linux-kernel - Re: [PATCH] arm: Add support for ZSTD compressed kernel

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Message-ID: <20200806003042.GB1551@shell.armlinux.org.uk>
Date:   Thu, 6 Aug 2020 01:30:42 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Norbert Lange <nolange79@...il.com>
Cc:     Arnd Bergmann <arnd@...db.de>, linux-kernel@...r.kernel.org,
        Petr Malat <oss@...at.biz>, Kees Cook <keescook@...omium.org>,
        Adam Borowski <kilobyte@...band.pl>,
        Sedat Dilek <sedat.dilek@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Nick Terrell <terrelln@...com>
Subject: Re: [PATCH] arm: Add support for ZSTD compressed kernel

On Thu, Aug 06, 2020 at 01:05:55AM +0200, Norbert Lange wrote:
> diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
> index 434a16982e34..1af01bfe6638 100644
> --- a/arch/arm/boot/compressed/head.S
> +++ b/arch/arm/boot/compressed/head.S
> @@ -614,7 +614,11 @@ not_relocated:	mov	r0, #0
>   */
>  		mov	r0, r4
>  		mov	r1, sp			@ malloc space above stack
> +#if defined(CONFIG_KERNEL_ZSTD)
> +		add	r2, sp, #0x30000	@ Context needs ~160K

That's going to mess up kexec:

        /*
         * The zImage length does not include its stack (4k) or its
         * malloc space (64k).  Include this.
         */
        len += 0x11000;

I guess we need to add this to the information provided to kexec.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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