tracing: x86, mmiotrace: only register for die notifier when tracer active
[linux-2.6.git] / arch / x86 / mm / mmio-mod.c
index e7397e1..132772a 100644 (file)
@@ -56,13 +56,6 @@ struct remap_trace {
 static DEFINE_PER_CPU(struct trap_reason, pf_reason);
 static DEFINE_PER_CPU(struct mmiotrace_rw, cpu_trace);
 
-#if 0 /* XXX: no way gather this info anymore */
-/* Access to this is not per-cpu. */
-static DEFINE_PER_CPU(atomic_t, dropped);
-#endif
-
-static struct dentry *marker_file;
-
 static DEFINE_MUTEX(mmiotrace_mutex);
 static DEFINE_SPINLOCK(trace_lock);
 static atomic_t mmiotrace_enabled;
@@ -75,7 +68,7 @@ static LIST_HEAD(trace_list);         /* struct remap_trace */
  *   and trace_lock.
  * - Routines depending on is_enabled() must take trace_lock.
  * - trace_list users must hold trace_lock.
- * - is_enabled() guarantees that mmio_trace_record is allowed.
+ * - is_enabled() guarantees that mmio_trace_{rw,mapping} are allowed.
  * - pre/post callbacks assume the effect of is_enabled() being true.
  */
 
@@ -97,44 +90,6 @@ static bool is_enabled(void)
        return atomic_read(&mmiotrace_enabled);
 }
 
-#if 0 /* XXX: needs rewrite */
-/*
- * Write callback for the debugfs entry:
- * Read a marker and write it to the mmio trace log
- */
-static ssize_t write_marker(struct file *file, const char __user *buffer,
-                                               size_t count, loff_t *ppos)
-{
-       char *event = NULL;
-       struct mm_io_header *headp;
-       ssize_t len = (count > 65535) ? 65535 : count;
-
-       event = kzalloc(sizeof(*headp) + len, GFP_KERNEL);
-       if (!event)
-               return -ENOMEM;
-
-       headp = (struct mm_io_header *)event;
-       headp->type = MMIO_MAGIC | (MMIO_MARKER << MMIO_OPCODE_SHIFT);
-       headp->data_len = len;
-
-       if (copy_from_user(event + sizeof(*headp), buffer, len)) {
-               kfree(event);
-               return -EFAULT;
-       }
-
-       spin_lock_irq(&trace_lock);
-#if 0 /* XXX: convert this to use tracing */
-       if (is_enabled())
-               relay_write(chan, event, sizeof(*headp) + len);
-       else
-#endif
-               len = -EINVAL;
-       spin_unlock_irq(&trace_lock);
-       kfree(event);
-       return len;
-}
-#endif
-
 static void print_pte(unsigned long address)
 {
        unsigned int level;
@@ -307,8 +262,10 @@ static void ioremap_trace_core(resource_size_t offset, unsigned long size,
        map.map_id = trace->id;
 
        spin_lock_irq(&trace_lock);
-       if (!is_enabled())
+       if (!is_enabled()) {
+               kfree(trace);
                goto not_enabled;
+       }
 
        mmio_trace_mapping(&map);
        list_add_tail(&trace->list, &trace_list);
@@ -377,6 +334,23 @@ void mmiotrace_iounmap(volatile void __iomem *addr)
                iounmap_trace_core(addr);
 }
 
+int mmiotrace_printk(const char *fmt, ...)
+{
+       int ret = 0;
+       va_list args;
+       unsigned long flags;
+       va_start(args, fmt);
+
+       spin_lock_irqsave(&trace_lock, flags);
+       if (is_enabled())
+               ret = mmio_trace_printk(fmt, args);
+       spin_unlock_irqrestore(&trace_lock, flags);
+
+       va_end(args);
+       return ret;
+}
+EXPORT_SYMBOL(mmiotrace_printk);
+
 static void clear_trace_list(void)
 {
        struct remap_trace *trace;
@@ -404,41 +378,50 @@ static void clear_trace_list(void)
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
-static cpumask_t downed_cpus;
+static cpumask_var_t downed_cpus;
 
 static void enter_uniprocessor(void)
 {
        int cpu;
        int err;
 
+       if (downed_cpus == NULL &&
+           !alloc_cpumask_var(&downed_cpus, GFP_KERNEL)) {
+               pr_notice(NAME "Failed to allocate mask\n");
+               goto out;
+       }
+
        get_online_cpus();
-       downed_cpus = cpu_online_map;
-       cpu_clear(first_cpu(cpu_online_map), downed_cpus);
+       cpumask_copy(downed_cpus, cpu_online_mask);
+       cpumask_clear_cpu(cpumask_first(cpu_online_mask), downed_cpus);
        if (num_online_cpus() > 1)
                pr_notice(NAME "Disabling non-boot CPUs...\n");
        put_online_cpus();
 
-       for_each_cpu_mask(cpu, downed_cpus) {
+       for_each_cpu(cpu, downed_cpus) {
                err = cpu_down(cpu);
                if (!err)
                        pr_info(NAME "CPU%d is down.\n", cpu);
                else
                        pr_err(NAME "Error taking CPU%d down: %d\n", cpu, err);
        }
+out:
        if (num_online_cpus() > 1)
                pr_warning(NAME "multiple CPUs still online, "
                                                "may miss events.\n");
 }
 
-static void leave_uniprocessor(void)
+/* __ref because leave_uniprocessor calls cpu_up which is __cpuinit,
+   but this whole function is ifdefed CONFIG_HOTPLUG_CPU */
+static void __ref leave_uniprocessor(void)
 {
        int cpu;
        int err;
 
-       if (cpus_weight(downed_cpus) == 0)
+       if (downed_cpus == NULL || cpumask_weight(downed_cpus) == 0)
                return;
        pr_notice(NAME "Re-enabling CPUs...\n");
-       for_each_cpu_mask(cpu, downed_cpus) {
+       for_each_cpu(cpu, downed_cpus) {
                err = cpu_up(cpu);
                if (!err)
                        pr_info(NAME "enabled CPU%d.\n", cpu);
@@ -460,28 +443,15 @@ static void leave_uniprocessor(void)
 }
 #endif
 
-#if 0 /* XXX: out of order */
-static struct file_operations fops_marker = {
-       .owner =        THIS_MODULE,
-       .write =        write_marker
-};
-#endif
-
 void enable_mmiotrace(void)
 {
        mutex_lock(&mmiotrace_mutex);
        if (is_enabled())
                goto out;
 
-#if 0 /* XXX: tracing does not support text entries */
-       marker_file = debugfs_create_file("marker", 0660, dir, NULL,
-                                                               &fops_marker);
-       if (!marker_file)
-               pr_err(NAME "marker file creation failed.\n");
-#endif
-
        if (nommiotrace)
                pr_info(NAME "MMIO tracing disabled.\n");
+       kmmio_init();
        enter_uniprocessor();
        spin_lock_irq(&trace_lock);
        atomic_inc(&mmiotrace_enabled);
@@ -504,11 +474,7 @@ void disable_mmiotrace(void)
 
        clear_trace_list(); /* guarantees: no more kmmio callbacks */
        leave_uniprocessor();
-       if (marker_file) {
-               debugfs_remove(marker_file);
-               marker_file = NULL;
-       }
-
+       kmmio_cleanup();
        pr_info(NAME "disabled.\n");
 out:
        mutex_unlock(&mmiotrace_mutex);