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ArmPkg/Mmu: do not configure block translations at level 0 

Now that the AArch64 MMU code correctly identifies and handles
naturally aligned regions of more than 2 MB in size, it will happily
try to use block mappings at level 0 to map huge memory regions, such
as the single cacheable 1:1 mapping we use for Xen domU to map the
entire PA space. However, block mappings are not supported at level 0
so the resulting translation tables will be incorrect, causing
execution to fail as soon as the MMU is enabled.

So use level 1 as the minimum level at which to perform block
translations.

Reported-by: Julien Grall <julien.grall@citrix.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18568 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
Ard Biesheuvel 2015-10-02 14:48:21 +00:00 committed by abiesheuvel
parent 3b03da4058
commit 54d8d4dc97
1 changed files with 3 additions and 2 deletions
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5
ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c
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@ -295,8 +295,9 @@ GetBlockEntryListFromAddress (
BaseAddressAlignment = LowBitSet64 (RegionStart); BaseAddressAlignment = LowBitSet64 (RegionStart);
} }
// Identify the Page Level the RegionStart must belongs to // Identify the Page Level the RegionStart must belong to. Note that PageLevel
PageLevel = 3 - ((BaseAddressAlignment - 12) / 9); // should be at least 1 since block translations are not supported at level 0
PageLevel = MAX (3 - ((BaseAddressAlignment - 12) / 9), 1);
// If the required size is smaller than the current block size then we need to go to the page below. // If the required size is smaller than the current block size then we need to go to the page below.
// The PageLevel was calculated on the Base Address alignment but did not take in account the alignment // The PageLevel was calculated on the Base Address alignment but did not take in account the alignment