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UefiCpuPkg/PiSmmCpuDxeSmm: Enable single step after SmmProfile start 

There is a bug in the existing code: the single step is always enabled
once the Page Fault (#PF) occurs, but it is only disabled when the SMM
Profile feature actually starts (see DebugExceptionHandler).
If the SMM Profile feature has not been started, this will result in
the single-step mode remaining enabled if a Page Fault occurs.

This patch is to enable the single-step debugging mode by setting the
Trap Flag only after SmmProfile feature starts.

Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
This commit is contained in:
Jiaxin Wu 2024-07-12 16:05:02 +08:00 committed by mergify[bot]
parent bbee1cc852
commit 9d8a5fbd0c
2 changed files with 11 additions and 5 deletions
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10
UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c
View File

@ -759,6 +759,11 @@ SmmProfileStart (
// The flag indicates SMM profile starts to work. // The flag indicates SMM profile starts to work.
// //
mSmmProfileStart = TRUE; mSmmProfileStart = TRUE;
//
// Tell #PF handler to prepare a #DB subsequently.
//
mSetupDebugTrap = TRUE;
} }
/** /**
@ -1146,11 +1151,6 @@ InitSmmProfile (
// Initialize profile IDT. // Initialize profile IDT.
// //
InitIdtr (); InitIdtr ();
//
// Tell #PF handler to prepare a #DB subsequently.
//
mSetupDebugTrap = TRUE;
} }
/** /**

6
UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiException.nasm
View File

@ -13,6 +13,7 @@
;------------------------------------------------------------------------------- ;-------------------------------------------------------------------------------
extern ASM_PFX(SmiPFHandler) extern ASM_PFX(SmiPFHandler)
extern ASM_PFX(mSetupDebugTrap)
global ASM_PFX(gcSmiIdtr) global ASM_PFX(gcSmiIdtr)
global ASM_PFX(gcSmiGdtr) global ASM_PFX(gcSmiGdtr)
@ -369,9 +370,14 @@ ASM_PFX(PageFaultIdtHandlerSmmProfile):
mov rsp, rbp mov rsp, rbp
; Check if mSetupDebugTrap is TRUE (non-zero)
cmp byte [dword ASM_PFX(mSetupDebugTrap)], 0
jz SkipSettingTF
; Enable TF bit after page fault handler runs ; Enable TF bit after page fault handler runs
bts dword [rsp + 40], 8 ;RFLAGS bts dword [rsp + 40], 8 ;RFLAGS
SkipSettingTF:
pop rbp pop rbp
add rsp, 16 ; skip INT# & ErrCode add rsp, 16 ; skip INT# & ErrCode
iretq iretq