mirror of https://github.com/acidanthera/audk.git
0930e7ff64
If CET shadows stack feature enabled in SMM and stack switch is enabled. When code execute from SMM handler to SMM exception, CPU will check SMM exception shadow stack token busy bit if it is cleared or not. If it is set, it will trigger #DF exception. If it is not set, CPU will set the busy bit when enter SMM exception. So, the busy bit should be cleared when return back form SMM exception to SMM handler. Otherwise, keeping busy bit 1 will cause to trigger #DF exception when enter SMM exception next time. So, we use instruction SAVEPREVSSP, CLRSSBSY and RSTORSSP to clear the shadow stack token busy bit before RETF instruction in SMM exception. REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3192 Signed-off-by: Sheng Wei <w.sheng@intel.com> Cc: Eric Dong <eric.dong@intel.com> Cc: Ray Ni <ray.ni@intel.com> Cc: Laszlo Ersek <lersek@redhat.com> Cc: Rahul Kumar <rahul1.kumar@intel.com> Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Roger Feng <roger.feng@intel.com> Reviewed-by: Jiewen Yao <jiewen.yao@intel.com> Reviewed-by: Ray Ni <ray.ni@intel.com> |
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| .. | ||
| ArchExceptionHandler.c | ||
| ArchInterruptDefs.h | ||
| ExceptionHandlerAsm.nasm | ||
| Xcode5ExceptionHandlerAsm.nasm | ||