zircon/kernel/tests/dpc_tests.cpp

// Copyright 2019 The Fuchsia Authors
//
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file or at
// https://opensource.org/licenses/MIT

#include "tests.h"

#include <arch/arch_ops.h>
#include <arch/mp.h>
#include <kernel/dpc.h>
#include <kernel/event.h>
#include <ktl/atomic.h>
#include <lib/unittest/unittest.h>

struct event_signal_from_dpc_context {
   dpc_t dpc;
   event_t event;
   ktl::atomic<uint> expected_cpu;
   ktl::atomic<bool> dpc_started;
};
static void event_signal_from_dpc_check_cpu(dpc_t* dpc) {
    auto* const context = reinterpret_cast<struct event_signal_from_dpc_context*>(dpc->arg);
    context->dpc_started = true;

    // DPCs allow interrupts and blocking.
    DEBUG_ASSERT(!arch_ints_disabled());
    DEBUG_ASSERT(!arch_blocking_disallowed());
    DEBUG_ASSERT(context->expected_cpu == arch_curr_cpu_num());

    event_signal(&context->event, /*reschedule=*/false);
}

static bool test_dpc_queue() {
    BEGIN_TEST;

    static constexpr int kNumDPCs = 72;
    struct event_signal_from_dpc_context context[kNumDPCs];

    // Init all the DPCs and supporting context.
    for (int i = 0; i < kNumDPCs; i++) {
        context[i].dpc = DPC_INITIAL_VALUE;
        event_init(&context[i].event, /*initial=*/false, /*flags=*/0);
        context[i].dpc_started = false;
    }

    // Fire off DPCs.
    for (int i = 0; i < kNumDPCs; i++) {
        context[i].dpc.func = event_signal_from_dpc_check_cpu;
        context[i].dpc.arg = reinterpret_cast<void*>(&context[i]);
        arch_disable_ints();
        context[i].expected_cpu = arch_curr_cpu_num();
        dpc_queue(&context[i].dpc, /*reschedule=*/false);
        arch_enable_ints();
    }
    for (int i = 0; i < kNumDPCs; i++) {
        if (context[i].dpc_started) {
            // Once the DPC has started executing, we can reclaim the submitted dpc_t. Zero it to
            // try to check this.
            context[i].dpc = DPC_INITIAL_VALUE;
        }
    }
    for (int i = 0; i < kNumDPCs; i++) {
        event_wait(&context[i].event);
    }
    for (int i = 0; i < kNumDPCs; i++) {
        event_destroy(&context[i].event);
    }

    END_TEST;
}

UNITTEST_START_TESTCASE(dpc_tests)
UNITTEST("basic test of dpc_queue", test_dpc_queue)
UNITTEST_END_TESTCASE(dpc_tests, "dpc_tests", "Tests of DPCs");