Re: [PATCH 2/4] UefiCpuPkg/CpuExceptionHandlerLib: support stack switch for PEI exceptions

["Dong, Eric" <eric.dong@intel.com>]

Reviewed-by: Eric Dong <eric.dong@intel.com>

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org]
> Sent: Monday, September 3, 2018 11:16 AM
> To: edk2-devel@lists.01.org
> Cc: Ni, Ruiyu <ruiyu.ni@intel.com>; Dong, Eric <eric.dong@intel.com>; Yao,
> Jiewen <jiewen.yao@intel.com>; Laszlo Ersek <lersek@redhat.com>; Zeng,
> Star <star.zeng@intel.com>
> Subject: [edk2] [PATCH 2/4] UefiCpuPkg/CpuExceptionHandlerLib: support
> stack switch for PEI exceptions
> 
> Stack Guard needs to setup stack switch capability to allow exception handler
> to be called with good stack if stack overflow is detected.
> This patch update InitializeCpuExceptionHandlersEx() to allow pass extra
> initialization data used to setup exception stack switch for specified
> exceptions.
> 
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Star Zeng <star.zeng@intel.com>
> Cc: "Ware, Ryan R" <ryan.r.ware@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
> ---
>  .../CpuExceptionHandlerLib/PeiCpuException.c       | 27
> +++++++++++++++++++++-
>  .../PeiCpuExceptionHandlerLib.inf                  |  4 ++++
>  2 files changed, 30 insertions(+), 1 deletion(-)
> 
> diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuException.c
> b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuException.c
> index 6f271983f2..5687c98c0d 100644
> --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuException.c
> +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuException.c
> @@ -17,6 +17,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY
> KIND, EITHER EXPRESS OR IMPLIED.
>  #include <Library/DebugLib.h>
>  #include <Library/HobLib.h>
>  #include <Library/MemoryAllocationLib.h>
> +#include <Library/PcdLib.h>
> 
>  CONST UINTN    mDoFarReturnFlag  = 0;
> 
> @@ -208,5 +209,29 @@ InitializeCpuExceptionHandlersEx (
>    IN CPU_EXCEPTION_INIT_DATA            *InitData OPTIONAL
>    )
>  {
> -  return InitializeCpuExceptionHandlers (VectorInfo);
> +  EFI_STATUS                        Status;
> +
> +  //
> +  // To avoid repeat initialization of default handlers, the caller
> + should pass  // an extended init data with InitDefaultHandlers set to
> + FALSE. There's no  // need to call this method to just initialize
> + default handlers. Call non-ex  // version instead; or this method must
> + be implemented as a simple wrapper of  // non-ex version of it, if this
> version has to be called.
> +  //
> +  if (InitData == NULL || InitData->Ia32.InitDefaultHandlers) {
> +    Status = InitializeCpuExceptionHandlers (VectorInfo);  } else {
> +    Status = EFI_SUCCESS;
> +  }
> +
> +  if (!EFI_ERROR (Status)) {
> +    //
> +    // Initializing stack switch is only necessary for Stack Guard functionality.
> +    //
> +    if (PcdGetBool (PcdCpuStackGuard) && InitData != NULL) {
> +      Status = ArchSetupExcpetionStack (InitData);
> +    }
> +  }
> +
> +  return  Status;
>  }
> diff --git
> a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.i
> nf
> b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.i
> nf
> index 783260e39a..0ea44b3052 100644
> ---
> a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.i
> nf
> +++
> b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLi
> +++ b.inf
> @@ -60,3 +60,7 @@
>    HobLib
>    MemoryAllocationLib
>    SynchronizationLib
> +
> +[Pcd]
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard
> +
> --
> 2.16.2.windows.1
> 
> _______________________________________________
> edk2-devel mailing list
> edk2-devel@lists.01.org
> https://lists.01.org/mailman/listinfo/edk2-devel