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

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

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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