[PATCH 2/2] bootm: add support for booting compressed images

[Ahmad Fatoum]

On 26.05.21 11:39, Lucas Stach wrote:
> Hi Ahmad,
> 
> Am Mittwoch, dem 26.05.2021 um 11:17 +0200 schrieb Ahmad Fatoum:
>> Hello Lucas,
>>
>> On 25.05.21 20:37, Lucas Stach wrote:
>>> ARM64 does not have a self extracting image format, but relies on the image
>>> being externally compressed with one of the standard compression algorithms.
>>>
>>> Add support for decompressing the bootm OS image. It is added in common
>>> code as it may also be useful for other images/architectures.
>>>
>>> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
>>> ---
>>>  common/bootm.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++
>>>  1 file changed, 92 insertions(+)
>>>
>>> diff --git a/common/bootm.c b/common/bootm.c
>>> index 092116beb94a..2bfb5cb01593 100644
>>> --- a/common/bootm.c
>>> +++ b/common/bootm.c
>>> @@ -12,6 +12,7 @@
>>>  #include <environment.h>
>>>  #include <linux/stat.h>
>>>  #include <magicvar.h>
>>> +#include <uncompress.h>
>>>  
>>>  static LIST_HEAD(handler_list);
>>>  
>>> @@ -808,6 +809,85 @@ err_out:
>>>  	return ret;
>>>  }
>>>  
>>> +static int do_bootm_compressed(struct image_data *img_data)
>>> +{
>>> +	struct bootm_data bootm_data = {
>>> +		.oftree_file = img_data->oftree_file,
>>> +		.initrd_file = img_data->initrd_file,
>>> +		.tee_file = img_data->tee_file,
>>> +		.verbose = img_data->verbose,
>>> +		.verify = img_data->verify,
>>> +		.force = img_data->force,
>>> +		.dryrun = img_data->dryrun,
>>> +		.initrd_address = img_data->initrd_address,
>>> +		.os_address = img_data->os_address,
>>
>> I am wondering whether it makes sense to directly extract
>> to os_address to avoid the extra copy. Depending on the subsequent
>> bootm handler, the image may still need to be relocated, but if
>> we choose a generous alignment here, the copy later on could
>> be avoided.
> 
> For the common case where we let Barebox/the bootm image handler decide
> where to put the OS image, we don't know this address yet when
> decompressing the image here. I don't think it makes sense to optimize
> the special case where the OS address is already known.

I see. A debug print for higher verbosity levels, just before invoking
bootm_boot would be nice, so it's easy to find out how long the
extraction took.

Cheers,
Ahmad


> 
> Regards,
> Lucas
> 
> 

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