Thanks Ersek, I did change my code to match what you have here as far as the allocation. I did some more debugging and registered up a callback in exit boot services, and did an integrity check of the memory I previously allocated and put the ramdisk in. I checked the memory right before I call loadimage (to launch the kernel), and then again I check in the callback during exit boot services. So some point between the memory actually does get changed. So it might be something happening during exit boot services.
Just a question, after allocating that memory as you mentioned below, other code should not be able to allocate and use that same address range right? Even during exit boot services? -----Original Message----- From: Laszlo Ersek [mailto:ler...@redhat.com] Sent: Tuesday, May 17, 2016 11:41 AM To: Foster, Matthew I <matthew.i.fos...@intel.com> Cc: edk2-devel@lists.01.org <edk2-de...@ml01.01.org> Subject: Re: [edk2] Using the Shell to launch a kernel using a RAMDISK On 05/17/16 19:13, Foster, Matthew I wrote: > I am trying to boot a linux kernel from within the shell that is using > a ramdisk filesystem. I allocate memory in the shell for a ramdisk. I > read the filesystem out of flash memory after allocating memory in the > shell: > > KernelRootFS = AllocatePages(((KernelFSSize/FOUR_KB_ALIGNED) +1)); > > I then use that address (KernelRootFS) to pass it to the kernel > command line to tell there kernel where the filesystem is in memory. > When it goes to use the ramdisk at some in the kernel boot, the > ramdisk appears to be corrupted and I get SQUASHFS errors. > > If I do that exact procedure in BdsBoot, I do not see the corruption. > Which leads me to believe the shell might be somehow trampling over > the memory. Does anyone have any ideas on what I might do, or what > could be going on here? Please see the following messages in the list archive: http://thread.gmane.org/gmane.comp.bios.edk2.devel/10766 http://thread.gmane.org/gmane.comp.bios.edk2.devel/9885/focus=9923 In a nutshell (basically just summarizing what others have described): - Reserved memory is needed only if you want to boot off of a RAM disk (as opposed to just playing with the filesystem on it while in the UEFI shell or similar). - If you want to boot off of a RAM disk, then reserved memory *is* necessary. - The RAM disks created with the firmware setup forms (HII) are not meant for booting off of. So, you should do something like this: EFI_STATUS Status; EFI_PHYSICAL_ADDRESS KernelRootFsAddress; Status = gBS->AllocatePages ( AllocateAnyPages, EfiReservedMemoryType, EFI_SIZE_TO_PAGES ((UINTN)KernelFsSize), &KernelRootFsAddress ); if (!EFI_ERROR (Status)) { VOID *KernelRootFs; KernelRootFs = (VOID *)(UINTN)KernelRootFsAddress; /* ... */ } Thanks, Laszlo _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
