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ArmPkg/ArmMmuLib ARM: Remove half baked large page support

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Large page support on 32-bit ARM is essentially a glorified contiguous
bit where 16 consecutive entries describing a contiguous range with the
same attributes are presented in a way that permits the TLB to cache its
translation with a single entry.

This was never wired up completely, and does not add a lot of value in
EFI, where the page granularity is 4k and we expect to be able to set RO
and XP permissions on individual pages.

Given that large page support complicates the handling of the XN bit at
the page level (which is in a different place depending on whether the
page is small or large), let's just rip it out.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
This commit is contained in:
Ard Biesheuvel
2023-02-09 09:46:37 +01:00
committed by mergify[bot]
parent 997c6967b0
commit 82ccaaf8e7
5 changed files with 19 additions and 38 deletions
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8
ArmPkg/Drivers/CpuDxe/Arm/Mmu.c
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@@ -165,7 +165,7 @@ SyncCacheConfigPage (
// Convert SectionAttributes into PageAttributes
NextPageAttributes =
TT_DESCRIPTOR_CONVERT_TO_PAGE_CACHE_POLICY (*NextSectionAttributes, 0) |
TT_DESCRIPTOR_CONVERT_TO_PAGE_CACHE_POLICY (*NextSectionAttributes) |
TT_DESCRIPTOR_CONVERT_TO_PAGE_AP (*NextSectionAttributes);
// obtain page table base
@@ -212,7 +212,7 @@ SyncCacheConfigPage (
// Convert back PageAttributes into SectionAttributes
*NextSectionAttributes =
TT_DESCRIPTOR_CONVERT_TO_SECTION_CACHE_POLICY (NextPageAttributes, 0) |
TT_DESCRIPTOR_CONVERT_TO_SECTION_CACHE_POLICY (NextPageAttributes) |
TT_DESCRIPTOR_CONVERT_TO_SECTION_AP (NextPageAttributes);
return EFI_SUCCESS;
@@ -399,7 +399,7 @@ GetMemoryRegionPage (
UINT32 PageDescriptor;
// Convert the section attributes into page attributes
PageAttributes = ConvertSectionAttributesToPageAttributes (*RegionAttributes, 0);
PageAttributes = ConvertSectionAttributesToPageAttributes (*RegionAttributes);
// Calculate index into first level translation table for start of modification
TableIndex = ((*BaseAddress) & TT_DESCRIPTOR_PAGE_INDEX_MASK) >> TT_DESCRIPTOR_PAGE_BASE_SHIFT;
@@ -479,7 +479,7 @@ GetMemoryRegion (
ASSERT (PageTableIndex < TRANSLATION_TABLE_PAGE_COUNT);
PageAttributes = PageTable[PageTableIndex] & TT_DESCRIPTOR_PAGE_ATTRIBUTE_MASK;
*RegionAttributes = TT_DESCRIPTOR_CONVERT_TO_SECTION_CACHE_POLICY (PageAttributes, 0) |
*RegionAttributes = TT_DESCRIPTOR_CONVERT_TO_SECTION_CACHE_POLICY (PageAttributes) |
TT_DESCRIPTOR_CONVERT_TO_SECTION_AP (PageAttributes);
}