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Date: Mon, 4 May 2020 17:02:27 +0200
From: Alexandre Chartre <alexandre.chartre@...cle.com>
To: tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, hpa@...or.com,
dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org,
x86@...nel.org, linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc: pbonzini@...hat.com, konrad.wilk@...cle.com,
jan.setjeeilers@...cle.com, liran.alon@...cle.com,
junaids@...gle.com, graf@...zon.de, rppt@...ux.vnet.ibm.com,
kuzuno@...il.com, mgross@...ux.intel.com,
alexandre.chartre@...cle.com
Subject: [RFC v4][PATCH part-3 06/14] asidrv: Sequence to test NMI on ASI
Add a sequence to test if an ASI remains active after receiving
an NMI.
Signed-off-by: Alexandre Chartre <alexandre.chartre@...cle.com>
---
drivers/staging/asi/asidrv.c | 116 ++++++++++++++++++++++++++++++++++-
drivers/staging/asi/asidrv.h | 4 ++
2 files changed, 118 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/asi/asidrv.c b/drivers/staging/asi/asidrv.c
index a3c7da2bf16e..8f964c9e0b14 100644
--- a/drivers/staging/asi/asidrv.c
+++ b/drivers/staging/asi/asidrv.c
@@ -6,6 +6,7 @@
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
+#include <linux/nmi.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
@@ -20,16 +21,21 @@
/* Number of read for mem/memmap test sequence */
#define ASIDRV_MEM_READ_COUNT 1000
-/* Timeout for target to be ready to receive an interrupt */
+/* Timeout for target to be ready to receive an interrupt or NMI */
#define ASIDRV_TIMEOUT_TARGET_READY 1
-/* Timeout for receiving an interrupt */
+/* Timeout for receiving an interrupt or NMI */
#define ASIDRV_TIMEOUT_INTERRUPT 5
+/* NMI handler name used for testing */
+#define ASIDRV_NMI_HANDLER_NAME "ASI Test"
+
enum asidrv_state {
ASIDRV_STATE_NONE,
ASIDRV_STATE_INTR_WAITING,
ASIDRV_STATE_INTR_RECEIVED,
+ ASIDRV_STATE_NMI_WAITING,
+ ASIDRV_STATE_NMI_RECEIVED,
};
struct asidrv_test {
@@ -53,6 +59,7 @@ struct asidrv_sequence {
};
static struct asidrv_test *asidrv_test;
+static struct asidrv_test *asidrv_nmi_target;
static void asidrv_test_destroy(struct asidrv_test *test);
static void asidrv_run_fini(struct asidrv_test *test);
@@ -211,6 +218,107 @@ static enum asidrv_run_error asidrv_wait_transition(struct asidrv_test *test,
return asidrv_wait(test, final, timeout);
}
+/*
+ * NMI Test Sequence
+ */
+
+static int asidrv_nmi_handler(unsigned int val, struct pt_regs *regs)
+{
+ struct asidrv_test *test = asidrv_nmi_target;
+
+ if (!test)
+ return NMI_DONE;
+
+ /* ASI should be interrupted by the NMI */
+ if (asidrv_asi_is_active(test->asi)) {
+ test->run_error = ASIDRV_RUN_ERR_NMI_ASI_ACTIVE;
+ atomic_set(&test->state, ASIDRV_STATE_NMI_RECEIVED);
+ return NMI_HANDLED;
+ }
+
+ pr_debug("Received NMI\n");
+ atomic_set(&test->state, ASIDRV_STATE_NMI_RECEIVED);
+ asidrv_nmi_target = NULL;
+
+ return NMI_HANDLED;
+}
+
+static void asidrv_nmi_send(struct work_struct *work)
+{
+ struct asidrv_test *test = container_of(work, struct asidrv_test, work);
+ cpumask_t mask = CPU_MASK_NONE;
+ enum asidrv_run_error err;
+
+ cpumask_set_cpu(test->cpu, &mask);
+
+ /* wait for cpu target to be ready, then send an NMI */
+ err = asidrv_wait(test,
+ ASIDRV_STATE_NMI_WAITING,
+ ASIDRV_TIMEOUT_TARGET_READY);
+ if (err) {
+ pr_debug("Target cpu %d not ready, NMI not sent: error %d\n",
+ test->cpu, err);
+ return;
+ }
+
+ pr_debug("Sending NMI to cpu %d\n", test->cpu);
+ asidrv_nmi_target = test;
+ /*
+ * The value of asidrv_nmi_target should be set and propagated
+ * before sending the IPI.
+ */
+ wmb();
+ apic->send_IPI_mask(&mask, NMI_VECTOR);
+}
+
+static enum asidrv_run_error asidrv_nmi_setup(struct asidrv_test *test)
+{
+ int err;
+
+ err = register_nmi_handler(NMI_LOCAL, asidrv_nmi_handler,
+ NMI_FLAG_FIRST,
+ ASIDRV_NMI_HANDLER_NAME);
+ if (err) {
+ pr_debug("Failed to register NMI handler\n");
+ return ASIDRV_RUN_ERR_NMI_REG;
+ }
+
+ /* set work to have another cpu to send us an NMI */
+ INIT_WORK(&test->work, asidrv_nmi_send);
+
+ test->work_set = true;
+
+ return ASIDRV_RUN_ERR_NONE;
+}
+
+static void asidrv_nmi_cleanup(struct asidrv_test *test)
+{
+ unregister_nmi_handler(NMI_LOCAL, ASIDRV_NMI_HANDLER_NAME);
+}
+
+static enum asidrv_run_error asidrv_nmi_run(struct asidrv_test *test)
+{
+ enum asidrv_run_error err;
+ unsigned long flags;
+
+ /* disable interrupts as we want to be interrupted by an NMI */
+ local_irq_save(flags);
+
+ /* wait for state changes indicating that an NMI was received */
+ err = asidrv_wait_transition(test,
+ ASIDRV_STATE_NMI_WAITING,
+ ASIDRV_STATE_NMI_RECEIVED,
+ ASIDRV_TIMEOUT_INTERRUPT);
+ if (err == ASIDRV_RUN_ERR_TIMEOUT) {
+ pr_debug("NMI wait timeout\n");
+ err = ASIDRV_RUN_ERR_NMI;
+ }
+
+ local_irq_restore(flags);
+
+ return err;
+}
+
/*
* Interrupt Test Sequence
*/
@@ -350,6 +458,10 @@ struct asidrv_sequence asidrv_sequences[] = {
"interrupt",
asidrv_intr_setup, asidrv_intr_run, NULL,
},
+ [ASIDRV_SEQ_NMI] = {
+ "nmi",
+ asidrv_nmi_setup, asidrv_nmi_run, asidrv_nmi_cleanup,
+ },
};
static enum asidrv_run_error asidrv_run_init(struct asidrv_test *test)
diff --git a/drivers/staging/asi/asidrv.h b/drivers/staging/asi/asidrv.h
index 8055d96a0058..6fac32d56f6f 100644
--- a/drivers/staging/asi/asidrv.h
+++ b/drivers/staging/asi/asidrv.h
@@ -11,6 +11,7 @@ enum asidrv_seqnum {
ASIDRV_SEQ_MEM, /* access unmapped memory */
ASIDRV_SEQ_MEMMAP, /* access mapped memory */
ASIDRV_SEQ_INTERRUPT, /* interrupt sequence */
+ ASIDRV_SEQ_NMI, /* NMI interrupt sequence */
};
enum asidrv_run_error {
@@ -25,6 +26,9 @@ enum asidrv_run_error {
ASIDRV_RUN_ERR_INTR, /* no interrupt received */
ASIDRV_RUN_ERR_INTR_ASI_ACTIVE, /* ASI active in interrupt handler */
ASIDRV_RUN_ERR_TIMEOUT,
+ 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 */
};
#define ASIDRV_IOCTL_RUN_SEQUENCE _IOWR('a', 1, struct asidrv_run_param)
--
2.18.2
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