diff mbox

[edk2,v4,5/5] ArmVirtualizationPkg: Xen: shuffle init order to deal with incoherency

Message ID 1428578932-24079-6-git-send-email-ard.biesheuvel@linaro.org
State New
Headers show

Commit Message

Ard Biesheuvel April 9, 2015, 11:28 a.m. UTC 
In order to prevent memory corruption issues caused by the fact that,
under virtualization, the guest is incoherent with the hypervisor's view
of memory until it enables its caches and MMU, this patch reshuffles the
init sequence so that the Xen shared memory regions are not touched
before the caches and MMU are enabled.

In addition, the loaded image itself is invalidated by virtual address,
to ensure that any runtime changes (such as the applied relocations) will
not suddenly become invisible once we turn the caches on.

Contributed-under: TianoCore Contribution Agreement 1.0
Reviewed-By: Olivier Martin <Olivier.Martin@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 ArmPlatformPkg/ArmVirtualizationPkg/PrePi/ArmVirtPrePiUniCoreRelocatable.inf |  1 +
 ArmPlatformPkg/ArmVirtualizationPkg/PrePi/PrePi.c                            | 20 ++++++++++++++------
 2 files changed, 15 insertions(+), 6 deletions(-)
diff mbox

Patch

diff --git a/ArmPlatformPkg/ArmVirtualizationPkg/PrePi/ArmVirtPrePiUniCoreRelocatable.inf b/ArmPlatformPkg/ArmVirtualizationPkg/PrePi/ArmVirtPrePiUniCoreRelocatable.inf
index 86cf870b79ac..16023382a679 100755
--- a/ArmPlatformPkg/ArmVirtualizationPkg/PrePi/ArmVirtPrePiUniCoreRelocatable.inf
+++ b/ArmPlatformPkg/ArmVirtualizationPkg/PrePi/ArmVirtPrePiUniCoreRelocatable.inf
@@ -55,6 +55,7 @@ 
   PrePiHobListPointerLib
   PlatformPeiLib
   MemoryInitPeiLib
+  CacheMaintenanceLib
 
 [Ppis]
   gArmMpCoreInfoPpiGuid
diff --git a/ArmPlatformPkg/ArmVirtualizationPkg/PrePi/PrePi.c b/ArmPlatformPkg/ArmVirtualizationPkg/PrePi/PrePi.c
index 0772805890f2..f9ad37427217 100755
--- a/ArmPlatformPkg/ArmVirtualizationPkg/PrePi/PrePi.c
+++ b/ArmPlatformPkg/ArmVirtualizationPkg/PrePi/PrePi.c
@@ -20,6 +20,7 @@ 
 #include <Library/PrePiHobListPointerLib.h>
 #include <Library/TimerLib.h>
 #include <Library/PerformanceLib.h>
+#include <Library/CacheMaintenanceLib.h>
 
 #include <Ppi/GuidedSectionExtraction.h>
 #include <Ppi/ArmMpCoreInfo.h>
@@ -102,12 +103,6 @@  PrePiMain (
   // Initialize the architecture specific bits
   ArchInitialize ();
 
-  // Initialize the Serial Port
-  SerialPortInitialize ();
-  CharCount = AsciiSPrint (Buffer,sizeof (Buffer),"UEFI firmware (version %s built at %a on %a)\n\r",
-    (CHAR16*)PcdGetPtr(PcdFirmwareVersionString), __TIME__, __DATE__);
-  SerialPortWrite ((UINT8 *) Buffer, CharCount);
-
   // Declare the PI/UEFI memory region
   HobList = HobConstructor (
     (VOID*)UefiMemoryBase,
@@ -117,10 +112,23 @@  PrePiMain (
     );
   PrePeiSetHobList (HobList);
 
+  //
+  // Ensure that the loaded image is invalidated in the caches, so that any
+  // modifications we made with the caches and MMU off (such as the applied
+  // relocations) don't become invisible once we turn them on.
+  //
+  InvalidateDataCacheRange((VOID *)(UINTN)PcdGet64 (PcdFdBaseAddress), PcdGet32 (PcdFdSize));
+
   // Initialize MMU and Memory HOBs (Resource Descriptor HOBs)
   Status = MemoryPeim (UefiMemoryBase, FixedPcdGet32 (PcdSystemMemoryUefiRegionSize));
   ASSERT_EFI_ERROR (Status);
 
+  // Initialize the Serial Port
+  SerialPortInitialize ();
+  CharCount = AsciiSPrint (Buffer,sizeof (Buffer),"UEFI firmware (version %s built at %a on %a)\n\r",
+    (CHAR16*)PcdGetPtr(PcdFirmwareVersionString), __TIME__, __DATE__);
+  SerialPortWrite ((UINT8 *) Buffer, CharCount);
+
   // Create the Stacks HOB (reserve the memory for all stacks)
   StacksSize = PcdGet32 (PcdCPUCorePrimaryStackSize);
   BuildStackHob (StacksBase, StacksSize);