[edk2-devel] [PATCH 8/9] ArmVirtPkg: introduce DebugLibFdtPL011Uart DXE Runtime instance

["Laszlo Ersek" <lersek@redhat.com>]

Introduce three new DebugLib instances, forked from
MdePkg/Library/BaseDebugLibSerialPort. All three instances rely on
PL011UartLib rather than SerialPortLib so that they can customize the
PL011 UART that the debug messages are written to. All three instances
direct the debug output to the first such PL011 UART that *differs* from
the one specified in the Device Tree's /chosen node's "stdout-path"
property.

From these, DxeRuntimeDebugLibFdtPL011Uart is identical to
DebugLibFdtPL011UartRam, with the addition that UART access is permanently
disabled when the containing DXE_RUNTIME_DRIVER module is notified about
exiting boot services.

The contexts in which these DebugLib instances run are identical to those
in which the corresponding SerialPortLib instances run. The particular
original dependency chain is

  DxeRuntimeDebugLibSerialPort (DXE_RUNTIME_DRIVER)
    FdtPL011SerialPortLib
      gEarlyPL011BaseAddressGuid
      HobLib
      PL011UartLib

and the new dependency chain is

  DxeRuntimeDebugLibFdtPL011Uart (DXE_RUNTIME_DRIVER)
    gEarlyPL011BaseAddressGuid
    HobLib
    PL011UartLib

The ArmVirtPkg DSC files will be switched to the new library instances in
a separate patch.

This patch is worth viewing with "git show --find-copies-harder".

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---
 ArmVirtPkg/Library/DebugLibFdtPL011Uart/{DebugLibFdtPL011UartRam.inf => DxeRuntimeDebugLibFdtPL011Uart.inf} | 17 ++--
 ArmVirtPkg/Library/DebugLibFdtPL011Uart/Runtime.c                                                           | 88 ++++++++++++++++++++
 2 files changed, 97 insertions(+), 8 deletions(-)

diff --git a/ArmVirtPkg/Library/DebugLibFdtPL011Uart/DebugLibFdtPL011UartRam.inf b/ArmVirtPkg/Library/DebugLibFdtPL011Uart/DxeRuntimeDebugLibFdtPL011Uart.inf
similarity index 71%
copy from ArmVirtPkg/Library/DebugLibFdtPL011Uart/DebugLibFdtPL011UartRam.inf
copy to ArmVirtPkg/Library/DebugLibFdtPL011Uart/DxeRuntimeDebugLibFdtPL011Uart.inf
index a5f4c2d80a3c..84e9dbae221b 100644
--- a/ArmVirtPkg/Library/DebugLibFdtPL011Uart/DebugLibFdtPL011UartRam.inf
+++ b/ArmVirtPkg/Library/DebugLibFdtPL011Uart/DxeRuntimeDebugLibFdtPL011Uart.inf
@@ -6,8 +6,8 @@
 # SerialPortLib IO, and -- via SerialDxe -- UEFI console IO, will occur on that
 # UART; and this DebugLib instance will produce output on a *different* UART.
 #
-# This instance is suitable for modules that can only run from RAM (except
-# DXE_RUNTIME_DRIVER).
+# This instance is suitable for DXE_RUNTIME_DRIVER modules. When exiting boot
+# services, UART access is stopped.
 #
 # Copyright (C) Red Hat
 #
@@ -16,18 +16,19 @@
 
 [Defines]
   INF_VERSION    = 1.27
-  BASE_NAME      = DebugLibFdtPL011UartRam
-  FILE_GUID      = 0584DE55-9C4C-49C1-ADA0-F62C9C1F3600
-  MODULE_TYPE    = BASE
+  BASE_NAME      = DxeRuntimeDebugLibFdtPL011Uart
+  FILE_GUID      = 8A6E0972-81B5-4FF4-BB24-A07748415947
+  MODULE_TYPE    = DXE_RUNTIME_DRIVER
   VERSION_STRING = 1.0
-  LIBRARY_CLASS  = DebugLib|DXE_CORE SMM_CORE MM_CORE_STANDALONE DXE_DRIVER DXE_SMM_DRIVER SMM_DRIVER MM_STANDALONE UEFI_DRIVER UEFI_APPLICATION
-  CONSTRUCTOR    = DebugLibFdtPL011UartRamConstructor
+  LIBRARY_CLASS  = DebugLib|DXE_RUNTIME_DRIVER
+  CONSTRUCTOR    = DxeRuntimeDebugLibFdtPL011UartConstructor
+  DESTRUCTOR     = DxeRuntimeDebugLibFdtPL011UartDestructor
 
 [Sources]
   DebugLib.c
   Ram.c
   Ram.h
-  RamNonRuntime.c
+  Runtime.c
   Write.h
 
 [Packages]
diff --git a/ArmVirtPkg/Library/DebugLibFdtPL011Uart/Runtime.c b/ArmVirtPkg/Library/DebugLibFdtPL011Uart/Runtime.c
new file mode 100644
index 000000000000..de7144739c4c
--- /dev/null
+++ b/ArmVirtPkg/Library/DebugLibFdtPL011Uart/Runtime.c
@@ -0,0 +1,88 @@
+/** @file
+  Permanently disable the library instance in DXE_RUNTIME_DRIVER modules when
+  exiting boot services.
+
+  Copyright (C) Red Hat
+  Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2018, Linaro, Ltd. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Uefi/UefiSpec.h>
+
+#include "Ram.h"
+
+STATIC EFI_EVENT  mExitBootServicesEvent;
+
+/**
+  Notification function that is triggered when the boot service
+  ExitBootServices() is called.
+
+  @param[in] Event    Event whose notification function is being invoked. Here,
+                      unused.
+
+  @param[in] Context  The pointer to the notification function's context, which
+                      is implementation-dependent. Here, unused.
+**/
+STATIC
+VOID
+EFIAPI
+ExitBootServicesNotify (
+  IN EFI_EVENT  Event,
+  IN VOID       *Context
+  )
+{
+  mDebugLibFdtPL011UartAddress         = 0;
+  mDebugLibFdtPL011UartPermanentStatus = RETURN_ABORTED;
+}
+
+/**
+  Library instance constructor, registering ExitBootServicesNotify().
+
+  @param[in] ImageHandle  The firmware-allocated handle for the EFI image.
+
+  @param[in] SystemTable  A pointer to the EFI System Table.
+
+  @retval EFI_SUCCESS  The operation completed successfully.
+
+  @return              Error codes propagated from CreateEvent(); the
+                       registration of ExitBootServicesNotify() failed.
+**/
+EFI_STATUS
+EFIAPI
+DxeRuntimeDebugLibFdtPL011UartConstructor (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  return SystemTable->BootServices->CreateEvent (
+                                      EVT_SIGNAL_EXIT_BOOT_SERVICES,
+                                      TPL_CALLBACK,
+                                      ExitBootServicesNotify,
+                                      NULL /* NotifyContext */,
+                                      &mExitBootServicesEvent
+                                      );
+}
+
+/**
+  Library instance destructor, deregistering ExitBootServicesNotify().
+
+  @param[in] ImageHandle  The firmware-allocated handle for the EFI image.
+
+  @param[in] SystemTable  A pointer to the EFI System Table.
+
+  @retval EFI_SUCCESS  Library instance tear-down complete.
+
+  @return              Error codes propagated from CloseEvent(); the
+                       deregistration of ExitBootServicesNotify() failed.
+**/
+EFI_STATUS
+EFIAPI
+DxeRuntimeDebugLibFdtPL011UartDestructor (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  return SystemTable->BootServices->CloseEvent (mExitBootServicesEvent);
+}



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