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, 26 insertions, 0 deletions

diff --git a/drivers/firewire/nosy-user.h b/drivers/firewire/nosy-user.h
new file mode 100644
index 000000000..3446c5b77
--- /dev/null
+++ b/drivers/firewire/nosy-user.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __nosy_user_h
+#define __nosy_user_h
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+#define NOSY_IOC_GET_STATS _IOR('&', 0, struct nosy_stats)
+#define NOSY_IOC_START     _IO('&', 1)
+#define NOSY_IOC_STOP      _IO('&', 2)
+#define NOSY_IOC_FILTER    _IOW('&', 2, __u32)
+
+struct nosy_stats {
+	__u32 total_packet_count;
+	__u32 lost_packet_count;
+};
+
+/*
+ * Format of packets returned from the kernel driver:
+ *
+ *	quadlet with timestamp		(microseconds, CPU endian)
+ *	quadlet-padded packet data...	(little endian)
+ *	quadlet with ack		(little endian)
+ */
+
+#endif /* __nosy_user_h */