31b1638468
In order to reduce the likelihood that we will need to rely on the logic that disables and re-enables the MMU for updating a page table entry safely, expose the XIP version of the helper routine via a HOB and use it instead of the one that is copied into DRAM. Since the XIP copy is already clean to the PoC, and will never end up getting unmapped during a block entry split, we can use it safely without any cache maintenance, and without running the risk of pulling the rug from under our feet when updating an entry by going through an invalid mapping. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Leif Lindholm <quic_llindhol@quicinc.com>
76 lines
2.4 KiB
C
76 lines
2.4 KiB
C
/** @file
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Copyright (c) 2016, Linaro Limited. All rights reserved.
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Copyright (c) 2021, Arm Limited. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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*/
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#include <Base.h>
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#include <Library/ArmLib.h>
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#include <Library/ArmMmuLib.h>
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#include <Library/CacheMaintenanceLib.h>
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#include <Library/DebugLib.h>
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#include <Library/HobLib.h>
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EFI_STATUS
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EFIAPI
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ArmMmuPeiLibConstructor (
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IN EFI_PEI_FILE_HANDLE FileHandle,
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IN CONST EFI_PEI_SERVICES **PeiServices
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)
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{
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extern UINT32 ArmReplaceLiveTranslationEntrySize;
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VOID *ArmReplaceLiveTranslationEntryFunc;
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VOID *Hob;
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EFI_FV_FILE_INFO FileInfo;
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EFI_STATUS Status;
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ASSERT (FileHandle != NULL);
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Status = (*PeiServices)->FfsGetFileInfo (FileHandle, &FileInfo);
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ASSERT_EFI_ERROR (Status);
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//
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// Some platforms do not cope very well with cache maintenance being
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// performed on regions backed by NOR flash. Since the firmware image
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// can be assumed to be clean to the PoC when running XIP, even when PEI
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// is executing from DRAM, we only need to perform the cache maintenance
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// when not executing in place.
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//
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if (((UINTN)FileInfo.Buffer <= (UINTN)ArmReplaceLiveTranslationEntry) &&
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((UINTN)FileInfo.Buffer + FileInfo.BufferSize >=
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(UINTN)ArmReplaceLiveTranslationEntry + ArmReplaceLiveTranslationEntrySize))
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{
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DEBUG ((DEBUG_INFO, "ArmMmuLib: skipping cache maintenance on XIP PEIM\n"));
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//
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// Expose the XIP version of the ArmReplaceLiveTranslationEntry() routine
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// via a HOB so we can fall back to it later when we need to split block
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// mappings in a way that adheres to break-before-make requirements.
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//
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ArmReplaceLiveTranslationEntryFunc = ArmReplaceLiveTranslationEntry;
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Hob = BuildGuidDataHob (
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&gArmMmuReplaceLiveTranslationEntryFuncGuid,
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&ArmReplaceLiveTranslationEntryFunc,
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sizeof ArmReplaceLiveTranslationEntryFunc
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);
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ASSERT (Hob != NULL);
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} else {
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DEBUG ((DEBUG_INFO, "ArmMmuLib: performing cache maintenance on shadowed PEIM\n"));
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//
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// The ArmReplaceLiveTranslationEntry () helper function may be invoked
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// with the MMU off so we have to ensure that it gets cleaned to the PoC
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//
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WriteBackDataCacheRange (
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(VOID *)(UINTN)ArmReplaceLiveTranslationEntry,
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ArmReplaceLiveTranslationEntrySize
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);
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}
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return RETURN_SUCCESS;
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}
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