Messages in this thread | | | From | Dmitry Vyukov <> | Date | Mon, 4 Jul 2022 17:09:42 +0200 | Subject | Re: [PATCH v3 02/14] perf/hw_breakpoint: Provide hw_breakpoint_is_used() and use in test |
| |
On Mon, 4 Jul 2022 at 17:06, Marco Elver <elver@google.com> wrote: > > Provide hw_breakpoint_is_used() to check if breakpoints are in use on > the system. > > Use it in the KUnit test to verify the global state before and after a > test case. > > Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
> --- > v3: > * New patch. > --- > include/linux/hw_breakpoint.h | 3 +++ > kernel/events/hw_breakpoint.c | 29 +++++++++++++++++++++++++++++ > kernel/events/hw_breakpoint_test.c | 12 +++++++++++- > 3 files changed, 43 insertions(+), 1 deletion(-) > > diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h > index 78dd7035d1e5..a3fb846705eb 100644 > --- a/include/linux/hw_breakpoint.h > +++ b/include/linux/hw_breakpoint.h > @@ -74,6 +74,7 @@ register_wide_hw_breakpoint(struct perf_event_attr *attr, > extern int register_perf_hw_breakpoint(struct perf_event *bp); > extern void unregister_hw_breakpoint(struct perf_event *bp); > extern void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events); > +extern bool hw_breakpoint_is_used(void); > > extern int dbg_reserve_bp_slot(struct perf_event *bp); > extern int dbg_release_bp_slot(struct perf_event *bp); > @@ -121,6 +122,8 @@ register_perf_hw_breakpoint(struct perf_event *bp) { return -ENOSYS; } > static inline void unregister_hw_breakpoint(struct perf_event *bp) { } > static inline void > unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) { } > +static inline bool hw_breakpoint_is_used(void) { return false; } > + > static inline int > reserve_bp_slot(struct perf_event *bp) {return -ENOSYS; } > static inline void release_bp_slot(struct perf_event *bp) { } > diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c > index f32320ac02fd..fd5cd1f9e7fc 100644 > --- a/kernel/events/hw_breakpoint.c > +++ b/kernel/events/hw_breakpoint.c > @@ -604,6 +604,35 @@ void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) > } > EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint); > > +/** > + * hw_breakpoint_is_used - check if breakpoints are currently used > + * > + * Returns: true if breakpoints are used, false otherwise. > + */ > +bool hw_breakpoint_is_used(void) > +{ > + int cpu; > + > + if (!constraints_initialized) > + return false; > + > + for_each_possible_cpu(cpu) { > + for (int type = 0; type < TYPE_MAX; ++type) { > + struct bp_cpuinfo *info = get_bp_info(cpu, type); > + > + if (info->cpu_pinned) > + return true; > + > + for (int slot = 0; slot < nr_slots[type]; ++slot) { > + if (info->tsk_pinned[slot]) > + return true; > + } > + } > + } > + > + return false; > +} > + > static struct notifier_block hw_breakpoint_exceptions_nb = { > .notifier_call = hw_breakpoint_exceptions_notify, > /* we need to be notified first */ > diff --git a/kernel/events/hw_breakpoint_test.c b/kernel/events/hw_breakpoint_test.c > index 433c5c45e2a5..5ced822df788 100644 > --- a/kernel/events/hw_breakpoint_test.c > +++ b/kernel/events/hw_breakpoint_test.c > @@ -294,7 +294,14 @@ static struct kunit_case hw_breakpoint_test_cases[] = { > static int test_init(struct kunit *test) > { > /* Most test cases want 2 distinct CPUs. */ > - return num_online_cpus() < 2 ? -EINVAL : 0; > + if (num_online_cpus() < 2) > + return -EINVAL; > + > + /* Want the system to not use breakpoints elsewhere. */ > + if (hw_breakpoint_is_used()) > + return -EBUSY; > + > + return 0; > } > > static void test_exit(struct kunit *test) > @@ -308,6 +315,9 @@ static void test_exit(struct kunit *test) > kthread_stop(__other_task); > __other_task = NULL; > } > + > + /* Verify that internal state agrees that no breakpoints are in use. */ > + KUNIT_EXPECT_FALSE(test, hw_breakpoint_is_used()); > } > > static struct kunit_suite hw_breakpoint_test_suite = { > -- > 2.37.0.rc0.161.g10f37bed90-goog >
| |