audk/MdePkg/Library/BaseIoLibIntrinsic/Arm/ArmVirtMmio.asm

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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>
2018-06-07 12:44:12 +02:00
;
; 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