#include <linux/percpu.h>
#include <linux/sched.h>
#include <linux/init.h>
+#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/hw_breakpoint.h>
static DEFINE_PER_CPU(unsigned int, nr_cpu_bp_pinned);
/* Number of pinned task breakpoints in a cpu */
-static DEFINE_PER_CPU(unsigned int, task_bp_pinned[HBP_NUM]);
+static DEFINE_PER_CPU(unsigned int, nr_task_bp_pinned[HBP_NUM]);
/* Number of non-pinned cpu/task breakpoints in a cpu */
static DEFINE_PER_CPU(unsigned int, nr_bp_flexible);
static unsigned int max_task_bp_pinned(int cpu)
{
int i;
- unsigned int *tsk_pinned = per_cpu(task_bp_pinned, cpu);
+ unsigned int *tsk_pinned = per_cpu(nr_task_bp_pinned, cpu);
for (i = HBP_NUM -1; i >= 0; i--) {
if (tsk_pinned[i] > 0)
list = &ctx->event_list;
- spin_lock_irqsave(&ctx->lock, flags);
+ raw_spin_lock_irqsave(&ctx->lock, flags);
/*
* The current breakpoint counter is not included in the list
count++;
}
- spin_unlock_irqrestore(&ctx->lock, flags);
+ raw_spin_unlock_irqrestore(&ctx->lock, flags);
return count;
}
count = task_bp_pinned(tsk);
- tsk_pinned = per_cpu(task_bp_pinned, cpu);
+ tsk_pinned = per_cpu(nr_task_bp_pinned, cpu);
if (enable) {
tsk_pinned[count]++;
if (count > 0)
* - If attached to a single cpu, check:
*
* (per_cpu(nr_bp_flexible, cpu) || (per_cpu(nr_cpu_bp_pinned, cpu)
- * + max(per_cpu(task_bp_pinned, cpu)))) < HBP_NUM
+ * + max(per_cpu(nr_task_bp_pinned, cpu)))) < HBP_NUM
*
* -> If there are already non-pinned counters in this cpu, it means
* there is already a free slot for them.
* - If attached to every cpus, check:
*
* (per_cpu(nr_bp_flexible, *) || (max(per_cpu(nr_cpu_bp_pinned, *))
- * + max(per_cpu(task_bp_pinned, *)))) < HBP_NUM
+ * + max(per_cpu(nr_task_bp_pinned, *)))) < HBP_NUM
*
* -> This is roughly the same, except we check the number of per cpu
* bp for every cpu and we keep the max one. Same for the per tasks
* - If attached to a single cpu, check:
*
* ((per_cpu(nr_bp_flexible, cpu) > 1) + per_cpu(nr_cpu_bp_pinned, cpu)
- * + max(per_cpu(task_bp_pinned, cpu))) < HBP_NUM
+ * + max(per_cpu(nr_task_bp_pinned, cpu))) < HBP_NUM
*
* -> Same checks as before. But now the nr_bp_flexible, if any, must keep
* one register at least (or they will never be fed).
* - If attached to every cpus, check:
*
* ((per_cpu(nr_bp_flexible, *) > 1) + max(per_cpu(nr_cpu_bp_pinned, *))
- * + max(per_cpu(task_bp_pinned, *))) < HBP_NUM
+ * + max(per_cpu(nr_task_bp_pinned, *))) < HBP_NUM
*/
-int reserve_bp_slot(struct perf_event *bp)
+static int __reserve_bp_slot(struct perf_event *bp)
{
struct bp_busy_slots slots = {0};
- int ret = 0;
-
- mutex_lock(&nr_bp_mutex);
fetch_bp_busy_slots(&slots, bp);
/* Flexible counters need to keep at least one slot */
- if (slots.pinned + (!!slots.flexible) == HBP_NUM) {
- ret = -ENOSPC;
- goto end;
- }
+ if (slots.pinned + (!!slots.flexible) == HBP_NUM)
+ return -ENOSPC;
toggle_bp_slot(bp, true);
-end:
+ return 0;
+}
+
+int reserve_bp_slot(struct perf_event *bp)
+{
+ int ret;
+
+ mutex_lock(&nr_bp_mutex);
+
+ ret = __reserve_bp_slot(bp);
+
mutex_unlock(&nr_bp_mutex);
return ret;
}
+static void __release_bp_slot(struct perf_event *bp)
+{
+ toggle_bp_slot(bp, false);
+}
+
void release_bp_slot(struct perf_event *bp)
{
mutex_lock(&nr_bp_mutex);
- toggle_bp_slot(bp, false);
+ __release_bp_slot(bp);
mutex_unlock(&nr_bp_mutex);
}
+/*
+ * Allow the kernel debugger to reserve breakpoint slots without
+ * taking a lock using the dbg_* variant of for the reserve and
+ * release breakpoint slots.
+ */
+int dbg_reserve_bp_slot(struct perf_event *bp)
+{
+ if (mutex_is_locked(&nr_bp_mutex))
+ return -1;
+
+ return __reserve_bp_slot(bp);
+}
+
+int dbg_release_bp_slot(struct perf_event *bp)
+{
+ if (mutex_is_locked(&nr_bp_mutex))
+ return -1;
+
+ __release_bp_slot(bp);
+
+ return 0;
+}
int register_perf_hw_breakpoint(struct perf_event *bp)
{
if (!bp->attr.disabled || !bp->overflow_handler)
ret = arch_validate_hwbkpt_settings(bp, bp->ctx->task);
+ /* if arch_validate_hwbkpt_settings() fails then release bp slot */
+ if (ret)
+ release_bp_slot(bp);
+
return ret;
}
* @triggered: callback to trigger when we hit the breakpoint
* @tsk: pointer to 'task_struct' of the process to which the address belongs
*/
-struct perf_event *
-modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr)
+int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr)
{
- /*
- * FIXME: do it without unregistering
- * - We don't want to lose our slot
- * - If the new bp is incorrect, don't lose the older one
- */
- unregister_hw_breakpoint(bp);
+ u64 old_addr = bp->attr.bp_addr;
+ u64 old_len = bp->attr.bp_len;
+ int old_type = bp->attr.bp_type;
+ int err = 0;
+
+ perf_event_disable(bp);
+
+ bp->attr.bp_addr = attr->bp_addr;
+ bp->attr.bp_type = attr->bp_type;
+ bp->attr.bp_len = attr->bp_len;
+
+ if (attr->disabled)
+ goto end;
+
+ err = arch_validate_hwbkpt_settings(bp, bp->ctx->task);
+ if (!err)
+ perf_event_enable(bp);
+
+ if (err) {
+ bp->attr.bp_addr = old_addr;
+ bp->attr.bp_type = old_type;
+ bp->attr.bp_len = old_len;
+ if (!bp->attr.disabled)
+ perf_event_enable(bp);
+
+ return err;
+ }
+
+end:
+ bp->attr.disabled = attr->disabled;
- return perf_event_create_kernel_counter(attr, -1, bp->ctx->task->pid,
- bp->overflow_handler);
+ return 0;
}
EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint);
*
* @return a set of per_cpu pointers to perf events
*/
-struct perf_event **
+struct perf_event * __percpu *
register_wide_hw_breakpoint(struct perf_event_attr *attr,
perf_overflow_handler_t triggered)
{
- struct perf_event **cpu_events, **pevent, *bp;
+ struct perf_event * __percpu *cpu_events, **pevent, *bp;
long err;
int cpu;
cpu_events = alloc_percpu(typeof(*cpu_events));
if (!cpu_events)
- return ERR_PTR(-ENOMEM);
+ return (void __percpu __force *)ERR_PTR(-ENOMEM);
- for_each_possible_cpu(cpu) {
+ get_online_cpus();
+ for_each_online_cpu(cpu) {
pevent = per_cpu_ptr(cpu_events, cpu);
bp = perf_event_create_kernel_counter(attr, cpu, -1, triggered);
goto fail;
}
}
+ put_online_cpus();
return cpu_events;
fail:
- for_each_possible_cpu(cpu) {
+ for_each_online_cpu(cpu) {
pevent = per_cpu_ptr(cpu_events, cpu);
if (IS_ERR(*pevent))
break;
unregister_hw_breakpoint(*pevent);
}
+ put_online_cpus();
+
free_percpu(cpu_events);
- /* return the error if any */
- return ERR_PTR(err);
+ return (void __percpu __force *)ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(register_wide_hw_breakpoint);
* unregister_wide_hw_breakpoint - unregister a wide breakpoint in the kernel
* @cpu_events: the per cpu set of events to unregister
*/
-void unregister_wide_hw_breakpoint(struct perf_event **cpu_events)
+void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events)
{
int cpu;
struct perf_event **pevent;
.enable = arch_install_hw_breakpoint,
.disable = arch_uninstall_hw_breakpoint,
.read = hw_breakpoint_pmu_read,
- .unthrottle = hw_breakpoint_pmu_unthrottle
};
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff