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

Stewart Smith stewart at linux.vnet.ibm.com
Mon Jul 4 14:03:43 AEST 2016

Andrew Donnellan <andrew.donnellan at au1.ibm.com> writes:
> 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?

Done. I also mentioned this means we get error *detection* in the
PAYLOAD partition, which is something that we previously did not have.

Stewart Smith
OPAL Architect, IBM.

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