From: Michael Kubacki <michael.kuba...@microsoft.com>
There's currently two approaches being considered for how to allocate the
context buffer passed to PRM handlers:
1. The context buffer is allocated and populated in firmware. As such, the
FW converts all pointers internal to the buffer to virtual memory
addresses at the virtual address change event. A single context buffer
pointer is given to the OS via the PRM ACPI table and the OS converts
this single physical address to a virtual address when it passes the
context buffer as a pointer to PRM handlers.
2. The context buffer is allocated and populated in the OS. The OS gets
all the information needed to populate the context buffer from other
pre-existing resources (mainly physical addresses in the PRM ACPI
table). The OS converts all the physical addresses to virtual addresses,
allocates the context buffer instances, and fills in the information.
The OS passes the context buffer virtual address to PRM handlers.
The prior behavior was (1). The current POR behavior has moved to (2).
Until (2) is used more widely, it can be kept around with fairly minimal
overhead via a build flag in a few places.
So the default behavior is now (2) (the expected permanent behavior) with
(1) easily enabled by defining "ALLOCATE_CONTEXT_BUFFER_IN_FW" in the
compiler defined macros. A DSC define was added in PrmPkg.dsc to set this
compiler macro in the package build.
At some point in the future, all code (and some peripheral code)
surrounded with this build flag can be removed if (2) is fully
decided upon.
Cc: Andrew Fish <af...@apple.com>
Cc: Kang Gao <kang....@intel.com>
Cc: Michael D Kinney <michael.d.kin...@intel.com>
Cc: Michael Kubacki <michael.kuba...@microsoft.com>
Cc: Leif Lindholm <l...@nuviainc.com>
Cc: Benjamin You <benjamin....@intel.com>
Cc: Liu Yun <yun.y....@intel.com>
Cc: Ankit Sinha <ankit.si...@intel.com>
Cc: Nate DeSimone <nathaniel.l.desim...@intel.com>
Signed-off-by: Michael Kubacki <michael.kuba...@microsoft.com>
---
PrmPkg/PrmConfigDxe/PrmConfigDxe.c
| 51 +++++++++++++-------
PrmPkg/PrmLoaderDxe/PrmLoaderDxe.c
| 6 ++-
PrmPkg/Samples/PrmSampleContextBufferModule/Library/DxeContextBufferModuleConfigLib/DxeContextBufferModuleConfigLib.c
| 16 ++++++
PrmPkg/PrmLoaderDxe/PrmAcpiTable.h
| 4 ++
PrmPkg/PrmPkg.dsc
| 5 ++
PrmPkg/Readme.md
| 12 +++++
6 files changed, 76 insertions(+), 18 deletions(-)
diff --git a/PrmPkg/PrmConfigDxe/PrmConfigDxe.c
b/PrmPkg/PrmConfigDxe/PrmConfigDxe.c
index cb38146bc9e0..7215c2e1dc6f 100644
--- a/PrmPkg/PrmConfigDxe/PrmConfigDxe.c
+++ b/PrmPkg/PrmConfigDxe/PrmConfigDxe.c
@@ -28,8 +28,8 @@
STATIC UINTN mMaxRuntimeMmioRangeCount;
STATIC UINTN mMaxStaticDataBufferCount;
-STATIC PRM_RUNTIME_MMIO_RANGES **mRuntimeMmioRanges;
-STATIC PRM_DATA_BUFFER ***mStaticDataBuffers;
+GLOBAL_REMOVE_IF_UNREFERENCED STATIC PRM_RUNTIME_MMIO_RANGES
**mRuntimeMmioRanges;
+GLOBAL_REMOVE_IF_UNREFERENCED STATIC PRM_DATA_BUFFER
***mStaticDataBuffers;
/**
Converts the runtime memory range physical addresses to virtual addresses.
@@ -178,32 +178,23 @@ StoreVirtualMemoryAddressChangePointers (
)
{
EFI_STATUS Status;
- UINTN BufferIndex;
UINTN HandleCount;
UINTN HandleIndex;
UINTN RangeIndex;
+#ifdef ALLOCATE_CONTEXT_BUFFER_IN_FW
+ UINTN BufferIndex;
UINTN StaticDataBufferIndex;
+ PRM_CONTEXT_BUFFER *CurrentContextBuffer;
+#endif
EFI_HANDLE *HandleBuffer;
PRM_CONFIG_PROTOCOL *PrmConfigProtocol;
- PRM_CONTEXT_BUFFER *CurrentContextBuffer;
DEBUG ((DEBUG_INFO, "%a %a - Entry.\n", _DBGMSGID_, __FUNCTION__));
RangeIndex = 0;
+#ifdef ALLOCATE_CONTEXT_BUFFER_IN_FW
StaticDataBufferIndex = 0;
- mRuntimeMmioRanges = AllocateRuntimeZeroPool (sizeof (*mRuntimeMmioRanges) *
mMaxRuntimeMmioRangeCount);
- if (mRuntimeMmioRanges == NULL && mMaxRuntimeMmioRangeCount > 0) {
- DEBUG ((
- DEBUG_ERROR,
- " %a %a: Memory allocation for runtime MMIO pointer array failed.\n",
- _DBGMSGID_,
- __FUNCTION__
- ));
- ASSERT (FALSE);
- return;
- }
-
mStaticDataBuffers = AllocateRuntimeZeroPool (sizeof (*mStaticDataBuffers) *
mMaxStaticDataBufferCount);
if (mStaticDataBuffers == NULL && mMaxStaticDataBufferCount > 0) {
DEBUG ((
@@ -215,6 +206,19 @@ StoreVirtualMemoryAddressChangePointers (
ASSERT (FALSE);
return;
}
+#endif
+
+ mRuntimeMmioRanges = AllocateRuntimeZeroPool (sizeof (*mRuntimeMmioRanges) *
mMaxRuntimeMmioRangeCount);
+ if (mRuntimeMmioRanges == NULL && mMaxRuntimeMmioRangeCount > 0) {
+ DEBUG ((
+ DEBUG_ERROR,
+ " %a %a: Memory allocation for runtime MMIO pointer array failed.\n",
+ _DBGMSGID_,
+ __FUNCTION__
+ ));
+ ASSERT (FALSE);
+ return;
+ }
HandleBuffer = NULL;
Status = gBS->LocateHandleBuffer (
@@ -236,6 +240,7 @@ StoreVirtualMemoryAddressChangePointers (
continue;
}
+#ifdef ALLOCATE_CONTEXT_BUFFER_IN_FW
for (BufferIndex = 0; BufferIndex <
PrmConfigProtocol->ModuleContextBuffers.BufferCount; BufferIndex++) {
CurrentContextBuffer =
&(PrmConfigProtocol->ModuleContextBuffers.Buffer[BufferIndex]);
@@ -256,6 +261,7 @@ StoreVirtualMemoryAddressChangePointers (
mStaticDataBuffers[StaticDataBufferIndex++] =
&CurrentContextBuffer->StaticDataBuffer;
}
}
+#endif
if (PrmConfigProtocol->ModuleContextBuffers.RuntimeMmioRanges != NULL) {
if (RangeIndex >= mMaxRuntimeMmioRangeCount) {
Status = EFI_BUFFER_TOO_SMALL;
@@ -280,6 +286,7 @@ StoreVirtualMemoryAddressChangePointers (
__FUNCTION__,
RangeIndex
));
+#ifdef ALLOCATE_CONTEXT_BUFFER_IN_FW
DEBUG ((
DEBUG_INFO,
" %a %a: %d static buffers saved for future virtual memory
conversion.\n",
@@ -287,6 +294,7 @@ StoreVirtualMemoryAddressChangePointers (
__FUNCTION__,
StaticDataBufferIndex
));
+#endif
}
}
@@ -388,12 +396,14 @@ PrmConfigVirtualAddressChangeEvent (
{
UINTN Index;
+#ifdef ALLOCATE_CONTEXT_BUFFER_IN_FW
//
// Convert static data buffer pointers
//
for (Index = 0; Index < mMaxStaticDataBufferCount; Index++) {
gRT->ConvertPointer (0x0, (VOID **) mStaticDataBuffers[Index]);
}
+#endif
//
// Convert runtime MMIO ranges
@@ -484,7 +494,7 @@ PrmConfigEndOfDxeNotification (
if (PrmConfigProtocol->ModuleContextBuffers.RuntimeMmioRanges != NULL) {
DEBUG ((
DEBUG_INFO,
- " %a %a: Found %d PRM runtime MMIO ranges to convert.\n",
+ " %a %a: Found %d PRM runtime MMIO ranges.\n",
_DBGMSGID_,
__FUNCTION__,
PrmConfigProtocol->ModuleContextBuffers.RuntimeMmioRanges->Count
@@ -541,6 +551,13 @@ PrmConfigEntryPoint (
);
ASSERT_EFI_ERROR (Status);
+ DEBUG ((DEBUG_INFO, " %a %a: Context buffers will be allocated in ",
_DBGMSGID_, __FUNCTION__));
+#ifdef ALLOCATE_CONTEXT_BUFFER_IN_FW
+ DEBUG ((DEBUG_INFO, "firmware.\n"));
+#else
+ DEBUG ((DEBUG_INFO, "the operating system.\n"));
+#endif
+
//
// Register a notification function for virtual address change
//
diff --git a/PrmPkg/PrmLoaderDxe/PrmLoaderDxe.c
b/PrmPkg/PrmLoaderDxe/PrmLoaderDxe.c
index b43e6d6bf078..85fffdcbd9f1 100644
--- a/PrmPkg/PrmLoaderDxe/PrmLoaderDxe.c
+++ b/PrmPkg/PrmLoaderDxe/PrmLoaderDxe.c
@@ -755,7 +755,11 @@ ProcessPrmModules (
&CurrentContextBuffer
);
if (!EFI_ERROR (Status)) {
- CurrentHandlerInfoStruct->PrmContextBuffer = (UINT64)
CurrentContextBuffer;
+#ifdef ALLOCATE_CONTEXT_BUFFER_IN_FW
+ CurrentHandlerInfoStruct->PrmContextBuffer = (UINT64) (UINTN)
CurrentContextBuffer;
+#else
+ CurrentHandlerInfoStruct->StaticDataBuffer = (UINT64) (UINTN)
CurrentContextBuffer->StaticDataBuffer;
+#endif
}
Status = GetExportEntryAddress (
diff --git
a/PrmPkg/Samples/PrmSampleContextBufferModule/Library/DxeContextBufferModuleConfigLib/DxeContextBufferModuleConfigLib.c
b/PrmPkg/Samples/PrmSampleContextBufferModule/Library/DxeContextBufferModuleConfigLib/DxeContextBufferModuleConfigLib.c
index 3bf5beba7d4a..b0b12c012a41 100644
---
a/PrmPkg/Samples/PrmSampleContextBufferModule/Library/DxeContextBufferModuleConfigLib/DxeContextBufferModuleConfigLib.c
+++
b/PrmPkg/Samples/PrmSampleContextBufferModule/Library/DxeContextBufferModuleConfigLib/DxeContextBufferModuleConfigLib.c
@@ -151,10 +151,26 @@ ContextBufferModuleConfigLibConstructor (
//
// Allocate and populate the context buffer
//
+#ifdef ALLOCATE_CONTEXT_BUFFER_IN_FW
+ //
+ // The context buffer allocated in FW will continue being used at OS runtime
so it must
+ // be a runtime services data buffer.
+ //
// This sample module uses a single context buffer for all the handlers
// Todo: This can be done more elegantly in the future. Likely though a
library service.
//
PrmContextBuffer = AllocateRuntimeZeroPool (sizeof (*PrmContextBuffer));
+#else
+ //
+ // This context buffer is not actually used by PRM handler at OS runtime.
The OS will allocate
+ // the actual context buffer passed to the PRM handler.
+ //
+ // This context buffer is used internally in the firmware to associate a PRM
handler with a
+ // a static data buffer and a runtime MMIO ranges array so those can be
placed into the
+ // PRM_HANDLER_INFORMATION_STRUCT and PRM_MODULE_INFORMATION_STRUCT
respectively for the PRM handler.
+ //
+ PrmContextBuffer = AllocateZeroPool (sizeof (*PrmContextBuffer));
+#endif
ASSERT (PrmContextBuffer != NULL);
if (PrmContextBuffer == NULL) {
Status = EFI_OUT_OF_RESOURCES;
diff --git a/PrmPkg/PrmLoaderDxe/PrmAcpiTable.h
b/PrmPkg/PrmLoaderDxe/PrmAcpiTable.h
index 6b9099ca7ba7..8a9c82347d93 100644
--- a/PrmPkg/PrmLoaderDxe/PrmAcpiTable.h
+++ b/PrmPkg/PrmLoaderDxe/PrmAcpiTable.h
@@ -30,8 +30,10 @@ typedef struct {
UINT16 StructureLength; ///< Length
in bytes of this structure
GUID Identifier; ///< GUID of
the PRM handler for this structure
UINT64 PhysicalAddress; ///<
Physical address of this PRM handler
+#ifdef ALLOCATE_CONTEXT_BUFFER_IN_FW
UINT64 PrmContextBuffer; ///<
Physical address of the context buffer for this
///< PRM
handler (PRM_CONTEXT_BUFFER *)
+#else
UINT64 StaticDataBuffer; ///<
Physical address of the static data buffer for
///< this
PRM handler (PRM_DATA_BUFFER *)
UINT64 AcpiParameterBuffer; ///<
Physical address of the parameter buffer
@@ -39,6 +41,8 @@ typedef struct {
///< that is
only used in the case of _DSM invocation.
///< If _DSM
invocation is not used, this value is
///< ignored.
+#endif
+
} PRM_HANDLER_INFORMATION_STRUCT;
typedef struct {
diff --git a/PrmPkg/PrmPkg.dsc b/PrmPkg/PrmPkg.dsc
index a0237d1fe059..1a0ddc6ac181 100644
--- a/PrmPkg/PrmPkg.dsc
+++ b/PrmPkg/PrmPkg.dsc
@@ -105,3 +105,8 @@ [Components]
[BuildOptions]
# Force deprecated interfaces off
*_*_*_CC_FLAGS = -D DISABLE_NEW_DEPRECATED_INTERFACES
+
+# Append package-specific build settings
+!ifdef $(ALLOCATE_CONTEXT_BUFFER_IN_FW)
+ *_*_*_CC_FLAGS = -D ALLOCATE_CONTEXT_BUFFER_IN_FW
+!endif
diff --git a/PrmPkg/Readme.md b/PrmPkg/Readme.md
index b67b3a391e37..00ef41bc5f42 100644
--- a/PrmPkg/Readme.md
+++ b/PrmPkg/Readme.md
@@ -68,6 +68,18 @@ record (POR) configuration.
The following list are the currently defined build flags (if any) that may be
passed to the `build` command
(e.g. -D FLAG=VALUE).
+* `ALLOCATE_CONTEXT_BUFFER_IN_FW` - Allocates the context buffer for each PRM
handler in the firmware instead of
+ the operating system (OS).
+
+ Additional detail: The context buffer structure is defined in
[PrmContextBuffer.h](PrmPkg/Include/PrmContextBuffer.h).
+ This structure can be instantiated by either firmware with a physical
pointer to the buffer placed in the
+ `PRM_HANDLER_INFORMATION_STRUCT` for each handler wherein the OS would
convert that physical pointer and pass it
+ as a virtual address pointer to each PRM handler. Alternatively, the
context buffer can be allocated and populated
+ by the OS where it would get all the information to populate the context
buffer from other structures.
+
+ The default is for the OS to allocate and populate the buffer. The
alternative option of the firmware doing this
+ work is kept in the source code until broader OS testing is completed.
+
## Overview
At a high-level, PRM can be viewed from three levels of granularity:
--
2.28.0.windows.1
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