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

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Message-ID: <20200806222254.GF1551@shell.armlinux.org.uk>
Date:   Thu, 6 Aug 2020 23:22:54 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Peter Geis <pgwipeout@...il.com>
Cc:     nolange79@...il.com, 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>, Arnd Bergmann <arnd@...db.de>,
        linux-tegra@...r.kernel.org
Subject: Re: [PATCH] arm: Add support for ZSTD compressed kernel

On Thu, Aug 06, 2020 at 05:46:50PM -0400, Peter Geis wrote:
> Good Evening,
> 
> I had attempted to get this working as well, but have run into
> difficulties with both my implementation and yours as well.
> My implementation was almost the same as yours, with the exception of
> also changing:
> @@ -303,7 +305,7 @@ restart: adr r0, LC1
> 
>  #ifndef CONFIG_ZBOOT_ROM
>   /* malloc space is above the relocated stack (64k max) */
> - add r10, sp, #0x10000
> + add r10, sp, #0x30000
>  #else
>   /*
>   * With ZBOOT_ROM the bss/stack is non relocatable,
> 
> On QEMU this implementation works fine.
> However on bare metal tegra30, I get the following error:
> 
> Jumping to kernel at:4861 ms
> 
> C:0x80A000C0-0x8112BA40->0x8152C700-0x81C58080
> Uncompressing Linux...
> 
> ZSTD-compressed dstSize is too small
> 
>  -- System halted
> 
> The only difference between the bare metal test and the qemu test is
> the zImage with appended dtb is packaged in the android boot format
> for the bare metal test.
> Otherwise it's exactly the same file.

So it's relocating the compressed kernel and decompressor from
0x80A000C0-0x8112BA40 to 0x8152C700-0x81C58080 and then failing.
Does the QEMU version also do similar?

On the off-hand, I'm not sure why it should fail.  I assume that
you've tried the other decompressors and they work fine on the
same setups?

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