On gfx11, with a sequence such as
s_trap 2
s_sendmsg sendmsg(MSG_DEALLOC_VGPRS)
s_endpgm
the s_sendmsg does deallocate registers while the wave is supposed to be
stopped. As a result, the wave cannot do the expected context save
operations, and cannot context save.
To avoid this problem, park the wave in the trap handler for gfx11.
Note that gfx11 has implemented an instruction cache prefetch. When
parked, the prefetch tries to access memory past the end of trap handler
which causes memory violation exceptions to be reported. To avoid this,
we need to add padding at the end of the trap handler. The padding
consists of `s_code_end` instructions Given that the trap handler is
loaded at a 0x1000 aligned address the maximum prefetch amount (in
bytes) is given by `256 - (trap_handler_size % 64)`.
Change-Id: I5446da54a965a64f21cb0fd3ce3caa4b6137a933
Lancelot SIX
2f2ba050f6