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 <[email protected]>
---
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
On Mon, 4 Jul 2022 at 17:06, Marco Elver <[email protected]> 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 <[email protected]>
Reviewed-by: Dmitry Vyukov <[email protected]>
> ---
> 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
>
On Mon, Jul 4, 2022 at 8:10 AM Dmitry Vyukov <[email protected]> wrote:
>
> On Mon, 4 Jul 2022 at 17:06, Marco Elver <[email protected]> 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 <[email protected]>
>
> Reviewed-by: Dmitry Vyukov <[email protected]>
Acked-by: Ian Rogers <[email protected]>
Thanks,
Ian
> > ---
> > 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
> >