Search memory resource HOB list to find one available system memory under 1MB
for AP reset code and exchange information between BSP and APs.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff....@intel.com>
CC: Feng Tian <feng.t...@intel.com>
CC: Jiewen Yao <jiewen....@intel.com>
CC: Michael Kinney <michael.d.kin...@intel.com>
---
UefiCpuPkg/CpuMpPei/CpuMpPei.c | 71 ++++++++++++++++++++++++++++++++++++++++
UefiCpuPkg/CpuMpPei/CpuMpPei.h | 1 +
UefiCpuPkg/CpuMpPei/CpuMpPei.inf | 1 +
3 files changed, 73 insertions(+)
diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.c b/UefiCpuPkg/CpuMpPei/CpuMpPei.c
index 78299b3..0e34f26 100644
--- a/UefiCpuPkg/CpuMpPei/CpuMpPei.c
+++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.c
@@ -38,6 +38,77 @@ GLOBAL_REMOVE_IF_UNREFERENCED IA32_DESCRIPTOR mGdt = {
(UINTN) mGdtEntries
};
+/**
+ Get available system memory below 1MB by specified size.
+
+ @param WakeupBufferSize Wakeup buffer size required
+
+ @retval other Return wakeup buffer address below 1MB.
+ @retval -1 Cannot find free memory below 1MB.
+**/
+UINTN
+GetWakeupBuffer (
+ IN UINTN WakeupBufferSize
+ )
+{
+ EFI_PEI_HOB_POINTERS Hob;
+ UINTN WakeupBufferStart;
+ UINTN WakeupBufferEnd;
+
+ //
+ // Get the HOB list for processing
+ //
+ Hob.Raw = GetHobList ();
+
+ //
+ // Collect memory ranges
+ //
+ while (!END_OF_HOB_LIST (Hob)) {
+ if (Hob.Header->HobType == EFI_HOB_TYPE_RESOURCE_DESCRIPTOR) {
+ if ((Hob.ResourceDescriptor->PhysicalStart < BASE_1MB) &&
+ (Hob.ResourceDescriptor->ResourceType == EFI_RESOURCE_SYSTEM_MEMORY)
&&
+ ((Hob.ResourceDescriptor->ResourceAttribute &
+ (EFI_RESOURCE_ATTRIBUTE_READ_PROTECTED |
+ EFI_RESOURCE_ATTRIBUTE_WRITE_PROTECTED |
+ EFI_RESOURCE_ATTRIBUTE_EXECUTION_PROTECTED
+ )) == 0)
+ ) {
+ //
+ // Need memory under 1MB to be collected here
+ //
+ WakeupBufferEnd = (UINTN) (Hob.ResourceDescriptor->PhysicalStart +
Hob.ResourceDescriptor->ResourceLength);
+ if (WakeupBufferEnd > BASE_1MB) {
+ //
+ // Wakeup buffer should be under 1MB
+ //
+ WakeupBufferEnd = BASE_1MB;
+ }
+ //
+ // Wakeup buffer should be aligned on 4KB
+ //
+ WakeupBufferStart = (WakeupBufferEnd - WakeupBufferSize) & ~(SIZE_4KB
- 1);
+ if (WakeupBufferStart < Hob.ResourceDescriptor->PhysicalStart) {
+ continue;
+ }
+ //
+ // Create a memory allocation HOB.
+ //
+ BuildMemoryAllocationHob (
+ WakeupBufferStart,
+ WakeupBufferSize,
+ EfiBootServicesData
+ );
+ return WakeupBufferStart;
+ }
+ }
+ //
+ // Find the next HOB
+ //
+ Hob.Raw = GET_NEXT_HOB (Hob);
+ }
+
+ return (UINTN) -1;
+}
/**
The Entry point of the MP CPU PEIM.
diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.h b/UefiCpuPkg/CpuMpPei/CpuMpPei.h
index 611a296..da01fda 100644
--- a/UefiCpuPkg/CpuMpPei/CpuMpPei.h
+++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.h
@@ -19,6 +19,7 @@
#include <Library/BaseLib.h>
+#include <Library/HobLib.h>
#include <Library/PeimEntryPoint.h>
#pragma pack(1)
diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.inf b/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
index 1dfee4e..7cf33d3 100644
--- a/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
+++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
@@ -49,6 +49,7 @@
[LibraryClasses]
BaseLib
+ HobLib
PeimEntryPoint
--
1.9.5.msysgit.0
------------------------------------------------------------------------------
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