5 files changed, 68 insertions, 31 deletions

diff --git a/arch/sh/include/asm/hw_breakpoint.h b/arch/sh/include/asm/hw_breakpoint.h
index 382bad937dcc..e14cad96798f 100644
--- a/arch/sh/include/asm/hw_breakpoint.h
+++ b/arch/sh/include/asm/hw_breakpoint.h
@@ -46,6 +46,11 @@ struct pmu;
 /* Maximum number of UBC channels */
 #define HBP_NUM         2
 
+static inline int hw_breakpoint_slots(int type)
+{
+        return HBP_NUM;
+}
+
 /* arch/sh/kernel/hw_breakpoint.c */
 extern int arch_check_bp_in_kernelspace(struct perf_event *bp);
 extern int arch_validate_hwbkpt_settings(struct perf_event *bp);
diff --git a/arch/x86/include/asm/hw_breakpoint.h b/arch/x86/include/asm/hw_breakpoint.h
index c77a5a6fab9d..942255310e6a 100644
--- a/arch/x86/include/asm/hw_breakpoint.h
+++ b/arch/x86/include/asm/hw_breakpoint.h
@@ -41,6 +41,11 @@ struct arch_hw_breakpoint {
 /* Total number of available HW breakpoint registers */
 #define HBP_NUM 4
 
+static inline int hw_breakpoint_slots(int type)
+{
+        return HBP_NUM;
+}
+
 struct perf_event;
 struct pmu;
 
diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h
index 7e8899093098..a2d6ea49ec56 100644
--- a/include/linux/hw_breakpoint.h
+++ b/include/linux/hw_breakpoint.h
@@ -17,6 +17,16 @@ enum {
         HW_BREAKPOINT_INVALID   = HW_BREAKPOINT_RW | HW_BREAKPOINT_X,
 };
 
+enum bp_type_idx {
+        TYPE_INST       = 0,
+#ifdef CONFIG_HAVE_MIXED_BREAKPOINTS_REGS
+        TYPE_DATA       = 0,
+#else
+        TYPE_DATA       = 1,
+#endif
+        TYPE_MAX
+};
+
 #ifdef __KERNEL__
 
 #include <linux/perf_event.h>
diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c
index 974498b858fc..684b710cbb91 100644
--- a/kernel/hw_breakpoint.c
+++ b/kernel/hw_breakpoint.c
@@ -40,20 +40,12 @@
 #include <linux/percpu.h>
 #include <linux/sched.h>
 #include <linux/init.h>
+#include <linux/slab.h>
 #include <linux/cpu.h>
 #include <linux/smp.h>
 
 #include <linux/hw_breakpoint.h>
 
-enum bp_type_idx {
-        TYPE_INST       = 0,
-#ifdef CONFIG_HAVE_MIXED_BREAKPOINTS_REGS
-        TYPE_DATA       = 0,
-#else
-        TYPE_DATA       = 1,
-#endif
-        TYPE_MAX
-};
 
 /*
  * Constraints data
@@ -63,11 +55,15 @@ enum bp_type_idx {
 static DEFINE_PER_CPU(unsigned int, nr_cpu_bp_pinned[TYPE_MAX]);
 
 /* Number of pinned task breakpoints in a cpu */
-static DEFINE_PER_CPU(unsigned int, nr_task_bp_pinned[TYPE_MAX][HBP_NUM]);
+static DEFINE_PER_CPU(unsigned int, *nr_task_bp_pinned[TYPE_MAX]);
 
 /* Number of non-pinned cpu/task breakpoints in a cpu */
 static DEFINE_PER_CPU(unsigned int, nr_bp_flexible[TYPE_MAX]);
 
+static int nr_slots[TYPE_MAX];
+
+static int constraints_initialized;
+
 /* Gather the number of total pinned and un-pinned bp in a cpuset */
 struct bp_busy_slots {
         unsigned int pinned;
@@ -99,7 +95,7 @@ static unsigned int max_task_bp_pinned(int cpu, enum bp_type_idx type)
         int i;
         unsigned int *tsk_pinned = per_cpu(nr_task_bp_pinned[type], cpu);
 
-        for (i = HBP_NUM -1; i >= 0; i--) {
+        for (i = nr_slots[type] - 1; i >= 0; i--) {
                 if (tsk_pinned[i] > 0)
                         return i + 1;
         }
@@ -292,6 +288,10 @@ static int __reserve_bp_slot(struct perf_event *bp)
         enum bp_type_idx type;
         int weight;
 
+        /* We couldn't initialize breakpoint constraints on boot */
+        if (!constraints_initialized)
+                return -ENOMEM;
+
         /* Basic checks */
         if (bp->attr.bp_type == HW_BREAKPOINT_EMPTY ||
             bp->attr.bp_type == HW_BREAKPOINT_INVALID)
@@ -304,7 +304,7 @@ static int __reserve_bp_slot(struct perf_event *bp)
         fetch_this_slot(&slots, weight);
 
         /* Flexible counters need to keep at least one slot */
-        if (slots.pinned + (!!slots.flexible) > HBP_NUM)
+        if (slots.pinned + (!!slots.flexible) > nr_slots[type])
                 return -ENOSPC;
 
         toggle_bp_slot(bp, true, type, weight);
@@ -551,7 +551,36 @@ static struct notifier_block hw_breakpoint_exceptions_nb = {
 
 static int __init init_hw_breakpoint(void)
 {
+        unsigned int **task_bp_pinned;
+        int cpu, err_cpu;
+        int i;
+
+        for (i = 0; i < TYPE_MAX; i++)
+                nr_slots[i] = hw_breakpoint_slots(i);
+
+        for_each_possible_cpu(cpu) {
+                for (i = 0; i < TYPE_MAX; i++) {
+                        task_bp_pinned = &per_cpu(nr_task_bp_pinned[i], cpu);
+                        *task_bp_pinned = kzalloc(sizeof(int) * nr_slots[i],
+                                                  GFP_KERNEL);
+                        if (!*task_bp_pinned)
+                                goto err_alloc;
+                }
+        }
+
+        constraints_initialized = 1;
+
         return register_die_notifier(&hw_breakpoint_exceptions_nb);
+
+ err_alloc:
+        for_each_possible_cpu(err_cpu) {
+                if (err_cpu == cpu)
+                        break;
+                for (i = 0; i < TYPE_MAX; i++)
+                        kfree(per_cpu(nr_task_bp_pinned[i], cpu));
+        }
+
+        return -ENOMEM;
 }
 core_initcall(init_hw_breakpoint);
 
diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
index d59cd6879477..8eaf00749b65 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -34,12 +34,6 @@
 
 #include <asm/atomic.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 {
@@ -53,7 +47,6 @@ struct trace_ksym {
 
 static struct trace_array *ksym_trace_array;
 
-static unsigned int ksym_filter_entry_count;
 static unsigned int ksym_tracing_enabled;
 
 static HLIST_HEAD(ksym_filter_head);
@@ -181,13 +174,6 @@ int process_new_ksym_entry(char *ksymname, int op, unsigned long addr)
         struct trace_ksym *entry;
         int ret = -ENOMEM;
 
-        if (ksym_filter_entry_count >= KSYM_TRACER_MAX) {
-                printk(KERN_ERR "ksym_tracer: Maximum limit:(%d) reached. No"
-                " new requests for tracing can be accepted now.\n",
-                        KSYM_TRACER_MAX);
-                return -ENOSPC;
-        }
-
         entry = kzalloc(sizeof(struct trace_ksym), GFP_KERNEL);
         if (!entry)
                 return -ENOMEM;
@@ -203,13 +189,17 @@ int process_new_ksym_entry(char *ksymname, int op, unsigned long addr)
 
         if (IS_ERR(entry->ksym_hbp)) {
                 ret = PTR_ERR(entry->ksym_hbp);
-                printk(KERN_INFO "ksym_tracer request failed. Try again"
-                                        " later!!\n");
+                if (ret == -ENOSPC) {
+                        printk(KERN_ERR "ksym_tracer: Maximum limit reached."
+                        " No new requests for tracing can be accepted now.\n");
+                } else {
+                        printk(KERN_INFO "ksym_tracer request failed. Try again"
+                                         " later!!\n");
+                }
                 goto err;
         }
 
         hlist_add_head_rcu(&(entry->ksym_hlist), &ksym_filter_head);
-        ksym_filter_entry_count++;
 
         return 0;
 
@@ -265,7 +255,6 @@ static void __ksym_trace_reset(void)
         hlist_for_each_entry_safe(entry, node, node1, &ksym_filter_head,
                                                                 ksym_hlist) {
                 unregister_wide_hw_breakpoint(entry->ksym_hbp);
-                ksym_filter_entry_count--;
                 hlist_del_rcu(&(entry->ksym_hlist));
                 synchronize_rcu();
                 kfree(entry);
@@ -338,7 +327,6 @@ static ssize_t ksym_trace_filter_write(struct file *file,
                                 goto out_unlock;
                 }
                 /* Error or "symbol:---" case: drop it */
-                ksym_filter_entry_count--;
                 hlist_del_rcu(&(entry->ksym_hlist));
                 synchronize_rcu();
                 kfree(entry);