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, 57 insertions, 0 deletions

diff --git a/include/trace/syscall.h b/include/trace/syscall.h
new file mode 100644
index 000000000..0dd7f2b33
--- /dev/null
+++ b/include/trace/syscall.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _TRACE_SYSCALL_H
+#define _TRACE_SYSCALL_H
+
+#include <linux/tracepoint.h>
+#include <linux/unistd.h>
+#include <linux/trace_events.h>
+#include <linux/thread_info.h>
+
+#include <asm/ptrace.h>
+
+
+/*
+ * A syscall entry in the ftrace syscalls array.
+ *
+ * @name: name of the syscall
+ * @syscall_nr: number of the syscall
+ * @nb_args: number of parameters it takes
+ * @user_arg_is_str: set if the arg for @user_arg_size is a string
+ * @user_arg_size: holds @arg that has size of the user space to read
+ * @user_mask: mask of @args that will read user space
+ * @types: list of types as strings
+ * @args: list of args as strings (args[i] matches types[i])
+ * @enter_fields: list of fields for syscall_enter trace event
+ * @enter_event: associated syscall_enter trace event
+ * @exit_event: associated syscall_exit trace event
+ */
+struct syscall_metadata {
+	const char	*name;
+	int		syscall_nr;
+	u8		nb_args:7;
+	u8		user_arg_is_str:1;
+	s8		user_arg_size;
+	short		user_mask;
+	const char	**types;
+	const char	**args;
+	struct list_head enter_fields;
+
+	struct trace_event_call *enter_event;
+	struct trace_event_call *exit_event;
+};
+
+#if defined(CONFIG_TRACEPOINTS) && defined(CONFIG_HAVE_SYSCALL_TRACEPOINTS)
+static inline void syscall_tracepoint_update(struct task_struct *p)
+{
+	if (test_syscall_work(SYSCALL_TRACEPOINT))
+		set_task_syscall_work(p, SYSCALL_TRACEPOINT);
+	else
+		clear_task_syscall_work(p, SYSCALL_TRACEPOINT);
+}
+#else
+static inline void syscall_tracepoint_update(struct task_struct *p)
+{
+}
+#endif
+
+#endif /* _TRACE_SYSCALL_H */