arm64/boot: Disable trapping of PMZR_EL0 writes to EL2grafted

__init_el2_fgt2() writes one mask to both HDFGRTR2_EL2 and HDFGWTR2_EL2.
PMZR_EL0 is write-only, so its trap bit, nPMZR_EL0, exists only in
HDFGWTR2_EL2 and is therefore never set: a PMZR_EL0 write from the host
traps to EL2, where the nVHE hypervisor has no handler and BUG()s. The
kernel never writes PMZR_EL0, but kernel.perf_user_access=1 has the PMU
driver set PMUSERENR_EL0.UEN for a task with a user-read event, so a
write from EL0 reaches the trap and takes the host down without a panic
message.

Accumulate the HDFGWTR2_EL2 bits separately, as __init_el2_fgt() already
does for HDFGWTR_EL2, and set nPMZR_EL0 with the other FEAT_PMUv3p9
bits.

Fixes: 858c7bfcb35e1 ("arm64/boot: Enable EL2 requirements for FEAT_PMUv3p9")
Cc: stable@vger.kernel.org
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/accessibility/speakup/TODO b/drivers/accessibility/speakup/TODO
new file mode 100644
index 000000000..d4ca093bf
--- /dev/null
+++ b/drivers/accessibility/speakup/TODO
@@ -0,0 +1,22 @@
+Speakup project home:  http://www.linux-speakup.org
+
+Mailing List:  speakup@linux-speakup.org
+
+Speakup is a kernel based screen review package for the linux operating
+system.  It allows blind users to interact with applications on the
+linux console by means of synthetic speech.
+
+Currently, speakup has one issue we know of.
+
+It seems to only happen on SMP systems. It seems that text in the output buffer
+gets garbled because a lock is not set. This bug happens regularly, but no one
+has been able to find a situation which produces it consistently.
+
+Patches, suggestions, corrections, etc, are definitely welcome.
+
+We prefer that you contact us on the mailing list; however, if you do
+not want to subscribe to a mailing list, send your email to all of the
+following:
+
+okash.khawaja@gmail.com, w.d.hubbs@gmail.com, chris@the-brannons.com,
+kirk@reisers.ca and samuel.thibault@ens-lyon.org.