From: Sascha Hauer <s.hauer@pengutronix.de>
To: "Stefan Müller-Klieser" <s.mueller-klieser@phytec.de>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH] ARM: bootm: recalculate decompression space
Date: Mon, 4 Jul 2016 11:32:04 +0200 [thread overview]
Message-ID: <20160704093204.GI20657@pengutronix.de> (raw)
In-Reply-To: <1467384519-23059-1-git-send-email-s.mueller-klieser@phytec.de>
On Fri, Jul 01, 2016 at 04:48:39PM +0200, Stefan Müller-Klieser wrote:
> According to the kernel documentation it is recommended to place the
> compressed image between 32 MiB and 128 MiB. The DTB and initrd should
> be placed above 128 MiB. We will follow the recommendation as long as we
> have enough RAM. If this is not the case, we fall back to the scheme.
> This change is required because of the ARM default kernel config changes
> regarding RODATA layout, which lead to an increased compression factor
> of the kernel image.
> This should be regarded as an intermediate solution until there is a
> mechanism for the kernel image to report the decompressed layout
> requirements to the bootloader.
>
> Signed-off-by: Stefan Müller-Klieser <s.mueller-klieser@phytec.de>
> ---
> arch/arm/lib/bootm.c | 18 +++++++++++++++---
> 1 file changed, 15 insertions(+), 3 deletions(-)
Applied, thanks.
Let's hope we don't have to revisit this too soon.
Sascha
>
> diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c
> index 803aa94..be1259b 100644
> --- a/arch/arm/lib/bootm.c
> +++ b/arch/arm/lib/bootm.c
> @@ -81,10 +81,15 @@ static int get_kernel_addresses(size_t image_size,
> return ret;
>
> /*
> - * We don't know the exact decompressed size so just use a conservative
> - * default of 4 times the size of the compressed image.
> + * The kernel documentation "Documentation/arm/Booting" advises
> + * to place the compressed image outside of the lowest 32 MiB to
> + * avoid relocation. We should do this if we have at least 64 MiB
> + * of ram. If we have less space, we assume a maximum
> + * compression factor of 5.
> */
> - image_decomp_size = PAGE_ALIGN(image_size * 4);
> + image_decomp_size = PAGE_ALIGN(image_size * 5);
> + if (mem_size >= SZ_64M)
> + image_decomp_size = max(image_decomp_size, SZ_32M);
>
> /*
> * By default put oftree/initrd close behind compressed kernel image to
> @@ -113,6 +118,13 @@ static int get_kernel_addresses(size_t image_size,
>
> *mem_free = PAGE_ALIGN(*load_address + image_size + spacing);
>
> + /*
> + * Place oftree/initrd outside of the first 128 MiB, if we have space
> + * for it. This avoids potential conflicts with the kernel decompressor.
> + */
> + if (mem_size > SZ_256M)
> + *mem_free = max(*mem_free, mem_start + SZ_128M);
> +
> return 0;
> }
>
> --
> 1.9.1
>
>
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> barebox mailing list
> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox
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next prev parent reply other threads:[~2016-07-04 9:32 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-01 14:48 Stefan Müller-Klieser
2016-07-04 9:32 ` Sascha Hauer [this message]
[not found] <alpine.DEB.2.00.1607051136430.23712@blala.de>
2016-07-05 9:47 ` Alexander Kurz
2016-07-05 9:58 ` Sascha Hauer
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