[RFC v4][PATCH part-3 09/14] asidrv: Add ioctls to manage ASI page faults

[Alexandre Chartre]

Add ioctls to list and clear ASI page faults. Also add an ioctl to display
or not stack trace on ASI page fault.

Signed-off-by: Alexandre Chartre <alexandre.chartre@xxxxxxxxxx>
---
 drivers/staging/asi/asidrv.c | 88 ++++++++++++++++++++++++++++++++++++
 drivers/staging/asi/asidrv.h | 32 +++++++++++++
 2 files changed, 120 insertions(+)

diff --git a/drivers/staging/asi/asidrv.c b/drivers/staging/asi/asidrv.c
index 9ca17e0b654e..e6edfbe5acea 100644
--- a/drivers/staging/asi/asidrv.c
+++ b/drivers/staging/asi/asidrv.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/fs.h>
+#include <linux/kallsyms.h>
 #include <linux/kthread.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
@@ -790,12 +791,99 @@ static int asidrv_ioctl_run_sequence(struct asidrv_test *test,
 	return 0;
 }
 
+/*
+ * ASI fault ioctls
+ */
+
+static int asidrv_ioctl_list_fault(struct asi *asi, unsigned long arg)
+{
+	struct asidrv_fault_list __user *uflist;
+	struct asidrv_fault_list *flist;
+	size_t flist_size;
+	__u32 uflist_len;
+	int i;
+
+	uflist = (struct asidrv_fault_list __user *)arg;
+	if (copy_from_user(&uflist_len, &uflist->length, sizeof(uflist_len)))
+		return -EFAULT;
+
+	uflist_len = min_t(unsigned int, uflist_len, ASI_FAULT_LOG_SIZE);
+
+	flist_size = sizeof(*flist) + sizeof(struct asidrv_fault) * uflist_len;
+	flist = kzalloc(flist_size, GFP_KERNEL);
+	if (!flist)
+		return -ENOMEM;
+
+	for (i = 0; i < ASI_FAULT_LOG_SIZE; i++) {
+		if (!asi->fault_log[i].address)
+			break;
+		if (i < uflist_len) {
+			flist->fault[i].addr = asi->fault_log[i].address;
+			flist->fault[i].count = asi->fault_log[i].count;
+			sprint_symbol(flist->fault[i].symbol,
+				      asi->fault_log[i].address);
+		}
+	}
+	flist->length = i;
+
+	if (copy_to_user(uflist, flist, flist_size)) {
+		kfree(flist);
+		return -EFAULT;
+	}
+
+	if (i >= ASI_FAULT_LOG_SIZE)
+		pr_warn("ASI %p: fault log buffer is full [%d]\n", asi, i);
+
+	kfree(flist);
+
+	return 0;
+}
+
+static int asidrv_ioctl_clear_fault(struct asi *asi)
+{
+	int i;
+
+	for (i = 0; i < ASI_FAULT_LOG_SIZE; i++) {
+		if (!asi->fault_log[i].address)
+			break;
+		asi->fault_log[i].address = 0;
+	}
+
+	pr_debug("ASI %p: faults cleared\n", asi);
+	return 0;
+}
+
+static int asidrv_ioctl_log_fault_stack(struct asi *asi, bool log_stack)
+{
+	if (log_stack) {
+		asi->fault_log_policy |= ASI_FAULT_LOG_STACK;
+		pr_debug("ASI %p: setting fault stack\n", asi);
+	} else {
+		asi->fault_log_policy &= ~ASI_FAULT_LOG_STACK;
+		pr_debug("ASI %p: clearing fault stack\n", asi);
+	}
+
+	return 0;
+}
+
 static long asidrv_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct asidrv_test *test = asidrv_test;
+	struct asi *asi = test->asi;
 
 	switch (cmd) {
 
+	/* ASI fault ioctls */
+
+	case ASIDRV_IOCTL_LIST_FAULT:
+		return asidrv_ioctl_list_fault(asi, arg);
+
+	case ASIDRV_IOCTL_CLEAR_FAULT:
+		return asidrv_ioctl_clear_fault(asi);
+
+	case ASIDRV_IOCTL_LOG_FAULT_STACK:
+		return asidrv_ioctl_log_fault_stack(asi, arg);
+
 	/* Test ioctls */
 
 	case ASIDRV_IOCTL_RUN_SEQUENCE:
diff --git a/drivers/staging/asi/asidrv.h b/drivers/staging/asi/asidrv.h
index 9f540b119883..99ab9843e36b 100644
--- a/drivers/staging/asi/asidrv.h
+++ b/drivers/staging/asi/asidrv.h
@@ -36,9 +36,41 @@ enum asidrv_run_error {
 
 #define ASIDRV_IOCTL_RUN_SEQUENCE	_IOWR('a', 1, struct asidrv_run_param)
 
+/*
+ * ASIDRV_IOCTL_LIST_FAULT: return the list of ASI faults.
+ *
+ * User should set 'length' with the number of entries available in the
+ * 'fault' array. On return, 'length' is set to the number of ASI faults
+ * (which can be larger than the original 'length' value), and the 'fault'
+ * array is filled with the ASI faults.
+ */
+#define ASIDRV_IOCTL_LIST_FAULT		_IOWR('a', 2, struct asidrv_fault_list)
+#define ASIDRV_IOCTL_CLEAR_FAULT	_IO('a', 3)
+#define ASIDRV_IOCTL_LOG_FAULT_STACK	_IO('a', 4)
+
+#define ASIDRV_KSYM_NAME_LEN	128
+/*
+ * We need KSYM_SYMBOL_LEN to lookup symbol. However it's not part of
+ * userland include. So we use a reasonably large value (KSYM_SYMBOL_LEN
+ * is around 310).
+ */
+#define ASIDRV_KSYM_SYMBOL_LEN	512
+
 struct asidrv_run_param {
 	__u32 sequence;		/* sequence to run */
 	__u32 run_error;	/* result error after run */
 	__u32 asi_active;	/* ASI is active after run? */
 };
+
+struct asidrv_fault {
+	__u64 addr;
+	char  symbol[ASIDRV_KSYM_SYMBOL_LEN];
+	__u32 count;
+};
+
+struct asidrv_fault_list {
+	__u32 length;
+	struct asidrv_fault fault[0];
+};
+
 #endif
-- 
2.18.2