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, 40 insertions, 0 deletions

diff --git a/drivers/input/vivaldi-fmap.c b/drivers/input/vivaldi-fmap.c
new file mode 100644
index 000000000..978949eba
--- /dev/null
+++ b/drivers/input/vivaldi-fmap.c
@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Helpers for ChromeOS Vivaldi keyboard function row mapping
+ *
+ * Copyright (C) 2022 Google, Inc
+ */
+
+#include <linux/export.h>
+#include <linux/input/vivaldi-fmap.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/types.h>
+
+/**
+ * vivaldi_function_row_physmap_show - Print vivaldi function row physmap attribute
+ * @data: The vivaldi function row map
+ * @buf: Buffer to print the function row phsymap to
+ */
+ssize_t vivaldi_function_row_physmap_show(const struct vivaldi_data *data,
+					  char *buf)
+{
+	ssize_t size = 0;
+	int i;
+	const u32 *physmap = data->function_row_physmap;
+
+	if (!data->num_function_row_keys)
+		return 0;
+
+	for (i = 0; i < data->num_function_row_keys; i++)
+		size += sysfs_emit_at(buf, size,
+				      "%s%02X", size ? " " : "", physmap[i]);
+	if (size)
+		size += sysfs_emit_at(buf, size, "\n");
+
+	return size;
+}
+EXPORT_SYMBOL_GPL(vivaldi_function_row_physmap_show);
+
+MODULE_DESCRIPTION("Helpers for ChromeOS Vivaldi keyboard function row mapping");
+MODULE_LICENSE("GPL");