[U-Boot] using different architecture / toolchain for SPL build

[Måns Rullgård]

Allen Martin <AMartin at nvidia.com> writes:

>> > only option I found that worked was to use an armv4 toolchain for
>> > the armv4 bits and armv7 toolchain for the armv7 bits.
>>  I'm not an expert in this area, but this cannot be the right
>> approach.  Did you try asking on the binutils mailing list?  This is
>> where experts should be available...
>
> I drilled down on this some more and I found that with an armv4t
> linker I can force it to generate armv7 compatible interworking code
> if I use the "--use-bx" switch.  Unfortunately there doesn't seem to
> be any inverse, so with a armv7 linker I can't force it to generate
> armv4t compatible interworking.  This does seem to be a linker
> limitation, I'll take it up on the linaro toolchain list.

You should compile with the -mthumb-interwork gcc flag if you need
old-style interworking veneers.

The --use-blx flag only affects PLT calls from Thumb code.  I doubt you
have a PLT in your SPL.

-- 
Måns Rullgård
mans at mansr.com