From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date: Fri, 24 Feb 2017 09:58:38 +0000 (+0000)
Subject: ArmPkg/CpuDxe: ignore attribute changes during SyncCacheConfig()
X-Git-Tag: edk2-stable201903~4528
X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=commitdiff_plain;h=3b44bb552781777d55661d3c5750bc85c9c17150

ArmPkg/CpuDxe: ignore attribute changes during SyncCacheConfig()

To prevent the initial MMU->GCD memory space map synchronization from
stripping permissions attributes [which we cannot use in the GCD memory
space map, unfortunately], implement the same approach as x86, and ignore
SetMemoryAttributes() calls during the time SyncCacheConfig() is in
progress. This is a horrible hack, but is currently the only way we can
implement strict permissions on arbitrary memory regions [as opposed to
PE/COFF text/data sections only]

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
---

diff --git a/ArmPkg/Drivers/CpuDxe/CpuDxe.c b/ArmPkg/Drivers/CpuDxe/CpuDxe.c
index 5aa5b87414..5e923d45b7 100644
--- a/ArmPkg/Drivers/CpuDxe/CpuDxe.c
+++ b/ArmPkg/Drivers/CpuDxe/CpuDxe.c
@@ -17,6 +17,7 @@
 
 #include <Guid/IdleLoopEvent.h>
 
+BOOLEAN                   mIsFlushingGCD;
 
 /**
   This function flushes the range of addresses from Start to Start+Length
@@ -261,7 +262,9 @@ CpuDxeInitialize (
   // and that calls EFI_CPU_ARCH_PROTOCOL.SetMemoryAttributes, so this code needs to go
   // after the protocol is installed
   //
+  mIsFlushingGCD = TRUE;
   SyncCacheConfig (&mCpu);
+  mIsFlushingGCD = FALSE;
 
   // If the platform is a MPCore system then install the Configuration Table describing the
   // secondary core states
diff --git a/ArmPkg/Drivers/CpuDxe/CpuDxe.h b/ArmPkg/Drivers/CpuDxe/CpuDxe.h
index a00fc30643..a46db8d257 100644
--- a/ArmPkg/Drivers/CpuDxe/CpuDxe.h
+++ b/ArmPkg/Drivers/CpuDxe/CpuDxe.h
@@ -37,6 +37,7 @@
 #include <Protocol/DebugSupportPeriodicCallback.h>
 #include <Protocol/LoadedImage.h>
 
+extern BOOLEAN mIsFlushingGCD;
 
 /**
   This function registers and enables the handler specified by InterruptHandler for a processor
diff --git a/ArmPkg/Drivers/CpuDxe/CpuMmuCommon.c b/ArmPkg/Drivers/CpuDxe/CpuMmuCommon.c
index ebe593d1c3..0f36a05840 100644
--- a/ArmPkg/Drivers/CpuDxe/CpuMmuCommon.c
+++ b/ArmPkg/Drivers/CpuDxe/CpuMmuCommon.c
@@ -188,6 +188,10 @@ CpuSetMemoryAttributes (
   UINTN       RegionLength;
   UINTN       RegionArmAttributes;
 
+  if (mIsFlushingGCD) {
+    return EFI_SUCCESS;
+  }
+
   if ((BaseAddress & (SIZE_4KB - 1)) != 0) {
     // Minimum granularity is SIZE_4KB (4KB on ARM)
     DEBUG ((EFI_D_PAGE, "CpuSetMemoryAttributes(%lx, %lx, %lx): Minimum ganularity is SIZE_4KB\n", BaseAddress, Length, EfiAttributes));