diff options
Diffstat (limited to 'kernel/hw_breakpoint.c')
| -rw-r--r-- | kernel/hw_breakpoint.c | 146 |
1 files changed, 88 insertions, 58 deletions
diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c index cf5ee1628411..dbcbf6a33a08 100644 --- a/kernel/hw_breakpoint.c +++ b/kernel/hw_breakpoint.c @@ -52,7 +52,7 @@ 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); @@ -73,7 +73,7 @@ static DEFINE_MUTEX(nr_bp_mutex); 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) @@ -83,15 +83,51 @@ static unsigned int max_task_bp_pinned(int cpu) return 0; } +static int task_bp_pinned(struct task_struct *tsk) +{ + struct perf_event_context *ctx = tsk->perf_event_ctxp; + struct list_head *list; + struct perf_event *bp; + unsigned long flags; + int count = 0; + + if (WARN_ONCE(!ctx, "No perf context for this task")) + return 0; + + list = &ctx->event_list; + + raw_spin_lock_irqsave(&ctx->lock, flags); + + /* + * The current breakpoint counter is not included in the list + * at the open() callback time + */ + list_for_each_entry(bp, list, event_entry) { + if (bp->attr.type == PERF_TYPE_BREAKPOINT) + count++; + } + + raw_spin_unlock_irqrestore(&ctx->lock, flags); + + return count; +} + /* * Report the number of pinned/un-pinned breakpoints we have in * a given cpu (cpu > -1) or in all of them (cpu = -1). */ -static void fetch_bp_busy_slots(struct bp_busy_slots *slots, int cpu) +static void +fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp) { + int cpu = bp->cpu; + struct task_struct *tsk = bp->ctx->task; + if (cpu >= 0) { slots->pinned = per_cpu(nr_cpu_bp_pinned, cpu); - slots->pinned += max_task_bp_pinned(cpu); + if (!tsk) + slots->pinned += max_task_bp_pinned(cpu); + else + slots->pinned += task_bp_pinned(tsk); slots->flexible = per_cpu(nr_bp_flexible, cpu); return; @@ -101,7 +137,10 @@ static void fetch_bp_busy_slots(struct bp_busy_slots *slots, int cpu) unsigned int nr; nr = per_cpu(nr_cpu_bp_pinned, cpu); - nr += max_task_bp_pinned(cpu); + if (!tsk) + nr += max_task_bp_pinned(cpu); + else + nr += task_bp_pinned(tsk); if (nr > slots->pinned) slots->pinned = nr; @@ -118,35 +157,12 @@ static void fetch_bp_busy_slots(struct bp_busy_slots *slots, int cpu) */ static void toggle_bp_task_slot(struct task_struct *tsk, int cpu, bool enable) { - int count = 0; - struct perf_event *bp; - struct perf_event_context *ctx = tsk->perf_event_ctxp; unsigned int *tsk_pinned; - struct list_head *list; - unsigned long flags; - - if (WARN_ONCE(!ctx, "No perf context for this task")) - return; - - list = &ctx->event_list; - - spin_lock_irqsave(&ctx->lock, flags); - - /* - * The current breakpoint counter is not included in the list - * at the open() callback time - */ - list_for_each_entry(bp, list, event_entry) { - if (bp->attr.type == PERF_TYPE_BREAKPOINT) - count++; - } - - spin_unlock_irqrestore(&ctx->lock, flags); + int count = 0; - if (WARN_ONCE(count < 0, "No breakpoint counter found in the counter list")) - return; + 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) @@ -193,7 +209,7 @@ static void toggle_bp_slot(struct perf_event *bp, bool enable) * - 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. @@ -204,7 +220,7 @@ static void toggle_bp_slot(struct perf_event *bp, bool enable) * - 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 @@ -216,7 +232,7 @@ static void toggle_bp_slot(struct perf_event *bp, bool enable) * - 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). @@ -224,7 +240,7 @@ static void toggle_bp_slot(struct perf_event *bp, bool enable) * - 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) { @@ -233,7 +249,7 @@ int reserve_bp_slot(struct perf_event *bp) mutex_lock(&nr_bp_mutex); - fetch_bp_busy_slots(&slots, bp->cpu); + fetch_bp_busy_slots(&slots, bp); /* Flexible counters need to keep at least one slot */ if (slots.pinned + (!!slots.flexible) == HBP_NUM) { @@ -259,7 +275,7 @@ void release_bp_slot(struct perf_event *bp) } -int __register_perf_hw_breakpoint(struct perf_event *bp) +int register_perf_hw_breakpoint(struct perf_event *bp) { int ret; @@ -276,19 +292,12 @@ int __register_perf_hw_breakpoint(struct perf_event *bp) * This is a quick hack that will be removed soon, once we remove * the tmp breakpoints from ptrace */ - if (!bp->attr.disabled || bp->callback == perf_bp_event) + if (!bp->attr.disabled || !bp->overflow_handler) ret = arch_validate_hwbkpt_settings(bp, bp->ctx->task); return ret; } -int register_perf_hw_breakpoint(struct perf_event *bp) -{ - bp->callback = perf_bp_event; - - return __register_perf_hw_breakpoint(bp); -} - /** * register_user_hw_breakpoint - register a hardware breakpoint for user space * @attr: breakpoint attributes @@ -297,7 +306,7 @@ int register_perf_hw_breakpoint(struct perf_event *bp) */ struct perf_event * register_user_hw_breakpoint(struct perf_event_attr *attr, - perf_callback_t triggered, + perf_overflow_handler_t triggered, struct task_struct *tsk) { return perf_event_create_kernel_counter(attr, -1, tsk->pid, triggered); @@ -311,19 +320,40 @@ EXPORT_SYMBOL_GPL(register_user_hw_breakpoint); * @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, - perf_callback_t triggered, - struct task_struct *tsk) +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; + int old_type = bp->attr.bp_type; + int old_len = bp->attr.bp_len; + int err = 0; - return perf_event_create_kernel_counter(attr, -1, tsk->pid, triggered); + 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 0; } EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint); @@ -348,7 +378,7 @@ EXPORT_SYMBOL_GPL(unregister_hw_breakpoint); */ struct perf_event ** register_wide_hw_breakpoint(struct perf_event_attr *attr, - perf_callback_t triggered) + perf_overflow_handler_t triggered) { struct perf_event **cpu_events, **pevent, *bp; long err; |