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, 207 insertions, 0 deletions

diff --git a/drivers/clocksource/timer-imx-sysctr.c b/drivers/clocksource/timer-imx-sysctr.c
new file mode 100644
index 000000000..dfbd77950
--- /dev/null
+++ b/drivers/clocksource/timer-imx-sysctr.c
@@ -0,0 +1,207 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Copyright 2017-2019 NXP
+
+#include <linux/interrupt.h>
+#include <linux/clockchips.h>
+#include <linux/slab.h>
+
+#include "timer-of.h"
+
+#define CMP_OFFSET	0x10000
+#define RD_OFFSET	0x20000
+
+#define CNTCV_LO	0x8
+#define CNTCV_HI	0xc
+#define CMPCV_LO	(CMP_OFFSET + 0x20)
+#define CMPCV_HI	(CMP_OFFSET + 0x24)
+#define CMPCR		(CMP_OFFSET + 0x2c)
+#define CNTCV_LO_IMX95	(RD_OFFSET + 0x8)
+#define CNTCV_HI_IMX95	(RD_OFFSET + 0xc)
+
+#define SYS_CTR_EN		0x1
+#define SYS_CTR_IRQ_MASK	0x2
+
+#define SYS_CTR_CLK_DIV		0x3
+
+struct sysctr_private {
+	u32 cmpcr;
+	u32 lo_off;
+	u32 hi_off;
+};
+
+static void sysctr_timer_enable(struct clock_event_device *evt, bool enable)
+{
+	struct timer_of *to = to_timer_of(evt);
+	struct sysctr_private *priv = to->private_data;
+	void __iomem *base = timer_of_base(to);
+
+	writel(enable ? priv->cmpcr | SYS_CTR_EN : priv->cmpcr, base + CMPCR);
+}
+
+static void sysctr_irq_acknowledge(struct clock_event_device *evt)
+{
+	/*
+	 * clear the enable bit(EN =0) will clear
+	 * the status bit(ISTAT = 0), then the interrupt
+	 * signal will be negated(acknowledged).
+	 */
+	sysctr_timer_enable(evt, false);
+}
+
+static inline u64 sysctr_read_counter(struct clock_event_device *evt)
+{
+	struct timer_of *to = to_timer_of(evt);
+	struct sysctr_private *priv = to->private_data;
+	void __iomem *base = timer_of_base(to);
+	u32 cnt_hi, tmp_hi, cnt_lo;
+
+	do {
+		cnt_hi = readl_relaxed(base + priv->hi_off);
+		cnt_lo = readl_relaxed(base + priv->lo_off);
+		tmp_hi = readl_relaxed(base + priv->hi_off);
+	} while (tmp_hi != cnt_hi);
+
+	return  ((u64) cnt_hi << 32) | cnt_lo;
+}
+
+static int sysctr_set_next_event(unsigned long delta,
+				 struct clock_event_device *evt)
+{
+	struct timer_of *to = to_timer_of(evt);
+	void __iomem *base = timer_of_base(to);
+	u32 cmp_hi, cmp_lo;
+	u64 next;
+
+	sysctr_timer_enable(evt, false);
+
+	next = sysctr_read_counter(evt);
+
+	next += delta;
+
+	cmp_hi = (next >> 32) & 0x00fffff;
+	cmp_lo = next & 0xffffffff;
+
+	writel_relaxed(cmp_hi, base + CMPCV_HI);
+	writel_relaxed(cmp_lo, base + CMPCV_LO);
+
+	sysctr_timer_enable(evt, true);
+
+	return 0;
+}
+
+static int sysctr_set_state_oneshot(struct clock_event_device *evt)
+{
+	return 0;
+}
+
+static int sysctr_set_state_shutdown(struct clock_event_device *evt)
+{
+	sysctr_timer_enable(evt, false);
+
+	return 0;
+}
+
+static irqreturn_t sysctr_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = dev_id;
+
+	sysctr_irq_acknowledge(evt);
+
+	evt->event_handler(evt);
+
+	return IRQ_HANDLED;
+}
+
+static struct timer_of to_sysctr = {
+	.flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE,
+	.clkevt = {
+		.name			= "i.MX system counter timer",
+		.features		= CLOCK_EVT_FEAT_ONESHOT |
+						CLOCK_EVT_FEAT_DYNIRQ,
+		.set_state_oneshot	= sysctr_set_state_oneshot,
+		.set_next_event		= sysctr_set_next_event,
+		.set_state_shutdown	= sysctr_set_state_shutdown,
+		.rating			= 200,
+	},
+	.of_irq = {
+		.handler		= sysctr_timer_interrupt,
+		.flags			= IRQF_TIMER,
+	},
+	.of_clk = {
+		.name = "per",
+	},
+};
+
+static int __init __sysctr_timer_init(struct device_node *np)
+{
+	struct sysctr_private *priv;
+	void __iomem *base;
+	int ret;
+
+	priv = kzalloc_obj(struct sysctr_private);
+	if (!priv)
+		return -ENOMEM;
+
+	ret = timer_of_init(np, &to_sysctr);
+	if (ret) {
+		kfree(priv);
+		return ret;
+	}
+
+	if (!of_property_read_bool(np, "nxp,no-divider")) {
+		/* system counter clock is divided by 3 internally */
+		to_sysctr.of_clk.rate /= SYS_CTR_CLK_DIV;
+	}
+
+	to_sysctr.clkevt.cpumask = cpu_possible_mask;
+	to_sysctr.private_data = priv;
+
+	base = timer_of_base(&to_sysctr);
+	priv->cmpcr = readl(base + CMPCR) & ~SYS_CTR_EN;
+
+	return 0;
+}
+
+static int __init sysctr_timer_init(struct device_node *np)
+{
+	struct sysctr_private *priv;
+	int ret;
+
+	ret = __sysctr_timer_init(np);
+	if (ret)
+		return ret;
+
+	priv = to_sysctr.private_data;
+	priv->lo_off = CNTCV_LO;
+	priv->hi_off = CNTCV_HI;
+
+	clockevents_config_and_register(&to_sysctr.clkevt,
+					timer_of_rate(&to_sysctr),
+					0xff, 0x7fffffff);
+
+	return 0;
+}
+
+static int __init sysctr_timer_imx95_init(struct device_node *np)
+{
+	struct sysctr_private *priv;
+	int ret;
+
+	ret = __sysctr_timer_init(np);
+	if (ret)
+		return ret;
+
+	priv = to_sysctr.private_data;
+	priv->lo_off = CNTCV_LO_IMX95;
+	priv->hi_off = CNTCV_HI_IMX95;
+
+	clockevents_config_and_register(&to_sysctr.clkevt,
+					timer_of_rate(&to_sysctr),
+					0xff, 0x7fffffff);
+
+	return 0;
+}
+
+TIMER_OF_DECLARE(sysctr_timer, "nxp,sysctr-timer", sysctr_timer_init);
+TIMER_OF_DECLARE(sysctr_timer_imx95, "nxp,imx95-sysctr-timer", sysctr_timer_imx95_init);