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, 27 insertions, 0 deletions

diff --git a/include/net/firewire.h b/include/net/firewire.h
new file mode 100644
index 000000000..8fbff8d77
--- /dev/null
+++ b/include/net/firewire.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _NET_FIREWIRE_H
+#define _NET_FIREWIRE_H
+
+#include <linux/types.h>
+
+/* Pseudo L2 address */
+#define FWNET_ALEN	16
+union fwnet_hwaddr {
+	u8 u[FWNET_ALEN];
+	/* "Hardware address" defined in RFC2734/RF3146 */
+	struct {
+		__be64 uniq_id;		/* EUI-64			*/
+		u8 max_rec;		/* max packet size		*/
+		u8 sspd;		/* max speed			*/
+		u8 fifo[6];		/* FIFO addr			*/
+	} __packed uc;
+};
+
+/* Pseudo L2 Header */
+#define FWNET_HLEN	18
+struct fwnet_header {
+	u8 h_dest[FWNET_ALEN];	/* destination address */
+	__be16 h_proto;		/* packet type ID field */
+} __packed;
+
+#endif