Rename the variable to "gPatchSmiStack" so that its association with PatchInstructionX86() is clear from the declaration. Also change its type to X86_ASSEMBLY_PATCH_LABEL.
Unlike "gSmbase" in the previous patch, "gSmiStack"'s patched value is also de-referenced by C code (in other words, it is read back after patching): the InstallSmiHandler() function stores "CpuIndex" to the given CPU's SMI stack through "gSmiStack". Introduce the local variable "CpuSmiStack" in InstallSmiHandler() for calculating the stack location separately, then use this variable for both patching into the assembly code, and for storing "CpuIndex" through it. It's assumed that "volatile" stood in the declaration of "gSmiStack" because we used to read "gSmiStack" back for de-referencing; with that use gone, we can remove "volatile" too. (Note that the *target* of the pointer was never volatile-qualified.) Finally, replace the binary (DB) encoding of "mov esp, imm32" in "SmiEntry.nasm". Cc: Eric Dong <[email protected]> Cc: Michael D Kinney <[email protected]> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=866 Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Laszlo Ersek <[email protected]> --- Notes: v2: - use the X86_ASSEMBLY_PATCH_LABEL type rather than UINT8 [Mike] UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm | 6 +++--- UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm | 6 +++--- UefiCpuPkg/PiSmmCpuDxeSmm/SmramSaveState.c | 8 +++++--- 3 files changed, 11 insertions(+), 9 deletions(-) diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm index e6e29128e64e..0ea3c1e4498d 100644 --- a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm @@ -45,7 +45,7 @@ extern ASM_PFX(CpuSmmDebugExit) global ASM_PFX(gcSmiHandlerTemplate) global ASM_PFX(gcSmiHandlerSize) global ASM_PFX(gSmiCr3) -global ASM_PFX(gSmiStack) +global ASM_PFX(gPatchSmiStack) global ASM_PFX(gPatchSmbase) global ASM_PFX(mXdSupported) extern ASM_PFX(gSmiHandlerIdtr) @@ -86,8 +86,8 @@ o16 mov es, ax o16 mov fs, ax o16 mov gs, ax o16 mov ss, ax - DB 0xbc ; mov esp, imm32 -ASM_PFX(gSmiStack): DD 0 + mov esp, strict dword 0 ; source operand will be patched +ASM_PFX(gPatchSmiStack): mov eax, ASM_PFX(gSmiHandlerIdtr) lidt [eax] jmp ProtFlatMode diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm index 0e314279a541..9cfa8e7fc8f4 100644 --- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm @@ -55,7 +55,7 @@ extern ASM_PFX(CpuSmmDebugExit) global ASM_PFX(gPatchSmbase) global ASM_PFX(mXdSupported) -global ASM_PFX(gSmiStack) +global ASM_PFX(gPatchSmiStack) global ASM_PFX(gSmiCr3) global ASM_PFX(gcSmiHandlerTemplate) global ASM_PFX(gcSmiHandlerSize) @@ -96,8 +96,8 @@ o16 mov es, ax o16 mov fs, ax o16 mov gs, ax o16 mov ss, ax - DB 0xbc ; mov esp, imm32 -ASM_PFX(gSmiStack): DD 0 + mov esp, strict dword 0 ; source operand will be patched +ASM_PFX(gPatchSmiStack): jmp ProtFlatMode BITS 64 diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/SmramSaveState.c b/UefiCpuPkg/PiSmmCpuDxeSmm/SmramSaveState.c index d34345d5ff80..f0c289254330 100644 --- a/UefiCpuPkg/PiSmmCpuDxeSmm/SmramSaveState.c +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/SmramSaveState.c @@ -106,7 +106,7 @@ typedef struct { /// Variables from SMI Handler /// X86_ASSEMBLY_PATCH_LABEL gPatchSmbase; -extern volatile UINT32 gSmiStack; +X86_ASSEMBLY_PATCH_LABEL gPatchSmiStack; extern UINT32 gSmiCr3; extern volatile UINT8 gcSmiHandlerTemplate[]; extern CONST UINT16 gcSmiHandlerSize; @@ -686,6 +686,7 @@ InstallSmiHandler ( ) { PROCESSOR_SMM_DESCRIPTOR *Psd; + UINT32 CpuSmiStack; // // Initialize PROCESSOR_SMM_DESCRIPTOR @@ -716,7 +717,8 @@ InstallSmiHandler ( // // Initialize values in template before copy // - gSmiStack = (UINT32)((UINTN)SmiStack + StackSize - sizeof (UINTN)); + CpuSmiStack = (UINT32)((UINTN)SmiStack + StackSize - sizeof (UINTN)); + PatchInstructionX86 (gPatchSmiStack, CpuSmiStack, 4); gSmiCr3 = Cr3; PatchInstructionX86 (gPatchSmbase, SmBase, 4); gSmiHandlerIdtr.Base = IdtBase; @@ -725,7 +727,7 @@ InstallSmiHandler ( // // Set the value at the top of the CPU stack to the CPU Index // - *(UINTN*)(UINTN)gSmiStack = CpuIndex; + *(UINTN*)(UINTN)CpuSmiStack = CpuIndex; // // Copy template to CPU specific SMI handler location -- 2.14.1.3.gb7cf6e02401b _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
