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, 169 insertions, 0 deletions

diff --git a/drivers/mfd/ab8500-sysctrl.c b/drivers/mfd/ab8500-sysctrl.c
new file mode 100644
index 000000000..b6b44e2e3
--- /dev/null
+++ b/drivers/mfd/ab8500-sysctrl.c
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AB8500 system control driver
+ *
+ * Copyright (C) ST-Ericsson SA 2010
+ * Author: Mattias Nilsson <mattias.i.nilsson@stericsson.com> for ST Ericsson.
+ */
+
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/export.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/reboot.h>
+#include <linux/signal.h>
+#include <linux/power_supply.h>
+#include <linux/mfd/abx500.h>
+#include <linux/mfd/abx500/ab8500.h>
+#include <linux/mfd/abx500/ab8500-sysctrl.h>
+
+/* RtcCtrl bits */
+#define AB8500_ALARM_MIN_LOW  0x08
+#define AB8500_ALARM_MIN_MID 0x09
+#define RTC_CTRL 0x0B
+#define RTC_ALARM_ENABLE 0x4
+
+static struct device *sysctrl_dev;
+
+static void ab8500_power_off(void)
+{
+	sigset_t old;
+	sigset_t all;
+	static const char * const pss[] = {"ab8500_ac", "ab8500_usb"};
+	int i;
+	bool charger_present = false;
+	union power_supply_propval val;
+	struct power_supply *psy;
+	int ret;
+
+	if (sysctrl_dev == NULL) {
+		pr_err("%s: sysctrl not initialized\n", __func__);
+		return;
+	}
+
+	/*
+	 * If we have a charger connected and we're powering off,
+	 * reboot into charge-only mode.
+	 */
+
+	for (i = 0; i < ARRAY_SIZE(pss); i++) {
+		psy = power_supply_get_by_name(pss[i]);
+		if (!psy)
+			continue;
+
+		ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_ONLINE,
+				&val);
+		power_supply_put(psy);
+
+		if (!ret && val.intval) {
+			charger_present = true;
+			break;
+		}
+	}
+
+	if (!charger_present)
+		goto shutdown;
+
+	/* Check if battery is known */
+	psy = power_supply_get_by_name("ab8500_btemp");
+	if (psy) {
+		ret = power_supply_get_property(psy,
+				POWER_SUPPLY_PROP_TECHNOLOGY, &val);
+		if (!ret && val.intval != POWER_SUPPLY_TECHNOLOGY_UNKNOWN) {
+			pr_info("Charger '%s' is connected with known battery",
+				pss[i]);
+			pr_info(" - Rebooting.\n");
+			machine_restart("charging");
+		}
+		power_supply_put(psy);
+	}
+
+shutdown:
+	sigfillset(&all);
+
+	if (!sigprocmask(SIG_BLOCK, &all, &old)) {
+		(void)ab8500_sysctrl_set(AB8500_STW4500CTRL1,
+					 AB8500_STW4500CTRL1_SWOFF |
+					 AB8500_STW4500CTRL1_SWRESET4500N);
+		(void)sigprocmask(SIG_SETMASK, &old, NULL);
+	}
+}
+
+static inline bool valid_bank(u8 bank)
+{
+	return ((bank == AB8500_SYS_CTRL1_BLOCK) ||
+		(bank == AB8500_SYS_CTRL2_BLOCK));
+}
+
+int ab8500_sysctrl_read(u16 reg, u8 *value)
+{
+	u8 bank;
+
+	if (sysctrl_dev == NULL)
+		return -EPROBE_DEFER;
+
+	bank = (reg >> 8);
+	if (!valid_bank(bank))
+		return -EINVAL;
+
+	return abx500_get_register_interruptible(sysctrl_dev, bank,
+		(u8)(reg & 0xFF), value);
+}
+EXPORT_SYMBOL(ab8500_sysctrl_read);
+
+int ab8500_sysctrl_write(u16 reg, u8 mask, u8 value)
+{
+	u8 bank;
+
+	if (sysctrl_dev == NULL)
+		return -EPROBE_DEFER;
+
+	bank = (reg >> 8);
+	if (!valid_bank(bank)) {
+		pr_err("invalid bank\n");
+		return -EINVAL;
+	}
+
+	return abx500_mask_and_set_register_interruptible(sysctrl_dev, bank,
+		(u8)(reg & 0xFF), mask, value);
+}
+EXPORT_SYMBOL(ab8500_sysctrl_write);
+
+static int ab8500_sysctrl_probe(struct platform_device *pdev)
+{
+	sysctrl_dev = &pdev->dev;
+
+	if (!pm_power_off)
+		pm_power_off = ab8500_power_off;
+
+	return 0;
+}
+
+static void ab8500_sysctrl_remove(struct platform_device *pdev)
+{
+	sysctrl_dev = NULL;
+
+	if (pm_power_off == ab8500_power_off)
+		pm_power_off = NULL;
+}
+
+static const struct of_device_id ab8500_sysctrl_match[] = {
+	{ .compatible = "stericsson,ab8500-sysctrl", },
+	{}
+};
+
+static struct platform_driver ab8500_sysctrl_driver = {
+	.driver = {
+		.name = "ab8500-sysctrl",
+		.of_match_table = ab8500_sysctrl_match,
+	},
+	.probe = ab8500_sysctrl_probe,
+	.remove = ab8500_sysctrl_remove,
+};
+
+static int __init ab8500_sysctrl_init(void)
+{
+	return platform_driver_register(&ab8500_sysctrl_driver);
+}
+arch_initcall(ab8500_sysctrl_init);