]> www.pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - kernel/trace/ftrace.c
Merge branch 'for-linus' of git://git.o-hand.com/linux-rpurdie-leds
[linux-2.6-omap-h63xx.git] / kernel / trace / ftrace.c
index f6e3af31b403d8eaa77128712fdb594ca48be0c0..4dda4f60a2a9262770e3195b894e48b8178296a3 100644 (file)
@@ -81,7 +81,7 @@ void clear_ftrace_function(void)
 
 static int __register_ftrace_function(struct ftrace_ops *ops)
 {
-       /* Should never be called by interrupts */
+       /* should not be called from interrupt context */
        spin_lock(&ftrace_lock);
 
        ops->next = ftrace_list;
@@ -115,6 +115,7 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
        struct ftrace_ops **p;
        int ret = 0;
 
+       /* should not be called from interrupt context */
        spin_lock(&ftrace_lock);
 
        /*
@@ -153,6 +154,30 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 
+#ifndef CONFIG_FTRACE_MCOUNT_RECORD
+/*
+ * The hash lock is only needed when the recording of the mcount
+ * callers are dynamic. That is, by the caller themselves and
+ * not recorded via the compilation.
+ */
+static DEFINE_SPINLOCK(ftrace_hash_lock);
+#define ftrace_hash_lock(flags)          spin_lock_irqsave(&ftrace_hash_lock, flags)
+#define ftrace_hash_unlock(flags) \
+                       spin_unlock_irqrestore(&ftrace_hash_lock, flags)
+#else
+/* This is protected via the ftrace_lock with MCOUNT_RECORD. */
+#define ftrace_hash_lock(flags)   do { (void)(flags); } while (0)
+#define ftrace_hash_unlock(flags) do { } while(0)
+#endif
+
+/*
+ * Since MCOUNT_ADDR may point to mcount itself, we do not want
+ * to get it confused by reading a reference in the code as we
+ * are parsing on objcopy output of text. Use a variable for
+ * it instead.
+ */
+static unsigned long mcount_addr = MCOUNT_ADDR;
+
 static struct task_struct *ftraced_task;
 
 enum {
@@ -171,7 +196,6 @@ static struct hlist_head ftrace_hash[FTRACE_HASHSIZE];
 
 static DEFINE_PER_CPU(int, ftrace_shutdown_disable_cpu);
 
-static DEFINE_SPINLOCK(ftrace_shutdown_lock);
 static DEFINE_MUTEX(ftraced_lock);
 static DEFINE_MUTEX(ftrace_regex_lock);
 
@@ -294,13 +318,37 @@ static inline void ftrace_del_hash(struct dyn_ftrace *node)
 
 static void ftrace_free_rec(struct dyn_ftrace *rec)
 {
-       /* no locking, only called from kstop_machine */
-
        rec->ip = (unsigned long)ftrace_free_records;
        ftrace_free_records = rec;
        rec->flags |= FTRACE_FL_FREE;
 }
 
+void ftrace_release(void *start, unsigned long size)
+{
+       struct dyn_ftrace *rec;
+       struct ftrace_page *pg;
+       unsigned long s = (unsigned long)start;
+       unsigned long e = s + size;
+       int i;
+
+       if (ftrace_disabled || !start)
+               return;
+
+       /* should not be called from interrupt context */
+       spin_lock(&ftrace_lock);
+
+       for (pg = ftrace_pages_start; pg; pg = pg->next) {
+               for (i = 0; i < pg->index; i++) {
+                       rec = &pg->records[i];
+
+                       if ((rec->ip >= s) && (rec->ip < e))
+                               ftrace_free_rec(rec);
+               }
+       }
+       spin_unlock(&ftrace_lock);
+
+}
+
 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
 {
        struct dyn_ftrace *rec;
@@ -338,7 +386,6 @@ ftrace_record_ip(unsigned long ip)
        unsigned long flags;
        unsigned long key;
        int resched;
-       int atomic;
        int cpu;
 
        if (!ftrace_enabled || ftrace_disabled)
@@ -368,9 +415,7 @@ ftrace_record_ip(unsigned long ip)
        if (ftrace_ip_in_hash(ip, key))
                goto out;
 
-       atomic = irqs_disabled();
-
-       spin_lock_irqsave(&ftrace_shutdown_lock, flags);
+       ftrace_hash_lock(flags);
 
        /* This ip may have hit the hash before the lock */
        if (ftrace_ip_in_hash(ip, key))
@@ -387,7 +432,7 @@ ftrace_record_ip(unsigned long ip)
        ftraced_trigger = 1;
 
  out_unlock:
-       spin_unlock_irqrestore(&ftrace_shutdown_lock, flags);
+       ftrace_hash_unlock(flags);
  out:
        per_cpu(ftrace_shutdown_disable_cpu, cpu)--;
 
@@ -531,6 +576,16 @@ static void ftrace_shutdown_replenish(void)
        ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL);
 }
 
+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)
 {
@@ -541,10 +596,27 @@ ftrace_code_disable(struct dyn_ftrace *rec)
        ip = rec->ip;
 
        nop = ftrace_nop_replace();
-       call = ftrace_call_replace(ip, MCOUNT_ADDR);
+       call = ftrace_call_replace(ip, mcount_addr);
 
        failed = ftrace_modify_code(ip, call, nop);
        if (failed) {
+               switch (failed) {
+               case 1:
+                       WARN_ON_ONCE(1);
+                       pr_info("ftrace faulted on modifying ");
+                       print_ip_sym(ip);
+                       break;
+               case 2:
+                       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;
+               }
+
                rec->flags |= FTRACE_FL_FAILED;
                return 0;
        }
@@ -792,47 +864,7 @@ 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 +891,9 @@ 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);
@@ -901,6 +935,8 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
 
        (*pos)++;
 
+       /* should not be called from interrupt context */
+       spin_lock(&ftrace_lock);
  retry:
        if (iter->idx >= iter->pg->index) {
                if (iter->pg->next) {
@@ -910,15 +946,13 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
                }
        } else {
                rec = &iter->pg->records[iter->idx++];
-               if ((!(iter->flags & FTRACE_ITER_FAILURES) &&
+               if ((rec->flags & FTRACE_FL_FREE) ||
+
+                   (!(iter->flags & FTRACE_ITER_FAILURES) &&
                     (rec->flags & FTRACE_FL_FAILED)) ||
 
                    ((iter->flags & FTRACE_ITER_FAILURES) &&
-                    (!(rec->flags & FTRACE_FL_FAILED) ||
-                     (rec->flags & FTRACE_FL_FREE))) ||
-
-                   ((iter->flags & FTRACE_ITER_FILTER) &&
-                    !(rec->flags & FTRACE_FL_FILTER)) ||
+                    !(rec->flags & FTRACE_FL_FAILED)) ||
 
                    ((iter->flags & FTRACE_ITER_NOTRACE) &&
                     !(rec->flags & FTRACE_FL_NOTRACE))) {
@@ -926,6 +960,7 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
                        goto retry;
                }
        }
+       spin_unlock(&ftrace_lock);
 
        iter->pos = *pos;
 
@@ -1039,8 +1074,8 @@ static void ftrace_filter_reset(int enable)
        unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
        unsigned i;
 
-       /* keep kstop machine from running */
-       preempt_disable();
+       /* should not be called from interrupt context */
+       spin_lock(&ftrace_lock);
        if (enable)
                ftrace_filtered = 0;
        pg = ftrace_pages_start;
@@ -1053,7 +1088,7 @@ static void ftrace_filter_reset(int enable)
                }
                pg = pg->next;
        }
-       preempt_enable();
+       spin_unlock(&ftrace_lock);
 }
 
 static int
@@ -1165,8 +1200,8 @@ ftrace_match(unsigned char *buff, int len, int enable)
                }
        }
 
-       /* keep kstop machine from running */
-       preempt_disable();
+       /* should not be called from interrupt context */
+       spin_lock(&ftrace_lock);
        if (enable)
                ftrace_filtered = 1;
        pg = ftrace_pages_start;
@@ -1203,7 +1238,7 @@ ftrace_match(unsigned char *buff, int len, int enable)
                }
                pg = pg->next;
        }
-       preempt_enable();
+       spin_unlock(&ftrace_lock);
 }
 
 static ssize_t
@@ -1556,6 +1591,114 @@ 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++);
+               /* should not be called from interrupt context */
+               spin_lock(&ftrace_lock);
+               ftrace_record_ip(addr);
+               spin_unlock(&ftrace_lock);
+               ftrace_shutdown_replenish();
+       }
+
+       /* p is ignored */
+       local_irq_save(flags);
+       __ftrace_update_code(p);
+       local_irq_restore(flags);
+
+       return 0;
+}
+
+void ftrace_init_module(unsigned long *start, unsigned long *end)
+{
+       if (ftrace_disabled || start == end)
+               return;
+       ftrace_convert_nops(start, end);
+}
+
+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 +1715,7 @@ 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 +1736,8 @@ 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)