334 lines
9.6 KiB
C
334 lines
9.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* KUnit test for hw_breakpoint constraints accounting logic.
|
|
*
|
|
* Copyright (C) 2022, Google LLC.
|
|
*/
|
|
|
|
#include <kunit/test.h>
|
|
#include <linux/cpumask.h>
|
|
#include <linux/hw_breakpoint.h>
|
|
#include <linux/kthread.h>
|
|
#include <linux/perf_event.h>
|
|
#include <asm/hw_breakpoint.h>
|
|
|
|
#define TEST_REQUIRES_BP_SLOTS(test, slots) \
|
|
do { \
|
|
if ((slots) > get_test_bp_slots()) { \
|
|
kunit_skip((test), "Requires breakpoint slots: %d > %d", slots, \
|
|
get_test_bp_slots()); \
|
|
} \
|
|
} while (0)
|
|
|
|
#define TEST_EXPECT_NOSPC(expr) KUNIT_EXPECT_EQ(test, -ENOSPC, PTR_ERR(expr))
|
|
|
|
#define MAX_TEST_BREAKPOINTS 512
|
|
|
|
static char break_vars[MAX_TEST_BREAKPOINTS];
|
|
static struct perf_event *test_bps[MAX_TEST_BREAKPOINTS];
|
|
static struct task_struct *__other_task;
|
|
|
|
static struct perf_event *register_test_bp(int cpu, struct task_struct *tsk, int idx)
|
|
{
|
|
struct perf_event_attr attr = {};
|
|
|
|
if (WARN_ON(idx < 0 || idx >= MAX_TEST_BREAKPOINTS))
|
|
return NULL;
|
|
|
|
hw_breakpoint_init(&attr);
|
|
attr.bp_addr = (unsigned long)&break_vars[idx];
|
|
attr.bp_len = HW_BREAKPOINT_LEN_1;
|
|
attr.bp_type = HW_BREAKPOINT_RW;
|
|
return perf_event_create_kernel_counter(&attr, cpu, tsk, NULL, NULL);
|
|
}
|
|
|
|
static void unregister_test_bp(struct perf_event **bp)
|
|
{
|
|
if (WARN_ON(IS_ERR(*bp)))
|
|
return;
|
|
if (WARN_ON(!*bp))
|
|
return;
|
|
unregister_hw_breakpoint(*bp);
|
|
*bp = NULL;
|
|
}
|
|
|
|
static int get_test_bp_slots(void)
|
|
{
|
|
static int slots;
|
|
|
|
if (!slots)
|
|
slots = hw_breakpoint_slots(TYPE_DATA);
|
|
|
|
return slots;
|
|
}
|
|
|
|
static void fill_one_bp_slot(struct kunit *test, int *id, int cpu, struct task_struct *tsk)
|
|
{
|
|
struct perf_event *bp = register_test_bp(cpu, tsk, *id);
|
|
|
|
KUNIT_ASSERT_NOT_NULL(test, bp);
|
|
KUNIT_ASSERT_FALSE(test, IS_ERR(bp));
|
|
KUNIT_ASSERT_NULL(test, test_bps[*id]);
|
|
test_bps[(*id)++] = bp;
|
|
}
|
|
|
|
/*
|
|
* Fills up the given @cpu/@tsk with breakpoints, only leaving @skip slots free.
|
|
*
|
|
* Returns true if this can be called again, continuing at @id.
|
|
*/
|
|
static bool fill_bp_slots(struct kunit *test, int *id, int cpu, struct task_struct *tsk, int skip)
|
|
{
|
|
for (int i = 0; i < get_test_bp_slots() - skip; ++i)
|
|
fill_one_bp_slot(test, id, cpu, tsk);
|
|
|
|
return *id + get_test_bp_slots() <= MAX_TEST_BREAKPOINTS;
|
|
}
|
|
|
|
static int dummy_kthread(void *arg)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static struct task_struct *get_other_task(struct kunit *test)
|
|
{
|
|
struct task_struct *tsk;
|
|
|
|
if (__other_task)
|
|
return __other_task;
|
|
|
|
tsk = kthread_create(dummy_kthread, NULL, "hw_breakpoint_dummy_task");
|
|
KUNIT_ASSERT_FALSE(test, IS_ERR(tsk));
|
|
__other_task = tsk;
|
|
return __other_task;
|
|
}
|
|
|
|
static int get_test_cpu(int num)
|
|
{
|
|
int cpu;
|
|
|
|
WARN_ON(num < 0);
|
|
|
|
for_each_online_cpu(cpu) {
|
|
if (num-- <= 0)
|
|
break;
|
|
}
|
|
|
|
return cpu;
|
|
}
|
|
|
|
/* ===== Test cases ===== */
|
|
|
|
static void test_one_cpu(struct kunit *test)
|
|
{
|
|
int idx = 0;
|
|
|
|
fill_bp_slots(test, &idx, get_test_cpu(0), NULL, 0);
|
|
TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
|
|
}
|
|
|
|
static void test_many_cpus(struct kunit *test)
|
|
{
|
|
int idx = 0;
|
|
int cpu;
|
|
|
|
/* Test that CPUs are independent. */
|
|
for_each_online_cpu(cpu) {
|
|
bool do_continue = fill_bp_slots(test, &idx, cpu, NULL, 0);
|
|
|
|
TEST_EXPECT_NOSPC(register_test_bp(cpu, NULL, idx));
|
|
if (!do_continue)
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void test_one_task_on_all_cpus(struct kunit *test)
|
|
{
|
|
int idx = 0;
|
|
|
|
fill_bp_slots(test, &idx, -1, current, 0);
|
|
TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
|
|
/* Remove one and adding back CPU-target should work. */
|
|
unregister_test_bp(&test_bps[0]);
|
|
fill_one_bp_slot(test, &idx, get_test_cpu(0), NULL);
|
|
}
|
|
|
|
static void test_two_tasks_on_all_cpus(struct kunit *test)
|
|
{
|
|
int idx = 0;
|
|
|
|
/* Test that tasks are independent. */
|
|
fill_bp_slots(test, &idx, -1, current, 0);
|
|
fill_bp_slots(test, &idx, -1, get_other_task(test), 0);
|
|
|
|
TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(-1, get_other_task(test), idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), get_other_task(test), idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
|
|
/* Remove one from first task and adding back CPU-target should not work. */
|
|
unregister_test_bp(&test_bps[0]);
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
|
|
}
|
|
|
|
static void test_one_task_on_one_cpu(struct kunit *test)
|
|
{
|
|
int idx = 0;
|
|
|
|
fill_bp_slots(test, &idx, get_test_cpu(0), current, 0);
|
|
TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
|
|
/*
|
|
* Remove one and adding back CPU-target should work; this case is
|
|
* special vs. above because the task's constraints are CPU-dependent.
|
|
*/
|
|
unregister_test_bp(&test_bps[0]);
|
|
fill_one_bp_slot(test, &idx, get_test_cpu(0), NULL);
|
|
}
|
|
|
|
static void test_one_task_mixed(struct kunit *test)
|
|
{
|
|
int idx = 0;
|
|
|
|
TEST_REQUIRES_BP_SLOTS(test, 3);
|
|
|
|
fill_one_bp_slot(test, &idx, get_test_cpu(0), current);
|
|
fill_bp_slots(test, &idx, -1, current, 1);
|
|
TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
|
|
|
|
/* Transition from CPU-dependent pinned count to CPU-independent. */
|
|
unregister_test_bp(&test_bps[0]);
|
|
unregister_test_bp(&test_bps[1]);
|
|
fill_one_bp_slot(test, &idx, get_test_cpu(0), NULL);
|
|
fill_one_bp_slot(test, &idx, get_test_cpu(0), NULL);
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
|
|
}
|
|
|
|
static void test_two_tasks_on_one_cpu(struct kunit *test)
|
|
{
|
|
int idx = 0;
|
|
|
|
fill_bp_slots(test, &idx, get_test_cpu(0), current, 0);
|
|
fill_bp_slots(test, &idx, get_test_cpu(0), get_other_task(test), 0);
|
|
|
|
TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(-1, get_other_task(test), idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), get_other_task(test), idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
|
|
/* Can still create breakpoints on some other CPU. */
|
|
fill_bp_slots(test, &idx, get_test_cpu(1), NULL, 0);
|
|
}
|
|
|
|
static void test_two_tasks_on_one_all_cpus(struct kunit *test)
|
|
{
|
|
int idx = 0;
|
|
|
|
fill_bp_slots(test, &idx, get_test_cpu(0), current, 0);
|
|
fill_bp_slots(test, &idx, -1, get_other_task(test), 0);
|
|
|
|
TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(-1, get_other_task(test), idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), get_other_task(test), idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
|
|
/* Cannot create breakpoints on some other CPU either. */
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(1), NULL, idx));
|
|
}
|
|
|
|
static void test_task_on_all_and_one_cpu(struct kunit *test)
|
|
{
|
|
int tsk_on_cpu_idx, cpu_idx;
|
|
int idx = 0;
|
|
|
|
TEST_REQUIRES_BP_SLOTS(test, 3);
|
|
|
|
fill_bp_slots(test, &idx, -1, current, 2);
|
|
/* Transitioning from only all CPU breakpoints to mixed. */
|
|
tsk_on_cpu_idx = idx;
|
|
fill_one_bp_slot(test, &idx, get_test_cpu(0), current);
|
|
fill_one_bp_slot(test, &idx, -1, current);
|
|
|
|
TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
|
|
|
|
/* We should still be able to use up another CPU's slots. */
|
|
cpu_idx = idx;
|
|
fill_one_bp_slot(test, &idx, get_test_cpu(1), NULL);
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(1), NULL, idx));
|
|
|
|
/* Transitioning back to task target on all CPUs. */
|
|
unregister_test_bp(&test_bps[tsk_on_cpu_idx]);
|
|
/* Still have a CPU target breakpoint in get_test_cpu(1). */
|
|
TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
|
|
/* Remove it and try again. */
|
|
unregister_test_bp(&test_bps[cpu_idx]);
|
|
fill_one_bp_slot(test, &idx, -1, current);
|
|
|
|
TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
|
|
TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(1), NULL, idx));
|
|
}
|
|
|
|
static struct kunit_case hw_breakpoint_test_cases[] = {
|
|
KUNIT_CASE(test_one_cpu),
|
|
KUNIT_CASE(test_many_cpus),
|
|
KUNIT_CASE(test_one_task_on_all_cpus),
|
|
KUNIT_CASE(test_two_tasks_on_all_cpus),
|
|
KUNIT_CASE(test_one_task_on_one_cpu),
|
|
KUNIT_CASE(test_one_task_mixed),
|
|
KUNIT_CASE(test_two_tasks_on_one_cpu),
|
|
KUNIT_CASE(test_two_tasks_on_one_all_cpus),
|
|
KUNIT_CASE(test_task_on_all_and_one_cpu),
|
|
{},
|
|
};
|
|
|
|
static int test_init(struct kunit *test)
|
|
{
|
|
/* Most test cases want 2 distinct CPUs. */
|
|
if (num_online_cpus() < 2)
|
|
kunit_skip(test, "not enough cpus");
|
|
|
|
/* Want the system to not use breakpoints elsewhere. */
|
|
if (hw_breakpoint_is_used())
|
|
kunit_skip(test, "hw breakpoint already in use");
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void test_exit(struct kunit *test)
|
|
{
|
|
for (int i = 0; i < MAX_TEST_BREAKPOINTS; ++i) {
|
|
if (test_bps[i])
|
|
unregister_test_bp(&test_bps[i]);
|
|
}
|
|
|
|
if (__other_task) {
|
|
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 = {
|
|
.name = "hw_breakpoint",
|
|
.test_cases = hw_breakpoint_test_cases,
|
|
.init = test_init,
|
|
.exit = test_exit,
|
|
};
|
|
|
|
kunit_test_suites(&hw_breakpoint_test_suite);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Marco Elver <elver@google.com>");
|