Re: [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid AP calls PeiService.

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

Agreed, Maybe it's time to add a new API like AcquireSpinLockWithoutTimeOut?

Thanks,
Eric
> -----Original Message-----
> From: Yao, Jiewen
> Sent: Thursday, December 20, 2018 9:19 AM
> To: Dong, Eric <eric.dong@intel.com>; edk2-devel@lists.01.org
> Cc: Ni, Ruiyu <ruiyu.ni@intel.com>; Laszlo Ersek <lersek@redhat.com>
> Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
> AP calls PeiService.
> 
> Hi
> If we think below code is generic, can we have an API for that?
> 
> +      //
> +      // Wait for the AP to release the MSR spin lock.
> +      //
> +      while (!AcquireSpinLockOrFail (&CpuFlags->ConsoleLogLock)) {
> +        CpuPause ();
> +      }
> 
> 
> 
> 
> > -----Original Message-----
> > From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> > Eric Dong
> > Sent: Thursday, December 20, 2018 9:16 AM
> > To: edk2-devel@lists.01.org
> > Cc: Ni, Ruiyu <ruiyu.ni@intel.com>; Laszlo Ersek <lersek@redhat.com>
> > Subject: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
> > AP calls PeiService.
> >
> > In AcquireSpinLock function, it calls GetPerformanceCounter which
> > final calls PeiService service. This patch avoid to call
> > AcquireSpinLock function.
> >
> > BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1411
> >
> > Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> > Cc: Laszlo Ersek <lersek@redhat.com>
> > Contributed-under: TianoCore Contribution Agreement 1.1
> > Signed-off-by: Eric Dong <eric.dong@intel.com>
> > ---
> >  UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c | 7
> > ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git
> > a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > index 624ddee055..a64326239f 100644
> > ---
> > a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > +++ b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.
> > +++ c
> > @@ -832,7 +832,12 @@ ProgramProcessorRegister (
> >      RegisterTableEntry = &RegisterTableEntryHead[Index];
> >
> >      DEBUG_CODE_BEGIN ();
> > -      AcquireSpinLock (&CpuFlags->ConsoleLogLock);
> > +      //
> > +      // Wait for the AP to release the MSR spin lock.
> > +      //
> > +      while (!AcquireSpinLockOrFail (&CpuFlags->ConsoleLogLock)) {
> > +        CpuPause ();
> > +      }
> >        ThreadIndex = ApLocation->Package * CpuStatus->MaxCoreCount *
> > CpuStatus->MaxThreadCount +
> >                ApLocation->Core * CpuStatus->MaxThreadCount +
> >                ApLocation->Thread;
> > --
> > 2.15.0.windows.1
> >
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