audk/OvmfPkg/Library/PlatformDebugLibIoPort
Laszlo Ersek 91a5b13650 OvmfPkg/PlatformDebugLibIoPort: fix port detection for use in the DXE Core
The DXE Core is one of those modules that call
ProcessLibraryConstructorList() manually.

Before DxeMain() [MdeModulePkg/Core/Dxe/DxeMain/DxeMain.c] calls
ProcessLibraryConstructorList(), and through it, our
PlatformDebugLibIoPortConstructor() function, DxeMain() invokes the
DEBUG() macro multiple times. That macro lands in our
PlatformDebugLibIoPortFound() function -- which currently relies on the
"mDebugIoPortFound" global variable that has (not yet) been set by the
constructor. As a result, early debug messages from the DXE Core are lost.

Move the device detection into PlatformDebugLibIoPortFound(), also caching
the fact (not just the result) of the device detection.

(We could introduce a separate DebugLib instance just for the DXE Core,
but the above approach works for all modules that currently consume the
PlatformDebugLibIoPort instance (which means "everything but SEC").)

This restores messages such as:

> CoreInitializeMemoryServices:
>   BaseAddress - 0x7AF21000 Length - 0x3CDE000 MinimalMemorySizeNeeded - 0x10F4000

Keep the empty constructor function -- OVMF's DebugLib instances have
always had constructors; we had better not upset constructor dependency
ordering by making our instance(s) constructor-less.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Fixes: c09d957130
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Tested-by: Brijesh Singh <brijesh.singh@amd.com>
[lersek@redhat.com: sanitize blank lines around "mDebugIoPortChecked"]
2018-08-06 20:56:12 +02:00
..
DebugLib.c OvmfPkg: save on I/O port accesses when the debug port is not in use 2017-11-17 18:35:12 +01:00
DebugLibDetect.c OvmfPkg/PlatformDebugLibIoPort: fix port detection for use in the DXE Core 2018-08-06 20:56:12 +02:00
DebugLibDetect.h OvmfPkg: save on I/O port accesses when the debug port is not in use 2017-11-17 18:35:12 +01:00
DebugLibDetectRom.c OvmfPkg: save on I/O port accesses when the debug port is not in use 2017-11-17 18:35:12 +01:00
PlatformDebugLibIoPort.inf OvmfPkg: Removing ipf which is no longer supported from edk2. 2018-06-29 16:19:47 +08:00
PlatformRomDebugLibIoPort.inf OvmfPkg: Removing ipf which is no longer supported from edk2. 2018-06-29 16:19:47 +08:00