1 files changed, 175 insertions, 129 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 54cb9a7d15e5..f212da486689 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -50,6 +50,9 @@ static int last_ftrace_enabled;
 /* Quick disabling of function tracer. */
 int function_trace_stop;
 
+/* By default, current tracing type is normal tracing. */
+enum ftrace_tracing_type_t ftrace_tracing_type = FTRACE_TYPE_ENTER;
+
 /*
  * ftrace_disabled is set when an anomaly is discovered.
  * ftrace_disabled is much stronger than ftrace_enabled.
@@ -334,7 +337,7 @@ ftrace_record_ip(unsigned long ip)
 {
         struct dyn_ftrace *rec;
 
-        if (!ftrace_enabled || ftrace_disabled)
+        if (ftrace_disabled)
                 return NULL;
 
         rec = ftrace_alloc_dyn_node(ip);
@@ -348,107 +351,138 @@ ftrace_record_ip(unsigned long ip)
         return rec;
 }
 
-#define FTRACE_ADDR ((long)(ftrace_caller))
+static void print_ip_ins(const char *fmt, unsigned char *p)
+{
+        int i;
+
+        printk(KERN_CONT "%s", fmt);
+
+        for (i = 0; i < MCOUNT_INSN_SIZE; i++)
+                printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
+}
+
+static void ftrace_bug(int failed, unsigned long ip)
+{
+        switch (failed) {
+        case -EFAULT:
+                FTRACE_WARN_ON_ONCE(1);
+                pr_info("ftrace faulted on modifying ");
+                print_ip_sym(ip);
+                break;
+        case -EINVAL:
+                FTRACE_WARN_ON_ONCE(1);
+                pr_info("ftrace failed to modify ");
+                print_ip_sym(ip);
+                print_ip_ins(" actual: ", (unsigned char *)ip);
+                printk(KERN_CONT "\n");
+                break;
+        case -EPERM:
+                FTRACE_WARN_ON_ONCE(1);
+                pr_info("ftrace faulted on writing ");
+                print_ip_sym(ip);
+                break;
+        default:
+                FTRACE_WARN_ON_ONCE(1);
+                pr_info("ftrace faulted on unknown error ");
+                print_ip_sym(ip);
+        }
+}
+
 
 static int
-__ftrace_replace_code(struct dyn_ftrace *rec,
-                      unsigned char *old, unsigned char *new, int enable)
+__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
 {
         unsigned long ip, fl;
+        unsigned long ftrace_addr;
+
+#ifdef CONFIG_FUNCTION_RET_TRACER
+        if (ftrace_tracing_type == FTRACE_TYPE_ENTER)
+                ftrace_addr = (unsigned long)ftrace_caller;
+        else
+                ftrace_addr = (unsigned long)ftrace_return_caller;
+#else
+        ftrace_addr = (unsigned long)ftrace_caller;
+#endif
 
         ip = rec->ip;
 
-        if (ftrace_filtered && enable) {
+        /*
+         * If this record is not to be traced and
+         * it is not enabled then do nothing.
+         *
+         * If this record is not to be traced and
+         * it is enabled then disabled it.
+         *
+         */
+        if (rec->flags & FTRACE_FL_NOTRACE) {
+                if (rec->flags & FTRACE_FL_ENABLED)
+                        rec->flags &= ~FTRACE_FL_ENABLED;
+                else
+                        return 0;
+
+        } else if (ftrace_filtered && enable) {
                 /*
-                 * If filtering is on:
-                 *
-                 * If this record is set to be filtered and
-                 * is enabled then do nothing.
-                 *
-                 * If this record is set to be filtered and
-                 * it is not enabled, enable it.
-                 *
-                 * If this record is not set to be filtered
-                 * and it is not enabled do nothing.
-                 *
-                 * If this record is set not to trace then
-                 * do nothing.
-                 *
-                 * If this record is set not to trace and
-                 * it is enabled then disable it.
-                 *
-                 * If this record is not set to be filtered and
-                 * it is enabled, disable it.
+                 * Filtering is on:
                  */
 
-                fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE |
-                                   FTRACE_FL_ENABLED);
+                fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
 
-                if ((fl ==  (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) ||
-                    (fl ==  (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE)) ||
-                    !fl || (fl == FTRACE_FL_NOTRACE))
+                /* Record is filtered and enabled, do nothing */
+                if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
                         return 0;
 
-                /*
-                 * If it is enabled disable it,
-                 * otherwise enable it!
-                 */
-                if (fl & FTRACE_FL_ENABLED) {
-                        /* swap new and old */
-                        new = old;
-                        old = ftrace_call_replace(ip, FTRACE_ADDR);
+                /* Record is not filtered and is not enabled do nothing */
+                if (!fl)
+                        return 0;
+
+                /* Record is not filtered but enabled, disable it */
+                if (fl == FTRACE_FL_ENABLED)
                         rec->flags &= ~FTRACE_FL_ENABLED;
-                } else {
-                        new = ftrace_call_replace(ip, FTRACE_ADDR);
+                else
+                /* Otherwise record is filtered but not enabled, enable it */
                         rec->flags |= FTRACE_FL_ENABLED;
-                }
         } else {
+                /* Disable or not filtered */
 
                 if (enable) {
-                        /*
-                         * If this record is set not to trace and is
-                         * not enabled, do nothing.
-                         */
-                        fl = rec->flags & (FTRACE_FL_NOTRACE | FTRACE_FL_ENABLED);
-                        if (fl == FTRACE_FL_NOTRACE)
-                                return 0;
-
-                        new = ftrace_call_replace(ip, FTRACE_ADDR);
-                } else
-                        old = ftrace_call_replace(ip, FTRACE_ADDR);
-
-                if (enable) {
+                        /* if record is enabled, do nothing */
                         if (rec->flags & FTRACE_FL_ENABLED)
                                 return 0;
+
                         rec->flags |= FTRACE_FL_ENABLED;
+
                 } else {
+
+                        /* if record is not enabled do nothing */
                         if (!(rec->flags & FTRACE_FL_ENABLED))
                                 return 0;
+
                         rec->flags &= ~FTRACE_FL_ENABLED;
                 }
         }
 
-        return ftrace_modify_code(ip, old, new);
+        if (rec->flags & FTRACE_FL_ENABLED)
+                return ftrace_make_call(rec, ftrace_addr);
+        else
+                return ftrace_make_nop(NULL, rec, ftrace_addr);
 }
 
 static void ftrace_replace_code(int enable)
 {
         int i, failed;
-        unsigned char *new = NULL, *old = NULL;
         struct dyn_ftrace *rec;
         struct ftrace_page *pg;
 
-        if (enable)
-                old = ftrace_nop_replace();
-        else
-                new = ftrace_nop_replace();
-
         for (pg = ftrace_pages_start; pg; pg = pg->next) {
                 for (i = 0; i < pg->index; i++) {
                         rec = &pg->records[i];
 
-                        /* don't modify code that has already faulted */
-                        if (rec->flags & FTRACE_FL_FAILED)
+                        /*
+                         * Skip over free records and records that have
+                         * failed.
+                         */
+                        if (rec->flags & FTRACE_FL_FREE ||
+                            rec->flags & FTRACE_FL_FAILED)
                                 continue;
 
                         /* ignore updates to this record's mcount site */
@@ -459,68 +493,30 @@ static void ftrace_replace_code(int enable)
                                 unfreeze_record(rec);
                         }
 
-                        failed = __ftrace_replace_code(rec, old, new, enable);
+                        failed = __ftrace_replace_code(rec, enable);
                         if (failed && (rec->flags & FTRACE_FL_CONVERTED)) {
                                 rec->flags |= FTRACE_FL_FAILED;
                                 if ((system_state == SYSTEM_BOOTING) ||
                                     !core_kernel_text(rec->ip)) {
                                         ftrace_free_rec(rec);
-                                }
+                                } else
+                                        ftrace_bug(failed, rec->ip);
                         }
                 }
         }
 }
 
-static void print_ip_ins(const char *fmt, unsigned char *p)
-{
-        int i;
-
-        printk(KERN_CONT "%s", fmt);
-
-        for (i = 0; i < MCOUNT_INSN_SIZE; i++)
-                printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
-}
-
 static int
-ftrace_code_disable(struct dyn_ftrace *rec)
+ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
 {
         unsigned long ip;
-        unsigned char *nop, *call;
         int ret;
 
         ip = rec->ip;
 
-        nop = ftrace_nop_replace();
-        call = ftrace_call_replace(ip, mcount_addr);
-
-        ret = ftrace_modify_code(ip, call, nop);
+        ret = ftrace_make_nop(mod, rec, mcount_addr);
         if (ret) {
-                switch (ret) {
-                case -EFAULT:
-                        FTRACE_WARN_ON_ONCE(1);
-                        pr_info("ftrace faulted on modifying ");
-                        print_ip_sym(ip);
-                        break;
-                case -EINVAL:
-                        FTRACE_WARN_ON_ONCE(1);
-                        pr_info("ftrace failed to modify ");
-                        print_ip_sym(ip);
-                        print_ip_ins(" expected: ", call);
-                        print_ip_ins(" actual: ", (unsigned char *)ip);
-                        print_ip_ins(" replace: ", nop);
-                        printk(KERN_CONT "\n");
-                        break;
-                case -EPERM:
-                        FTRACE_WARN_ON_ONCE(1);
-                        pr_info("ftrace faulted on writing ");
-                        print_ip_sym(ip);
-                        break;
-                default:
-                        FTRACE_WARN_ON_ONCE(1);
-                        pr_info("ftrace faulted on unknown error ");
-                        print_ip_sym(ip);
-                }
-
+                ftrace_bug(ret, ip);
                 rec->flags |= FTRACE_FL_FAILED;
                 return 0;
         }
@@ -560,8 +556,7 @@ static void ftrace_startup(void)
 
         mutex_lock(&ftrace_start_lock);
         ftrace_start_up++;
-        if (ftrace_start_up == 1)
-                command |= FTRACE_ENABLE_CALLS;
+        command |= FTRACE_ENABLE_CALLS;
 
         if (saved_ftrace_func != ftrace_trace_function) {
                 saved_ftrace_func = ftrace_trace_function;
@@ -639,7 +634,7 @@ static cycle_t		ftrace_update_time;
 static unsigned long    ftrace_update_cnt;
 unsigned long           ftrace_update_tot_cnt;
 
-static int ftrace_update_code(void)
+static int ftrace_update_code(struct module *mod)
 {
         struct dyn_ftrace *p, *t;
         cycle_t start, stop;
@@ -656,7 +651,7 @@ static int ftrace_update_code(void)
                 list_del_init(&p->list);
 
                 /* convert record (i.e, patch mcount-call with NOP) */
-                if (ftrace_code_disable(p)) {
+                if (ftrace_code_disable(mod, p)) {
                         p->flags |= FTRACE_FL_CONVERTED;
                         ftrace_update_cnt++;
                 } else
@@ -699,7 +694,7 @@ static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 
         cnt = num_to_init / ENTRIES_PER_PAGE;
         pr_info("ftrace: allocating %ld entries in %d pages\n",
-                num_to_init, cnt);
+                num_to_init, cnt + 1);
 
         for (i = 0; i < cnt; i++) {
                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
@@ -782,13 +777,11 @@ static void *t_start(struct seq_file *m, loff_t *pos)
         void *p = NULL;
         loff_t l = -1;
 
-        if (*pos != iter->pos) {
-                for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l))
-                        ;
-        } else {
-                l = *pos;
-                p = t_next(m, p, &l);
-        }
+        if (*pos > iter->pos)
+                *pos = iter->pos;
+
+        l = *pos;
+        p = t_next(m, p, &l);
 
         return p;
 }
@@ -799,15 +792,21 @@ static void t_stop(struct seq_file *m, void *p)
 
 static int t_show(struct seq_file *m, void *v)
 {
+        struct ftrace_iterator *iter = m->private;
         struct dyn_ftrace *rec = v;
         char str[KSYM_SYMBOL_LEN];
+        int ret = 0;
 
         if (!rec)
                 return 0;
 
         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 
-        seq_printf(m, "%s\n", str);
+        ret = seq_printf(m, "%s\n", str);
+        if (ret < 0) {
+                iter->pos--;
+                iter->idx--;
+        }
 
         return 0;
 }
@@ -833,7 +832,7 @@ ftrace_avail_open(struct inode *inode, struct file *file)
                 return -ENOMEM;
 
         iter->pg = ftrace_pages_start;
-        iter->pos = -1;
+        iter->pos = 0;
 
         ret = seq_open(file, &show_ftrace_seq_ops);
         if (!ret) {
@@ -920,7 +919,7 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable)
 
         if (file->f_mode & FMODE_READ) {
                 iter->pg = ftrace_pages_start;
-                iter->pos = -1;
+                iter->pos = 0;
                 iter->flags = enable ? FTRACE_ITER_FILTER :
                         FTRACE_ITER_NOTRACE;
 
@@ -1211,7 +1210,7 @@ ftrace_regex_release(struct inode *inode, struct file *file, int enable)
 
         mutex_lock(&ftrace_sysctl_lock);
         mutex_lock(&ftrace_start_lock);
-        if (iter->filtered && ftrace_start_up && ftrace_enabled)
+        if (ftrace_start_up && ftrace_enabled)
                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
         mutex_unlock(&ftrace_start_lock);
         mutex_unlock(&ftrace_sysctl_lock);
@@ -1298,7 +1297,8 @@ static __init int ftrace_init_debugfs(void)
 
 fs_initcall(ftrace_init_debugfs);
 
-static int ftrace_convert_nops(unsigned long *start,
+static int ftrace_convert_nops(struct module *mod,
+                               unsigned long *start,
                                unsigned long *end)
 {
         unsigned long *p;
@@ -1309,23 +1309,32 @@ static int ftrace_convert_nops(unsigned long *start,
         p = start;
         while (p < end) {
                 addr = ftrace_call_adjust(*p++);
+                /*
+                 * Some architecture linkers will pad between
+                 * the different mcount_loc sections of different
+                 * object files to satisfy alignments.
+                 * Skip any NULL pointers.
+                 */
+                if (!addr)
+                        continue;
                 ftrace_record_ip(addr);
         }
 
         /* disable interrupts to prevent kstop machine */
         local_irq_save(flags);
-        ftrace_update_code();
+        ftrace_update_code(mod);
         local_irq_restore(flags);
         mutex_unlock(&ftrace_start_lock);
 
         return 0;
 }
 
-void ftrace_init_module(unsigned long *start, unsigned long *end)
+void ftrace_init_module(struct module *mod,
+                        unsigned long *start, unsigned long *end)
 {
         if (ftrace_disabled || start == end)
                 return;
-        ftrace_convert_nops(start, end);
+        ftrace_convert_nops(mod, start, end);
 }
 
 extern unsigned long __start_mcount_loc[];
@@ -1355,7 +1364,8 @@ void __init ftrace_init(void)
 
         last_ftrace_enabled = ftrace_enabled = 1;
 
-        ret = ftrace_convert_nops(__start_mcount_loc,
+        ret = ftrace_convert_nops(NULL,
+                                  __start_mcount_loc,
                                   __stop_mcount_loc);
 
         return;
@@ -1411,10 +1421,17 @@ int register_ftrace_function(struct ftrace_ops *ops)
                 return -1;
 
         mutex_lock(&ftrace_sysctl_lock);
+
+        if (ftrace_tracing_type == FTRACE_TYPE_RETURN) {
+                ret = -EBUSY;
+                goto out;
+        }
+
         ret = __register_ftrace_function(ops);
         ftrace_startup();
-        mutex_unlock(&ftrace_sysctl_lock);
 
+out:
+        mutex_unlock(&ftrace_sysctl_lock);
         return ret;
 }
 
@@ -1480,16 +1497,45 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
 }
 
 #ifdef CONFIG_FUNCTION_RET_TRACER
+
+/* The callback that hooks the return of a function */
 trace_function_return_t ftrace_function_return =
                         (trace_function_return_t)ftrace_stub;
-void register_ftrace_return(trace_function_return_t func)
+
+int register_ftrace_return(trace_function_return_t func)
 {
+        int ret = 0;
+
+        mutex_lock(&ftrace_sysctl_lock);
+
+        /*
+         * Don't launch return tracing if normal function
+         * tracing is already running.
+         */
+        if (ftrace_trace_function != ftrace_stub) {
+                ret = -EBUSY;
+                goto out;
+        }
+
+        ftrace_tracing_type = FTRACE_TYPE_RETURN;
         ftrace_function_return = func;
+        ftrace_startup();
+
+out:
+        mutex_unlock(&ftrace_sysctl_lock);
+        return ret;
 }
 
 void unregister_ftrace_return(void)
 {
+        mutex_lock(&ftrace_sysctl_lock);
+
         ftrace_function_return = (trace_function_return_t)ftrace_stub;
+        ftrace_shutdown();
+        /* Restore normal tracing type */
+        ftrace_tracing_type = FTRACE_TYPE_ENTER;
+
+        mutex_unlock(&ftrace_sysctl_lock);
 }
 #endif