diff options
Diffstat (limited to 'kernel/events/hw_breakpoint.c')
| -rw-r--r-- | kernel/events/hw_breakpoint.c | 124 |
1 files changed, 83 insertions, 41 deletions
diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c index 3f8cb1e14588..6e28d2866be5 100644 --- a/kernel/events/hw_breakpoint.c +++ b/kernel/events/hw_breakpoint.c @@ -44,6 +44,7 @@ #include <linux/list.h> #include <linux/cpu.h> #include <linux/smp.h> +#include <linux/bug.h> #include <linux/hw_breakpoint.h> /* @@ -85,9 +86,9 @@ __weak int hw_breakpoint_weight(struct perf_event *bp) 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; @@ -122,7 +123,7 @@ static int task_bp_pinned(int cpu, struct perf_event *bp, enum bp_type_idx type) 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); } @@ -277,7 +278,7 @@ __weak void arch_unregister_hw_breakpoint(struct perf_event *bp) * ((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; @@ -288,11 +289,11 @@ static int __reserve_bp_slot(struct perf_event *bp) 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); @@ -317,19 +318,19 @@ int reserve_bp_slot(struct perf_event *bp) 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); } @@ -339,11 +340,43 @@ void release_bp_slot(struct perf_event *bp) 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 @@ -354,7 +387,7 @@ int dbg_reserve_bp_slot(struct perf_event *bp) 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) @@ -362,7 +395,7 @@ 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; } @@ -423,20 +456,45 @@ register_user_hw_breakpoint(struct perf_event_attr *attr, } 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 * @attr: new breakpoint attributes - * @triggered: callback to trigger when we hit the breakpoint - * @tsk: pointer to 'task_struct' of the process to which the address belongs */ int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr) { - u64 old_addr = bp->attr.bp_addr; - u64 old_len = bp->attr.bp_len; - int old_type = bp->attr.bp_type; - int err = 0; - /* * modify_user_hw_breakpoint can be invoked with IRQs disabled and hence it * will not be possible to raise IPIs that invoke __perf_event_disable. @@ -448,30 +506,14 @@ int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *att 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; - - if (attr->disabled) - goto end; + if (!attr->disabled) { + int err = modify_user_hw_breakpoint_check(bp, attr, false); - err = validate_hw_breakpoint(bp); - if (!err) + if (err) + return 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; + bp->attr.disabled = 0; } - -end: - bp->attr.disabled = attr->disabled; - return 0; } EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint); |