--- zzzz-none-000/linux-3.10.107/kernel/trace/trace_syscalls.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/kernel/trace/trace_syscalls.c	2021-02-04 17:41:59.000000000 +0000
@@ -13,13 +13,13 @@
 
 static DEFINE_MUTEX(syscall_trace_lock);
 
-static int syscall_enter_register(struct ftrace_event_call *event,
+static int syscall_enter_register(struct trace_event_call *event,
 				 enum trace_reg type, void *data);
-static int syscall_exit_register(struct ftrace_event_call *event,
+static int syscall_exit_register(struct trace_event_call *event,
 				 enum trace_reg type, void *data);
 
 static struct list_head *
-syscall_get_enter_fields(struct ftrace_event_call *call)
+syscall_get_enter_fields(struct trace_event_call *call)
 {
 	struct syscall_metadata *entry = call->data;
 
@@ -110,11 +110,12 @@
 print_syscall_enter(struct trace_iterator *iter, int flags,
 		    struct trace_event *event)
 {
+	struct trace_array *tr = iter->tr;
 	struct trace_seq *s = &iter->seq;
 	struct trace_entry *ent = iter->ent;
 	struct syscall_trace_enter *trace;
 	struct syscall_metadata *entry;
-	int i, ret, syscall;
+	int i, syscall;
 
 	trace = (typeof(trace))ent;
 	syscall = trace->nr;
@@ -128,35 +129,28 @@
 		goto end;
 	}
 
-	ret = trace_seq_printf(s, "%s(", entry->name);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(s, "%s(", entry->name);
 
 	for (i = 0; i < entry->nb_args; i++) {
+
+		if (trace_seq_has_overflowed(s))
+			goto end;
+
 		/* parameter types */
-		if (trace_flags & TRACE_ITER_VERBOSE) {
-			ret = trace_seq_printf(s, "%s ", entry->types[i]);
-			if (!ret)
-				return TRACE_TYPE_PARTIAL_LINE;
-		}
+		if (tr->trace_flags & TRACE_ITER_VERBOSE)
+			trace_seq_printf(s, "%s ", entry->types[i]);
+
 		/* parameter values */
-		ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
-				       trace->args[i],
-				       i == entry->nb_args - 1 ? "" : ", ");
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
+		trace_seq_printf(s, "%s: %lx%s", entry->args[i],
+				 trace->args[i],
+				 i == entry->nb_args - 1 ? "" : ", ");
 	}
 
-	ret = trace_seq_putc(s, ')');
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
+	trace_seq_putc(s, ')');
 end:
-	ret =  trace_seq_putc(s, '\n');
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_putc(s, '\n');
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t
@@ -168,15 +162,14 @@
 	struct syscall_trace_exit *trace;
 	int syscall;
 	struct syscall_metadata *entry;
-	int ret;
 
 	trace = (typeof(trace))ent;
 	syscall = trace->nr;
 	entry = syscall_nr_to_meta(syscall);
 
 	if (!entry) {
-		trace_seq_printf(s, "\n");
-		return TRACE_TYPE_HANDLED;
+		trace_seq_putc(s, '\n');
+		goto out;
 	}
 
 	if (entry->exit_event->event.type != ent->type) {
@@ -184,12 +177,11 @@
 		return TRACE_TYPE_UNHANDLED;
 	}
 
-	ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
+	trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
 				trace->ret);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
 
-	return TRACE_TYPE_HANDLED;
+ out:
+	return trace_handle_return(s);
 }
 
 extern char *__bad_type_size(void);
@@ -200,8 +192,8 @@
 		#type, #name, offsetof(typeof(trace), name),		\
 		sizeof(trace.name), is_signed_type(type)
 
-static
-int  __set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
+static int __init
+__set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
 {
 	int i;
 	int pos = 0;
@@ -228,7 +220,7 @@
 	return pos;
 }
 
-static int set_syscall_print_fmt(struct ftrace_event_call *call)
+static int __init set_syscall_print_fmt(struct trace_event_call *call)
 {
 	char *print_fmt;
 	int len;
@@ -253,7 +245,7 @@
 	return 0;
 }
 
-static void free_syscall_print_fmt(struct ftrace_event_call *call)
+static void __init free_syscall_print_fmt(struct trace_event_call *call)
 {
 	struct syscall_metadata *entry = call->data;
 
@@ -261,7 +253,7 @@
 		kfree(call->print_fmt);
 }
 
-static int __init syscall_enter_define_fields(struct ftrace_event_call *call)
+static int __init syscall_enter_define_fields(struct trace_event_call *call)
 {
 	struct syscall_trace_enter trace;
 	struct syscall_metadata *meta = call->data;
@@ -284,7 +276,7 @@
 	return ret;
 }
 
-static int __init syscall_exit_define_fields(struct ftrace_event_call *call)
+static int __init syscall_exit_define_fields(struct trace_event_call *call)
 {
 	struct syscall_trace_exit trace;
 	int ret;
@@ -302,6 +294,7 @@
 static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
 {
 	struct trace_array *tr = data;
+	struct trace_event_file *trace_file;
 	struct syscall_trace_enter *entry;
 	struct syscall_metadata *sys_data;
 	struct ring_buffer_event *event;
@@ -314,7 +307,13 @@
 	syscall_nr = trace_get_syscall_nr(current, regs);
 	if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
 		return;
-	if (!test_bit(syscall_nr, tr->enabled_enter_syscalls))
+
+	/* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE) */
+	trace_file = rcu_dereference_sched(tr->enter_syscall_files[syscall_nr]);
+	if (!trace_file)
+		return;
+
+	if (trace_trigger_soft_disabled(trace_file))
 		return;
 
 	sys_data = syscall_nr_to_meta(syscall_nr);
@@ -336,15 +335,14 @@
 	entry->nr = syscall_nr;
 	syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
 
-	if (!filter_current_check_discard(buffer, sys_data->enter_event,
-					  entry, event))
-		trace_current_buffer_unlock_commit(buffer, event,
-						   irq_flags, pc);
+	event_trigger_unlock_commit(trace_file, buffer, event, entry,
+				    irq_flags, pc);
 }
 
 static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
 {
 	struct trace_array *tr = data;
+	struct trace_event_file *trace_file;
 	struct syscall_trace_exit *entry;
 	struct syscall_metadata *sys_data;
 	struct ring_buffer_event *event;
@@ -356,7 +354,13 @@
 	syscall_nr = trace_get_syscall_nr(current, regs);
 	if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
 		return;
-	if (!test_bit(syscall_nr, tr->enabled_exit_syscalls))
+
+	/* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE()) */
+	trace_file = rcu_dereference_sched(tr->exit_syscall_files[syscall_nr]);
+	if (!trace_file)
+		return;
+
+	if (trace_trigger_soft_disabled(trace_file))
 		return;
 
 	sys_data = syscall_nr_to_meta(syscall_nr);
@@ -377,14 +381,12 @@
 	entry->nr = syscall_nr;
 	entry->ret = syscall_get_return_value(current, regs);
 
-	if (!filter_current_check_discard(buffer, sys_data->exit_event,
-					  entry, event))
-		trace_current_buffer_unlock_commit(buffer, event,
-						   irq_flags, pc);
+	event_trigger_unlock_commit(trace_file, buffer, event, entry,
+				    irq_flags, pc);
 }
 
-static int reg_event_syscall_enter(struct ftrace_event_file *file,
-				   struct ftrace_event_call *call)
+static int reg_event_syscall_enter(struct trace_event_file *file,
+				   struct trace_event_call *call)
 {
 	struct trace_array *tr = file->tr;
 	int ret = 0;
@@ -397,15 +399,15 @@
 	if (!tr->sys_refcount_enter)
 		ret = register_trace_sys_enter(ftrace_syscall_enter, tr);
 	if (!ret) {
-		set_bit(num, tr->enabled_enter_syscalls);
+		rcu_assign_pointer(tr->enter_syscall_files[num], file);
 		tr->sys_refcount_enter++;
 	}
 	mutex_unlock(&syscall_trace_lock);
 	return ret;
 }
 
-static void unreg_event_syscall_enter(struct ftrace_event_file *file,
-				      struct ftrace_event_call *call)
+static void unreg_event_syscall_enter(struct trace_event_file *file,
+				      struct trace_event_call *call)
 {
 	struct trace_array *tr = file->tr;
 	int num;
@@ -415,14 +417,14 @@
 		return;
 	mutex_lock(&syscall_trace_lock);
 	tr->sys_refcount_enter--;
-	clear_bit(num, tr->enabled_enter_syscalls);
+	RCU_INIT_POINTER(tr->enter_syscall_files[num], NULL);
 	if (!tr->sys_refcount_enter)
 		unregister_trace_sys_enter(ftrace_syscall_enter, tr);
 	mutex_unlock(&syscall_trace_lock);
 }
 
-static int reg_event_syscall_exit(struct ftrace_event_file *file,
-				  struct ftrace_event_call *call)
+static int reg_event_syscall_exit(struct trace_event_file *file,
+				  struct trace_event_call *call)
 {
 	struct trace_array *tr = file->tr;
 	int ret = 0;
@@ -435,15 +437,15 @@
 	if (!tr->sys_refcount_exit)
 		ret = register_trace_sys_exit(ftrace_syscall_exit, tr);
 	if (!ret) {
-		set_bit(num, tr->enabled_exit_syscalls);
+		rcu_assign_pointer(tr->exit_syscall_files[num], file);
 		tr->sys_refcount_exit++;
 	}
 	mutex_unlock(&syscall_trace_lock);
 	return ret;
 }
 
-static void unreg_event_syscall_exit(struct ftrace_event_file *file,
-				     struct ftrace_event_call *call)
+static void unreg_event_syscall_exit(struct trace_event_file *file,
+				     struct trace_event_call *call)
 {
 	struct trace_array *tr = file->tr;
 	int num;
@@ -453,13 +455,13 @@
 		return;
 	mutex_lock(&syscall_trace_lock);
 	tr->sys_refcount_exit--;
-	clear_bit(num, tr->enabled_exit_syscalls);
+	RCU_INIT_POINTER(tr->exit_syscall_files[num], NULL);
 	if (!tr->sys_refcount_exit)
 		unregister_trace_sys_exit(ftrace_syscall_exit, tr);
 	mutex_unlock(&syscall_trace_lock);
 }
 
-static int init_syscall_trace(struct ftrace_event_call *call)
+static int __init init_syscall_trace(struct trace_event_call *call)
 {
 	int id;
 	int num;
@@ -492,7 +494,7 @@
 	.trace		= print_syscall_exit,
 };
 
-struct ftrace_event_class __refdata event_class_syscall_enter = {
+struct trace_event_class __refdata event_class_syscall_enter = {
 	.system		= "syscalls",
 	.reg		= syscall_enter_register,
 	.define_fields	= syscall_enter_define_fields,
@@ -500,7 +502,7 @@
 	.raw_init	= init_syscall_trace,
 };
 
-struct ftrace_event_class __refdata event_class_syscall_exit = {
+struct trace_event_class __refdata event_class_syscall_exit = {
 	.system		= "syscalls",
 	.reg		= syscall_exit_register,
 	.define_fields	= syscall_exit_define_fields,
@@ -513,7 +515,7 @@
 	return (unsigned long)sys_call_table[nr];
 }
 
-static int __init init_ftrace_syscalls(void)
+void __init init_ftrace_syscalls(void)
 {
 	struct syscall_metadata *meta;
 	unsigned long addr;
@@ -523,7 +525,7 @@
 				    GFP_KERNEL);
 	if (!syscalls_metadata) {
 		WARN_ON(1);
-		return -ENOMEM;
+		return;
 	}
 
 	for (i = 0; i < NR_syscalls; i++) {
@@ -535,10 +537,7 @@
 		meta->syscall_nr = i;
 		syscalls_metadata[i] = meta;
 	}
-
-	return 0;
 }
-early_initcall(init_ftrace_syscalls);
 
 #ifdef CONFIG_PERF_EVENTS
 
@@ -566,29 +565,27 @@
 	if (!sys_data)
 		return;
 
+	head = this_cpu_ptr(sys_data->enter_event->perf_events);
+	if (hlist_empty(head))
+		return;
+
 	/* get the size after alignment with the u32 buffer size field */
 	size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
 	size = ALIGN(size + sizeof(u32), sizeof(u64));
 	size -= sizeof(u32);
 
-	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-		      "perf buffer not large enough"))
-		return;
-
 	rec = (struct syscall_trace_enter *)perf_trace_buf_prepare(size,
-				sys_data->enter_event->event.type, regs, &rctx);
+				sys_data->enter_event->event.type, NULL, &rctx);
 	if (!rec)
 		return;
 
 	rec->nr = syscall_nr;
 	syscall_get_arguments(current, regs, 0, sys_data->nb_args,
 			       (unsigned long *)&rec->args);
-
-	head = this_cpu_ptr(sys_data->enter_event->perf_events);
 	perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
 }
 
-static int perf_sysenter_enable(struct ftrace_event_call *call)
+static int perf_sysenter_enable(struct trace_event_call *call)
 {
 	int ret = 0;
 	int num;
@@ -609,7 +606,7 @@
 	return ret;
 }
 
-static void perf_sysenter_disable(struct ftrace_event_call *call)
+static void perf_sysenter_disable(struct trace_event_call *call)
 {
 	int num;
 
@@ -642,31 +639,25 @@
 	if (!sys_data)
 		return;
 
+	head = this_cpu_ptr(sys_data->exit_event->perf_events);
+	if (hlist_empty(head))
+		return;
+
 	/* We can probably do that at build time */
 	size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
 	size -= sizeof(u32);
 
-	/*
-	 * Impossible, but be paranoid with the future
-	 * How to put this check outside runtime?
-	 */
-	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-		"exit event has grown above perf buffer size"))
-		return;
-
 	rec = (struct syscall_trace_exit *)perf_trace_buf_prepare(size,
-				sys_data->exit_event->event.type, regs, &rctx);
+				sys_data->exit_event->event.type, NULL, &rctx);
 	if (!rec)
 		return;
 
 	rec->nr = syscall_nr;
 	rec->ret = syscall_get_return_value(current, regs);
-
-	head = this_cpu_ptr(sys_data->exit_event->perf_events);
 	perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
 }
 
-static int perf_sysexit_enable(struct ftrace_event_call *call)
+static int perf_sysexit_enable(struct trace_event_call *call)
 {
 	int ret = 0;
 	int num;
@@ -687,7 +678,7 @@
 	return ret;
 }
 
-static void perf_sysexit_disable(struct ftrace_event_call *call)
+static void perf_sysexit_disable(struct trace_event_call *call)
 {
 	int num;
 
@@ -703,10 +694,10 @@
 
 #endif /* CONFIG_PERF_EVENTS */
 
-static int syscall_enter_register(struct ftrace_event_call *event,
+static int syscall_enter_register(struct trace_event_call *event,
 				 enum trace_reg type, void *data)
 {
-	struct ftrace_event_file *file = data;
+	struct trace_event_file *file = data;
 
 	switch (type) {
 	case TRACE_REG_REGISTER:
@@ -731,10 +722,10 @@
 	return 0;
 }
 
-static int syscall_exit_register(struct ftrace_event_call *event,
+static int syscall_exit_register(struct trace_event_call *event,
 				 enum trace_reg type, void *data)
 {
-	struct ftrace_event_file *file = data;
+	struct trace_event_file *file = data;
 
 	switch (type) {
 	case TRACE_REG_REGISTER: