tracing: Call arch_init_ftrace_syscalls at boot

Call arch_init_ftrace_syscalls at boot, so we can determine early the
set of syscalls for the syscall trace events.

Signed-off-by: Jason Baron <jbaron@redhat.com>
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: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index afb31d7..0d93d40 100644 (file)
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -516,31 +516,24 @@ int syscall_name_to_nr(char *name)
        return -1;
 }
 
-void arch_init_ftrace_syscalls(void)
+static int __init arch_init_ftrace_syscalls(void)
 {
        int i;
        struct syscall_metadata *meta;
        unsigned long **psys_syscall_table = &sys_call_table;
-       static atomic_t refs;
-
-       if (atomic_inc_return(&refs) != 1)
-               goto end;
 
        syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) *
                                        FTRACE_SYSCALL_MAX, GFP_KERNEL);
        if (!syscalls_metadata) {
                WARN_ON(1);
-               return;
+               return -ENOMEM;
        }
 
        for (i = 0; i < FTRACE_SYSCALL_MAX; i++) {
                meta = find_syscall_meta(psys_syscall_table[i]);
                syscalls_metadata[i] = meta;
        }
-       return;
-
-       /* Paranoid: avoid overflow */
-end:
-       atomic_dec(&refs);
+       return 0;
 }
+arch_initcall(arch_init_ftrace_syscalls);
 #endif

diff --git a/include/trace/syscall.h b/include/trace/syscall.h
index 8cfe515..c55fcce 100644 (file)
--- a/include/trace/syscall.h
+++ b/include/trace/syscall.h
@@ -19,7 +19,6 @@ struct syscall_metadata {
 };
 
 #ifdef CONFIG_FTRACE_SYSCALLS
-extern void arch_init_ftrace_syscalls(void);
 extern struct syscall_metadata *syscall_nr_to_meta(int nr);
 extern void start_ftrace_syscalls(void);
 extern void stop_ftrace_syscalls(void);

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 5e57964..08aed43 100644 (file)
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -106,7 +106,6 @@ void start_ftrace_syscalls(void)
        if (++refcount != 1)
                goto unlock;
 
-       arch_init_ftrace_syscalls();
        read_lock_irqsave(&tasklist_lock, flags);
 
        do_each_thread(g, t) {