4 files changed, 124 insertions, 43 deletions

diff --git a/include/asm-x86/ftrace.h b/include/asm-x86/ftrace.h
index be0e004ad148..1bb6f9bbe1ab 100644
--- a/include/asm-x86/ftrace.h
+++ b/include/asm-x86/ftrace.h
@@ -7,6 +7,16 @@
 
 #ifndef __ASSEMBLY__
 extern void mcount(void);
+
+static inline unsigned long ftrace_call_adjust(unsigned long addr)
+{
+        /*
+         * call mcount is "e8 <4 byte offset>"
+         * The addr points to the 4 byte offset and the caller of this
+         * function wants the pointer to e8. Simply subtract one.
+         */
+        return addr - 1;
+}
 #endif
 
 #endif /* CONFIG_FTRACE */
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index bb384068272e..d4d6ab453b78 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -162,4 +162,10 @@ static inline void
 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
 #endif
 
+#ifdef CONFIG_FTRACE_MCOUNT_RECORD
+extern void ftrace_init(void);
+#else
+static inline void ftrace_init(void) { }
+#endif
+
 #endif /* _LINUX_FTRACE_H */
diff --git a/init/main.c b/init/main.c
index 3820323c4c84..ded1fae965ab 100644
--- a/init/main.c
+++ b/init/main.c
@@ -60,6 +60,7 @@
 #include <linux/sched.h>
 #include <linux/signal.h>
 #include <linux/idr.h>
+#include <linux/ftrace.h>
 
 #include <asm/io.h>
 #include <asm/bugs.h>
@@ -687,6 +688,8 @@ asmlinkage void __init start_kernel(void)
 
         acpi_early_init(); /* before LAPIC and SMP init */
 
+        ftrace_init();
+
         /* Do the rest non-__init'ed, we're now alive */
         rest_init();
 }
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index f6e3af31b403..df96d5990c04 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -792,47 +792,7 @@ static int ftrace_update_code(void)
         return 1;
 }
 
-static int ftraced(void *ignore)
-{
-        unsigned long usecs;
-
-        while (!kthread_should_stop()) {
-
-                set_current_state(TASK_INTERRUPTIBLE);
-
-                /* check once a second */
-                schedule_timeout(HZ);
-
-                if (unlikely(ftrace_disabled))
-                        continue;
-
-                mutex_lock(&ftrace_sysctl_lock);
-                mutex_lock(&ftraced_lock);
-                if (!ftraced_suspend && !ftraced_stop &&
-                    ftrace_update_code()) {
-                        usecs = nsecs_to_usecs(ftrace_update_time);
-                        if (ftrace_update_tot_cnt > 100000) {
-                                ftrace_update_tot_cnt = 0;
-                                pr_info("hm, dftrace overflow: %lu change%s"
-                                        " (%lu total) in %lu usec%s\n",
-                                        ftrace_update_cnt,
-                                        ftrace_update_cnt != 1 ? "s" : "",
-                                        ftrace_update_tot_cnt,
-                                        usecs, usecs != 1 ? "s" : "");
-                                ftrace_disabled = 1;
-                                WARN_ON_ONCE(1);
-                        }
-                }
-                mutex_unlock(&ftraced_lock);
-                mutex_unlock(&ftrace_sysctl_lock);
-
-                ftrace_shutdown_replenish();
-        }
-        __set_current_state(TASK_RUNNING);
-        return 0;
-}
-
-static int __init ftrace_dyn_table_alloc(void)
+static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 {
         struct ftrace_page *pg;
         int cnt;
@@ -859,7 +819,9 @@ static int __init ftrace_dyn_table_alloc(void)
 
         pg = ftrace_pages = ftrace_pages_start;
 
-        cnt = NR_TO_INIT / ENTRIES_PER_PAGE;
+        cnt = num_to_init / ENTRIES_PER_PAGE;
+        pr_info("ftrace: allocating %ld hash entries in %d pages\n",
+                num_to_init, cnt);
 
         for (i = 0; i < cnt; i++) {
                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
@@ -1556,6 +1518,104 @@ static __init int ftrace_init_debugfs(void)
 
 fs_initcall(ftrace_init_debugfs);
 
+#ifdef CONFIG_FTRACE_MCOUNT_RECORD
+static int ftrace_convert_nops(unsigned long *start,
+                               unsigned long *end)
+{
+        unsigned long *p;
+        unsigned long addr;
+        unsigned long flags;
+
+        p = start;
+        while (p < end) {
+                addr = ftrace_call_adjust(*p++);
+                ftrace_record_ip(addr);
+                ftrace_shutdown_replenish();
+        }
+
+        /* p is ignored */
+        local_irq_save(flags);
+        __ftrace_update_code(p);
+        local_irq_restore(flags);
+
+        return 0;
+}
+
+extern unsigned long __start_mcount_loc[];
+extern unsigned long __stop_mcount_loc[];
+
+void __init ftrace_init(void)
+{
+        unsigned long count, addr, flags;
+        int ret;
+
+        /* Keep the ftrace pointer to the stub */
+        addr = (unsigned long)ftrace_stub;
+
+        local_irq_save(flags);
+        ftrace_dyn_arch_init(&addr);
+        local_irq_restore(flags);
+
+        /* ftrace_dyn_arch_init places the return code in addr */
+        if (addr)
+                goto failed;
+
+        count = __stop_mcount_loc - __start_mcount_loc;
+
+        ret = ftrace_dyn_table_alloc(count);
+        if (ret)
+                goto failed;
+
+        last_ftrace_enabled = ftrace_enabled = 1;
+
+        ret = ftrace_convert_nops(__start_mcount_loc,
+                                  __stop_mcount_loc);
+
+        return;
+ failed:
+        ftrace_disabled = 1;
+}
+#else /* CONFIG_FTRACE_MCOUNT_RECORD */
+static int ftraced(void *ignore)
+{
+        unsigned long usecs;
+
+        while (!kthread_should_stop()) {
+
+                set_current_state(TASK_INTERRUPTIBLE);
+
+                /* check once a second */
+                schedule_timeout(HZ);
+
+                if (unlikely(ftrace_disabled))
+                        continue;
+
+                mutex_lock(&ftrace_sysctl_lock);
+                mutex_lock(&ftraced_lock);
+                if (!ftraced_suspend && !ftraced_stop &&
+                    ftrace_update_code()) {
+                        usecs = nsecs_to_usecs(ftrace_update_time);
+                        if (ftrace_update_tot_cnt > 100000) {
+                                ftrace_update_tot_cnt = 0;
+                                pr_info("hm, dftrace overflow: %lu change%s"
+                                        " (%lu total) in %lu usec%s\n",
+                                        ftrace_update_cnt,
+                                        ftrace_update_cnt != 1 ? "s" : "",
+                                        ftrace_update_tot_cnt,
+                                        usecs, usecs != 1 ? "s" : "");
+                                ftrace_disabled = 1;
+                                WARN_ON_ONCE(1);
+                        }
+                }
+                mutex_unlock(&ftraced_lock);
+                mutex_unlock(&ftrace_sysctl_lock);
+
+                ftrace_shutdown_replenish();
+        }
+        __set_current_state(TASK_RUNNING);
+        return 0;
+}
+
 static int __init ftrace_dynamic_init(void)
 {
         struct task_struct *p;
@@ -1572,7 +1632,7 @@ static int __init ftrace_dynamic_init(void)
                 goto failed;
         }
 
-        ret = ftrace_dyn_table_alloc();
+        ret = ftrace_dyn_table_alloc(NR_TO_INIT);
         if (ret)
                 goto failed;
 
@@ -1593,6 +1653,8 @@ static int __init ftrace_dynamic_init(void)
 }
 
 core_initcall(ftrace_dynamic_init);
+#endif /* CONFIG_FTRACE_MCOUNT_RECORD */
+
 #else
 # define ftrace_startup()               do { } while (0)
 # define ftrace_shutdown()              do { } while (0)