Add a sequence to test if an ASI remains active after it is
scheduled out and then scheduled back in.

Signed-off-by: Alexandre Chartre <alexandre.char...@oracle.com>
---
 drivers/staging/asi/asidrv.c | 98 ++++++++++++++++++++++++++++++++++++
 drivers/staging/asi/asidrv.h |  2 +
 2 files changed, 100 insertions(+)

diff --git a/drivers/staging/asi/asidrv.c b/drivers/staging/asi/asidrv.c
index e08f2a107e89..9ca17e0b654e 100644
--- a/drivers/staging/asi/asidrv.c
+++ b/drivers/staging/asi/asidrv.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/fs.h>
+#include <linux/kthread.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/nmi.h>
@@ -21,17 +22,24 @@
 /* Number of read for mem/memmap test sequence */
 #define ASIDRV_MEM_READ_COUNT          1000
 
+/* Number of loop for the sched test sequence */
+#define ASIDRV_SCHED_LOOP_COUNT                20
+
 /* Timeout for target to be ready to receive an interrupt or NMI */
 #define ASIDRV_TIMEOUT_TARGET_READY    1
 
 /* Timeout for receiving an interrupt or NMI */
 #define ASIDRV_TIMEOUT_INTERRUPT       5
 
+/* Timeout before thread can start its job */
+#define ASIDRV_TIMEOUT_THREAD_START    5
+
 /* NMI handler name used for testing */
 #define ASIDRV_NMI_HANDLER_NAME                "ASI Test"
 
 enum asidrv_state {
        ASIDRV_STATE_NONE,
+       ASIDRV_STATE_START,
        ASIDRV_STATE_INTR_WAITING,
        ASIDRV_STATE_INTR_RECEIVED,
        ASIDRV_STATE_NMI_WAITING,
@@ -50,6 +58,8 @@ struct asidrv_test {
        bool                    work_set;
        enum asidrv_run_error   run_error;
        bool                    intrnmi;
+       struct task_struct      *kthread; /* work on same cpu */
+       int                     count;
 };
 
 struct asidrv_sequence {
@@ -438,6 +448,66 @@ static enum asidrv_run_error asidrv_intrnmi_run(struct 
asidrv_test *test)
        return err;
 }
 
+/*
+ * Sched Test Sequence
+ */
+
+static void asidrv_sched_loop(struct asidrv_test *test)
+{
+       int last_count = 0;
+
+       while (test->count < ASIDRV_SCHED_LOOP_COUNT) {
+               test->count++;
+               last_count = test->count;
+               /*
+                * Call into the scheduler, until it runs the other
+                * asidrv_sched_loop() task. We know it has run when
+                * test->count changes.
+                */
+               while (last_count == test->count)
+                       schedule();
+       }
+       test->count++;
+}
+
+static int asidrv_sched_kthread(void *data)
+{
+       struct asidrv_test *test = data;
+       enum asidrv_run_error err;
+
+       err = asidrv_wait(test, ASIDRV_STATE_START,
+                         ASIDRV_TIMEOUT_THREAD_START);
+       if (err) {
+               pr_debug("Error waiting for start state: error %d\n", err);
+               return err;
+       }
+       asidrv_sched_loop(test);
+
+       return 0;
+}
+
+static enum asidrv_run_error asidrv_sched_init(struct asidrv_test *test)
+{
+       test->kthread = kthread_create_on_node(asidrv_sched_kthread, test,
+                                              cpu_to_node(test->cpu),
+                                              "sched test");
+       if (!test->kthread)
+               return ASIDRV_RUN_ERR_KTHREAD;
+
+       kthread_bind(test->kthread, test->cpu);
+       test->count = 0;
+
+       return ASIDRV_RUN_ERR_NONE;
+}
+
+static enum asidrv_run_error asidrv_sched_run(struct asidrv_test *test)
+{
+       atomic_set(&test->state, ASIDRV_STATE_START);
+       asidrv_sched_loop(test);
+
+       return ASIDRV_RUN_ERR_NONE;
+}
+
 /*
  * Memory Buffer Access Test Sequences
  */
@@ -521,14 +591,28 @@ struct asidrv_sequence asidrv_sequences[] = {
                "intr+nmi",
                asidrv_intrnmi_setup, asidrv_intrnmi_run, asidrv_nmi_cleanup,
        },
+       [ASIDRV_SEQ_SCHED] = {
+               "sched",
+               asidrv_sched_init, asidrv_sched_run, NULL,
+       },
 };
 
 static enum asidrv_run_error asidrv_run_init(struct asidrv_test *test)
 {
+       cpumask_t mask = CPU_MASK_NONE;
        int err;
 
        test->run_error = ASIDRV_RUN_ERR_NONE;
 
+       /*
+        * Binding ourself to the current cpu but keep preemption
+        * enabled.
+        */
+       test->cpu = get_cpu();
+       cpumask_set_cpu(test->cpu, &mask);
+       set_cpus_allowed_ptr(current, &mask);
+       put_cpu();
+
        /*
         * Map the current stack, we need it to enter ASI.
         */
@@ -589,12 +673,26 @@ static enum asidrv_run_error asidrv_run_setup(struct 
asidrv_test *test,
                schedule_work_on(other_cpu, &test->work);
        }
 
+       if (test->kthread)
+               wake_up_process(test->kthread);
+
        return ASIDRV_RUN_ERR_NONE;
 }
 
 static void asidrv_run_cleanup(struct asidrv_test *test,
                               struct asidrv_sequence *sequence)
 {
+       if (test->kthread) {
+               kthread_stop(test->kthread);
+               test->kthread = NULL;
+       }
+
+       if (test->work_set) {
+               /* ensure work has completed */
+               flush_work(&test->work);
+               test->work_set = false;
+       }
+
        if (sequence->cleanup)
                sequence->cleanup(test);
 }
diff --git a/drivers/staging/asi/asidrv.h b/drivers/staging/asi/asidrv.h
index de9f7ad993e0..9f540b119883 100644
--- a/drivers/staging/asi/asidrv.h
+++ b/drivers/staging/asi/asidrv.h
@@ -13,6 +13,7 @@ enum asidrv_seqnum {
        ASIDRV_SEQ_INTERRUPT,   /* interrupt sequence */
        ASIDRV_SEQ_NMI,         /* NMI interrupt sequence */
        ASIDRV_SEQ_INTRNMI,     /* NMI in interrupt sequence */
+       ASIDRV_SEQ_SCHED,       /* schedule() sequence */
 };
 
 enum asidrv_run_error {
@@ -30,6 +31,7 @@ enum asidrv_run_error {
        ASIDRV_RUN_ERR_NMI,     /* no NMI received */
        ASIDRV_RUN_ERR_NMI_REG, /* failed to register NMI handler */
        ASIDRV_RUN_ERR_NMI_ASI_ACTIVE, /* ASI active in NMI handler */
+       ASIDRV_RUN_ERR_KTHREAD, /* failed to create kernel thread */
 };
 
 #define ASIDRV_IOCTL_RUN_SEQUENCE      _IOWR('a', 1, struct asidrv_run_param)
-- 
2.18.2

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