Hey Star, > I am still curious what is the real issue Marvin met.
There is no issue I met, I simply want to save another call to GetMemoryMap() because it may be altered during ExitBS(). It's a break of the specification, but it sounds like Intel complying to its own sepcification is not a good-enough reason... Regards, Marvin. > -----Original Message----- > From: Zeng, Star [mailto:star.z...@intel.com] > Sent: Wednesday, June 22, 2016 11:18 AM > To: Bruce Cran <br...@cran.org.uk>; marvin.haeu...@outlook.com; edk2- > de...@lists.01.org > Cc: Tian, Feng <feng.t...@intel.com> > Subject: Re: [edk2] [PATCH v1 1/2] MdeModulePkg: Minimize usage of > FreePool() during ExitBS(). > > On 2016/6/22 13:39, Bruce Cran wrote: > > On 6/19/16 9:21 PM, Zeng, Star wrote: > > > >> 1. The memory allocate and free in PiSmmCore are SMRAM that is not > >> related to UEFI memory map. > >> 2. According to UEFI 2.6 spec page 222 below, the UEFI OS loader > >> should have got the memory map before ExitBootServices. > >> That means the memory free should not impact the memory map *got by > >> UEFI OS loader*, it will only impact the memory map if the UEFI OS > >> loader will call GetMemoryMap() again. > > > > > > I just found the following post about Linux and how it calls > > ExitBootServices, which may be relevant: > > > > http://linux-kernel.2935.n7.nabble.com/PATCH-x86-efi-retry-ExitBootSer > > vices-on-failure-td664938.html > > > > > > "ExitBootServices is absolutely supposed to return a failure if any > > ExitBootServices event handler changes the memory map. Basically the > > get_map loop should run again if ExitBootServices returns an error the > > first time. I would say it would be fair that if ExitBootServices > > gives an error the second time then Linux would be fine in returning > > control back to BIOS." > > > > Good information that does not assume ExitBootServices event handlers are > not using memory allocation services. > In reality, the CoreExitBootServices() in DxeMain.c of EDK2 will never return > error after calling CoreNotifySignalList (&gEfiEventExitBootServicesGuid). > > I am still curious what is the real issue Marvin met. > > If we are going to clean up, we may need to review all the ExitBootServices > event handlers to see if they are using memory allocation services directly or > indirectly and find the method to clean up them. > > Cc more related people. > > Thanks, > Star _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
