Follow-up to remaining issue with alignment of __log_buf in printk.c

[robert.jarzmik@free.fr (Robert Jarzmik)]

Hi Stephen and others,

I have a XScale PXA based board with has the alignement issue which makes the
kernel trap during its early stage.

I wonder what is the status now, is there a fix available ?

I have tracked what happens on PXA. The pxa is an ARM v5TE chip. The new printk
version you submitted is translated to the following assembly on the line :
        msg->ts_nsec = local_clock();
Into:
=> 0xc001bbe0 <log_store+496>:	strd	r0, [r4, r5]

In ARMv5, the "strd" assembly opcode expects the address to be 64bits aligned,
hence the bug.

Now the solutions I have seen so far in the mailing lists :
 - #define LOG_ALIGN (__alignof__(u64))
   Does always work.
 - #define LOG_ALIGN (__alignof__(struct log))
   Doesn't work with my toolchain, as __alignof__(struct log) is 4, not 8

What are you intending to do to solve the ARMv5 issue ? Are you waiting for
someone to submit a patch ?

Cheers.

-- 
Robert