#include <linux/list.h>
#include <linux/cpu.h>
#include <linux/smp.h>
+#include <linux/bug.h>
#include <linux/hw_breakpoint.h>
/*
return 1;
}
-static inline enum bp_type_idx find_slot_idx(struct perf_event *bp)
+static inline enum bp_type_idx find_slot_idx(u64 bp_type)
{
- if (bp->attr.bp_type & HW_BREAKPOINT_RW)
+ if (bp_type & HW_BREAKPOINT_RW)
return TYPE_DATA;
return TYPE_INST;
list_for_each_entry(iter, &bp_task_head, hw.bp_list) {
if (iter->hw.target == tsk &&
- find_slot_idx(iter) == type &&
+ find_slot_idx(iter->attr.bp_type) == type &&
(iter->cpu < 0 || cpu == iter->cpu))
count += hw_breakpoint_weight(iter);
}
* ((per_cpu(info->flexible, *) > 1) + max(per_cpu(info->cpu_pinned, *))
* + max(per_cpu(info->tsk_pinned, *))) < HBP_NUM
*/
-static int __reserve_bp_slot(struct perf_event *bp)
+static int __reserve_bp_slot(struct perf_event *bp, u64 bp_type)
{
struct bp_busy_slots slots = {0};
enum bp_type_idx type;
return -ENOMEM;
/* Basic checks */
- if (bp->attr.bp_type == HW_BREAKPOINT_EMPTY ||
- bp->attr.bp_type == HW_BREAKPOINT_INVALID)
+ if (bp_type == HW_BREAKPOINT_EMPTY ||
+ bp_type == HW_BREAKPOINT_INVALID)
return -EINVAL;
- type = find_slot_idx(bp);
+ type = find_slot_idx(bp_type);
weight = hw_breakpoint_weight(bp);
fetch_bp_busy_slots(&slots, bp, type);
mutex_lock(&nr_bp_mutex);
- ret = __reserve_bp_slot(bp);
+ ret = __reserve_bp_slot(bp, bp->attr.bp_type);
mutex_unlock(&nr_bp_mutex);
return ret;
}
-static void __release_bp_slot(struct perf_event *bp)
+static void __release_bp_slot(struct perf_event *bp, u64 bp_type)
{
enum bp_type_idx type;
int weight;
- type = find_slot_idx(bp);
+ type = find_slot_idx(bp_type);
weight = hw_breakpoint_weight(bp);
toggle_bp_slot(bp, false, type, weight);
}
mutex_lock(&nr_bp_mutex);
arch_unregister_hw_breakpoint(bp);
- __release_bp_slot(bp);
+ __release_bp_slot(bp, bp->attr.bp_type);
mutex_unlock(&nr_bp_mutex);
}
+static int __modify_bp_slot(struct perf_event *bp, u64 old_type)
+{
+ int err;
+
+ __release_bp_slot(bp, old_type);
+
+ err = __reserve_bp_slot(bp, bp->attr.bp_type);
+ if (err) {
+ /*
+ * Reserve the old_type slot back in case
+ * there's no space for the new type.
+ *
+ * This must succeed, because we just released
+ * the old_type slot in the __release_bp_slot
+ * call above. If not, something is broken.
+ */
+ WARN_ON(__reserve_bp_slot(bp, old_type));
+ }
+
+ return err;
+}
+
+static int modify_bp_slot(struct perf_event *bp, u64 old_type)
+{
+ int ret;
+
+ mutex_lock(&nr_bp_mutex);
+ ret = __modify_bp_slot(bp, old_type);
+ mutex_unlock(&nr_bp_mutex);
+ return ret;
+}
+
/*
* Allow the kernel debugger to reserve breakpoint slots without
* taking a lock using the dbg_* variant of for the reserve and
if (mutex_is_locked(&nr_bp_mutex))
return -1;
- return __reserve_bp_slot(bp);
+ return __reserve_bp_slot(bp, bp->attr.bp_type);
}
int dbg_release_bp_slot(struct perf_event *bp)
if (mutex_is_locked(&nr_bp_mutex))
return -1;
- __release_bp_slot(bp);
+ __release_bp_slot(bp, bp->attr.bp_type);
return 0;
}
}
EXPORT_SYMBOL_GPL(register_user_hw_breakpoint);
+int
+modify_user_hw_breakpoint_check(struct perf_event *bp, struct perf_event_attr *attr,
+ bool check)
+{
+ u64 old_addr = bp->attr.bp_addr;
+ u64 old_len = bp->attr.bp_len;
+ int old_type = bp->attr.bp_type;
+ bool modify = attr->bp_type != old_type;
+ int err = 0;
+
+ bp->attr.bp_addr = attr->bp_addr;
+ bp->attr.bp_type = attr->bp_type;
+ bp->attr.bp_len = attr->bp_len;
+
+ if (check && memcmp(&bp->attr, attr, sizeof(*attr)))
+ return -EINVAL;
+
+ err = validate_hw_breakpoint(bp);
+ if (!err && modify)
+ err = modify_bp_slot(bp, old_type);
+
+ if (err) {
+ bp->attr.bp_addr = old_addr;
+ bp->attr.bp_type = old_type;
+ bp->attr.bp_len = old_len;
+ return err;
+ }
+
+ bp->attr.disabled = attr->disabled;
+ return 0;
+}
+
/**
* modify_user_hw_breakpoint - modify a user-space hardware breakpoint
* @bp: the breakpoint structure to modify
else
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;
- bp->attr.disabled = 1;
-
if (!attr->disabled) {
- int err = validate_hw_breakpoint(bp);
+ int err = modify_user_hw_breakpoint_check(bp, attr, false);
if (err)
return err;
-
perf_event_enable(bp);
bp->attr.disabled = 0;
}
-
return 0;
}
EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint);