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62 lines
1.1 KiB
C
62 lines
1.1 KiB
C
/** @file
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Copyright (c) 2024, Mikhail Krichanov. All rights reserved.
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SPDX-License-Identifier: BSD-3-Clause
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**/
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#include <Chipset/AArch64.h>
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#include <Library/ArmLib.h>
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#include "DxeMain.h"
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VOID
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EFIAPI
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InitializeMsr (
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VOID
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)
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{
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UINTN Tcr;
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//
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// If HCR_EL2.NV is 1 and the current Exception level is EL1,
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// then EL1 read accesses to the CurrentEL register return a value of 0x2 in bits[3:2].
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// CurrentEL == 1 -> HCR_EL2.NV == 0
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//
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// If stage 1 is enabled and stage 1 Base permissions use Direct permissions,
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// then GCS access is not permitted and UnprivGCS and PrivGCS are not present.
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//
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// Disable Hierarchical permissions just in case.
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//
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Tcr = ArmGetTCR ();
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Tcr |= TCR_EL1_HPD0_MASK | TCR_EL1_HPD1_MASK;
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ArmSetTCR (Tcr);
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if (ArmHasPan ()) {
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//
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// Enable Privileged Access Never feature.
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//
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ArmSetPan ();
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} else {
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DEBUG ((DEBUG_ERROR, "Core: Failed to initialize MSRs for Ring3.\n"));
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ASSERT (FALSE);
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}
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}
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VOID
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EFIAPI
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DisableSMAP (
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VOID
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)
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{
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ArmClearPan ();
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}
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VOID
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EFIAPI
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EnableSMAP (
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VOID
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)
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{
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ArmSetPan ();
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}
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