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-rw-r--r--arch/sh/include/asm/hw_breakpoint.h5
-rw-r--r--arch/x86/include/asm/hw_breakpoint.h5
-rw-r--r--include/linux/hw_breakpoint.h10
-rw-r--r--kernel/hw_breakpoint.c53
-rw-r--r--kernel/trace/trace_ksym.c26
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 382bad937dc..e14cad96798 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 c77a5a6fab9..942255310e6 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 7e889909309..a2d6ea49ec5 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 974498b858f..684b710cbb9 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 d59cd687947..8eaf00749b6 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);