From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755751AbaHFMkl (ORCPT ); Wed, 6 Aug 2014 08:40:41 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:59469 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752363AbaHFMk2 (ORCPT ); Wed, 6 Aug 2014 08:40:28 -0400 Date: Wed, 6 Aug 2014 13:39:59 +0100 From: Will Deacon To: Dave Young Cc: Catalin Marinas , "matt.fleming@intel.com" , "leif.lindholm@linaro.org" , "ard.biesheuvel@linaro.org" , "msalter@redhat.com" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 1/2] UEFI arm64: add noefi boot param Message-ID: <20140806123958.GK25953@arm.com> References: <20140806083825.GA31711@dhcp-16-198.nay.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140806083825.GA31711@dhcp-16-198.nay.redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 06, 2014 at 09:38:25AM +0100, Dave Young wrote: > Adding a noefi boot param like in X86 to disable efi runtime services support. > > This will be useful for debugging uefi problems. Also it will be useful > for later kexec/kdump work. Kexec on uefi support in X86 depends on a fixed vm > area specific for uefi runtime 1:1 mapping, kernel will switch to a different > page table for any uefi runtime callback in virtual mode. In arm64 similar > work probably is necessary. But kexec boot will just works with 'noefi' with > the limitaion of lacking runtime services. The runtime services is not critical > for kdump kernel for now. So as for kexec/kdump just leave the 1:1 mapping a > future work. > > Signed-off-by: Dave Young This looks fine to me, but I'd like Leif's ack before I merge it. Leif? Will > --- > arch/arm64/kernel/efi.c | 17 ++++++++++++++--- > 1 file changed, 14 insertions(+), 3 deletions(-) > > Index: linux-2.6/arch/arm64/kernel/efi.c > =================================================================== > --- linux-2.6.orig/arch/arm64/kernel/efi.c > +++ linux-2.6/arch/arm64/kernel/efi.c > @@ -31,6 +31,14 @@ static efi_runtime_services_t *runtime; > > static u64 efi_system_table; > > +static bool disable_runtime __initdata = false; > +static int __init setup_noefi(char *arg) > +{ > + disable_runtime = true; > + return 0; > +} > +early_param("noefi", setup_noefi); > + > static int uefi_debug __initdata; > static int __init uefi_debug_setup(char *str) > { > @@ -391,11 +399,14 @@ static int __init arm64_enter_virtual_mo > return -1; > } > > - pr_info("Remapping and enabling EFI services.\n"); > - > - /* replace early memmap mapping with permanent mapping */ > mapsize = memmap.map_end - memmap.map; > early_memunmap(memmap.map, mapsize); > + > + if (disable_runtime) > + return -ENODEV; > + > + pr_info("Remapping and enabling EFI services.\n"); > + /* replace early memmap mapping with permanent mapping */ > memmap.map = (__force void *)ioremap_cache((phys_addr_t)memmap.phys_map, > mapsize); > memmap.map_end = memmap.map + mapsize; >