Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967060Ab3E2WXX (ORCPT ); Wed, 29 May 2013 18:23:23 -0400 Received: from cantor2.suse.de ([195.135.220.15]:46645 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966196Ab3E2WXQ (ORCPT ); Wed, 29 May 2013 18:23:16 -0400 Date: Thu, 30 May 2013 00:22:13 +0200 (CEST) From: Jiri Kosina X-X-Sender: jikos@twin.jikos.cz To: Russ Anderson Cc: Matt Fleming , Matthew Garrett , matt.fleming@intel.com, linux-efi@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , Borislav Petkov Subject: Re: [regression, bisected] x86: efi: Pass boot services variable info to runtime code In-Reply-To: <20130529210115.GC28027@sgi.com> Message-ID: References: <20130522162747.GA20816@sgi.com> <20130523115801.GJ14575@console-pimps.org> <20130523203234.GD20913@sgi.com> <20130524074331.GL14575@console-pimps.org> <20130529210115.GC28027@sgi.com> User-Agent: Alpine 2.00 (LRH 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3299 Lines: 76 On Wed, 29 May 2013, Russ Anderson wrote: > > What appears to be happening is that your the EFI runtime services code > > is calling into the EFI boot services code, which is definitely a bug in > > your firmware because we're at runtime, but we've seen other machines > > that do similar things so we usually handle it just fine. However, what > > makes your case different, and the reason you see the above splat, is > > that it's using the physical address of the EFI boot services region, > > not the virtual one we setup with SetVirtualAddressMap(). Which is a > > second firmware bug. Again, we have seen other machines that access > > physical addresses after SetVirtualAddressMap(), but until now we > > haven't had any non-optional code that triggered them. > > > > The only reason I can see that the offending commit would introduce this > > problem is because it calls QueryVariableInfo() at boot time. I notice > > that your machine is an SGI UV one, is there any chance you could get a > > firmware fix for this? If possible, it would be also good to confirm > > that it's this chunk of code in setup_efi_vars(), > > > > status = efi_call_phys4(sys_table->runtime->query_variable_info, > > EFI_VARIABLE_NON_VOLATILE | > > EFI_VARIABLE_BOOTSERVICE_ACCESS | > > EFI_VARIABLE_RUNTIME_ACCESS, &store_size, > > &remaining_size, &var_size); > > This does trigger the problem. Note that the definition of > QueryVariableInfo() in the UEFI spec says: > > The returned MaximumVariableStorageSize, RemainingVariableStorageSize, > MaximumVariableSize information may change immediately after the call > based on other runtime activities including asynchronous error events. > Also, these values associated with different attributes are not > additive in nature. > > Note the values may be accurate at the point in time when returned, > but may not be after that. > > After the system has transitioned into runtime (after > ExitBootServices() is called), an implementation may not be able to > accurately return information about the Boot Services variable store. > In such cases, EFI_INVALID_PARAMETER should be returned. > > It is not clear to me exactly when ExitBootServices() is called. > Our bios is returning a failing indication on the call. Yes, but this call is clearly happening way before ExitBootServices() -- see the surrounding code, see for example this in efi_main(): [ ... snip ... ] setup_efi_vars(boot_params); setup_efi_pci(boot_params); status = efi_call_phys3(sys_table->boottime->allocate_pool, EFI_LOADER_DATA, sizeof(*gdt), (void **)&gdt); if (status != EFI_SUCCESS) { efi_printk("Failed to alloc mem for gdt structure\n"); goto fail; } [ ... snip ... ] We are calling QueryVariableInfo() in setup_efi_vars(), and later on AllocatePool is being called (through boot table). That'd inherently fail if we were calling it after ExitBootServices() has happened, but I believe that call is succeeding on your affected system as well. -- Jiri Kosina SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/