On Tue, 11 Dec 2018 at 19:13, Mark Cave-Ayland
<mark.cave-ayl...@ilande.co.uk> wrote:
> On 10/12/2018 16:56, Peter Maydell wrote:
> > Anyway, I send it out as a skeleton for comments, because
> > it would be nice to get rid of the old unassigned_access
> > hook, which is fundamentally broken (it's still used by m68k,
> > microblaze, mips and sparc).
>
> Laurent is really the expert here (my work on the q800 was purely on the
> device
> side), however is this also a nudge to see if the unassigned_access hook can
> be
> eliminated from sparc too? ;)
It would certainly be great to convert sparc too;
it and mips are a little more complicated than these
ones, but the principle is the same:
* helper functions in target/sparc which call
cpu_unassigned_access() should be changed to call
some sparc-internal function to raise the right
exception
* callsites in target/sparc which do loads or stores
by physical address should be checked to ensure they
do the right thing when a bus error is detected;
this usually means changing them to use address_space_*
functions and check they return MEMTX_OK. (With the
old unassigned_access hook these would result in calls
to the hook, which was often the wrong thing anyway.
The transaction_failed hook is called only for accesses
via the TCG MMU.) The docs/devel/loads-stores.rst docs
have some handy regexes for use with 'git grep'; for sparc
these catch everything:
git grep '\<ldu\?[bwlq]\(_[bl]e\)\?_phys\>' target/sparc/
git grep '\<st[bwlq]\(_[bl]e\)\?_phys\>' target/sparc/
* convert the hook itself: this requires a little fiddling
of parameters, and the addition of the cpu_restore_state()
call
(MIPS has some odd board-specific handling on top of that
which will need to be fixed too.)
thanks
-- PMM
