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, 112 insertions, 0 deletions

diff --git a/drivers/input/misc/cpcap-pwrbutton.c b/drivers/input/misc/cpcap-pwrbutton.c
new file mode 100644
index 000000000..85cddb847
--- /dev/null
+++ b/drivers/input/misc/cpcap-pwrbutton.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * CPCAP Power Button Input Driver
+ *
+ * Copyright (C) 2017 Sebastian Reichel <sre@kernel.org>
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/regmap.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/motorola-cpcap.h>
+
+#define CPCAP_IRQ_ON 23
+#define CPCAP_IRQ_ON_BITMASK (1 << (CPCAP_IRQ_ON % 16))
+
+struct cpcap_power_button {
+	struct regmap *regmap;
+	struct input_dev *idev;
+	struct device *dev;
+};
+
+static irqreturn_t powerbutton_irq(int irq, void *_button)
+{
+	struct cpcap_power_button *button = _button;
+	int val;
+
+	val = cpcap_sense_virq(button->regmap, irq);
+	if (val < 0) {
+		dev_err(button->dev, "irq read failed: %d", val);
+		return IRQ_HANDLED;
+	}
+
+	pm_wakeup_event(button->dev, 0);
+	input_report_key(button->idev, KEY_POWER, val);
+	input_sync(button->idev);
+
+	return IRQ_HANDLED;
+}
+
+static int cpcap_power_button_probe(struct platform_device *pdev)
+{
+	struct cpcap_power_button *button;
+	int irq;
+	int err;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	button = devm_kmalloc(&pdev->dev, sizeof(*button), GFP_KERNEL);
+	if (!button)
+		return -ENOMEM;
+
+	button->idev = devm_input_allocate_device(&pdev->dev);
+	if (!button->idev)
+		return -ENOMEM;
+
+	button->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!button->regmap)
+		return -ENODEV;
+
+	button->dev = &pdev->dev;
+
+	button->idev->name = "cpcap-pwrbutton";
+	button->idev->phys = "cpcap-pwrbutton/input0";
+	input_set_capability(button->idev, EV_KEY, KEY_POWER);
+
+	err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+		powerbutton_irq, IRQF_ONESHOT, "cpcap_pwrbutton", button);
+	if (err < 0) {
+		dev_err(&pdev->dev, "IRQ request failed: %d\n", err);
+		return err;
+	}
+
+	err = input_register_device(button->idev);
+	if (err) {
+		dev_err(&pdev->dev, "Input register failed: %d\n", err);
+		return err;
+	}
+
+	device_init_wakeup(&pdev->dev, true);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id cpcap_pwrbutton_dt_match_table[] = {
+	{ .compatible = "motorola,cpcap-pwrbutton" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, cpcap_pwrbutton_dt_match_table);
+#endif
+
+static struct platform_driver cpcap_power_button_driver = {
+	.probe		= cpcap_power_button_probe,
+	.driver		= {
+		.name	= "cpcap-pwrbutton",
+		.of_match_table = of_match_ptr(cpcap_pwrbutton_dt_match_table),
+	},
+};
+module_platform_driver(cpcap_power_button_driver);
+
+MODULE_ALIAS("platform:cpcap-pwrbutton");
+MODULE_DESCRIPTION("CPCAP Power Button");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");