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, 74 insertions, 0 deletions

diff --git a/drivers/comedi/proc.c b/drivers/comedi/proc.c
new file mode 100644
index 000000000..2e4496633
--- /dev/null
+++ b/drivers/comedi/proc.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * /proc interface for comedi
+ *
+ * COMEDI - Linux Control and Measurement Device Interface
+ * Copyright (C) 1998 David A. Schleef <ds@schleef.org>
+ */
+
+/*
+ * This is some serious bloatware.
+ *
+ * Taken from Dave A.'s PCL-711 driver, 'cuz I thought it
+ * was cool.
+ */
+
+#include <linux/comedi/comedidev.h>
+#include "comedi_internal.h"
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+static int comedi_read(struct seq_file *m, void *v)
+{
+	int i;
+	int devices_q = 0;
+	struct comedi_driver *driv;
+
+	seq_printf(m, "comedi version " COMEDI_RELEASE "\nformat string: %s\n",
+		   "\"%2d: %-20s %-20s %4d\", i, driver_name, board_name, n_subdevices");
+
+	for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
+		struct comedi_device *dev = comedi_dev_get_from_minor(i);
+
+		if (!dev)
+			continue;
+
+		down_read(&dev->attach_lock);
+		if (dev->attached) {
+			devices_q = 1;
+			seq_printf(m, "%2d: %-20s %-20s %4d\n",
+				   i, dev->driver->driver_name,
+				   dev->board_name, dev->n_subdevices);
+		}
+		up_read(&dev->attach_lock);
+		comedi_dev_put(dev);
+	}
+	if (!devices_q)
+		seq_puts(m, "no devices\n");
+
+	mutex_lock(&comedi_drivers_list_lock);
+	for (driv = comedi_drivers; driv; driv = driv->next) {
+		seq_printf(m, "%s:\n", driv->driver_name);
+		for (i = 0; i < driv->num_names; i++)
+			seq_printf(m, " %s\n",
+				   *(char **)((char *)driv->board_name +
+					      i * driv->offset));
+
+		if (!driv->num_names)
+			seq_printf(m, " %s\n", driv->driver_name);
+	}
+	mutex_unlock(&comedi_drivers_list_lock);
+
+	return 0;
+}
+
+void __init comedi_proc_init(void)
+{
+	if (!proc_create_single("comedi", 0444, NULL, comedi_read))
+		pr_warn("comedi: unable to create proc entry\n");
+}
+
+void comedi_proc_cleanup(void)
+{
+	remove_proc_entry("comedi", NULL);
+}