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, 91 insertions, 0 deletions

diff --git a/drivers/regulator/event.c b/drivers/regulator/event.c
new file mode 100644
index 000000000..ea3bd4954
--- /dev/null
+++ b/drivers/regulator/event.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Regulator event over netlink
+ *
+ * Author: Naresh Solanki <Naresh.Solanki@9elements.com>
+ */
+
+#include <regulator/regulator.h>
+#include <net/netlink.h>
+#include <net/genetlink.h>
+#include <linux/atomic.h>
+
+#include "regnl.h"
+
+static atomic_t reg_event_seqnum = ATOMIC_INIT(0);
+
+static const struct genl_multicast_group reg_event_mcgrps[] = {
+	{ .name = REG_GENL_MCAST_GROUP_NAME, },
+};
+
+static struct genl_family reg_event_genl_family __ro_after_init = {
+	.module = THIS_MODULE,
+	.name = REG_GENL_FAMILY_NAME,
+	.version = REG_GENL_VERSION,
+	.maxattr = REG_GENL_ATTR_MAX,
+	.mcgrps = reg_event_mcgrps,
+	.n_mcgrps = ARRAY_SIZE(reg_event_mcgrps),
+};
+
+int reg_generate_netlink_event(const char *reg_name, u64 event)
+{
+	struct sk_buff *skb;
+	struct nlattr *attr;
+	struct reg_genl_event *edata;
+	void *msg_header;
+	int size;
+
+	/* allocate memory */
+	size = nla_total_size(sizeof(struct reg_genl_event)) +
+	    nla_total_size(0);
+
+	skb = genlmsg_new(size, GFP_ATOMIC);
+	if (!skb)
+		return -ENOMEM;
+
+	/* add the genetlink message header */
+	msg_header = genlmsg_put(skb, 0, atomic_inc_return(&reg_event_seqnum),
+				 &reg_event_genl_family, 0, REG_GENL_CMD_EVENT);
+	if (!msg_header) {
+		nlmsg_free(skb);
+		return -ENOMEM;
+	}
+
+	/* fill the data */
+	attr = nla_reserve(skb, REG_GENL_ATTR_EVENT, sizeof(struct reg_genl_event));
+	if (!attr) {
+		nlmsg_free(skb);
+		return -EINVAL;
+	}
+
+	edata = nla_data(attr);
+	memset(edata, 0, sizeof(struct reg_genl_event));
+
+	strscpy(edata->reg_name, reg_name, sizeof(edata->reg_name));
+	edata->event = event;
+
+	/* send multicast genetlink message */
+	genlmsg_end(skb, msg_header);
+	size = genlmsg_multicast(&reg_event_genl_family, skb, 0, 0, GFP_ATOMIC);
+
+	return size;
+}
+
+static int __init reg_event_genetlink_init(void)
+{
+	return genl_register_family(&reg_event_genl_family);
+}
+
+static int __init reg_event_init(void)
+{
+	int error;
+
+	/* create genetlink for acpi event */
+	error = reg_event_genetlink_init();
+	if (error)
+		pr_warn("Failed to create genetlink family for reg event\n");
+
+	return 0;
+}
+
+fs_initcall(reg_event_init);