[LEDE-DEV] Identifying kernel version (major) during build (.mk file)

[Mauro Mozzarelli]

Thanks to those who provided directions.

I will settle with checking on LINUX_3_18.

I am not sure who manages build variables, but in future it would be 
useful to be able to identify which kernel major version we are building 
for.


Mauro


On 18/02/17 20:51, Magnus Kroken wrote:
> Hi Mauro
>
> On 18.02.2017 12.49, Mauro Mozzarelli wrote:
>> So far with trial and error (unfortunately I could not find specific
>> documentation) I found that I can test reliably a variable that includes
>> both kernel version and patchlevel as follows:
>>
>> LINUX_4_0||LINUX_4_1||LINUX_4_2||LINUX_4_3||LINUX_4_4||LINUX_4_5
>>
>> However all I would need is something like LINUX_4 or LINUX_3
>
> At this point, the only supported 3.x kernel is 3.18 (LINUX_3_18), 
> everything else is 4.x. With a recent tree, you should be able to 
> depend on LINUX_3_18 to select your 3.x configuration, and depend on 
> !LINUX_3_18 (not 3.18) to select your 4.x configuration. Unless you 
> need this to work with old trees when several 3.x kernels were in the 
> tree, this should be sufficient.
>
> If you have to support multiple 3.x kernels, you could list all the 
> 3.x patchlevels that have been in tree at some point, as that is a 
> finite and known list. Unless you need to support *very* old trees 
> with 2.6 kernels, that should have you covered.
>
> The OpenWrt wiki refers to symbols named LINUX_3_X, which presumably 
> is what you're after, 3.x. I can't find this in the LEDE wiki, and I 
> can't figure out where LINUX_* symbols are defined, so I don't know if 
> those will still work, but you could try and see what happens.
>
>> Thank you in advance,
>>
>> Mauro
>
> Regards
> /Magnus