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authorTan, Dun <dun.tan@intel.com>2022-09-29 17:06:51 +0800
committermergify[bot] <37929162+mergify[bot]@users.noreply.github.com>2022-10-08 05:45:22 +0000
commita670f12a741a9511d9cedc7257d3693567f8fc43 (patch)
treec43c15d00b26101ecdd0f626c8635f8e2601e8ee /UefiCpuPkg
parent406ad0582a3df7af498ec4f0adee1a95ceeae64f (diff)
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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>
Diffstat (limited to 'UefiCpuPkg')
-rw-r--r--UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c5
-rw-r--r--UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c5
2 files changed, 8 insertions, 2 deletions
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c
index 8c398ebc5b..c30ece1dc9 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c
+++ b/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) {
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c
index 80e9f08e5b..4e85880ed4 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c
+++ b/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) {