Re: [PATCH v4 1/4] MdeModulePkg/CapsuleRuntimeDxe: clean the capsule payload to DRAM

["Zeng, Star" <star.zeng@intel.com>]

With 'EFIAPI' removed from IsPersistAcrossResetCapsuleSupported and CapsuleCacheWriteBack definitions, Reviewed-by: Star Zeng <star.zeng@intel.com>.

You can wait a little more time in case Jiewen/Mike has comments.



Thanks,
Star
-----Original Message-----
From: Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org] 
Sent: Wednesday, June 13, 2018 4:09 PM
To: edk2-devel@lists.01.org
Cc: leif.lindholm@linaro.org; Zeng, Star <star.zeng@intel.com>; Yao, Jiewen <jiewen.yao@intel.com>; Kinney, Michael D <michael.d.kinney@intel.com>; Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: [PATCH v4 1/4] MdeModulePkg/CapsuleRuntimeDxe: clean the capsule payload to DRAM

When capsule updates are staged for processing after a warm reboot, they are copied into memory with the MMU and caches enabled. When the capsule PEI gets around to coalescing the capsule, the MMU and caches may still be disabled, and so on architectures where uncached accesses are incoherent with the caches (such as ARM and AARCH64), we need to ensure that the data passed into UpdateCapsule() is written back to main memory before performing the warm reboot.

Unfortunately, on ARM, the only type of cache maintenance instructions that are suitable for this purpose operate on virtual addresses only, and given that the UpdateCapsule() prototype includes the physical address of a linked list of scatter/gather data structures that are mapped at an address that is unknown to the firmware (and may not even be mapped at all when UpdateCapsule() is invoked), we can only perform this cache maintenance at boot time. Fortunately, both Windows and Linux only invoke UpdateCapsule() before calling ExitBootServices(), so this is not a problem in practice.

In the future, we may propose adding a secure firmware service that permits performing the cache maintenance at OS runtime, in which case this code may be enhanced to call that service if available. For now, we just fail any UpdateCapsule() calls performed at OS runtime on ARM.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 MdeModulePkg/Universal/CapsuleRuntimeDxe/Arm/CapsuleReset.c    | 77 ++++++++++++++++++++
 MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleReset.c        | 51 +++++++++++++
 MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleRuntimeDxe.inf | 14 +++-
 MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleService.c      | 33 ++-------
 MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleService.h      | 73 +++++++++++++++++++
 5 files changed, 219 insertions(+), 29 deletions(-)

diff --git a/MdeModulePkg/Universal/CapsuleRuntimeDxe/Arm/CapsuleReset.c b/MdeModulePkg/Universal/CapsuleRuntimeDxe/Arm/CapsuleReset.c
new file mode 100644
index 000000000000..7e0ca06ce7d0
--- /dev/null
+++ b/MdeModulePkg/Universal/CapsuleRuntimeDxe/Arm/CapsuleReset.c
@@ -0,0 +1,77 @@
+ /** @file
+  ARM implementation of architecture specific routines related to  
+ PersistAcrossReset capsules
+
+  Copyright (c) 2018, Linaro, Ltd. All rights reserved.<BR>
+
+  This program and the accompanying materials are licensed and made 
+ available  under the terms and conditions of the BSD License which 
+ accompanies this  distribution.  The full text of the license may be 
+ found at  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,  
+ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include "CapsuleService.h"
+
+#include <Library/CacheMaintenanceLib.h>
+
+/**
+  Whether the platform supports capsules that persist across reset. 
+Note that
+  some platforms only support such capsules at boot time.
+
+  @return TRUE  if a PersistAcrossReset capsule may be passed to UpdateCapsule()
+                at this time
+          FALSE otherwise
+**/
+BOOLEAN
+EFIAPI
+IsPersistAcrossResetCapsuleSupported (
+  VOID
+  )
+{
+  //
+  // ARM requires the capsule payload to be cleaned to the point of 
+coherency
+  // (PoC), but only permits doing so using cache maintenance 
+instructions that
+  // operate on virtual addresses. Since at runtime, we don't know the 
+virtual
+  // addresses of the data structures that make up the scatter/gather 
+list, we
+  // cannot perform the maintenance, and all we can do is give up.
+  //
+  return FeaturePcdGet (PcdSupportUpdateCapsuleReset) && !EfiAtRuntime 
+(); }
+
+/**
+  Writes Back a range of data cache lines covering a set of capsules in memory.
+
+  Writes Back the data cache lines specified by ScatterGatherList.
+
+  @param  ScatterGatherList Physical address of the data structure that
+                            describes a set of capsules in memory
+
+**/
+VOID
+EFIAPI
+CapsuleCacheWriteBack (
+  IN  EFI_PHYSICAL_ADDRESS    ScatterGatherList
+  )
+{
+  EFI_CAPSULE_BLOCK_DESCRIPTOR    *Desc;
+
+  Desc = (EFI_CAPSULE_BLOCK_DESCRIPTOR *)(UINTN)ScatterGatherList;  do 
+ {
+    WriteBackDataCacheRange (Desc, sizeof *Desc);
+
+    if (Desc->Length > 0) {
+      WriteBackDataCacheRange ((VOID *)(UINTN)Desc->Union.DataBlock,
+                               Desc->Length
+                               );
+      Desc++;
+    } else if (Desc->Union.ContinuationPointer > 0) {
+      Desc = (EFI_CAPSULE_BLOCK_DESCRIPTOR *)(UINTN)Desc->Union.ContinuationPointer;
+    }
+  } while (Desc->Length > 0 || Desc->Union.ContinuationPointer > 0);
+
+  WriteBackDataCacheRange (Desc, sizeof *Desc); }
diff --git a/MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleReset.c b/MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleReset.c
new file mode 100644
index 000000000000..09616999e3f8
--- /dev/null
+++ b/MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleReset.c
@@ -0,0 +1,51 @@
+/** @file
+  Default implementation of architecture specific routines related to
+  PersistAcrossReset capsules
+
+  Copyright (c) 2018, Linaro, Ltd. All rights reserved.<BR>
+
+  This program and the accompanying materials are licensed and made 
+ available  under the terms and conditions of the BSD License which 
+ accompanies this  distribution.  The full text of the license may be 
+ found at  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,  
+ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include "CapsuleService.h"
+
+/**
+  Whether the platform supports capsules that persist across reset. 
+Note that
+  some platforms only support such capsules at boot time.
+
+  @return TRUE  if a PersistAcrossReset capsule may be passed to UpdateCapsule()
+                at this time
+          FALSE otherwise
+**/
+BOOLEAN
+EFIAPI
+IsPersistAcrossResetCapsuleSupported (
+  VOID
+  )
+{
+  return FeaturePcdGet (PcdSupportUpdateCapsuleReset); }
+
+/**
+  Writes Back a range of data cache lines covering a set of capsules in memory.
+
+  Writes Back the data cache lines specified by ScatterGatherList.
+
+  @param  ScatterGatherList Physical address of the data structure that
+                            describes a set of capsules in memory
+
+**/
+VOID
+EFIAPI
+CapsuleCacheWriteBack (
+  IN  EFI_PHYSICAL_ADDRESS    ScatterGatherList
+  )
+{
+}
diff --git a/MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleRuntimeDxe.inf b/MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleRuntimeDxe.inf
index 9ab04ce1b301..43a29ee22948 100644
--- a/MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleRuntimeDxe.inf
+++ b/MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleRuntimeDxe.inf
@@ -27,17 +27,24 @@ [Defines]
 #
 # The following information is for reference only and not required by the build tools.
 #
-#  VALID_ARCHITECTURES           = IA32 X64 IPF EBC
+#  VALID_ARCHITECTURES           = IA32 X64 IPF EBC ARM AARCH64
 #
 
 [Sources]
   CapsuleService.c
+  CapsuleService.h
 
-[Sources.Ia32, Sources.IPF, Sources.EBC, Sources.ARM, Sources.AARCH64]
+[Sources.Ia32, Sources.IPF, Sources.EBC]
   SaveLongModeContext.c
+  CapsuleReset.c
 
 [Sources.X64]
   X64/SaveLongModeContext.c
+  CapsuleReset.c
+
+[Sources.ARM, Sources.AARCH64]
+  SaveLongModeContext.c
+  Arm/CapsuleReset.c
 
 [Packages]
   MdePkg/MdePkg.dec
@@ -59,6 +66,9 @@ [LibraryClasses.X64]
   UefiLib
   BaseMemoryLib
 
+[LibraryClasses.ARM, LibraryClasses.AARCH64]
+  CacheMaintenanceLib
+
 [Guids]
   ## SOMETIMES_PRODUCES   ## Variable:L"CapsuleUpdateData" # (Process across reset capsule image) for capsule updated data
   ## SOMETIMES_PRODUCES   ## Variable:L"CapsuleLongModeBuffer" # The long mode buffer used by IA32 Capsule PEIM to call X64 CapsuleCoalesce code to handle >4GB capsule blocks
diff --git a/MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleService.c b/MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleService.c
index 216798d1617e..23fd6d59c59e 100644
--- a/MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleService.c
+++ b/MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleService.c
@@ -15,22 +15,8 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 
 **/
 
-#include <Uefi.h>
-
-#include <Protocol/Capsule.h>
-#include <Guid/CapsuleVendor.h>
-#include <Guid/FmpCapsule.h>
-
-#include <Library/DebugLib.h>
-#include <Library/PcdLib.h>
-#include <Library/CapsuleLib.h>
-#include <Library/UefiDriverEntryPoint.h> -#include <Library/UefiBootServicesTableLib.h>
-#include <Library/UefiRuntimeServicesTableLib.h>
-#include <Library/UefiRuntimeLib.h>
-#include <Library/BaseLib.h>
-#include <Library/PrintLib.h>
-#include <Library/BaseMemoryLib.h>
+#include "CapsuleService.h"
+
 //
 // Handle for the installation of Capsule Architecture Protocol.
 //
@@ -44,15 +30,6 @@ UINTN       mTimes      = 0;
 UINT32      mMaxSizePopulateCapsule     = 0;
 UINT32      mMaxSizeNonPopulateCapsule  = 0;
 
-/**
-  Create the variable to save the base address of page table and stack
-  for transferring into long mode in IA32 PEI.
-**/
-VOID
-SaveLongModeContext (
-  VOID
-  );
-
 /**
   Passes capsules to the firmware with both virtual and physical mapping. Depending on the intended
   consumption, the firmware may process the capsule immediately. If the payload should persist @@ -194,10 +171,12 @@ UpdateCapsule (
   //
   // Check if the platform supports update capsule across a system reset
   //
-  if (!FeaturePcdGet(PcdSupportUpdateCapsuleReset)) {
+  if (!IsPersistAcrossResetCapsuleSupported ()) {
     return EFI_UNSUPPORTED;
   }
 
+  CapsuleCacheWriteBack (ScatterGatherList);
+
   //
   // Construct variable name CapsuleUpdateData, CapsuleUpdateData1, CapsuleUpdateData2...
   // if user calls UpdateCapsule multiple times.
@@ -344,7 +323,7 @@ QueryCapsuleCapabilities (
     //
     //Check if the platform supports update capsule across a system reset
     //
-    if (!FeaturePcdGet(PcdSupportUpdateCapsuleReset)) {
+    if (!IsPersistAcrossResetCapsuleSupported ()) {
       return EFI_UNSUPPORTED;
     }
     *ResetType = EfiResetWarm;
diff --git a/MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleService.h b/MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleService.h
new file mode 100644
index 000000000000..85aafc144b41
--- /dev/null
+++ b/MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleService.h
@@ -0,0 +1,73 @@
+/** @file
+  Capsule Runtime Driver produces two UEFI capsule runtime services.
+  (UpdateCapsule, QueryCapsuleCapabilities)
+  It installs the Capsule Architectural Protocol defined in PI1.0a to 
+signify
+  the capsule runtime services are ready.
+
+  Copyright (c) 2006 - 2017, Intel Corporation. All rights 
+ reserved.<BR>  Copyright (c) 2018, Linaro, Ltd. All rights 
+ reserved.<BR>
+
+  This program and the accompanying materials are licensed and made 
+ available  under the terms and conditions of the BSD License which 
+ accompanies this  distribution.  The full text of the license may be 
+ found at  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,  
+ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <Uefi.h>
+
+#include <Protocol/Capsule.h>
+#include <Guid/CapsuleVendor.h>
+#include <Guid/FmpCapsule.h>
+
+#include <Library/DebugLib.h>
+#include <Library/PcdLib.h>
+#include <Library/CapsuleLib.h>
+#include <Library/UefiDriverEntryPoint.h> #include 
+<Library/UefiBootServicesTableLib.h>
+#include <Library/UefiRuntimeServicesTableLib.h>
+#include <Library/UefiRuntimeLib.h>
+#include <Library/BaseLib.h>
+#include <Library/PrintLib.h>
+#include <Library/BaseMemoryLib.h>
+
+/**
+  Create the variable to save the base address of page table and stack
+  for transferring into long mode in IA32 PEI.
+**/
+VOID
+SaveLongModeContext (
+  VOID
+  );
+
+/**
+  Whether the platform supports capsules that persist across reset. 
+Note that
+  some platforms only support such capsules at boot time.
+
+  @return TRUE  if a PersistAcrossReset capsule may be passed to UpdateCapsule()
+                at this time
+          FALSE otherwise
+**/
+BOOLEAN
+EFIAPI
+IsPersistAcrossResetCapsuleSupported (
+  VOID
+  );
+
+/**
+  Writes Back a range of data cache lines covering a set of capsules in memory.
+
+  Writes Back the data cache lines specified by ScatterGatherList.
+
+  @param  ScatterGatherList Physical address of the data structure that
+                            describes a set of capsules in memory
+
+**/
+VOID
+EFIAPI
+CapsuleCacheWriteBack (
+  IN  EFI_PHYSICAL_ADDRESS    ScatterGatherList
+  );
--
2.17.1