tracing: Add syscall tracepoints - s390 arch update

This patch includes s390 arch updates to synchronize with latest
core changes in the syscalls tracing area.

- tracing: Map syscall name to number (syscall_name_to_nr())
- tracing: Call arch_init_ftrace_syscalls at boot
- tracing: add support tracepoint ids (set_syscall_{enter,exit}_id())

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
LKML-Reference: <20090825123111.GD4639@cetus.boeblingen.de.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

arch/s390/kernel/ftrace.c

@@ -220,6 +220,29 @@ struct syscall_metadata *syscall_nr_to_meta(int nr)
 	return syscalls_metadata[nr];
 }
 
+int syscall_name_to_nr(char *name)
+{
+	int i;
+
+	if (!syscalls_metadata)
+		return -1;
+	for (i = 0; i < NR_syscalls; i++)
+		if (syscalls_metadata[i])
+			if (!strcmp(syscalls_metadata[i]->name, name))
+				return i;
+	return -1;
+}
+
+void set_syscall_enter_id(int num, int id)
+{
+	syscalls_metadata[num]->enter_id = id;
+}
+
+void set_syscall_exit_id(int num, int id)
+{
+	syscalls_metadata[num]->exit_id = id;
+}
+
 static struct syscall_metadata *find_syscall_meta(unsigned long syscall)
 {
 	struct syscall_metadata *start;
@@ -237,24 +260,19 @@ static struct syscall_metadata *find_syscall_meta(unsigned long syscall)
 	return NULL;
 }
 
-void arch_init_ftrace_syscalls(void)
+static int __init arch_init_ftrace_syscalls(void)
 {
 	struct syscall_metadata *meta;
 	int i;
-	static atomic_t refs;
-
-	if (atomic_inc_return(&refs) != 1)
-		goto out;
 	syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) * NR_syscalls,
 				    GFP_KERNEL);
 	if (!syscalls_metadata)
-		goto out;
+		return -ENOMEM;
 	for (i = 0; i < NR_syscalls; i++) {
 		meta = find_syscall_meta((unsigned long)sys_call_table[i]);
 		syscalls_metadata[i] = meta;
 	}
-	return;
-out:
-	atomic_dec(&refs);
+	return 0;
 }
+arch_initcall(arch_init_ftrace_syscalls);
 #endif