Re: [PATCH v8 03/14] powerpc/vas: Define nx_fault_stamp in coprocessor_request_block

Haren Myneni [off-list ref] writes:

On Mon, 2020-03-23 at 22:32 +1100, Michael Ellerman wrote:

quoted

Nicholas Piggin [off-list ref] writes:

quoted

Haren Myneni's on March 19, 2020 4:13 pm:

quoted

Kernel sets fault address and status in CRB for NX page fault on user
space address after processing page fault. User space gets the signal
and handles the fault mentioned in CRB by bringing the page in to
memory and send NX request again.

Signed-off-by: Sukadev Bhattiprolu <redacted>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/include/asm/icswx.h | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/icswx.h b/arch/powerpc/include/asm/icswx.h
index 9872f85..b233d1e 100644
--- a/arch/powerpc/include/asm/icswx.h
+++ b/arch/powerpc/include/asm/icswx.h

"icswx" is not a thing anymore, after 6ff4d3e96652 ("powerpc: Remove old 
unused icswx based coprocessor support").

Yeah that commit ripped out some parts of the previous attempt at a user
visible API for this sort of "coprocessor" stuff. VAS is yet another
attempt to do something useful with most of the same pieces but some
slightly different details.

quoted

I guess NX is reusing some 
things from it, but it would be good to get rid of the cruft and re-name
this file and and relevant names.

quoted

NX already uses this file, so I guesss that can happen after this series.

A lot of the CRB/CSB stuff is still the same, and P8 still uses icswx.
But I'd be happy if the header was renamed eventually, as icswx is now a
legacy name.

We can move all macros and struct definitions to vas.h and remove
icswx.h. Can I do this after this series? 

Well they're still needed by the non-vas Power8 code, so that wouldn't
be quite right either :)

But yeah we can do whatever movement later as a cleanup.

cheers