From mboxrd@z Thu Jan 1 00:00:00 1970 From: Timur Tabi Subject: Re: [PATCH] [v2] arm64: efi: make sure vmlinux load address aligned on 2MB Date: Wed, 28 Oct 2015 13:12:36 -0500 Message-ID: <56311014.9020400@codeaurora.org> References: <1446053844-27281-1-git-send-email-timur@codeaurora.org> <20151028180836.GB26777@leverpostej> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20151028180836.GB26777@leverpostej> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Mark Rutland Cc: ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, Mark Salter , "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Will Deacon , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, Shanker Donthineni , Mark Langsdorf , Jon Masters List-Id: linux-efi@vger.kernel.org On 10/28/2015 01:08 PM, Mark Rutland wrote: > arm64: efi: ensure kernel is loaded at correct address > > The kernel image needs to be loaded text_offset_bytes from a 2M-aligned > base, per Documentation/arm64/booting.txt. If loaded at the wrong offset > modulo 2M, __create_page_tables will create incorrect page tables. > > The EFI stub implicitly assumes that dram_base (i.e. the lowest address > with a EFI_MEMORY_WB attribute) is 2M-aligned, and tries to load the > kernel at dram_base + TEXT_OFFSET. If dram_base is not 2M-aligned, the > kernel will be loaded at the wrong offset from 2M. Thanks, I'll use that. I messed up a couple other things, so I need to send out a v3 anyway. >> - *image_addr = *reserve_addr = dram_base + TEXT_OFFSET; >> + *image_addr = *reserve_addr = >> + round_up(dram_base, SZ_2M) + TEXT_OFFSET; > > We also need to fix the test for whether we need to relocate the kernel: > (*image_addr != (dram_base + TEXT_OFFSET)). > > When dram_base is not 2M aligned, that is broken, and it's been broken > since it was introduced in commit 3c7f255039a2ad6e ("arm64: efi: add EFI > stub") in v3.16. > > It's a bit hideous to fix the general case, though, it seems. Um, so I should I do something more in my v3 patch, or is this a change for a different patch? -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.