should slightly help proton
requires reordering the uvs lowering to be after tes lowering since that can
insert psiz writes.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35658>
This is the most serious bug we've had in a long time due to a fundamental
misunderstanding of the hardware (due to incomplete reverse-engineering). It
caught me off guard.
The texture descriptor has "mode" bits which configure two aspects of how the
address pointer is interpreted:
* whether it is indirected, pointing to a secondary page table for sparse
* whether it writes texture access counters (for Metal's idea of sparse).
...Neither of these is a "null texture" mode.
So why did I see Apple's blob using a non-normal mode for null textures, and why
did I copy those settings?
1. Because the hardware texture access counters provide a cheap way to detect
null texture accesses after the fact, which I think their GPU debug tools
use. I'm not sure why release builds of the driver do/did that, but whatever.
2. Because I assumed Cupertino knew best and I didn't bother looking too close.
We can't use them here (without doing extra memory allocations), since then
the GPU will increment access counters. And since our null texture address used
to just be a pointer in the command buffer, that mean the GPU will trash
whatever memory happened to be 0x400 bytes after the start of the null texture
descriptor. The symptom being random faults.
This bug was caught when trying to use the zero-page instead, which raised a
permission fault when the GPU tried to write counts. Then I remembered the
sparse mechanism and had a bit of a eureka moment. Immediately followed by an
"oh, f#$&" moment as I realized how many random bugs could potentially be root
caused to this.
The fix is two-fold:
1. Use normal layout instead.
2. Set the address to the zero-page (which is a fixed VA) and detect null
textures by checking the address, instead of the mode.
The latter is a good idea anyway, but both parts needs to be done atomically to
maintain bisectability.
Backport-to: 25.1
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34703>
this xml (and the sparse page table structure itself) was r/e'd blackbox since
that was easier than writing tests, lol. but it seems to work.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33682>
this isn't a Null layout only, it's also used with sparse. update the name to
reduce confusion. Unsure if we have a use case yet but maybe as an optimization
later?
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33682>
libwrap.dylib is helpful to trace control streams on macOS. When it was
originally implemented, we..
* supported macOS in our OpenGL driver and needed to actually exercise these
interfaces
* didn't have Linux support or hypervisor support or anything so needed the
traces to be utterly thorough
* only had a single macOS version to worry about
The landscape today is very different
* no macOS support in our driver stack
* we can trace registers via the hypervisor - libwrap.dylib is no longer
"correctness" bearing, it's just a convenience tool
* what counts is the hardware side - tracing all the macOS software structs is
not actually useful, the hypervisor is the right place to grab control regs
* piles of macOS versions, this code only ever worked properly on 11.x and 12.x,
but with m4 r/e coming up soon we need a lot more versions working.
So... we keep around libwrap.dylib, but slim it down to only decode the bare
minimum of macOS versioned structures, just enough to grab the control stream
pointer and dump that. This is a loss of functionality around CRs (but we have the
hypervisor as a much better way to grab CRs). In exchange it makes the code much
more manageable and less likely to break every 6 months.
So in exchange for all this deletion we also get things working again, this time
on 13.x. But porting back to 12.x or 11.x would be a very small diffstat given
the reduced focus of the new code.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33682>
I don't know of any case of Apple's driver using this, but it seems to work. The
stream link bit is identical to VDM so that was easy, the tricky part was the
return but I bruteforced the encoding space and this is the (only) thing that
worked. So add the XML.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32320>
