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[Ard Biesheuvel]

On 21 April 2015 at 12:46, Dave P Martin <Dave.Martin at arm.com> wrote:
> On Tue, Apr 21, 2015 at 11:18:08AM +0100, Ard Biesheuvel wrote:
>> On 21 April 2015 at 12:13, Russell King - ARM Linux
>> <linux at arm.linux.org.uk> wrote:
>> > On Tue, Apr 21, 2015 at 12:08:51PM +0200, Ard Biesheuvel wrote:
>> >> This updates the PROCINFO offset-to-setup-function fields of the
>> >> Thumb2 capable CPU definitions to include the Thumb bit when building
>> >> a Thumb2 kernel. This ensures that these function are always called
>> >> in the correct mode.
>> >
>> > I don't think this is necessary, in fact, I think this is positively
>> > regression causing.
>> >
>> > The symbol 'initfunc' is known to the assembler to be a thumb symbol.
>> > As we have seen already from the kernel dumps from the V7M kernel, when
>> > it calculates initfunc - name in a T2 kernel, the resulting value is an
>> > _odd_ number.
>> >
>>
>> OK, so BSYM() uses '+ 1' rather than ' | 1'? I wasn't expecting that, sorry.
>
> '| 1' is more logical, but can't be resolved at link time because
> there's no relocation for this operation.  Hence '+ 1'.  This matters
> for local cross-section references that can't be resolved at assembly
> time.
>

OK, that makes sense. But it does appear that the local cross-section
references are working just fine, i.e., references from other sections
in the same .o have the thumb bit set correctly even without BSYM()

>> But looking at proc-v7.S again, the problem may just be the missing
>> ENDPROC() declarations for a couple of the setup() functions, which
>> explains why they are lacking the Thumb annotations.
>
> Yes, if any are missing ENDPROC() then it should be added there.
>

I am putting together a v2 with this instead of the BSYM() on the initfn


Cheers,
Ard.