Mirror the logic in the sun4u handler, we have to update
both registers even when we branch out to window fault
fixup handling.
The way it works is that if we are in etrap processing a
fault already, g4/g5 holds the original fault information.
If we take a window spill fault while doing etrap, then
we put the window spill fault info into g4/g5 and this is
what the top-level fault handler ends up processing first.
Then we retry the originally faulting instruction, and
process the original fault at that time.
This is all necessary because of how constrained the trap
registers are in these code paths. These cases trigger
very rarely, so even if there is some performance implication
it's doesn't happen very often. In fact the rarity is why
it took so long to trigger and find this particular bug.
Signed-off-by: David S. Miller <davem@davemloft.net>
We were clobbering a base register before we were done
using it. Fix a comment typo while we're here.
Signed-off-by: David S. Miller <davem@davemloft.net>
First of all, use the known _PAGE_EXEC_{4U,4V} value instead
of loading _PAGE_EXEC from memory. We either know which one
to use by context, or we can code patch the test.
Next, we need to check executability of a PTE in the generic
TSB miss handler.
Signed-off-by: David S. Miller <davem@davemloft.net>
Another case where we have to force ourselves into global register
level one. Also make sure the arguments passed to sun4v_do_mna() are
correct.
This area actually needs some more work, for example spill fixup is
not necessarily going to do the right thing for this case.
Signed-off-by: David S. Miller <davem@davemloft.net>
The SUN4V convention with non-shared TSBs is that the context
bit of the TAG is clear. So we have to choose an "invalid"
bit and initialize new TSBs appropriately. Otherwise a zero
TAG looks "valid".
Make sure, for the window fixup cases, that we use the right
global registers and that we don't potentially trample on
the live global registers in etrap/rtrap handling (%g2 and
%g6) and that we put the missing virtual address properly
in %g5.
Signed-off-by: David S. Miller <davem@davemloft.net>
1) Add error return checking for TLB load hypervisor
calls.
2) Don't fallthru to dtlb tsb miss handler from itlb tsb
miss handler, oops.
3) On window fixups, propagate fault information to fixup
handler correctly.
Signed-off-by: David S. Miller <davem@davemloft.net>
Yes, you heard it right, they changed the PTE layout for
SUN4V. Ho hum...
This is the simple and inefficient way to support this.
It'll get optimized, don't worry.
Signed-off-by: David S. Miller <davem@davemloft.net>
Code patching did not sign extend negative branch
offsets correctly.
Kernel TLB miss path needs patching and %g4 register
preservation in order to handle SUN4V correctly.
Signed-off-by: David S. Miller <davem@davemloft.net>
There was also a bug in sun4v_itlb_miss, it loaded the
MMU Fault Status base into %g3 instead of %g2.
This pointed out a fast path for TSB miss processing,
since we have %g2 with the MMU Fault Status base, we
can use that to quickly load up the PGD phys address.
Signed-off-by: David S. Miller <davem@davemloft.net>
This is where the virtual address of the fault status
area belongs.
To set it up we don't make a hypervisor call, instead
we call OBP's SUNW,set-trap-table with the real address
of the fault status area as the second argument. And
right before that call we write the virtual address into
ASI_SCRATCHPAD vaddr 0x0.
Signed-off-by: David S. Miller <davem@davemloft.net>
When we register a TSB with the hypervisor, so that it or hardware can
handle TLB misses and do the TSB walk for us, the hypervisor traps
down to these trap when it incurs a TSB miss.
Processing is simple, we load the missing virtual address and context,
and do a full page table walk.
Signed-off-by: David S. Miller <davem@davemloft.net>
Things are a little tricky because, unlike sun4u, we have
to:
1) do a hypervisor trap to do the TLB load.
2) do the TSB lookup calculations by hand
Signed-off-by: David S. Miller <davem@davemloft.net>
