Fault handler is created as kernel thread for each VAS instance and
invoked whenever NX generates page fault. This thread reads CRBs
from fault FIFO and process them.
Signed-off-by: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>
Signed-off-by: Haren Myneni <ha...@us.ibm.com>
---
arch/powerpc/platforms/powernv/vas-fault.c | 54 ++++++++++++++++++++++++++++++
arch/powerpc/platforms/powernv/vas.c | 7 ++++
arch/powerpc/platforms/powernv/vas.h | 6 ++++
3 files changed, 67 insertions(+)
diff --git a/arch/powerpc/platforms/powernv/vas-fault.c
b/arch/powerpc/platforms/powernv/vas-fault.c
index a5e63a5..c6c105c 100644
--- a/arch/powerpc/platforms/powernv/vas-fault.c
+++ b/arch/powerpc/platforms/powernv/vas-fault.c
@@ -11,6 +11,7 @@
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/kthread.h>
+#include <linux/sched/signal.h>
#include <asm/icswx.h>
#include "vas.h"
@@ -24,6 +25,54 @@
*/
#define VAS_FAULT_WIN_FIFO_SIZE (4 << 20)
+struct task_struct *fault_handler;
+
+void vas_wakeup_fault_handler(int virq, void *arg)
+{
+ struct vas_instance *vinst = arg;
+
+ atomic_inc(&vinst->pending_fault);
+ wake_up(&vinst->fault_wq);
+}
+
+/*
+ * Fault handler thread for each VAS instance and process fault CRBs.
+ */
+static int fault_handler_func(void *arg)
+{
+ struct vas_instance *vinst = (struct vas_instance *)arg;
+
+ do {
+ if (signal_pending(current))
+ flush_signals(current);
+
+ wait_event_interruptible(vinst->fault_wq,
+ atomic_read(&vinst->pending_fault) ||
+ kthread_should_stop());
+
+ if (kthread_should_stop())
+ break;
+
+ atomic_dec(&vinst->pending_fault);
+ } while (!kthread_should_stop());
+
+ return 0;
+}
+
+/*
+ * Create a thread that processes the fault CRBs.
+ */
+int vas_setup_fault_handler(struct vas_instance *vinst)
+{
+ vinst->fault_handler = kthread_run(fault_handler_func, (void *)vinst,
+ "vas-fault-%u", vinst->vas_id);
+
+ if (IS_ERR(vinst->fault_handler))
+ return PTR_ERR(vinst->fault_handler);
+
+ return 0;
+}
+
/*
* Fault window is opened per VAS instance. NX pastes fault CRB in fault
* FIFO upon page faults.
@@ -102,4 +151,9 @@ int vas_cleanup_fault_window(struct vas_instance *vinst)
return rc;
}
+
+void vas_cleanup_fault_handler(struct vas_instance *vinst)
+{
+ kthread_stop(vinst->fault_handler);
+}
#endif
diff --git a/arch/powerpc/platforms/powernv/vas.c
b/arch/powerpc/platforms/powernv/vas.c
index dd0e06c..db2aca4 100644
--- a/arch/powerpc/platforms/powernv/vas.c
+++ b/arch/powerpc/platforms/powernv/vas.c
@@ -30,6 +30,7 @@ static irqreturn_t vas_irq_handler(int virq, void *data)
struct vas_instance *vinst = data;
pr_devel("VAS %d: virq %d\n", vinst->vas_id, virq);
+ vas_wakeup_fault_handler(virq, data);
return IRQ_HANDLED;
}
@@ -54,6 +55,10 @@ static void vas_irq_fault_handle_setup(struct vas_instance
*vinst)
* for user space.
*/
rc = vas_setup_fault_window(vinst);
+
+ if (!rc)
+ rc = vas_setup_fault_handler(vinst);
+
if (rc) {
free_irq(vinst->virq, vinst);
vinst->virq = 0;
@@ -129,6 +134,8 @@ static int init_vas_instance(struct platform_device *pdev)
}
}
+ init_waitqueue_head(&vinst->fault_wq);
+
pr_devel("Initialized instance [%s, %d] paste_base 0x%llx
paste_win_id_shift 0x%llx IRQ %d Port 0x%llx\n",
pdev->name, vasid, vinst->paste_base_addr,
vinst->paste_win_id_shift, vinst->virq,
diff --git a/arch/powerpc/platforms/powernv/vas.h
b/arch/powerpc/platforms/powernv/vas.h
index e23fd69..ee284b3 100644
--- a/arch/powerpc/platforms/powernv/vas.h
+++ b/arch/powerpc/platforms/powernv/vas.h
@@ -317,6 +317,9 @@ struct vas_instance {
int virq;
int fault_fifo_size;
void *fault_fifo;
+ atomic_t pending_fault;
+ wait_queue_head_t fault_wq;
+ struct task_struct *fault_handler;
struct vas_window *fault_win; /* Fault window */
struct mutex mutex;
@@ -414,6 +417,9 @@ struct vas_winctx {
extern void vas_window_free_dbgdir(struct vas_window *win);
extern int vas_setup_fault_window(struct vas_instance *vinst);
extern int vas_cleanup_fault_window(struct vas_instance *vinst);
+extern void vas_wakeup_fault_handler(int virq, void *arg);
+extern int vas_setup_fault_handler(struct vas_instance *vinst);
+extern void vas_cleanup_fault_handler(struct vas_instance *vinst);
static inline void vas_log_write(struct vas_window *win, char *name,
void *regptr, u64 val)
--
1.8.3.1
