瀏覽代碼

UefiCpuPkg/CpuExceptionHandlerLib: Code optimization to allow bigger stack

This commit is a code optimization to allow bigger seperate stack size in
ArchSetupExceptionStack. In previous code logic, CPU_STACK_ALIGNMENT bytes
will be wasted if StackTop is already CPU_STACK_ALIGNMENT aligned.

Signed-off-by: Dun Tan <dun.tan@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Reviewed-by: Abner Chang <abner.chang@amd.com>
Tan, Dun 1 年之前
父節點
當前提交
a670f12a74

+ 4 - 1
UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c

@@ -215,7 +215,10 @@ ArchSetupExceptionStack (
   // Fixup exception task descriptor and task-state segment
   //
   AsmGetTssTemplateMap (&TemplateMap);
-  StackTop = StackTop - CPU_STACK_ALIGNMENT;
+  //
+  // Plus 1 byte is for compact stack layout in case StackTop is already aligned.
+  //
+  StackTop = StackTop - CPU_STACK_ALIGNMENT + 1;
   StackTop = (UINTN)ALIGN_POINTER (StackTop, CPU_STACK_ALIGNMENT);
   IdtTable = (IA32_IDT_GATE_DESCRIPTOR  *)Idtr.Base;
   for (Index = 0; Index < CPU_STACK_SWITCH_EXCEPTION_NUMBER; ++Index) {

+ 4 - 1
UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c

@@ -223,7 +223,10 @@ ArchSetupExceptionStack (
   // Fixup exception task descriptor and task-state segment
   //
   ZeroMem (Tss, sizeof (*Tss));
-  StackTop = StackTop - CPU_STACK_ALIGNMENT;
+  //
+  // Plus 1 byte is for compact stack layout in case StackTop is already aligned.
+  //
+  StackTop = StackTop - CPU_STACK_ALIGNMENT + 1;
   StackTop = (UINTN)ALIGN_POINTER (StackTop, CPU_STACK_ALIGNMENT);
   IdtTable = (IA32_IDT_GATE_DESCRIPTOR  *)Idtr.Base;
   for (Index = 0; Index < CPU_STACK_SWITCH_EXCEPTION_NUMBER; ++Index) {