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audk/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibConvert.c

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ArmPkg/ArmMmuLib ARM: split ArmMmuLibCore.c into core and update code Unlike the AArch64 implementation of ArmMmuLib, which combines the initial page table population code with the code that runs at later stages to manage permission attributes in the page tables, ARM uses two completely separate sets of routines for this. Since ArmMmuLib is a static library, we can prevent duplication of this code between different users, which usually only need one or the other. (Note that LTO should also achieve the same.) This also makes it easier to reason about modifying the cache maintenance handling, and replace the set/way ops with by-VA ops, since the code that performs the set/way ops only executes when the MMU is still off. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Leif Lindholm <leif@nuviainc.com>
2020-02-26 10:36:49 +01:00
/** @file
* File managing the MMU for ARMv7 architecture
*
* Copyright (c) 2011-2016, ARM Limited. All rights reserved.
*
* SPDX-License-Identifier: BSD-2-Clause-Patent
*
**/
#include <Uefi.h>
#include <Library/ArmLib.h>
#include <Chipset/ArmV7.h>
UINT32
ConvertSectionAttributesToPageAttributes (
ArmPkg/ArmMmuLib ARM: Remove half baked large page support 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>
2023-02-09 09:46:37 +01:00
IN UINT32 SectionAttributes
ArmPkg/ArmMmuLib ARM: split ArmMmuLibCore.c into core and update code Unlike the AArch64 implementation of ArmMmuLib, which combines the initial page table population code with the code that runs at later stages to manage permission attributes in the page tables, ARM uses two completely separate sets of routines for this. Since ArmMmuLib is a static library, we can prevent duplication of this code between different users, which usually only need one or the other. (Note that LTO should also achieve the same.) This also makes it easier to reason about modifying the cache maintenance handling, and replace the set/way ops with by-VA ops, since the code that performs the set/way ops only executes when the MMU is still off. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Leif Lindholm <leif@nuviainc.com>
2020-02-26 10:36:49 +01:00
)
{
UINT32 PageAttributes;
PageAttributes = 0;
ArmPkg/ArmMmuLib ARM: Remove half baked large page support 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>
2023-02-09 09:46:37 +01:00
PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_CACHE_POLICY (SectionAttributes);
ArmPkg/ArmMmuLib ARM: split ArmMmuLibCore.c into core and update code Unlike the AArch64 implementation of ArmMmuLib, which combines the initial page table population code with the code that runs at later stages to manage permission attributes in the page tables, ARM uses two completely separate sets of routines for this. Since ArmMmuLib is a static library, we can prevent duplication of this code between different users, which usually only need one or the other. (Note that LTO should also achieve the same.) This also makes it easier to reason about modifying the cache maintenance handling, and replace the set/way ops with by-VA ops, since the code that performs the set/way ops only executes when the MMU is still off. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Leif Lindholm <leif@nuviainc.com>
2020-02-26 10:36:49 +01:00
PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_AP (SectionAttributes);
ArmPkg/ArmMmuLib ARM: Isolate the access flag from AP mask Split the ARM permission fields in the short descriptors into an access flag and AP[2:1] as per the recommendation in the ARM ARM. This makes the access flag available separately, which allows us to implement EFI_MEMORY_RP memory analogous to how it will be implemented for AArch64. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
2023-02-07 17:32:19 +01:00
PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_AF (SectionAttributes);
ArmPkg/ArmMmuLib ARM: Remove half baked large page support 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>
2023-02-09 09:46:37 +01:00
PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_XN (SectionAttributes);
ArmPkg/ArmMmuLib ARM: split ArmMmuLibCore.c into core and update code Unlike the AArch64 implementation of ArmMmuLib, which combines the initial page table population code with the code that runs at later stages to manage permission attributes in the page tables, ARM uses two completely separate sets of routines for this. Since ArmMmuLib is a static library, we can prevent duplication of this code between different users, which usually only need one or the other. (Note that LTO should also achieve the same.) This also makes it easier to reason about modifying the cache maintenance handling, and replace the set/way ops with by-VA ops, since the code that performs the set/way ops only executes when the MMU is still off. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Leif Lindholm <leif@nuviainc.com>
2020-02-26 10:36:49 +01:00
PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_NG (SectionAttributes);
PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_S (SectionAttributes);
return PageAttributes;
}