hw-breakpoints: Rewrite the hw-breakpoints layer on top of perf events
[linux-2.6-block.git] / kernel / trace / trace_ksym.c
index 6d5609c67378f846345d60cd6f512ac56624df78..fea83eeeef0918ad689cb30df7c0fb5d2ae2e8a8 100644 (file)
 #include "trace_stat.h"
 #include "trace.h"
 
-/* For now, let us restrict the no. of symbols traced simultaneously to number
+#include <linux/hw_breakpoint.h>
+#include <asm/hw_breakpoint.h>
+
+/*
+ * For now, let us restrict the no. of symbols traced simultaneously to number
  * of available hardware breakpoint registers.
  */
 #define KSYM_TRACER_MAX HBP_NUM
 #define KSYM_TRACER_OP_LEN 3 /* rw- */
 
 struct trace_ksym {
-       struct hw_breakpoint    *ksym_hbp;
+       struct perf_event       **ksym_hbp;
        unsigned long           ksym_addr;
+       int                     type;
+       int                     len;
 #ifdef CONFIG_PROFILE_KSYM_TRACER
        unsigned long           counter;
 #endif
@@ -75,10 +81,11 @@ void ksym_collect_stats(unsigned long hbp_hit_addr)
 }
 #endif /* CONFIG_PROFILE_KSYM_TRACER */
 
-void ksym_hbp_handler(struct hw_breakpoint *hbp, struct pt_regs *regs)
+void ksym_hbp_handler(struct perf_event *hbp, void *data)
 {
        struct ring_buffer_event *event;
        struct ksym_trace_entry *entry;
+       struct pt_regs *regs = data;
        struct ring_buffer *buffer;
        int pc;
 
@@ -96,12 +103,12 @@ void ksym_hbp_handler(struct hw_breakpoint *hbp, struct pt_regs *regs)
 
        entry           = ring_buffer_event_data(event);
        entry->ip       = instruction_pointer(regs);
-       entry->type     = hbp->info.type;
-       strlcpy(entry->ksym_name, hbp->info.name, KSYM_SYMBOL_LEN);
+       entry->type     = hw_breakpoint_type(hbp);
+       entry->addr     = hw_breakpoint_addr(hbp);
        strlcpy(entry->cmd, current->comm, TASK_COMM_LEN);
 
 #ifdef CONFIG_PROFILE_KSYM_TRACER
-       ksym_collect_stats(hbp->info.address);
+       ksym_collect_stats(hw_breakpoint_addr(hbp));
 #endif /* CONFIG_PROFILE_KSYM_TRACER */
 
        trace_buffer_unlock_commit(buffer, event, 0, pc);
@@ -120,31 +127,21 @@ static int ksym_trace_get_access_type(char *str)
        int access = 0;
 
        if (str[0] == 'r')
-               access += 4;
-       else if (str[0] != '-')
-               return -EINVAL;
+               access |= HW_BREAKPOINT_R;
 
        if (str[1] == 'w')
-               access += 2;
-       else if (str[1] != '-')
-               return -EINVAL;
+               access |= HW_BREAKPOINT_W;
 
-       if (str[2] != '-')
-               return -EINVAL;
+       if (str[2] == 'x')
+               access |= HW_BREAKPOINT_X;
 
        switch (access) {
-       case 6:
-               access = HW_BREAKPOINT_RW;
-               break;
-       case 4:
-               access = -EINVAL;
-               break;
-       case 2:
-               access = HW_BREAKPOINT_WRITE;
-               break;
+       case HW_BREAKPOINT_W:
+       case HW_BREAKPOINT_W | HW_BREAKPOINT_R:
+               return access;
+       default:
+               return -EINVAL;
        }
-
-       return access;
 }
 
 /*
@@ -194,36 +191,33 @@ int process_new_ksym_entry(char *ksymname, int op, unsigned long addr)
        if (!entry)
                return -ENOMEM;
 
-       entry->ksym_hbp = kzalloc(sizeof(struct hw_breakpoint), GFP_KERNEL);
-       if (!entry->ksym_hbp)
-               goto err;
-
-       entry->ksym_hbp->info.name = kstrdup(ksymname, GFP_KERNEL);
-       if (!entry->ksym_hbp->info.name)
-               goto err;
-
-       entry->ksym_hbp->info.type = op;
-       entry->ksym_addr = entry->ksym_hbp->info.address = addr;
-#ifdef CONFIG_X86
-       entry->ksym_hbp->info.len = HW_BREAKPOINT_LEN_4;
-#endif
-       entry->ksym_hbp->triggered = (void *)ksym_hbp_handler;
+       entry->type = op;
+       entry->ksym_addr = addr;
+       entry->len = HW_BREAKPOINT_LEN_4;
+
+       ret = -EAGAIN;
+       entry->ksym_hbp = register_wide_hw_breakpoint(entry->ksym_addr,
+                                       entry->len, entry->type,
+                                       ksym_hbp_handler, true);
+       if (IS_ERR(entry->ksym_hbp)) {
+               entry->ksym_hbp = NULL;
+               ret = PTR_ERR(entry->ksym_hbp);
+       }
 
-       ret = register_kernel_hw_breakpoint(entry->ksym_hbp);
-       if (ret < 0) {
+       if (!entry->ksym_hbp) {
                printk(KERN_INFO "ksym_tracer request failed. Try again"
                                        " later!!\n");
-               ret = -EAGAIN;
                goto err;
        }
+
        hlist_add_head_rcu(&(entry->ksym_hlist), &ksym_filter_head);
        ksym_filter_entry_count++;
+
        return 0;
+
 err:
-       if (entry->ksym_hbp)
-               kfree(entry->ksym_hbp->info.name);
-       kfree(entry->ksym_hbp);
        kfree(entry);
+
        return ret;
 }
 
@@ -244,10 +238,10 @@ static ssize_t ksym_trace_filter_read(struct file *filp, char __user *ubuf,
        mutex_lock(&ksym_tracer_mutex);
 
        hlist_for_each_entry(entry, node, &ksym_filter_head, ksym_hlist) {
-               ret = trace_seq_printf(s, "%s:", entry->ksym_hbp->info.name);
-               if (entry->ksym_hbp->info.type == HW_BREAKPOINT_WRITE)
+               ret = trace_seq_printf(s, "%pS:", (void *)entry->ksym_addr);
+               if (entry->type == HW_BREAKPOINT_W)
                        ret = trace_seq_puts(s, "-w-\n");
-               else if (entry->ksym_hbp->info.type == HW_BREAKPOINT_RW)
+               else if (entry->type == (HW_BREAKPOINT_W | HW_BREAKPOINT_R))
                        ret = trace_seq_puts(s, "rw-\n");
                WARN_ON_ONCE(!ret);
        }
@@ -269,12 +263,10 @@ static void __ksym_trace_reset(void)
        mutex_lock(&ksym_tracer_mutex);
        hlist_for_each_entry_safe(entry, node, node1, &ksym_filter_head,
                                                                ksym_hlist) {
-               unregister_kernel_hw_breakpoint(entry->ksym_hbp);
+               unregister_wide_hw_breakpoint(entry->ksym_hbp);
                ksym_filter_entry_count--;
                hlist_del_rcu(&(entry->ksym_hlist));
                synchronize_rcu();
-               kfree(entry->ksym_hbp->info.name);
-               kfree(entry->ksym_hbp);
                kfree(entry);
        }
        mutex_unlock(&ksym_tracer_mutex);
@@ -327,7 +319,7 @@ static ssize_t ksym_trace_filter_write(struct file *file,
        hlist_for_each_entry(entry, node, &ksym_filter_head, ksym_hlist) {
                if (entry->ksym_addr == ksym_addr) {
                        /* Check for malformed request: (6) */
-                       if (entry->ksym_hbp->info.type != op)
+                       if (entry->type != op)
                                changed = 1;
                        else
                                goto out;
@@ -335,18 +327,21 @@ static ssize_t ksym_trace_filter_write(struct file *file,
                }
        }
        if (changed) {
-               unregister_kernel_hw_breakpoint(entry->ksym_hbp);
-               entry->ksym_hbp->info.type = op;
+               unregister_wide_hw_breakpoint(entry->ksym_hbp);
+               entry->type = op;
                if (op > 0) {
-                       ret = register_kernel_hw_breakpoint(entry->ksym_hbp);
-                       if (ret == 0)
+                       entry->ksym_hbp =
+                               register_wide_hw_breakpoint(entry->ksym_addr,
+                                       entry->len, entry->type,
+                                       ksym_hbp_handler, true);
+                       if (IS_ERR(entry->ksym_hbp))
+                               entry->ksym_hbp = NULL;
+                       if (!entry->ksym_hbp)
                                goto out;
                }
                ksym_filter_entry_count--;
                hlist_del_rcu(&(entry->ksym_hlist));
                synchronize_rcu();
-               kfree(entry->ksym_hbp->info.name);
-               kfree(entry->ksym_hbp);
                kfree(entry);
                ret = 0;
                goto out;
@@ -413,16 +408,16 @@ static enum print_line_t ksym_trace_output(struct trace_iterator *iter)
 
        trace_assign_type(field, entry);
 
-       ret = trace_seq_printf(s, "%11s-%-5d [%03d] %-30s ", field->cmd,
-                               entry->pid, iter->cpu, field->ksym_name);
+       ret = trace_seq_printf(s, "%11s-%-5d [%03d] %pS", field->cmd,
+                               entry->pid, iter->cpu, (char *)field->addr);
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;
 
        switch (field->type) {
-       case HW_BREAKPOINT_WRITE:
+       case HW_BREAKPOINT_W:
                ret = trace_seq_printf(s, " W  ");
                break;
-       case HW_BREAKPOINT_RW:
+       case HW_BREAKPOINT_R | HW_BREAKPOINT_W:
                ret = trace_seq_printf(s, " RW ");
                break;
        default:
@@ -490,14 +485,13 @@ static int ksym_tracer_stat_show(struct seq_file *m, void *v)
 
        entry = hlist_entry(stat, struct trace_ksym, ksym_hlist);
 
-       if (entry->ksym_hbp)
-               access_type = entry->ksym_hbp->info.type;
+       access_type = entry->type;
 
        switch (access_type) {
-       case HW_BREAKPOINT_WRITE:
+       case HW_BREAKPOINT_W:
                seq_puts(m, "  W           ");
                break;
-       case HW_BREAKPOINT_RW:
+       case HW_BREAKPOINT_R | HW_BREAKPOINT_W:
                seq_puts(m, "  RW          ");
                break;
        default: