1 files changed, 75 insertions, 0 deletions
diff --git a/arch/sh/mm/asids-debugfs.c b/arch/sh/mm/asids-debugfs.c
new file mode 100644
index 000000000..e5539e0f8
--- /dev/null
+++ b/arch/sh/mm/asids-debugfs.c
@@ -0,0 +1,75 @@
+/*
+ * debugfs ops for process ASIDs
+ *
+ *  Copyright (C) 2000, 2001  Paolo Alberelli
+ *  Copyright (C) 2003 - 2008  Paul Mundt
+ *  Copyright (C) 2003, 2004  Richard Curnow
+ *
+ * Provides a debugfs file that lists out the ASIDs currently associated
+ * with the processes.
+ *
+ * In the SH-5 case, if the DM.PC register is examined through the debug
+ * link, this shows ASID + PC. To make use of this, the PID->ASID
+ * relationship needs to be known. This is primarily for debugging.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/init.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/spinlock.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/task.h>
+
+#include <asm/processor.h>
+#include <asm/mmu_context.h>
+
+static int asids_seq_show(struct seq_file *file, void *iter)
+{
+	struct task_struct *p;
+
+	read_lock(&tasklist_lock);
+
+	for_each_process(p) {
+		int pid = p->pid;
+
+		if (unlikely(!pid))
+			continue;
+
+		if (p->mm)
+			seq_printf(file, "%5d : %04lx\n", pid,
+				   cpu_asid(smp_processor_id(), p->mm));
+	}
+
+	read_unlock(&tasklist_lock);
+
+	return 0;
+}
+
+static int asids_debugfs_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, asids_seq_show, inode->i_private);
+}
+
+static const struct file_operations asids_debugfs_fops = {
+	.owner		= THIS_MODULE,
+	.open		= asids_debugfs_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int __init asids_debugfs_init(void)
+{
+	struct dentry *asids_dentry;
+
+	asids_dentry = debugfs_create_file("asids", S_IRUSR, arch_debugfs_dir,
+					   NULL, &asids_debugfs_fops);
+	if (!asids_dentry)
+		return -ENOMEM;
+
+	return PTR_ERR_OR_ZERO(asids_dentry);
+}
+device_initcall(asids_debugfs_init);