4 files changed, 91 insertions, 140 deletions

diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 57bdcb1e3cdf..7c5752c3423d 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -206,73 +206,10 @@ out:
 
 #ifdef CONFIG_FTRACE_SYSCALLS
 
-extern unsigned long __start_syscalls_metadata[];
-extern unsigned long __stop_syscalls_metadata[];
 extern unsigned int sys_call_table[];
 
-static struct syscall_metadata **syscalls_metadata;
-
-struct syscall_metadata *syscall_nr_to_meta(int nr)
-{
-        if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
-                return NULL;
-
-        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)
+unsigned long __init arch_syscall_addr(int nr)
 {
-        syscalls_metadata[num]->exit_id = id;
-}
-
-static struct syscall_metadata *find_syscall_meta(unsigned long syscall)
-{
-        struct syscall_metadata *start;
-        struct syscall_metadata *stop;
-        char str[KSYM_SYMBOL_LEN];
-
-        start = (struct syscall_metadata *)__start_syscalls_metadata;
-        stop = (struct syscall_metadata *)__stop_syscalls_metadata;
-        kallsyms_lookup(syscall, NULL, NULL, NULL, str);
-
-        for ( ; start < stop; start++) {
-                if (start->name && !strcmp(start->name + 3, str + 3))
-                        return start;
-        }
-        return NULL;
-}
-
-static int __init arch_init_ftrace_syscalls(void)
-{
-        struct syscall_metadata *meta;
-        int i;
-        syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) * NR_syscalls,
-                                    GFP_KERNEL);
-        if (!syscalls_metadata)
-                return -ENOMEM;
-        for (i = 0; i < NR_syscalls; i++) {
-                meta = find_syscall_meta((unsigned long)sys_call_table[i]);
-                syscalls_metadata[i] = meta;
-        }
-        return 0;
+        return (unsigned long)sys_call_table[nr];
 }
-arch_initcall(arch_init_ftrace_syscalls);
 #endif
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 25e6f5fc4b1e..5a1b9758fd62 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -470,82 +470,10 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
 
 #ifdef CONFIG_FTRACE_SYSCALLS
 
-extern unsigned long __start_syscalls_metadata[];
-extern unsigned long __stop_syscalls_metadata[];
 extern unsigned long *sys_call_table;
 
-static struct syscall_metadata **syscalls_metadata;
-
-static struct syscall_metadata *find_syscall_meta(unsigned long *syscall)
-{
-        struct syscall_metadata *start;
-        struct syscall_metadata *stop;
-        char str[KSYM_SYMBOL_LEN];
-
-
-        start = (struct syscall_metadata *)__start_syscalls_metadata;
-        stop = (struct syscall_metadata *)__stop_syscalls_metadata;
-        kallsyms_lookup((unsigned long) syscall, NULL, NULL, NULL, str);
-
-        for ( ; start < stop; start++) {
-                if (start->name && !strcmp(start->name, str))
-                        return start;
-        }
-        return NULL;
-}
-
-struct syscall_metadata *syscall_nr_to_meta(int nr)
-{
-        if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
-                return NULL;
-
-        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)
+unsigned long __init arch_syscall_addr(int nr)
 {
-        syscalls_metadata[num]->exit_id = id;
-}
-
-static int __init arch_init_ftrace_syscalls(void)
-{
-        int i;
-        struct syscall_metadata *meta;
-        unsigned long **psys_syscall_table = &sys_call_table;
-
-        syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) *
-                                        NR_syscalls, GFP_KERNEL);
-        if (!syscalls_metadata) {
-                WARN_ON(1);
-                return -ENOMEM;
-        }
-
-        for (i = 0; i < NR_syscalls; i++) {
-                meta = find_syscall_meta(psys_syscall_table[i]);
-                syscalls_metadata[i] = meta;
-        }
-        return 0;
+        return (unsigned long)(&sys_call_table)[nr];
 }
-arch_initcall(arch_init_ftrace_syscalls);
 #endif
diff --git a/include/trace/syscall.h b/include/trace/syscall.h
index 5dc283ba5ae0..e972f0a40f8d 100644
--- a/include/trace/syscall.h
+++ b/include/trace/syscall.h
@@ -33,7 +33,7 @@ struct syscall_metadata {
 };
 
 #ifdef CONFIG_FTRACE_SYSCALLS
-extern struct syscall_metadata *syscall_nr_to_meta(int nr);
+extern unsigned long arch_syscall_addr(int nr);
 extern int syscall_name_to_nr(char *name);
 void set_syscall_enter_id(int num, int id);
 void set_syscall_exit_id(int num, int id);
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 9fbce6c9d2e1..8bda4bff2286 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -14,6 +14,69 @@ static int sys_refcount_exit;
 static DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls);
 static DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls);
 
+extern unsigned long __start_syscalls_metadata[];
+extern unsigned long __stop_syscalls_metadata[];
+
+static struct syscall_metadata **syscalls_metadata;
+
+static struct syscall_metadata *find_syscall_meta(unsigned long syscall)
+{
+        struct syscall_metadata *start;
+        struct syscall_metadata *stop;
+        char str[KSYM_SYMBOL_LEN];
+
+
+        start = (struct syscall_metadata *)__start_syscalls_metadata;
+        stop = (struct syscall_metadata *)__stop_syscalls_metadata;
+        kallsyms_lookup(syscall, NULL, NULL, NULL, str);
+
+        for ( ; start < stop; start++) {
+                /*
+                 * Only compare after the "sys" prefix. Archs that use
+                 * syscall wrappers may have syscalls symbols aliases prefixed
+                 * with "SyS" instead of "sys", leading to an unwanted
+                 * mismatch.
+                 */
+                if (start->name && !strcmp(start->name + 3, str + 3))
+                        return start;
+        }
+        return NULL;
+}
+
+static struct syscall_metadata *syscall_nr_to_meta(int nr)
+{
+        if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
+                return NULL;
+
+        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;
+}
+
 enum print_line_t
 print_syscall_enter(struct trace_iterator *iter, int flags)
 {
@@ -375,6 +438,29 @@ struct trace_event event_syscall_exit = {
         .trace                  = print_syscall_exit,
 };
 
+int __init init_ftrace_syscalls(void)
+{
+        struct syscall_metadata *meta;
+        unsigned long addr;
+        int i;
+
+        syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) *
+                                        NR_syscalls, GFP_KERNEL);
+        if (!syscalls_metadata) {
+                WARN_ON(1);
+                return -ENOMEM;
+        }
+
+        for (i = 0; i < NR_syscalls; i++) {
+                addr = arch_syscall_addr(i);
+                meta = find_syscall_meta(addr);
+                syscalls_metadata[i] = meta;
+        }
+
+        return 0;
+}
+core_initcall(init_ftrace_syscalls);
+
 #ifdef CONFIG_EVENT_PROFILE
 
 static DECLARE_BITMAP(enabled_prof_enter_syscalls, NR_syscalls);