Re: [PATCH v2 2/8] MdeModulePkg/CpuExceptionHandlerLib.h: Add a new API

["Yao, Jiewen" <jiewen.yao@intel.com>]

Hi
I am a little worried about the way to use VOID * to pass arch dependent data.

Can we define it clearly in each ARCH in the header file, and use a UNION to include all arch?

I think both the caller and the callee need parse it. As such, VOID * is not a good way.

Thank you
Yao Jiewen

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Jian J
> Wang
> Sent: Wednesday, November 22, 2017 4:46 PM
> To: edk2-devel@lists.01.org
> Cc: Yao, Jiewen <jiewen.yao@intel.com>; Dong, Eric <eric.dong@intel.com>;
> Zeng, Star <star.zeng@intel.com>
> Subject: [edk2] [PATCH v2 2/8] MdeModulePkg/CpuExceptionHandlerLib.h: Add
> a new API
> 
> > v2:
> >    Add prototype definition of InitializeCpuExceptionStackSwitchHandlers()
> 
> A new API InitializeCpuExceptionStackSwitchHandlers() is introduced to support
> initializing exception handlers being able to switch stack. StackSwitchData is
> arch dependent and required by IA32 processor to convey resources reserved in
> advance. This is necessary because the CpuExceptionHandlerLib will be linked
> in different phases, in which there's no common way to reserve resources.
> 
> EFI_STATUS
> EFIAPI
> InitializeCpuExceptionStackSwitchHandlers (
>   IN VOID       *StackSwitchData  OPTIONAL
>   );
> 
> Cc: Star Zeng <star.zeng@intel.com>
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Suggested-by: Ayellet Wolman <ayellet.wolman@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
> ---
>  MdeModulePkg/Include/Library/CpuExceptionHandlerLib.h | 18
> ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/MdeModulePkg/Include/Library/CpuExceptionHandlerLib.h
> b/MdeModulePkg/Include/Library/CpuExceptionHandlerLib.h
> index 6cd8230127..68de4850e1 100644
> --- a/MdeModulePkg/Include/Library/CpuExceptionHandlerLib.h
> +++ b/MdeModulePkg/Include/Library/CpuExceptionHandlerLib.h
> @@ -41,6 +41,24 @@ InitializeCpuExceptionHandlers (
>    IN EFI_VECTOR_HANDOFF_INFO       *VectorInfo OPTIONAL
>    );
> 
> +/**
> +  Setup separate stack for given exceptions. StackSwitchData is optional and its
> +  content depends one the specific arch of CPU.
> +
> +  @param[in] StackSwitchData      Pointer to data required for setuping up
> +                                  stack switch.
> +
> +  @retval EFI_SUCCESS             The exceptions have been successfully
> +                                  initialized.
> +  @retval EFI_INVALID_PARAMETER   StackSwitchData contains invalid
> content.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +InitializeCpuExceptionStackSwitchHandlers (
> +  IN VOID       *StackSwitchData  OPTIONAL
> +  );
> +
>  /**
>    Initializes all CPU interrupt/exceptions entries and provides the default
> interrupt/exception handlers.
> 
> --
> 2.14.1.windows.1
> 
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