From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752522AbbJJRVt (ORCPT ); Sat, 10 Oct 2015 13:21:49 -0400 Received: from mail-lb0-f171.google.com ([209.85.217.171]:35480 "EHLO mail-lb0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752415AbbJJRVr (ORCPT ); Sat, 10 Oct 2015 13:21:47 -0400 Date: Sat, 10 Oct 2015 19:22:03 +0200 From: Christoffer Dall To: "Suzuki K. Poulose" Cc: linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, ard.biesheuvel@linaro.org, Marc.Zyngier@arm.com, Catalin.Marinas@arm.com, Will.Deacon@arm.com, linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu Subject: Re: [PATCH 09/15] arm64: Add page size to the kernel image header Message-ID: <20151010172203.GI29128@cbox> References: <1442331684-28818-1-git-send-email-suzuki.poulose@arm.com> <1442331684-28818-10-git-send-email-suzuki.poulose@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1442331684-28818-10-git-send-email-suzuki.poulose@arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 15, 2015 at 04:41:18PM +0100, Suzuki K. Poulose wrote: > From: Ard Biesheuvel > > This patch adds the page size to the arm64 kernel image header > so that one can infer the PAGESIZE used by the kernel. This will > be helpful to diagnose failures to boot the kernel with page size > not supported by the CPU. > > Signed-off-by: Ard Biesheuvel > --- > Documentation/arm64/booting.txt | 7 ++++++- > arch/arm64/kernel/image.h | 5 ++++- > 2 files changed, 10 insertions(+), 2 deletions(-) > > diff --git a/Documentation/arm64/booting.txt b/Documentation/arm64/booting.txt > index 7d9d3c2..aaf6d77 100644 > --- a/Documentation/arm64/booting.txt > +++ b/Documentation/arm64/booting.txt > @@ -104,7 +104,12 @@ Header notes: > - The flags field (introduced in v3.17) is a little-endian 64-bit field > composed as follows: > Bit 0: Kernel endianness. 1 if BE, 0 if LE. > - Bits 1-63: Reserved. > + Bit 1-2: Kernel Page size. > + 0 - Unspecified. > + 1 - 4K > + 2 - 16K > + 3 - 64K > + Bits 3-63: Reserved. > > - When image_size is zero, a bootloader should attempt to keep as much > memory as possible free for use by the kernel immediately after the > diff --git a/arch/arm64/kernel/image.h b/arch/arm64/kernel/image.h > index 8fae075..73b736c 100644 > --- a/arch/arm64/kernel/image.h > +++ b/arch/arm64/kernel/image.h > @@ -47,7 +47,10 @@ > #define __HEAD_FLAG_BE 0 > #endif > > -#define __HEAD_FLAGS (__HEAD_FLAG_BE << 0) > +#define __HEAD_FLAG_PAGE_SIZE ((PAGE_SHIFT - 10) / 2) > + > +#define __HEAD_FLAGS (__HEAD_FLAG_BE << 0) | \ > + (__HEAD_FLAG_PAGE_SIZE << 1) > > /* > * These will output as part of the Image header, which should be little-endian > -- > 1.7.9.5 > Reviewed-by: Christoffer Dall