On Thu, Apr 25, 2024 at 04:06:13PM +0800, Chao Li wrote: > Hi Gerd, > > > Thanks, > Chao > On 2024/4/25 15:53, Gerd Hoffmann wrote: > > Hi, > > > > > +UINTN mFwCfgSelectorAddress; > > > +UINTN mFwCfgDataAddress; > > > +UINTN mFwCfgDmaAddress; > > Hmm, global variables for PEI? I think the point of storing these in > > the HOB is to avoid the need for global variables? Also does that work > > when running PEI in-place from flash? > I think it would be useful if some platforms(not LoongArch) could use the > global variables in PEI, because the global variables are faster.
Performance isn't my main concern here, I very much prefer code which is easy to maintain. Taking the same code path on all platforms is good for that. It's less code and it also makes testing easier. The risk of breaking loongarch when changing something for riscv or arm is much lower if all platforms work the same way. I'd suggest to first refactor the existing DXE code to use a HOB instead of global variables. Have a helper function which looks up the HOB and returns a pointer to the configuration struct. That helper function can be slightly different for DXE/PEI, the DXE variant can cache the pointer to the struct in a global variable so it needs to do the lookup only once. > > > + UINT64 FwCfgDataSize; > > > + UINT64 FwCfgDmaAddress; > > > + UINT64 FwCfgDmaSize; > > First thing this function should do is check whenever the HOB already > > exists. Should that be the case there is no need to parse the device > > tree. > This is a constructor in PEI, that has to parse the device tree and then > build the HOBs. This is a library, so it can be linked into multiple PEI and DXE modules. So it must be prepared to run multiple times. On the second and all following runs the HOB will already exist. The DXE variant will need the check for sure. I'd strongly suggest to add it to the PEI variant too, even though it might not be needed right now because PlatformPei is the only PEI module using the library. take care, Gerd -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#118282): https://edk2.groups.io/g/devel/message/118282 Mute This Topic: https://groups.io/mt/105724970/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
