From 54d7a130ec482a93fc64e927862b79bb16dc31e5 Mon Sep 17 00:00:00 2001
From: Mikhail Krichanov <mikhailkrichanov@gmail.com>
Date: Thu, 4 Jul 2024 17:21:51 +0300
Subject: [PATCH] Ring3: Added PAN support for ARM.
---
ArmPkg/Include/Chipset/ArmV7.h | 3 ++
ArmPkg/Include/Library/ArmLib.h | 24 +++++------
ArmPkg/Library/ArmLib/Arm/ArmLibSupportV7.S | 4 ++
ArmPkg/Library/ArmLib/Arm/ArmV7Lib.c | 15 +++++++
ArmPkg/Library/ArmLib/Arm/ArmV7Lib.h | 10 +++++
.../Arm/DefaultExceptionHandler.c | 5 ++-
.../Core/Dxe/SysCall/ARM/CoreBootServices.S | 42 ++++++++++---------
.../Core/Dxe/SysCall/ARM/InitializeMsr.c | 42 ++++++++++++++++++-
8 files changed, 112 insertions(+), 33 deletions(-)
diff --git a/ArmPkg/Include/Chipset/ArmV7.h b/ArmPkg/Include/Chipset/ArmV7.h
index 94620c087d..a8db422b93 100644
--- a/ArmPkg/Include/Chipset/ArmV7.h
+++ b/ArmPkg/Include/Chipset/ArmV7.h
@@ -20,6 +20,9 @@
#define ARM_PFR1_TIMER (0xFUL << 16)
#define ARM_PFR1_GIC (0xFUL << 28)
+// ID_MMFR3 - ARM Memory Model Feature Register 3 definitions
+#define ARM_MMFR3_PAN (0xFUL << 16)
+
// Domain Access Control Register
#define DOMAIN_ACCESS_CONTROL_MASK(a) (3UL << (2 * (a)))
#define DOMAIN_ACCESS_CONTROL_NONE(a) (0UL << (2 * (a)))
diff --git a/ArmPkg/Include/Library/ArmLib.h b/ArmPkg/Include/Library/ArmLib.h
index e13f36ce53..fb9a8646f7 100644
--- a/ArmPkg/Include/Library/ArmLib.h
+++ b/ArmPkg/Include/Library/ArmLib.h
@@ -764,6 +764,18 @@ ArmHasCcidx (
VOID
);
+/**
+ Checks whether the CPU implements the Privileged Access Never.
+
+ @retval TRUE FEAT_PAN is implemented.
+ @retval FALSE FEAT_PAN is not mplemented.
+**/
+BOOLEAN
+EFIAPI
+ArmHasPan (
+ VOID
+ );
+
#ifdef MDE_CPU_AARCH64
///
/// AArch64-only ID Register Helper functions
@@ -781,18 +793,6 @@ ArmHasVhe (
VOID
);
-/**
- Checks whether the CPU implements the Privileged Access Never.
-
- @retval TRUE FEAT_PAN is implemented.
- @retval FALSE FEAT_PAN is not mplemented.
-**/
-BOOLEAN
-EFIAPI
-ArmHasPan (
- VOID
- );
-
/**
Checks whether the CPU implements the Trace Buffer Extension.
diff --git a/ArmPkg/Library/ArmLib/Arm/ArmLibSupportV7.S b/ArmPkg/Library/ArmLib/Arm/ArmLibSupportV7.S
index d843f91dfc..d1558c3cec 100644
--- a/ArmPkg/Library/ArmLib/Arm/ArmLibSupportV7.S
+++ b/ArmPkg/Library/ArmLib/Arm/ArmLibSupportV7.S
@@ -64,6 +64,10 @@ ASM_FUNC(ArmReadIdMmfr4)
mrc p15,0,r0,c0,c2,6 @ Read ID_MMFR4 Register
bx lr
+ASM_FUNC(ArmReadIdMmfr3)
+ mrc p15,0,r0,c0,c1,7 @ Read ID_MMFR3 Register
+ bx lr
+
// UINTN
// ReadCCSIDR (
// IN UINT32 CSSELR
diff --git a/ArmPkg/Library/ArmLib/Arm/ArmV7Lib.c b/ArmPkg/Library/ArmLib/Arm/ArmV7Lib.c
index 521d5be0de..2775f24fbd 100644
--- a/ArmPkg/Library/ArmLib/Arm/ArmV7Lib.c
+++ b/ArmPkg/Library/ArmLib/Arm/ArmV7Lib.c
@@ -119,3 +119,18 @@ ArmHasCcidx (
Mmfr4 = ArmReadIdMmfr4 ();
return (((Mmfr4 >> 24) & 0xF) == 1) ? TRUE : FALSE;
}
+
+/**
+ Checks whether the CPU implements the Privileged Access Never.
+
+ @retval TRUE FEAT_PAN is implemented.
+ @retval FALSE FEAT_PAN is not mplemented.
+**/
+BOOLEAN
+EFIAPI
+ArmHasPan (
+ VOID
+ )
+{
+ return ((ArmReadIdMmfr3 () & ARM_MMFR3_PAN) != 0);
+}
diff --git a/ArmPkg/Library/ArmLib/Arm/ArmV7Lib.h b/ArmPkg/Library/ArmLib/Arm/ArmV7Lib.h
index 404ff92c4e..9e033cfd3d 100644
--- a/ArmPkg/Library/ArmLib/Arm/ArmV7Lib.h
+++ b/ArmPkg/Library/ArmLib/Arm/ArmV7Lib.h
@@ -60,6 +60,16 @@ ArmReadIdMmfr4 (
VOID
);
+/** Reads the ID_MMFR3 register.
+
+ @return The contents of the ID_MMFR3 register.
+**/
+UINT32
+EFIAPI
+ArmReadIdMmfr3 (
+ VOID
+ );
+
UINTN
EFIAPI
ArmReadIdPfr1 (
diff --git a/ArmPkg/Library/DefaultExceptionHandlerLib/Arm/DefaultExceptionHandler.c b/ArmPkg/Library/DefaultExceptionHandlerLib/Arm/DefaultExceptionHandler.c
index 653035daa8..006db6d517 100644
--- a/ArmPkg/Library/DefaultExceptionHandlerLib/Arm/DefaultExceptionHandler.c
+++ b/ArmPkg/Library/DefaultExceptionHandlerLib/Arm/DefaultExceptionHandler.c
@@ -197,7 +197,8 @@ STATIC CHAR8 *gExceptionTypeString[] = {
**/
-VOID
+EFI_STATUS
+EFIAPI
DefaultExceptionHandler (
IN EFI_EXCEPTION_TYPE ExceptionType,
IN OUT EFI_SYSTEM_CONTEXT SystemContext
@@ -316,4 +317,6 @@ DefaultExceptionHandler (
// If some one is stepping past the exception handler adjust the PC to point to the next instruction
SystemContext.SystemContextArm->PC += PcAdjust;
+
+ return EFI_SUCCESS;
}
diff --git a/MdeModulePkg/Core/Dxe/SysCall/ARM/CoreBootServices.S b/MdeModulePkg/Core/Dxe/SysCall/ARM/CoreBootServices.S
index 406a7f66cf..90b000fc0d 100644
--- a/MdeModulePkg/Core/Dxe/SysCall/ARM/CoreBootServices.S
+++ b/MdeModulePkg/Core/Dxe/SysCall/ARM/CoreBootServices.S
@@ -7,25 +7,7 @@
#include <AsmMacroIoLib.h>
-//------------------------------------------------------------------------------
-// VOID
-// EFIAPI
-// DisableSMAP (
-// VOID
-// );
-//------------------------------------------------------------------------------
-ASM_FUNC(DisableSMAP)
- bx LR
-
-//------------------------------------------------------------------------------
-// VOID
-// EFIAPI
-// EnableSMAP (
-// VOID
-// );
-//------------------------------------------------------------------------------
-ASM_FUNC(EnableSMAP)
- bx LR
+.arch armv8.1a
//------------------------------------------------------------------------------
// EFI_STATUS
@@ -71,3 +53,25 @@ ASM_FUNC(CoreBootServices)
//------------------------------------------------------------------------------
ASM_FUNC(CallRing3)
bx LR
+
+//------------------------------------------------------------------------------
+// VOID
+// EFIAPI
+// ArmSetPan (
+// VOID
+// );
+//------------------------------------------------------------------------------
+ASM_FUNC(ArmSetPan)
+ setpan #1
+ bx LR
+
+//------------------------------------------------------------------------------
+// VOID
+// EFIAPI
+// ArmClearPan (
+// VOID
+// );
+//------------------------------------------------------------------------------
+ASM_FUNC(ArmClearPan)
+ setpan #0
+ bx LR
diff --git a/MdeModulePkg/Core/Dxe/SysCall/ARM/InitializeMsr.c b/MdeModulePkg/Core/Dxe/SysCall/ARM/InitializeMsr.c
index fb7c2c35b6..02845996d9 100644
--- a/MdeModulePkg/Core/Dxe/SysCall/ARM/InitializeMsr.c
+++ b/MdeModulePkg/Core/Dxe/SysCall/ARM/InitializeMsr.c
@@ -5,8 +5,22 @@
**/
+#include <Library/ArmLib.h>
+
#include "DxeMain.h"
+VOID
+EFIAPI
+ArmSetPan (
+ VOID
+ );
+
+VOID
+EFIAPI
+ArmClearPan (
+ VOID
+ );
+
VOID
EFIAPI
InitializeMsr (
@@ -14,5 +28,31 @@ InitializeMsr (
IN UINTN NumberOfEntries
)
{
-
+ if (ArmHasPan ()) {
+ //
+ // Enable Privileged Access Never feature.
+ //
+ ArmSetPan ();
+ } else {
+ DEBUG ((DEBUG_ERROR, "Core: Failed to initialize MSRs for Ring3.\n"));
+ ASSERT (FALSE);
+ }
+}
+
+VOID
+EFIAPI
+DisableSMAP (
+ VOID
+ )
+{
+ ArmClearPan ();
+}
+
+VOID
+EFIAPI
+EnableSMAP (
+ VOID
+ )
+{
+ ArmSetPan ();
}