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, 135 insertions, 0 deletions

diff --git a/drivers/leds/trigger/ledtrig-timer.c b/drivers/leds/trigger/ledtrig-timer.c
new file mode 100644
index 000000000..1d213c999
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-timer.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * LED Kernel Timer Trigger
+ *
+ * Copyright 2005-2006 Openedhand Ltd.
+ *
+ * Author: Richard Purdie <rpurdie@openedhand.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/ctype.h>
+#include <linux/slab.h>
+#include <linux/leds.h>
+
+static ssize_t led_delay_on_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev = led_trigger_get_led(dev);
+
+	return sprintf(buf, "%lu\n", led_cdev->blink_delay_on);
+}
+
+static ssize_t led_delay_on_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct led_classdev *led_cdev = led_trigger_get_led(dev);
+	unsigned long state;
+	ssize_t ret;
+
+	ret = kstrtoul(buf, 10, &state);
+	if (ret)
+		return ret;
+
+	led_blink_set(led_cdev, &state, &led_cdev->blink_delay_off);
+	led_cdev->blink_delay_on = state;
+
+	return size;
+}
+
+static ssize_t led_delay_off_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev = led_trigger_get_led(dev);
+
+	return sprintf(buf, "%lu\n", led_cdev->blink_delay_off);
+}
+
+static ssize_t led_delay_off_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct led_classdev *led_cdev = led_trigger_get_led(dev);
+	unsigned long state;
+	ssize_t ret;
+
+	ret = kstrtoul(buf, 10, &state);
+	if (ret)
+		return ret;
+
+	led_blink_set(led_cdev, &led_cdev->blink_delay_on, &state);
+	led_cdev->blink_delay_off = state;
+
+	return size;
+}
+
+static DEVICE_ATTR(delay_on, 0644, led_delay_on_show, led_delay_on_store);
+static DEVICE_ATTR(delay_off, 0644, led_delay_off_show, led_delay_off_store);
+
+static struct attribute *timer_trig_attrs[] = {
+	&dev_attr_delay_on.attr,
+	&dev_attr_delay_off.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(timer_trig);
+
+static void pattern_init(struct led_classdev *led_cdev)
+{
+	u32 *pattern;
+	unsigned int size = 0;
+
+	pattern = led_get_default_pattern(led_cdev, &size);
+	if (!pattern)
+		return;
+
+	if (size != 2) {
+		dev_warn(led_cdev->dev,
+			 "Expected 2 but got %u values for delays pattern\n",
+			 size);
+		goto out;
+	}
+
+	led_cdev->blink_delay_on = pattern[0];
+	led_cdev->blink_delay_off = pattern[1];
+	/* led_blink_set() called by caller */
+
+out:
+	kfree(pattern);
+}
+
+static int timer_trig_activate(struct led_classdev *led_cdev)
+{
+	if (led_cdev->flags & LED_INIT_DEFAULT_TRIGGER) {
+		pattern_init(led_cdev);
+		/*
+		 * Mark as initialized even on pattern_init() error because
+		 * any consecutive call to it would produce the same error.
+		 */
+		led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;
+	}
+
+	led_blink_set(led_cdev, &led_cdev->blink_delay_on,
+		      &led_cdev->blink_delay_off);
+
+	return 0;
+}
+
+static void timer_trig_deactivate(struct led_classdev *led_cdev)
+{
+	/* Stop blinking */
+	led_set_brightness(led_cdev, LED_OFF);
+}
+
+static struct led_trigger timer_led_trigger = {
+	.name     = "timer",
+	.activate = timer_trig_activate,
+	.deactivate = timer_trig_deactivate,
+	.groups = timer_trig_groups,
+};
+module_led_trigger(timer_led_trigger);
+
+MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
+MODULE_DESCRIPTION("Timer LED trigger");
+MODULE_LICENSE("GPL v2");