1 files changed, 146 insertions, 0 deletions
diff --git a/arch/x86/mm/testmmiotrace.c b/arch/x86/mm/testmmiotrace.c
new file mode 100644
index 0000000000..bda73cb7a0
--- /dev/null
+++ b/arch/x86/mm/testmmiotrace.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Written by Pekka Paalanen, 2008-2009 <pq@iki.fi>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/mmiotrace.h>
+#include <linux/security.h>
+
+static unsigned long mmio_address;
+module_param_hw(mmio_address, ulong, iomem, 0);
+MODULE_PARM_DESC(mmio_address, " Start address of the mapping of 16 kB "
+				"(or 8 MB if read_far is non-zero).");
+
+static unsigned long read_far = 0x400100;
+module_param(read_far, ulong, 0);
+MODULE_PARM_DESC(read_far, " Offset of a 32-bit read within 8 MB "
+				"(default: 0x400100).");
+
+static unsigned v16(unsigned i)
+{
+	return i * 12 + 7;
+}
+
+static unsigned v32(unsigned i)
+{
+	return i * 212371 + 13;
+}
+
+static void do_write_test(void __iomem *p)
+{
+	unsigned int i;
+	pr_info("write test.\n");
+	mmiotrace_printk("Write test.\n");
+
+	for (i = 0; i < 256; i++)
+		iowrite8(i, p + i);
+
+	for (i = 1024; i < (5 * 1024); i += 2)
+		iowrite16(v16(i), p + i);
+
+	for (i = (5 * 1024); i < (16 * 1024); i += 4)
+		iowrite32(v32(i), p + i);
+}
+
+static void do_read_test(void __iomem *p)
+{
+	unsigned int i;
+	unsigned errs[3] = { 0 };
+	pr_info("read test.\n");
+	mmiotrace_printk("Read test.\n");
+
+	for (i = 0; i < 256; i++)
+		if (ioread8(p + i) != i)
+			++errs[0];
+
+	for (i = 1024; i < (5 * 1024); i += 2)
+		if (ioread16(p + i) != v16(i))
+			++errs[1];
+
+	for (i = (5 * 1024); i < (16 * 1024); i += 4)
+		if (ioread32(p + i) != v32(i))
+			++errs[2];
+
+	mmiotrace_printk("Read errors: 8-bit %d, 16-bit %d, 32-bit %d.\n",
+						errs[0], errs[1], errs[2]);
+}
+
+static void do_read_far_test(void __iomem *p)
+{
+	pr_info("read far test.\n");
+	mmiotrace_printk("Read far test.\n");
+
+	ioread32(p + read_far);
+}
+
+static void do_test(unsigned long size)
+{
+	void __iomem *p = ioremap(mmio_address, size);
+	if (!p) {
+		pr_err("could not ioremap, aborting.\n");
+		return;
+	}
+	mmiotrace_printk("ioremap returned %p.\n", p);
+	do_write_test(p);
+	do_read_test(p);
+	if (read_far && read_far < size - 4)
+		do_read_far_test(p);
+	iounmap(p);
+}
+
+/*
+ * Tests how mmiotrace behaves in face of multiple ioremap / iounmaps in
+ * a short time. We had a bug in deferred freeing procedure which tried
+ * to free this region multiple times (ioremap can reuse the same address
+ * for many mappings).
+ */
+static void do_test_bulk_ioremapping(void)
+{
+	void __iomem *p;
+	int i;
+
+	for (i = 0; i < 10; ++i) {
+		p = ioremap(mmio_address, PAGE_SIZE);
+		if (p)
+			iounmap(p);
+	}
+
+	/* Force freeing. If it will crash we will know why. */
+	synchronize_rcu();
+}
+
+static int __init init(void)
+{
+	unsigned long size = (read_far) ? (8 << 20) : (16 << 10);
+	int ret = security_locked_down(LOCKDOWN_MMIOTRACE);
+
+	if (ret)
+		return ret;
+
+	if (mmio_address == 0) {
+		pr_err("you have to use the module argument mmio_address.\n");
+		pr_err("DO NOT LOAD THIS MODULE UNLESS YOU REALLY KNOW WHAT YOU ARE DOING!\n");
+		return -ENXIO;
+	}
+
+	pr_warn("WARNING: mapping %lu kB @ 0x%08lx in PCI address space, "
+		"and writing 16 kB of rubbish in there.\n",
+		size >> 10, mmio_address);
+	do_test(size);
+	do_test_bulk_ioremapping();
+	pr_info("All done.\n");
+	return 0;
+}
+
+static void __exit cleanup(void)
+{
+	pr_debug("unloaded.\n");
+}
+
+module_init(init);
+module_exit(cleanup);
+MODULE_LICENSE("GPL");