]> git.kernelconcepts.de Git - karo-tx-linux.git/blobdiff - kernel/trace/trace_stack.c
Merge remote-tracking branch 'ftrace/for-next'
[karo-tx-linux.git] / kernel / trace / trace_stack.c
index 8abf1ba18085742af78176dbc514095a47643c9c..dda9e6742950305f36fbe920f9fe0c6f68d83fbf 100644 (file)
 
 #include "trace.h"
 
-#define STACK_TRACE_ENTRIES 500
-
 static unsigned long stack_dump_trace[STACK_TRACE_ENTRIES+1] =
         { [0 ... (STACK_TRACE_ENTRIES)] = ULONG_MAX };
-static unsigned stack_dump_index[STACK_TRACE_ENTRIES];
+unsigned stack_trace_index[STACK_TRACE_ENTRIES];
 
 /*
  * Reserve one entry for the passed in ip. This will allow
  * us to remove most or all of the stack size overhead
  * added by the stack tracer itself.
  */
-static struct stack_trace max_stack_trace = {
+struct stack_trace stack_trace_max = {
        .max_entries            = STACK_TRACE_ENTRIES - 1,
        .entries                = &stack_dump_trace[0],
 };
 
-static unsigned long max_stack_size;
-static arch_spinlock_t max_stack_lock =
+unsigned long stack_trace_max_size;
+arch_spinlock_t stack_trace_max_lock =
        (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
 
 static DEFINE_PER_CPU(int, trace_active);
@@ -42,30 +40,38 @@ static DEFINE_MUTEX(stack_sysctl_mutex);
 int stack_tracer_enabled;
 static int last_stack_tracer_enabled;
 
-static inline void print_max_stack(void)
+void stack_trace_print(void)
 {
        long i;
        int size;
 
        pr_emerg("        Depth    Size   Location    (%d entries)\n"
                           "        -----    ----   --------\n",
-                          max_stack_trace.nr_entries);
+                          stack_trace_max.nr_entries);
 
-       for (i = 0; i < max_stack_trace.nr_entries; i++) {
+       for (i = 0; i < stack_trace_max.nr_entries; i++) {
                if (stack_dump_trace[i] == ULONG_MAX)
                        break;
-               if (i+1 == max_stack_trace.nr_entries ||
+               if (i+1 == stack_trace_max.nr_entries ||
                                stack_dump_trace[i+1] == ULONG_MAX)
-                       size = stack_dump_index[i];
+                       size = stack_trace_index[i];
                else
-                       size = stack_dump_index[i] - stack_dump_index[i+1];
+                       size = stack_trace_index[i] - stack_trace_index[i+1];
 
-               pr_emerg("%3ld) %8d   %5d   %pS\n", i, stack_dump_index[i],
+               pr_emerg("%3ld) %8d   %5d   %pS\n", i, stack_trace_index[i],
                                size, (void *)stack_dump_trace[i]);
        }
 }
 
-static inline void
+/*
+ * When arch-specific code overides this function, the following
+ * data should be filled up, assuming stack_trace_max_lock is held to
+ * prevent concurrent updates.
+ *     stack_trace_index[]
+ *     stack_trace_max
+ *     stack_trace_max_size
+ */
+void __weak
 check_stack(unsigned long ip, unsigned long *stack)
 {
        unsigned long this_size, flags; unsigned long *p, *top, *start;
@@ -78,7 +84,7 @@ check_stack(unsigned long ip, unsigned long *stack)
        /* Remove the frame of the tracer */
        this_size -= frame_size;
 
-       if (this_size <= max_stack_size)
+       if (this_size <= stack_trace_max_size)
                return;
 
        /* we do not handle interrupt stacks yet */
@@ -90,7 +96,7 @@ check_stack(unsigned long ip, unsigned long *stack)
                return;
 
        local_irq_save(flags);
-       arch_spin_lock(&max_stack_lock);
+       arch_spin_lock(&stack_trace_max_lock);
 
        /*
         * RCU may not be watching, make it see us.
@@ -103,18 +109,18 @@ check_stack(unsigned long ip, unsigned long *stack)
                this_size -= tracer_frame;
 
        /* a race could have already updated it */
-       if (this_size <= max_stack_size)
+       if (this_size <= stack_trace_max_size)
                goto out;
 
-       max_stack_size = this_size;
+       stack_trace_max_size = this_size;
 
-       max_stack_trace.nr_entries = 0;
-       max_stack_trace.skip = 3;
+       stack_trace_max.nr_entries = 0;
+       stack_trace_max.skip = 3;
 
-       save_stack_trace(&max_stack_trace);
+       save_stack_trace(&stack_trace_max);
 
        /* Skip over the overhead of the stack tracer itself */
-       for (i = 0; i < max_stack_trace.nr_entries; i++) {
+       for (i = 0; i < stack_trace_max.nr_entries; i++) {
                if (stack_dump_trace[i] == ip)
                        break;
        }
@@ -134,18 +140,18 @@ check_stack(unsigned long ip, unsigned long *stack)
         * loop will only happen once. This code only takes place
         * on a new max, so it is far from a fast path.
         */
-       while (i < max_stack_trace.nr_entries) {
+       while (i < stack_trace_max.nr_entries) {
                int found = 0;
 
-               stack_dump_index[x] = this_size;
+               stack_trace_index[x] = this_size;
                p = start;
 
-               for (; p < top && i < max_stack_trace.nr_entries; p++) {
+               for (; p < top && i < stack_trace_max.nr_entries; p++) {
                        if (stack_dump_trace[i] == ULONG_MAX)
                                break;
                        if (*p == stack_dump_trace[i]) {
                                stack_dump_trace[x] = stack_dump_trace[i++];
-                               this_size = stack_dump_index[x++] =
+                               this_size = stack_trace_index[x++] =
                                        (top - p) * sizeof(unsigned long);
                                found = 1;
                                /* Start the search from here */
@@ -160,7 +166,7 @@ check_stack(unsigned long ip, unsigned long *stack)
                                if (unlikely(!tracer_frame)) {
                                        tracer_frame = (p - stack) *
                                                sizeof(unsigned long);
-                                       max_stack_size -= tracer_frame;
+                                       stack_trace_max_size -= tracer_frame;
                                }
                        }
                }
@@ -169,18 +175,18 @@ check_stack(unsigned long ip, unsigned long *stack)
                        i++;
        }
 
-       max_stack_trace.nr_entries = x;
+       stack_trace_max.nr_entries = x;
        for (; x < i; x++)
                stack_dump_trace[x] = ULONG_MAX;
 
        if (task_stack_end_corrupted(current)) {
-               print_max_stack();
+               stack_trace_print();
                BUG();
        }
 
  out:
        rcu_irq_exit();
-       arch_spin_unlock(&max_stack_lock);
+       arch_spin_unlock(&stack_trace_max_lock);
        local_irq_restore(flags);
 }
 
@@ -251,9 +257,9 @@ stack_max_size_write(struct file *filp, const char __user *ubuf,
        cpu = smp_processor_id();
        per_cpu(trace_active, cpu)++;
 
-       arch_spin_lock(&max_stack_lock);
+       arch_spin_lock(&stack_trace_max_lock);
        *ptr = val;
-       arch_spin_unlock(&max_stack_lock);
+       arch_spin_unlock(&stack_trace_max_lock);
 
        per_cpu(trace_active, cpu)--;
        local_irq_restore(flags);
@@ -273,7 +279,7 @@ __next(struct seq_file *m, loff_t *pos)
 {
        long n = *pos - 1;
 
-       if (n > max_stack_trace.nr_entries || stack_dump_trace[n] == ULONG_MAX)
+       if (n > stack_trace_max.nr_entries || stack_dump_trace[n] == ULONG_MAX)
                return NULL;
 
        m->private = (void *)n;
@@ -296,7 +302,7 @@ static void *t_start(struct seq_file *m, loff_t *pos)
        cpu = smp_processor_id();
        per_cpu(trace_active, cpu)++;
 
-       arch_spin_lock(&max_stack_lock);
+       arch_spin_lock(&stack_trace_max_lock);
 
        if (*pos == 0)
                return SEQ_START_TOKEN;
@@ -308,7 +314,7 @@ static void t_stop(struct seq_file *m, void *p)
 {
        int cpu;
 
-       arch_spin_unlock(&max_stack_lock);
+       arch_spin_unlock(&stack_trace_max_lock);
 
        cpu = smp_processor_id();
        per_cpu(trace_active, cpu)--;
@@ -343,9 +349,9 @@ static int t_show(struct seq_file *m, void *v)
                seq_printf(m, "        Depth    Size   Location"
                           "    (%d entries)\n"
                           "        -----    ----   --------\n",
-                          max_stack_trace.nr_entries);
+                          stack_trace_max.nr_entries);
 
-               if (!stack_tracer_enabled && !max_stack_size)
+               if (!stack_tracer_enabled && !stack_trace_max_size)
                        print_disabled(m);
 
                return 0;
@@ -353,17 +359,17 @@ static int t_show(struct seq_file *m, void *v)
 
        i = *(long *)v;
 
-       if (i >= max_stack_trace.nr_entries ||
+       if (i >= stack_trace_max.nr_entries ||
            stack_dump_trace[i] == ULONG_MAX)
                return 0;
 
-       if (i+1 == max_stack_trace.nr_entries ||
+       if (i+1 == stack_trace_max.nr_entries ||
            stack_dump_trace[i+1] == ULONG_MAX)
-               size = stack_dump_index[i];
+               size = stack_trace_index[i];
        else
-               size = stack_dump_index[i] - stack_dump_index[i+1];
+               size = stack_trace_index[i] - stack_trace_index[i+1];
 
-       seq_printf(m, "%3ld) %8d   %5d   ", i, stack_dump_index[i], size);
+       seq_printf(m, "%3ld) %8d   %5d   ", i, stack_trace_index[i], size);
 
        trace_lookup_stack(m, i);
 
@@ -453,7 +459,7 @@ static __init int stack_trace_init(void)
                return 0;
 
        trace_create_file("stack_max_size", 0644, d_tracer,
-                       &max_stack_size, &stack_max_size_fops);
+                       &stack_trace_max_size, &stack_max_size_fops);
 
        trace_create_file("stack_trace", 0444, d_tracer,
                        NULL, &stack_trace_fops);