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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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ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibUpdate.c
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@@ -53,7 +53,7 @@ ConvertSectionToPages (
// Get section attributes and convert to page attributes
SectionDescriptor = FirstLevelTable[FirstLevelIdx];
PageDescriptor = TT_DESCRIPTOR_PAGE_TYPE_PAGE | ConvertSectionAttributesToPageAttributes (SectionDescriptor, FALSE);
PageDescriptor = TT_DESCRIPTOR_PAGE_TYPE_PAGE | ConvertSectionAttributesToPageAttributes (SectionDescriptor);
// Allocate a page table for the 4KB entries (we use up a full page even though we only need 1KB)
PageTable = (volatile ARM_PAGE_TABLE_ENTRY *)AllocatePages (1);