.c | |
| parent | efi: Add "efi_fake_mem" boot option (diff) | |
| download | linux-2c66e24d75d424919c42288b418d2e593fa818b1.tar.xz linux-2c66e24d75d424919c42288b418d2e593fa818b1.zip | |
x86/efi: Fix kernel panic when CONFIG_DEBUG_VIRTUAL is enabled
When CONFIG_DEBUG_VIRTUAL is enabled, all accesses to __pa(address) are
monitored to see whether address falls in direct mapping or kernel text
mapping (see Documentation/x86/x86_64/mm.txt for details), if it does
not, the kernel panics. During 1:1 mapping of EFI runtime services we access
virtual addresses which are == physical addresses, thus the 1:1 mapping
and these addresses do not fall in either of the above two regions and
hence when passed as arguments to __pa() kernel panics as reported by
Dave Hansen here https://lkml.kernel.org/r/5462999A.7090706@intel.com.
So, before calling __pa() virtual addresses should be validated which
results in skipping call to split_page_count() and that should be fine
because it is used to keep track of everything *but* 1:1 mappings.
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Reported-by: Dave Hansen <dave.hansen@intel.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Glenn P Williamson <glenn.p.williamson@intel.com>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Diffstat (limited to 'arch/x86/mm/pageattr.c')
| -rw-r--r-- | arch/x86/mm/pageattr.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 727158cb3b3c..9abe0c9b1098 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -648,9 +648,12 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, for (i = 0; i < PTRS_PER_PTE; i++, pfn += pfninc) set_pte(&pbase[i], pfn_pte(pfn, canon_pgprot(ref_prot))); - if (pfn_range_is_mapped(PFN_DOWN(__pa(address)), - PFN_DOWN(__pa(address)) + 1)) - split_page_count(level); + if (virt_addr_valid(address)) { + unsigned long pfn = PFN_DOWN(__pa(address)); + + if (pfn_range_is_mapped(pfn, pfn + 1)) + split_page_count(level); + } /* * Install the new, split up pagetable. |