MdePkg/BaseLib: implement SpeculationBarrier() for ARM and AArch64

Replace the dummy C implementation of SpeculationBarrier() with
implementations consisting of the recommended DSB SY + ISB sequence,
as recommended by ARM in the whitepaper "Cache Speculation Side-channels"
version 2.4, dated October 2018.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

6 files changed, 160 insertions, 32 deletions

diff --git a/MdePkg/Library/BaseLib/AArch64/SpeculationBarrier.S b/MdePkg/Library/BaseLib/AArch64/SpeculationBarrier.S
new file mode 100644
index 0000000..500bdad
--- /dev/null
+++ b/MdePkg/Library/BaseLib/AArch64/SpeculationBarrier.S
@@ -0,0 +1,39 @@
+##------------------------------------------------------------------------------

+#

+# SpeculationBarrier() for AArch64

+#

+# Copyright (c) 2019, Linaro Ltd. All rights reserved.

+#

+# 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.

+#

+##------------------------------------------------------------------------------

+

+.text

+.p2align 2

+

+GCC_ASM_EXPORT(SpeculationBarrier)

+

+

+#/**

+#  Uses as a barrier to stop speculative execution.

+#

+#  Ensures that no later instruction will execute speculatively, until all prior

+#  instructions have completed.

+#

+#**/

+#VOID

+#EFIAPI

+#SpeculationBarrier (

+#  VOID

+#  );

+#

+ASM_PFX(SpeculationBarrier):

+    dsb  sy

+    isb

+    ret

diff --git a/MdePkg/Library/BaseLib/AArch64/SpeculationBarrier.asm b/MdePkg/Library/BaseLib/AArch64/SpeculationBarrier.asm
new file mode 100644
index 0000000..0c4b915
--- /dev/null
+++ b/MdePkg/Library/BaseLib/AArch64/SpeculationBarrier.asm
@@ -0,0 +1,38 @@
+;------------------------------------------------------------------------------

+;

+; SpeculationBarrier() for AArch64

+;

+; Copyright (c) 2019, Linaro Ltd. All rights reserved.

+;

+; 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.

+;

+;------------------------------------------------------------------------------

+

+  EXPORT SpeculationBarrier

+  AREA BaseLib_LowLevel, CODE, READONLY

+

+;/**

+;  Uses as a barrier to stop speculative execution.

+;

+;  Ensures that no later instruction will execute speculatively, until all prior

+;  instructions have completed.

+;

+;**/

+;VOID

+;EFIAPI

+;SpeculationBarrier (

+;  VOID

+;  );

+;

+SpeculationBarrier

+    dsb   sy

+    isb

+    ret

+

+  END

diff --git a/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.S b/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.S
new file mode 100644
index 0000000..7857558
--- /dev/null
+++ b/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.S
@@ -0,0 +1,39 @@
+##------------------------------------------------------------------------------

+#

+# SpeculationBarrier() for AArch64

+#

+# Copyright (c) 2019, Linaro Ltd. All rights reserved.

+#

+# 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.

+#

+##------------------------------------------------------------------------------

+

+.text

+.p2align 2

+

+GCC_ASM_EXPORT(SpeculationBarrier)

+

+

+#/**

+#  Uses as a barrier to stop speculative execution.

+#

+#  Ensures that no later instruction will execute speculatively, until all prior

+#  instructions have completed.

+#

+#**/

+#VOID

+#EFIAPI

+#SpeculationBarrier (

+#  VOID

+#  );

+#

+ASM_PFX(SpeculationBarrier):

+    dsb

+    isb

+    bx   lr

diff --git a/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.asm b/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.asm
new file mode 100644
index 0000000..425cd3d
--- /dev/null
+++ b/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.asm
@@ -0,0 +1,39 @@
+;------------------------------------------------------------------------------

+;

+; SpeculationBarrier() for AArch64

+;

+; Copyright (c) 2019, Linaro Ltd. All rights reserved.

+;

+; 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.

+;

+;------------------------------------------------------------------------------

+

+    EXPORT SpeculationBarrier

+

+    AREA MemoryBarriers, CODE, READONLY

+

+;/**

+;  Uses as a barrier to stop speculative execution.

+;

+;  Ensures that no later instruction will execute speculatively, until all prior

+;  instructions have completed.

+;

+;**/

+;VOID

+;EFIAPI

+;SpeculationBarrier (

+;  VOID

+;  );

+;

+SpeculationBarrier

+    dsb

+    isb

+    bx    lr

+

+  END

diff --git a/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.c b/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.c
deleted file mode 100644
index 8a6165a..0000000
--- a/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.c
+++ /dev/null
@@ -1,30 +0,0 @@
-/** @file

-  SpeculationBarrier() function for ARM.

-

-  Copyright (C) 2018, Intel Corporation. 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.

-

-**/

-

-

-/**

-  Uses as a barrier to stop speculative execution.

-

-  Ensures that no later instruction will execute speculatively, until all prior

-  instructions have completed.

-

-**/

-VOID

-EFIAPI

-SpeculationBarrier (

-  VOID

-  )

-{

-}

diff --git a/MdePkg/Library/BaseLib/BaseLib.inf b/MdePkg/Library/BaseLib/BaseLib.inf
index d195c54..f25a067 100644
--- a/MdePkg/Library/BaseLib/BaseLib.inf
+++ b/MdePkg/Library/BaseLib/BaseLib.inf
@@ -552,7 +552,6 @@
 [Sources.ARM]

   Arm/InternalSwitchStack.c

   Arm/Unaligned.c

-  Arm/SpeculationBarrier.c

   Math64.c                   | RVCT

   Math64.c                   | MSFT

 

@@ -564,6 +563,7 @@
   Arm/CpuPause.asm           | RVCT

   Arm/CpuBreakpoint.asm      | RVCT

   Arm/MemoryFence.asm        | RVCT

+  Arm/SpeculationBarrier.S   | RVCT

 

   Arm/SwitchStack.asm        | MSFT

   Arm/SetJumpLongJump.asm    | MSFT

@@ -573,6 +573,7 @@
   Arm/CpuPause.asm           | MSFT

   Arm/CpuBreakpoint.asm      | MSFT

   Arm/MemoryFence.asm        | MSFT

+  Arm/SpeculationBarrier.asm | MSFT

 

   Arm/Math64.S                  | GCC

   Arm/SwitchStack.S             | GCC

@@ -582,11 +583,11 @@
   Arm/SetJumpLongJump.S         | GCC

   Arm/CpuBreakpoint.S           | GCC

   Arm/MemoryFence.S             | GCC

+  Arm/SpeculationBarrier.S      | GCC

 

 [Sources.AARCH64]

   Arm/InternalSwitchStack.c

   Arm/Unaligned.c

-  Arm/SpeculationBarrier.c

   Math64.c

 

   AArch64/MemoryFence.S             | GCC

@@ -596,6 +597,7 @@
   AArch64/GetInterruptsState.S      | GCC

   AArch64/SetJumpLongJump.S         | GCC

   AArch64/CpuBreakpoint.S           | GCC

+  AArch64/SpeculationBarrier.S      | GCC

 

   AArch64/MemoryFence.asm           | MSFT

   AArch64/SwitchStack.asm           | MSFT

@@ -604,6 +606,7 @@
   AArch64/GetInterruptsState.asm    | MSFT

   AArch64/SetJumpLongJump.asm       | MSFT

   AArch64/CpuBreakpoint.asm         | MSFT

+  AArch64/SpeculationBarrier.asm    | MSFT

 

 [Packages]

   MdePkg/MdePkg.dec