MdePkg/BaseIoLibIntrinsic: make BaseIoLibIntrinsic safe for ArmVirt/KVM

KVM on ARM refuses to decode load/store instructions used to perform
I/O to emulated devices, and instead relies on the exception syndrome
information to describe the operand register, access size, etc.
This is only possible for instructions that have a single input/output
register (as opposed to ones that increment the offset register, or
load/store pair instructions, etc). Otherwise, QEMU crashes with the
following error

  error: kvm run failed Function not implemented
  R00=01010101 R01=00000008 R02=00000048 R03=08000820
  R04=00000120 R05=7faaa0e0 R06=7faaa0dc R07=7faaa0e8
  R08=7faaa0ec R09=7faaa088 R10=000000ff R11=00000080
  R12=ff000000 R13=7fccfe08 R14=7faa835f R15=7faa887c
  PSR=800001f3 N--- T svc32
  QEMU: Terminated

and KVM produces a warning such as the following in the kernel log

  kvm [17646]: load/store instruction decoding not implemented

The IoLib implementation provided by MdePkg/Library/BaseIoLibIntrinsic
is based on C code, and when LTO is in effect, the MMIO accesses could
be merged with, e.g., manipulations of the loop counter, producing
opcodes that KVM does not support for emulated MMIO.

So let's add a special ArmVirt flavor of this library that implements
that actual load/store operations in assembler, ensuring that the
instructions involved can be emulated by KVM.

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

2 files changed, 294 insertions, 0 deletions

diff --git a/MdePkg/Library/BaseIoLibIntrinsic/Arm/ArmVirtMmio.S b/MdePkg/Library/BaseIoLibIntrinsic/Arm/ArmVirtMmio.S
new file mode 100644
index 0000000000..1e91e87fb8
--- /dev/null
+++ b/MdePkg/Library/BaseIoLibIntrinsic/Arm/ArmVirtMmio.S
@@ -0,0 +1,145 @@
+#
+#  Copyright (c) 2014-2018, Linaro Limited. 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.
+#
+#
+
+GCC_ASM_EXPORT(MmioRead8Internal)
+GCC_ASM_EXPORT(MmioWrite8Internal)
+GCC_ASM_EXPORT(MmioRead16Internal)
+GCC_ASM_EXPORT(MmioWrite16Internal)
+GCC_ASM_EXPORT(MmioRead32Internal)
+GCC_ASM_EXPORT(MmioWrite32Internal)
+GCC_ASM_EXPORT(MmioRead64Internal)
+GCC_ASM_EXPORT(MmioWrite64Internal)
+
+//
+//  Reads an 8-bit MMIO register.
+//
+//  Reads the 8-bit MMIO register specified by Address. The 8-bit read value is
+//  returned. This function must guarantee that all MMIO read and write
+//  operations are serialized.
+//
+//  @param  Address The MMIO register to read.
+//
+//  @return The value read.
+//
+ASM_PFX(MmioRead8Internal):
+  ldrb    r0, [r0]
+  dmb
+  bx      lr
+
+//
+//  Writes an 8-bit MMIO register.
+//
+//  Writes the 8-bit MMIO register specified by Address with the value specified
+//  by Value and returns Value. This function must guarantee that all MMIO read
+//  and write operations are serialized.
+//
+//  @param  Address The MMIO register to write.
+//  @param  Value   The value to write to the MMIO register.
+//
+ASM_PFX(MmioWrite8Internal):
+  dmb     st
+  strb    r1, [r0]
+  bx      lr
+
+//
+//  Reads a 16-bit MMIO register.
+//
+//  Reads the 16-bit MMIO register specified by Address. The 16-bit read value is
+//  returned. This function must guarantee that all MMIO read and write
+//  operations are serialized.
+//
+//  @param  Address The MMIO register to read.
+//
+//  @return The value read.
+//
+ASM_PFX(MmioRead16Internal):
+  ldrh    r0, [r0]
+  dmb
+  bx      lr
+
+//
+//  Writes a 16-bit MMIO register.
+//
+//  Writes the 16-bit MMIO register specified by Address with the value specified
+//  by Value and returns Value. This function must guarantee that all MMIO read
+//  and write operations are serialized.
+//
+//  @param  Address The MMIO register to write.
+//  @param  Value   The value to write to the MMIO register.
+//
+ASM_PFX(MmioWrite16Internal):
+  dmb     st
+  strh    r1, [r0]
+  bx      lr
+
+//
+//  Reads a 32-bit MMIO register.
+//
+//  Reads the 32-bit MMIO register specified by Address. The 32-bit read value is
+//  returned. This function must guarantee that all MMIO read and write
+//  operations are serialized.
+//
+//  @param  Address The MMIO register to read.
+//
+//  @return The value read.
+//
+ASM_PFX(MmioRead32Internal):
+  ldr     r0, [r0]
+  dmb
+  bx      lr
+
+//
+//  Writes a 32-bit MMIO register.
+//
+//  Writes the 32-bit MMIO register specified by Address with the value specified
+//  by Value and returns Value. This function must guarantee that all MMIO read
+//  and write operations are serialized.
+//
+//  @param  Address The MMIO register to write.
+//  @param  Value   The value to write to the MMIO register.
+//
+ASM_PFX(MmioWrite32Internal):
+  dmb     st
+  str     r1, [r0]
+  bx      lr
+
+//
+//  Reads a 64-bit MMIO register.
+//
+//  Reads the 64-bit MMIO register specified by Address. The 64-bit read value is
+//  returned. This function must guarantee that all MMIO read and write
+//  operations are serialized.
+//
+//  @param  Address The MMIO register to read.
+//
+//  @return The value read.
+//
+ASM_PFX(MmioRead64Internal):
+  ldrd    r0, r1, [r0]
+  dmb
+  bx      lr
+
+//
+//  Writes a 64-bit MMIO register.
+//
+//  Writes the 64-bit MMIO register specified by Address with the value specified
+//  by Value and returns Value. This function must guarantee that all MMIO read
+//  and write operations are serialized.
+//
+//  @param  Address The MMIO register to write.
+//  @param  Value   The value to write to the MMIO register.
+//
+ASM_PFX(MmioWrite64Internal):
+  dmb     st
+  strd    r2, r3, [r0]
+  bx      lr
diff --git a/MdePkg/Library/BaseIoLibIntrinsic/Arm/ArmVirtMmio.asm b/MdePkg/Library/BaseIoLibIntrinsic/Arm/ArmVirtMmio.asm
new file mode 100644
index 0000000000..cff99b86a9
--- /dev/null
+++ b/MdePkg/Library/BaseIoLibIntrinsic/Arm/ArmVirtMmio.asm
@@ -0,0 +1,149 @@
+;
+;  Copyright (c) 2014-2018, Linaro Limited. 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.
+;
+
+
+AREA IoLibMmio, CODE, READONLY
+
+EXPORT MmioRead8Internal
+EXPORT MmioWrite8Internal
+EXPORT MmioRead16Internal
+EXPORT MmioWrite16Internal
+EXPORT MmioRead32Internal
+EXPORT MmioWrite32Internal
+EXPORT MmioRead64Internal
+EXPORT MmioWrite64Internal
+
+;
+;  Reads an 8-bit MMIO register.
+;
+;  Reads the 8-bit MMIO register specified by Address. The 8-bit read value is
+;  returned. This function must guarantee that all MMIO read and write
+;  operations are serialized.
+;
+;  @param  Address The MMIO register to read.
+;
+;  @return The value read.
+;
+MmioRead8Internal
+  ldrb    r0, [r0]
+  dmb
+  bx      lr
+
+;
+;  Writes an 8-bit MMIO register.
+;
+;  Writes the 8-bit MMIO register specified by Address with the value specified
+;  by Value and returns Value. This function must guarantee that all MMIO read
+;  and write operations are serialized.
+;
+;  @param  Address The MMIO register to write.
+;  @param  Value   The value to write to the MMIO register.
+;
+MmioWrite8Internal
+  dmb     st
+  strb    r1, [r0]
+  bx      lr
+
+;
+;  Reads a 16-bit MMIO register.
+;
+;  Reads the 16-bit MMIO register specified by Address. The 16-bit read value is
+;  returned. This function must guarantee that all MMIO read and write
+;  operations are serialized.
+;
+;  @param  Address The MMIO register to read.
+;
+;  @return The value read.
+;
+MmioRead16Internal
+  ldrh    r0, [r0]
+  dmb
+  bx      lr
+
+;
+;  Writes a 16-bit MMIO register.
+;
+;  Writes the 16-bit MMIO register specified by Address with the value specified
+;  by Value and returns Value. This function must guarantee that all MMIO read
+;  and write operations are serialized.
+;
+;  @param  Address The MMIO register to write.
+;  @param  Value   The value to write to the MMIO register.
+;
+MmioWrite16Internal
+  dmb     st
+  strh    r1, [r0]
+  bx      lr
+
+;
+;  Reads a 32-bit MMIO register.
+;
+;  Reads the 32-bit MMIO register specified by Address. The 32-bit read value is
+;  returned. This function must guarantee that all MMIO read and write
+;  operations are serialized.
+;
+;  @param  Address The MMIO register to read.
+;
+;  @return The value read.
+;
+MmioRead32Internal
+  ldr     r0, [r0]
+  dmb
+  bx      lr
+
+;
+;  Writes a 32-bit MMIO register.
+;
+;  Writes the 32-bit MMIO register specified by Address with the value specified
+;  by Value and returns Value. This function must guarantee that all MMIO read
+;  and write operations are serialized.
+;
+;  @param  Address The MMIO register to write.
+;  @param  Value   The value to write to the MMIO register.
+;
+MmioWrite32Internal
+  dmb     st
+  str     r1, [r0]
+  bx      lr
+
+;
+;  Reads a 64-bit MMIO register.
+;
+;  Reads the 64-bit MMIO register specified by Address. The 64-bit read value is
+;  returned. This function must guarantee that all MMIO read and write
+;  operations are serialized.
+;
+;  @param  Address The MMIO register to read.
+;
+;  @return The value read.
+;
+MmioRead64Internal
+  ldrd    r0, r1, [r0]
+  dmb
+  bx      lr
+
+;
+;  Writes a 64-bit MMIO register.
+;
+;  Writes the 64-bit MMIO register specified by Address with the value specified
+;  by Value and returns Value. This function must guarantee that all MMIO read
+;  and write operations are serialized.
+;
+;  @param  Address The MMIO register to write.
+;  @param  Value   The value to write to the MMIO register.
+;
+MmioWrite64Internal
+  dmb     st
+  strd    r2, r3, [r0]
+  bx      lr
+
+  END