From: Catalin Marinas <catalin.marinas@arm.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Steve Capper <steve.capper@linaro.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Suzuki K. Poulose" <Suzuki.Poulose@arm.com>,
Marc Zyngier <Marc.Zyngier@arm.com>,
Will Deacon <Will.Deacon@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 12/14] arm64: Check for selected granule support
Date: Fri, 4 Sep 2015 14:58:17 +0100 [thread overview]
Message-ID: <20150904135817.GE17253@e104818-lin.cambridge.arm.com> (raw)
In-Reply-To: <CAKv+Gu-eWRcFQkn_99WF_3H=u8qAAVis60SuegdxyeYK3v5QdQ@mail.gmail.com>
On Wed, Sep 02, 2015 at 12:19:07PM +0200, Ard Biesheuvel wrote:
> On 2 September 2015 at 11:48, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> > Couldn't we allocate some flag bits in the Image header to communicate
> > the page size to the bootloader?
>
> Something like this perhaps?
>
> ------------8<---------------
> diff --git a/Documentation/arm64/booting.txt b/Documentation/arm64/booting.txt
> index 7d9d3c2286b2..13a8aaa9a6e9 100644
> --- a/Documentation/arm64/booting.txt
> +++ b/Documentation/arm64/booting.txt
> @@ -104,7 +104,8 @@ 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.
> + Bits 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 8fae0756e175..5def289bda84 100644
> --- a/arch/arm64/kernel/image.h
> +++ b/arch/arm64/kernel/image.h
> @@ -47,7 +47,9 @@
> #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)
I'm fine with this.
--
Catalin
next prev parent reply other threads:[~2015-09-04 13:58 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-13 11:33 [PATCH 00/14] arm64: 16K translation granule support Suzuki K. Poulose
2015-08-13 11:33 ` [PATCH 01/14] arm64: Move swapper pagetable definitions Suzuki K. Poulose
2015-08-13 11:33 ` [PATCH 02/14] arm64: Handle section maps for swapper/idmap Suzuki K. Poulose
2015-09-02 9:38 ` Ard Biesheuvel
2015-09-02 9:42 ` Suzuki K. Poulose
2015-09-02 10:00 ` Ard Biesheuvel
2015-08-13 11:33 ` [PATCH 03/14] arm64: Introduce helpers for page table levels Suzuki K. Poulose
2015-08-13 11:33 ` [PATCH 04/14] arm64: Calculate size for idmap_pg_dir at compile time Suzuki K. Poulose
2015-08-13 11:33 ` [PATCH 05/14] arm64: Handle 4 level page table for swapper Suzuki K. Poulose
2015-08-13 11:33 ` [PATCH 06/14] arm64: Clean config usages for page size Suzuki K. Poulose
2015-08-13 11:33 ` [PATCH 07/14] arm64: Kconfig: Fix help text about AArch32 support with 64K pages Suzuki K. Poulose
2015-08-13 11:33 ` [PATCH 08/14] arm64: kvm: Fix {V}TCR_EL2_TG0 mask Suzuki K. Poulose
2015-08-13 11:33 ` [PATCH 09/14] arm64: Cleanup VTCR_EL2 computation Suzuki K. Poulose
2015-08-13 11:34 ` [PATCH 10/14] arm: kvm: Move fake PGD handling to arch specific files Suzuki K. Poulose
2015-08-13 11:34 ` [PATCH 11/14] arm64: kvm: Rewrite fake pgd handling Suzuki K. Poulose
2015-08-13 11:34 ` [PATCH 12/14] arm64: Check for selected granule support Suzuki K. Poulose
2015-08-13 12:28 ` Steve Capper
2015-08-13 14:45 ` Suzuki K. Poulose
2015-08-13 17:29 ` Catalin Marinas
2015-09-02 9:48 ` Ard Biesheuvel
2015-09-02 10:19 ` Ard Biesheuvel
2015-09-04 13:58 ` Catalin Marinas [this message]
2015-08-13 11:34 ` [PATCH 13/14] arm64: Add 16K page size support Suzuki K. Poulose
2015-08-13 11:34 ` [PATCH 14/14] arm64: 36 bit VA Suzuki K. Poulose
2015-09-02 9:55 ` [PATCH 00/14] arm64: 16K translation granule support Ard Biesheuvel
2015-09-02 10:11 ` Suzuki K. Poulose
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