mirror of https://github.com/acidanthera/audk.git
54d1e76f4e
Today's logic sets X2ApicEnable flag in each AP's initialization path when InitFlag == ApInitConfig. Since all CPUs update the same global data, a spin-lock is used to avoid modifications from multiple CPUs happen at the same time. The spin-lock causes two problems: 1. Potential performance downgrade. 2. Undefined behavior when improper timer lib is used. For example we saw certain platforms used AcpiTimerLib from PcAtChipsetPkg and that library depends on retrieving PeiServices from idtr. But in fact AP's (idtr - 4) doesn't point to PeiServices. The patch simplifies the code to let BSP set the X2ApicEnable flag so the spin-lock acquisition from AP is not needed any more. Signed-off-by: Ray Ni <ray.ni@intel.com> Reviewed-by: Eric Dong <eric.dong@intel.com> Acked-by: Laszlo Ersek <lersek@redhat.com> |
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| .. | ||
| BaseUefiCpuLib | ||
| BaseXApicLib | ||
| BaseXApicX2ApicLib | ||
| CpuCommonFeaturesLib | ||
| CpuExceptionHandlerLib | ||
| CpuTimerLib | ||
| MpInitLib | ||
| MpInitLibUp | ||
| MtrrLib | ||
| PlatformSecLibNull | ||
| RegisterCpuFeaturesLib | ||
| SecPeiDxeTimerLibUefiCpu | ||
| SmmCpuFeaturesLib | ||
| SmmCpuPlatformHookLibNull | ||