On Saturday 16 June 2007, Arnd Bergmann wrote:
> On Saturday 16 June 2007, David Woodhouse wrote:
> > Will GCC know that it needs to emit code to handle that (mis)alignment?
>
> I've tested this with gcc-4.0.3, and it does the right thing, which
> is to split a 4 byte aligned 64 bit load/store into two 32 bit accesses,
> if you pass -mstrict-align.
I just realized this was correct but slightly misleading. On powerpc, we
don't set the 'attribute((aligned(4)))' on compat_64, so there is never
a reason to handle the misalignment, even though it would work.
On x86_64, misaligned loads are always ok, so gcc never needs to
care about this, even attribute((packed)) does not cause byte access
here.
Arnd <><
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
