On 2/28/24 03:27, Zhiguang Liu wrote:
> In last patch, we add code support to unregister SMI handler inside
> itself. However, the code doesn't support unregister SMI handler
> insider other SMI handler. While this is not a must-have usage.
> So add check to disallow unregister SMI handler in other SMI handler.
>
> Cc: Liming Gao <[email protected]>
> Cc: Jiaxin Wu <[email protected]>
> Cc: Ray Ni <[email protected]>
> Cc: Laszlo Ersek <[email protected]>
> Signed-off-by: Zhiguang Liu <[email protected]>
> ---
> MdeModulePkg/Core/PiSmmCore/Smi.c | 32 +++++++++++++++++++++++--------
> 1 file changed, 24 insertions(+), 8 deletions(-)
>
> diff --git a/MdeModulePkg/Core/PiSmmCore/Smi.c
> b/MdeModulePkg/Core/PiSmmCore/Smi.c
> index 3489c130fd..1bfbc635fc 100644
> --- a/MdeModulePkg/Core/PiSmmCore/Smi.c
> +++ b/MdeModulePkg/Core/PiSmmCore/Smi.c
> @@ -8,7 +8,8 @@
>
> #include "PiSmmCore.h"
>
> -LIST_ENTRY mSmiEntryList = INITIALIZE_LIST_HEAD_VARIABLE (mSmiEntryList);
> +SMI_HANDLER *gCurrentSmiHandler = NULL;
> +LIST_ENTRY mSmiEntryList = INITIALIZE_LIST_HEAD_VARIABLE
> (mSmiEntryList);
>
> SMI_ENTRY mRootSmiEntry = {
> SMI_ENTRY_SIGNATURE,
> @@ -142,13 +143,18 @@ SmiManage (
> // Link points to may be freed if unregister SMI handler.
> //
> Link = Link->ForwardLink;
> -
> - Status = SmiHandler->Handler (
> - (EFI_HANDLE)SmiHandler,
> - Context,
> - CommBuffer,
> - CommBufferSize
> - );
> + //
> + // Assign gCurrentSmiHandle before calling the SMI handler and
> + // set to NULL when it returns.
> + //
> + gCurrentSmiHandler = SmiHandler;
> + Status = SmiHandler->Handler (
> + (EFI_HANDLE)SmiHandler,
> + Context,
> + CommBuffer,
> + CommBufferSize
> + );
> + gCurrentSmiHandler = NULL;
>
> switch (Status) {
> case EFI_INTERRUPT_PENDING:
> @@ -328,6 +334,16 @@ SmiHandlerUnRegister (
> return EFI_INVALID_PARAMETER;
> }
>
> + //
> + // Check if unregister SMI handler inside a SMI Handler
> + //
> + if (gCurrentSmiHandler != NULL) {
> + //
> + // Only allow to unregister SMI Handler inside itself.
> + //
> + ASSERT (gCurrentSmiHandler == SmiHandler);
> + }
> +
> SmiEntry = SmiHandler->SmiEntry;
>
> RemoveEntryList (&SmiHandler->Link);
(1) Why not:
if ((gCurrentSmiHandler != NULL) && (gCurrentSmiHandler != SmiHandler)) {
return EFI_INVALID_PARAMETER;
}
?
(2) Why do we call the new global variable "gCurrentSmiHandler" rather than
"mCurrentSmiHandler"?
Thanks
Laszlo
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