1 files changed, 64 insertions, 0 deletions
diff --git a/arch/powerpc/mm/dump_sr.c b/arch/powerpc/mm/dump_sr.c
new file mode 100644
index 000000000000..501843664bb9
--- /dev/null
+++ b/arch/powerpc/mm/dump_sr.c
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2018, Christophe Leroy CS S.I.
+ * <christophe.leroy@c-s.fr>
+ *
+ * This dumps the content of Segment Registers
+ */
+
+#include <asm/debugfs.h>
+
+static void seg_show(struct seq_file *m, int i)
+{
+	u32 val = mfsrin(i << 28);
+
+	seq_printf(m, "0x%01x0000000-0x%01xfffffff ", i, i);
+	seq_printf(m, "Kern key %d ", (val >> 30) & 1);
+	seq_printf(m, "User key %d ", (val >> 29) & 1);
+	if (val & 0x80000000) {
+		seq_printf(m, "Device 0x%03x", (val >> 20) & 0x1ff);
+		seq_printf(m, "-0x%05x", val & 0xfffff);
+	} else {
+		if (val & 0x10000000)
+			seq_puts(m, "No Exec ");
+		seq_printf(m, "VSID 0x%06x", val & 0xffffff);
+	}
+	seq_puts(m, "\n");
+}
+
+static int sr_show(struct seq_file *m, void *v)
+{
+	int i;
+
+	seq_puts(m, "---[ User Segments ]---\n");
+	for (i = 0; i < TASK_SIZE >> 28; i++)
+		seg_show(m, i);
+
+	seq_puts(m, "\n---[ Kernel Segments ]---\n");
+	for (; i < 16; i++)
+		seg_show(m, i);
+
+	return 0;
+}
+
+static int sr_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, sr_show, NULL);
+}
+
+static const struct file_operations sr_fops = {
+	.open		= sr_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int __init sr_init(void)
+{
+	struct dentry *debugfs_file;
+
+	debugfs_file = debugfs_create_file("segment_registers", 0400,
+					   powerpc_debugfs_root, NULL, &sr_fops);
+	return debugfs_file ? 0 : -ENOMEM;
+}
+device_initcall(sr_init);