Re: [RFC PATCH 08/17] powerpc/e500: Remove conditional "lwsync" substitution

On Nov 10, 2011, at 10:31 AM, Scott Wood wrote:

On Thu, Nov 10, 2011 at 07:40:04AM -0600, Kumar Gala wrote:

quoted

=20
On Nov 9, 2011, at 6:07 PM, Kyle Moffett wrote:
=20

quoted

As FreeScale e500 systems have different cacheline sizes from =

e500mc, it

quoted

quoted

is basically impossible for the kernel to support both in a single
system image at present.
=20
Given that one is SPE-float and the other is classic-float, they are =

not

quoted

quoted

generally userspace-compatible either.
=20
This patch updates the conditional to depend on whether the system =

is

quoted

quoted

actually targetting an "e500" or "e500mc" core and entirely removes =

the

quoted

quoted

unused sync-to-lwsync-replacement on e500v1/e500v2 systems.
=20
Signed-off-by: Kyle Moffett <redacted>
---
arch/powerpc/include/asm/synch.h |   16 ++++------------
1 files changed, 4 insertions(+), 12 deletions(-)

=20
Nak, we can run an e500mc in a mode that is compatible with =

e500v1/v2.  I see no reason to change the support we have there.

=20
What "mode" do you mean?  DCBZ32?  We don't support using that =

currently,

and I'd imagine the performance implication would be such that you'd
never want to do it unless it's the only way to make some piece of =

legacy

software work.

Correct, DCBZ32, we've had customers that go down this path.

quoted

I see no reason to change the support we have there.

=20
No reason to remove complexity that is not needed, and is not planned =

to

be needed?

I'd rather wait for at least 2 years for e500mc devices to have further =
deployment before we'd remove this.

- k=