From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Fleming Subject: Re: [PATCH v2] arm64/efi: prefer AllocatePages() over efi_low_alloc() for vmlinux Date: Tue, 28 Jul 2015 22:17:52 +0100 Message-ID: <20150728211752.GE2773@codeblueprint.co.uk> References: <1437737907-10477-1-git-send-email-ard.biesheuvel@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1437737907-10477-1-git-send-email-ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ard Biesheuvel Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, msalter-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, will.deacon-5wv7dgnIgG8@public.gmane.org List-Id: linux-efi@vger.kernel.org On Fri, 24 Jul, at 01:38:27PM, Ard Biesheuvel wrote: > When allocating memory for the kernel image, try the AllocatePages() > boot service to obtain memory at the preferred offset of > 'dram_base + TEXT_OFFSET', and only revert to efi_low_alloc() if that > fails. This is the only way to allocate at the base of DRAM if DRAM > starts at 0x0, since efi_low_alloc() refuses to allocate at 0x0. > > Tested-by: Haojian Zhuang > Signed-off-by: Ard Biesheuvel > --- > v2: > - reshuffle code flow to make it more logical, and have only a single > memcpy() invocation at the end of the function > --- > arch/arm64/kernel/efi-stub.c | 41 ++++++++++++++++++++++++++++++++--------- > 1 file changed, 32 insertions(+), 9 deletions(-) Would it be easier if we allow efi_low_alloc() to return 0x0 for some uses? If you don't need the preference for low allocations, probably not, but I don't want to see us working around limitations in efi_low_alloc() instead of just fixing it. -- Matt Fleming, Intel Open Source Technology Center