[Skiboot] [PATCH] Produce XZ compressed skiboot.lid as part of build

[oliver]

On Mon, Jul 4, 2016 at 1:37 PM, Andrew Donnellan
<andrew.donnellan at au1.ibm.com> wrote:
> On 04/07/16 13:27, Stewart Smith wrote:
>>
>> With a recent HostBoot change, we can have an XZ compressed PAYLOAD
>> that's automagically detected (looking at magic numbers).
>>
>> This gives us three great benefits:
>> 1) it's transparent, uncompressed skiboot.lid works everywhere
>> 2) it lets us grow greater than 1MB binary, as long as we compress
>>    down to <1MB
>> 3) It speeds up boot. We currently compress down to 230kb rather than
>>    922kb, which is much quicker to read off flash.
>>
>> This patch produces skiboot.lid.xz alongside standard skiboot.lid.
>>
>> Signed-off-by: Stewart Smith <stewart at linux.vnet.ibm.com>
>> ---
>> +$(TARGET).lid.xz: $(TARGET).lid
>> +       $(call Q,XZ, cat $^ | xz -9 -C crc32 > $@, $@)
>
>
> Is crc32 the only check algorithm supported by Hostboot? *searches hostboot
> source code...*
>
> A quick look at the relevant Hostboot source code seems to indicate that
> crc64 can be enabled but is disabled by default. Mention this in commit
> message?

The options are there because hostboot uses the embedded xz library
which can be configured to use crc64. Unfortunately, it looks like
hostboot only provides a crc32 implementation so we need to use that.


>
> --
> Andrew Donnellan              OzLabs, ADL Canberra
> andrew.donnellan at au1.ibm.com  IBM Australia Limited
>
>
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