[PATCH] ARM: decompressor: clear SCTLR.A bit for v7 cores

On Thu, 11 Oct 2012, Russell King - ARM Linux wrote:

On Thu, Oct 11, 2012 at 08:31:47AM -0500, Rob Herring wrote:

quoted

This only affects v7 cores. It should not vary for v7 cores as unaligned
access is a required feature. So how is it going to vary on v7 CPUs?
We've got bigger problems if there are v7 cores that don't handle
unaligned accesses.

Oh, and this gives me a third reason to NAK this patch.  Why only ensure
that the A bit is clear for v7 CPUs?  Why not v6, v5, v4 too?  Why does
ARMv7 get this special treatment?

As I said, gcc knows that ARMv7 can perform word sized accesses even 
with misaligned pointers.  So when it is passed a pointer marked with 
the packed attribute, it will generate a series of byte accesses when 
compiling for anything but ARMv7, and use a single ldr or str when 
compiling for ARMv7.


Nicolas