On 19 September 2018 at 16:58, Vladimir Olovyannikov < [email protected]> wrote:
> >From: Ard Biesheuvel [mailto:[email protected]] > >Sent: Wednesday, September 19, 2018 4:38 PM > >To: Vladimir Olovyannikov > >Cc: [email protected] > >Subject: Re: Stack issue after warm UEFI reset and MMU enabling on an > Armv8 > >platform > > > >On 19 September 2018 at 15:55, Vladimir Olovyannikov > ><[email protected]> wrote: > >>Hi All, > > >>I need UEFI experts help on the problem with Armv8 board on warm UEFI > >>reset. > >>Cold reset works fine. > > >>Here is how I set up a warm reset: > > >>STATIC > >>EFI_STATUS > >>ShutdownUefiBootServices ( > >> VOID > >> ) > >>{ > >> EFI_STATUS Status; > >> UINTN MemoryMapSize; > >> EFI_MEMORY_DESCRIPTOR *MemoryMap; > >> UINTN MapKey; > >> UINTN DescriptorSize; > >> UINT32 DescriptorVersion; > >> UINTN Pages; > > >> MemoryMap = NULL; > >> MemoryMapSize = 0; > >> Pages = 0; > >> > >> do { > >> Status = gBS->GetMemoryMap ( > >> &MemoryMapSize, > >> MemoryMap, > >> &MapKey, > >> &DescriptorSize, > >> &DescriptorVersion > >> ); > >> if (Status == EFI_BUFFER_TOO_SMALL) { > >> > >> Pages = EFI_SIZE_TO_PAGES (MemoryMapSize) + 1; > >> MemoryMap = AllocatePages (Pages); > >> > >> // > >> // Get System MemoryMap > >> // > >> Status = gBS->GetMemoryMap ( > >> &MemoryMapSize, > >> MemoryMap, > >> &MapKey, > >> &DescriptorSize, > >> &DescriptorVersion > >> ); > >> } > >> > >> // Don't do anything between the GetMemoryMap() and > ExitBootServices() > >> if (!EFI_ERROR(Status)) { > >> Status = gBS->ExitBootServices (gImageHandle, MapKey); > >> if (EFI_ERROR(Status)) { > >> FreePages (MemoryMap, Pages); > >> MemoryMap = NULL; > >> MemoryMapSize = 0; > >> } > >> } > >> } while (EFI_ERROR(Status)); > >> > >> return Status; > >>} > >> > >>Then perform > >>ArmCleanDataCache (); > >>ArmInvalidateDataCache (); > >>ArmDisableInstructionCache (); > >>ArmInvalidateInstructionCache (); > > >These don't do anything useful on ARM. You can only reliably perform cache > >maintenance by virtual address. > So, should I just remove them altogether? > > >>ArmDisableMmu (); > > >... so after this call returns, all bets are off with regards to whether > >what is popped from the stack is actually what we pushed when we entered > >the function. > OK, thank you for explanation. > But this call returns back into ResetLib implementation as it should, and > then there is a direct jump to the start of FV. > Am I doing anything wrong here? > Then, up to the point of enabling of MMU the stack is OK. But right after > enabling MMU it points at _ModuleEntryPoint end of function in > DxeCoreEntryPoint.c > Am I missing anything? Maybe some stack cleanup before jumping to the start > of FV? > > I guess you should be disabling interrupts as well. And quiesce all DMA capable devices like network controllers that may corrupt your memory. _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
