Re: [PATCH] UefiCpuPkg/MpInitLib: Fix incorrect Guard page setup for APs

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

I do not think we have AP guard page before, right?
So I suggest we change commit message to be: Add missing Guard page setup for APs.

With commit message update, reviewed-by: Jiewen.yao@intel.com


> -----Original Message-----
> From: Wang, Jian J
> Sent: Friday, December 22, 2017 12:26 PM
> To: Wang, Jian J <jian.j.wang@intel.com>; edk2-devel@lists.01.org
> Cc: Laszlo Ersek <lersek@redhat.com>; Yao, Jiewen <jiewen.yao@intel.com>;
> Dong, Eric <eric.dong@intel.com>
> Subject: RE: [edk2] [PATCH] UefiCpuPkg/MpInitLib: Fix incorrect Guard page
> setup for APs
> 
> Hi,
> 
> Anyone has any comments on this?
> 
> Regards,
> Jian
> 
> 
> > -----Original Message-----
> > From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Jian
> J
> > Wang
> > Sent: Thursday, December 21, 2017 9:27 AM
> > To: edk2-devel@lists.01.org
> > Cc: Laszlo Ersek <lersek@redhat.com>; Yao, Jiewen <jiewen.yao@intel.com>;
> > Dong, Eric <eric.dong@intel.com>
> > Subject: [edk2] [PATCH] UefiCpuPkg/MpInitLib: Fix incorrect Guard page setup
> > for APs
> >
> > AP has its own stack for code execution. If PcdCpuStackGuard is enabled,
> > the page at the bottom of stack of AP will be disabled (NOT PRESENT) to
> > monitor the stack overflow issue. This requires PcdCpuApStackSize to be
> > set with value more than one page of memory.
> >
> > Cc: Jiewen Yao <jiewen.yao@intel.com>
> > Cc: Eric Dong <eric.dong@intel.com>
> > Cc: Laszlo Ersek <lersek@redhat.com>
> > Contributed-under: TianoCore Contribution Agreement 1.1
> > Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
> > ---
> >  UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf |  1 +
> >  UefiCpuPkg/Library/MpInitLib/DxeMpLib.c       | 34
> > ++++++++++++++++++++++++---
> >  2 files changed, 32 insertions(+), 3 deletions(-)
> >
> > diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
> > b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
> > index 805641b516..e7b9eb4462 100644
> > --- a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
> > +++ b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
> > @@ -73,4 +73,5 @@
> >    gUefiCpuPkgTokenSpaceGuid.PcdCpuMicrocodePatchRegionSize
> ##
> > CONSUMES
> >    gUefiCpuPkgTokenSpaceGuid.PcdCpuApLoopMode
> ## CONSUMES
> >    gUefiCpuPkgTokenSpaceGuid.PcdCpuApTargetCstate
> ##
> > SOMETIMES_CONSUMES
> > +  gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard
> ##
> > CONSUMES
> >
> > diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
> > b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
> > index 479f8189f6..40c1bf407a 100644
> > --- a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
> > +++ b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
> > @@ -17,6 +17,7 @@
> >  #include <Library/UefiLib.h>
> >  #include <Library/UefiBootServicesTableLib.h>
> >  #include <Library/DebugAgentLib.h>
> > +#include <Library/DxeServicesTableLib.h>
> >
> >  #include <Protocol/Timer.h>
> >
> > @@ -288,9 +289,12 @@ InitMpGlobalData (
> >    IN CPU_MP_DATA               *CpuMpData
> >    )
> >  {
> > -  EFI_STATUS                 Status;
> > -  EFI_PHYSICAL_ADDRESS       Address;
> > -  UINTN                      ApSafeBufferSize;
> > +  EFI_STATUS                          Status;
> > +  EFI_PHYSICAL_ADDRESS                Address;
> > +  UINTN                               ApSafeBufferSize;
> > +  UINTN                               Index;
> > +  EFI_GCD_MEMORY_SPACE_DESCRIPTOR     MemDesc;
> > +  UINTN                               StackBase;
> >
> >    SaveCpuMpData (CpuMpData);
> >
> > @@ -301,6 +305,30 @@ InitMpGlobalData (
> >      return;
> >    }
> >
> > +  if (PcdGetBool (PcdCpuStackGuard)) {
> > +    //
> > +    // One extra page at the bottom of the stack is needed for Guard page.
> > +    //
> > +    if (CpuMpData->CpuApStackSize <= EFI_PAGE_SIZE) {
> > +      DEBUG ((DEBUG_ERROR, "PcdCpuApStackSize is not big enough for
> Stack
> > Guard!\n"));
> > +      ASSERT (FALSE);
> > +    }
> > +
> > +    for (Index = 0; Index < CpuMpData->CpuCount; ++Index) {
> > +      StackBase = CpuMpData->Buffer + Index *
> CpuMpData->CpuApStackSize;
> > +
> > +      Status = gDS->GetMemorySpaceDescriptor (StackBase, &MemDesc);
> > +      ASSERT_EFI_ERROR (Status);
> > +
> > +      Status = gDS->SetMemorySpaceAttributes (
> > +                      StackBase,
> > +                      EFI_PAGES_TO_SIZE (1),
> > +                      MemDesc.Attributes | EFI_MEMORY_RP
> > +                      );
> > +      ASSERT_EFI_ERROR (Status);
> > +    }
> > +  }
> > +
> >    //
> >    // Avoid APs access invalid buffer data which allocated by BootServices,
> >    // so we will allocate reserved data for AP loop code. We also need to
> > --
> > 2.15.1.windows.2
> >
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