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, 51 insertions, 0 deletions

diff --git a/drivers/hid/hid-keytouch.c b/drivers/hid/hid-keytouch.c
new file mode 100644
index 000000000..b9abd53a5
--- /dev/null
+++ b/drivers/hid/hid-keytouch.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for Keytouch devices not fully compliant with HID standard
+ *
+ *  Copyright (c) 2011 Jiri Kosina
+ */
+
+/*
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+/* Replace the broken report descriptor of this device with rather
+ * a default one */
+static const __u8 keytouch_fixed_rdesc[] = {
+0x05, 0x01, 0x09, 0x06, 0xa1, 0x01, 0x05, 0x07, 0x19, 0xe0, 0x29, 0xe7, 0x15,
+0x00, 0x25, 0x01, 0x75, 0x01, 0x95, 0x08, 0x81, 0x02, 0x95, 0x01, 0x75, 0x08,
+0x81, 0x01, 0x95, 0x03, 0x75, 0x01, 0x05, 0x08, 0x19, 0x01, 0x29, 0x03, 0x91,
+0x02, 0x95, 0x05, 0x75, 0x01, 0x91, 0x01, 0x95, 0x06, 0x75, 0x08, 0x15, 0x00,
+0x26, 0xff, 0x00, 0x05, 0x07, 0x19, 0x00, 0x2a, 0xff, 0x00, 0x81, 0x00, 0xc0
+};
+
+static const __u8 *keytouch_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	hid_info(hdev, "fixing up Keytouch IEC report descriptor\n");
+
+	*rsize = sizeof(keytouch_fixed_rdesc);
+	return keytouch_fixed_rdesc;
+}
+
+static const struct hid_device_id keytouch_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_KEYTOUCH, USB_DEVICE_ID_KEYTOUCH_IEC) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, keytouch_devices);
+
+static struct hid_driver keytouch_driver = {
+	.name = "keytouch",
+	.id_table = keytouch_devices,
+	.report_fixup = keytouch_report_fixup,
+};
+module_hid_driver(keytouch_driver);
+
+MODULE_DESCRIPTION("HID driver for Keytouch devices not fully compliant with HID standard");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jiri Kosina");