ClabureDB: Classified Bug-Reports Database

  /*
   * Memory mapped I/O tracing
   *
   * Copyright (C) 2008 Pekka Paalanen <pq@iki.fi>
   */
  
  #define DEBUG 1
  
  #include <linux/kernel.h>
 #include <linux/mmiotrace.h>
 #include <linux/pci.h>
 
 #include "trace.h"
 
 struct header_iter {
         struct pci_dev *dev;
 };
 
 static struct trace_array *mmio_trace_array;
 static bool overrun_detected;
 static unsigned long prev_overruns;
 
 static void mmio_reset_data(struct trace_array *tr)
 {
         int cpu;
 
         overrun_detected = false;
         prev_overruns = 0;
         tr->time_start = ftrace_now(tr->cpu);
 
         for_each_online_cpu(cpu)
                 tracing_reset(tr, cpu);
 }
 
 static void mmio_trace_init(struct trace_array *tr)
 {
         pr_debug("in %s\n", __func__);
         mmio_trace_array = tr;
         if (tr->ctrl) {
                 mmio_reset_data(tr);
                 enable_mmiotrace();
         }
 }
 
 static void mmio_trace_reset(struct trace_array *tr)
 {
         pr_debug("in %s\n", __func__);
         if (tr->ctrl)
                 disable_mmiotrace();
         mmio_reset_data(tr);
         mmio_trace_array = NULL;
 }
 
 static void mmio_trace_ctrl_update(struct trace_array *tr)
 {
         pr_debug("in %s\n", __func__);
         if (tr->ctrl) {
                 mmio_reset_data(tr);
                 enable_mmiotrace();
         } else {
                 disable_mmiotrace();
         }
 }
 
 static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
 {
         int ret = 0;
         int i;
         resource_size_t start, end;
         const struct pci_driver *drv = pci_dev_driver(dev);
 
         /* XXX: incomplete checks for trace_seq_printf() return value */
         ret += trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
                                 dev->bus->number, dev->devfn,
                                 dev->vendor, dev->device, dev->irq);
         /*
          * XXX: is pci_resource_to_user() appropriate, since we are
          * supposed to interpret the __ioremap() phys_addr argument based on
          * these printed values?
          */
         for (i = 0; i < 7; i++) {
                 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
                 ret += trace_seq_printf(s, " %llx",
                         (unsigned long long)(start |
                         (dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
         }
         for (i = 0; i < 7; i++) {
                 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
                 ret += trace_seq_printf(s, " %llx",
                         dev->resource[i].start < dev->resource[i].end ?
                         (unsigned long long)(end - start) + 1 : 0);
         }
         if (drv)
                 ret += trace_seq_printf(s, " %s\n", drv->name);
         else
                 ret += trace_seq_printf(s, " \n");
         return ret;
 }
 
static void destroy_header_iter(struct header_iter *hiter)
{
        if (!hiter)
                return;
        pci_dev_put(hiter->dev);
        kfree(hiter);
}

static void mmio_pipe_open(struct trace_iterator *iter)
{
        struct header_iter *hiter;
        struct trace_seq *s = &iter->seq;

        trace_seq_printf(s, "VERSION 20070824\n");

        hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
        if (!hiter)
                return;

        hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
        iter->private = hiter;
}

/* XXX: This is not called when the pipe is closed! */
static void mmio_close(struct trace_iterator *iter)
{
        struct header_iter *hiter = iter->private;
        destroy_header_iter(hiter);
        iter->private = NULL;
}

static unsigned long count_overruns(struct trace_iterator *iter)
{
        unsigned long cnt = 0;
        unsigned long over = ring_buffer_overruns(iter->tr->buffer);

        if (over > prev_overruns)
                cnt = over - prev_overruns;
        prev_overruns = over;
        return cnt;
}

static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
                                char __user *ubuf, size_t cnt, loff_t *ppos)
{
        ssize_t ret;
        struct header_iter *hiter = iter->private;
        struct trace_seq *s = &iter->seq;
        unsigned long n;

        n = count_overruns(iter);
        if (n) {
                /* XXX: This is later than where events were lost. */
                trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
                if (!overrun_detected)
                        pr_warning("mmiotrace has lost events.\n");
                overrun_detected = true;
                goto print_out;
        }

        if (!hiter)
                return 0;

        mmio_print_pcidev(s, hiter->dev);
        hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);

        if (!hiter->dev) {
                destroy_header_iter(hiter);
                iter->private = NULL;
        }

print_out:
        ret = trace_seq_to_user(s, ubuf, cnt);
        return (ret == -EBUSY) ? 0 : ret;
}

static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
{
        struct trace_entry *entry = iter->ent;
        struct trace_mmiotrace_rw *field;
        struct mmiotrace_rw *rw;
        struct trace_seq *s        = &iter->seq;
        unsigned long long t        = ns2usecs(iter->ts);
        unsigned long usec_rem        = do_div(t, 1000000ULL);
        unsigned secs                = (unsigned long)t;
        int ret = 1;

        trace_assign_type(field, entry);
        rw = &field->rw;

        switch (rw->opcode) {
        case MMIO_READ:
                ret = trace_seq_printf(s,
                        "R %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
                        rw->width, secs, usec_rem, rw->map_id,
                        (unsigned long long)rw->phys,
                        rw->value, rw->pc, 0);
                break;
        case MMIO_WRITE:
                ret = trace_seq_printf(s,
                        "W %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
                        rw->width, secs, usec_rem, rw->map_id,
                        (unsigned long long)rw->phys,
                        rw->value, rw->pc, 0);
                break;
        case MMIO_UNKNOWN_OP:
                ret = trace_seq_printf(s,
                        "UNKNOWN %lu.%06lu %d 0x%llx %02x,%02x,%02x 0x%lx %d\n",
                        secs, usec_rem, rw->map_id,
                        (unsigned long long)rw->phys,
                        (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
                        (rw->value >> 0) & 0xff, rw->pc, 0);
                break;
        default:
                ret = trace_seq_printf(s, "rw what?\n");
                break;
        }
        if (ret)
                return TRACE_TYPE_HANDLED;
        return TRACE_TYPE_PARTIAL_LINE;
}

static enum print_line_t mmio_print_map(struct trace_iterator *iter)
{
        struct trace_entry *entry = iter->ent;
        struct trace_mmiotrace_map *field;
        struct mmiotrace_map *m;
        struct trace_seq *s        = &iter->seq;
        unsigned long long t        = ns2usecs(iter->ts);
        unsigned long usec_rem        = do_div(t, 1000000ULL);
        unsigned secs                = (unsigned long)t;
        int ret;

        trace_assign_type(field, entry);
        m = &field->map;

        switch (m->opcode) {
        case MMIO_PROBE:
                ret = trace_seq_printf(s,
                        "MAP %lu.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
                        secs, usec_rem, m->map_id,
                        (unsigned long long)m->phys, m->virt, m->len,
                        0UL, 0);
                break;
        case MMIO_UNPROBE:
                ret = trace_seq_printf(s,
                        "UNMAP %lu.%06lu %d 0x%lx %d\n",
                        secs, usec_rem, m->map_id, 0UL, 0);
                break;
        default:
                ret = trace_seq_printf(s, "map what?\n");
                break;
        }
        if (ret)
                return TRACE_TYPE_HANDLED;
        return TRACE_TYPE_PARTIAL_LINE;
}

static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
{
        struct trace_entry *entry = iter->ent;
        struct print_entry *print = (struct print_entry *)entry;
        const char *msg                = print->buf;
        struct trace_seq *s        = &iter->seq;
        unsigned long long t        = ns2usecs(iter->ts);
        unsigned long usec_rem        = do_div(t, 1000000ULL);
        unsigned secs                = (unsigned long)t;
        int ret;

        /* The trailing newline must be in the message. */
        ret = trace_seq_printf(s, "MARK %lu.%06lu %s", secs, usec_rem, msg);
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;

        if (entry->flags & TRACE_FLAG_CONT)
                trace_seq_print_cont(s, iter);

        return TRACE_TYPE_HANDLED;
}

static enum print_line_t mmio_print_line(struct trace_iterator *iter)
{
        switch (iter->ent->type) {
        case TRACE_MMIO_RW:
                return mmio_print_rw(iter);
        case TRACE_MMIO_MAP:
                return mmio_print_map(iter);
        case TRACE_PRINT:
                return mmio_print_mark(iter);
        default:
                return TRACE_TYPE_HANDLED; /* ignore unknown entries */
        }
}

static struct tracer mmio_tracer __read_mostly =
{
        .name                = "mmiotrace",
        .init                = mmio_trace_init,
        .reset                = mmio_trace_reset,
        .pipe_open        = mmio_pipe_open,
        .close                = mmio_close,
        .read                = mmio_read,
        .ctrl_update        = mmio_trace_ctrl_update,
        .print_line        = mmio_print_line,
};

__init static int init_mmio_trace(void)
{
        return register_tracer(&mmio_tracer);
}
device_initcall(init_mmio_trace);

static void __trace_mmiotrace_rw(struct trace_array *tr,
                                struct trace_array_cpu *data,
                                struct mmiotrace_rw *rw)
{
        struct ring_buffer_event *event;
        struct trace_mmiotrace_rw *entry;
        unsigned long irq_flags;

        event        = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
                                           &irq_flags);
        if (!event)
                return;
        entry        = ring_buffer_event_data(event);
        tracing_generic_entry_update(&entry->ent, 0, preempt_count());
        entry->ent.type                        = TRACE_MMIO_RW;
        entry->rw                        = *rw;
        ring_buffer_unlock_commit(tr->buffer, event, irq_flags);

        trace_wake_up();
}

void mmio_trace_rw(struct mmiotrace_rw *rw)
{
        struct trace_array *tr = mmio_trace_array;
        struct trace_array_cpu *data = tr->data[smp_processor_id()];
        __trace_mmiotrace_rw(tr, data, rw);
}

static void __trace_mmiotrace_map(struct trace_array *tr,
                                struct trace_array_cpu *data,
                                struct mmiotrace_map *map)
{
        struct ring_buffer_event *event;
        struct trace_mmiotrace_map *entry;
        unsigned long irq_flags;

        event        = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
                                           &irq_flags);
        if (!event)
                return;
        entry        = ring_buffer_event_data(event);
        tracing_generic_entry_update(&entry->ent, 0, preempt_count());
        entry->ent.type                        = TRACE_MMIO_MAP;
        entry->map                        = *map;
        ring_buffer_unlock_commit(tr->buffer, event, irq_flags);

        trace_wake_up();
}

void mmio_trace_mapping(struct mmiotrace_map *map)
{
        struct trace_array *tr = mmio_trace_array;
        struct trace_array_cpu *data;

        preempt_disable();
        data = tr->data[smp_processor_id()];
        __trace_mmiotrace_map(tr, data, map);
        preempt_enable();
}

int mmio_trace_printk(const char *fmt, va_list args)
{
        return trace_vprintk(0, fmt, args);
}