ramoops: Move to fs/pstore/ram.c

Since ramoops was converted to pstore, it has nothing to do with character
devices nowadays. Instead, today it is just a RAM backend for pstore.

The patch just moves things around. There are a few changes were needed
because of the move:

1. Kconfig and Makefiles fixups, of course.

2. In pstore/ram.c we have to play a bit with MODULE_PARAM_PREFIX, this
   is needed to keep user experience the same as with ramoops driver
   (i.e. so that ramoops.foo kernel command line arguments would still
   work).

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: Marco Stornelli <marco.stornelli@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 379 insertions, 0 deletions

diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index 8007ae7..b75ee51 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -11,3 +11,17 @@ config PSTORE
 	   (e.g. ACPI_APEI on X86) which will select this for you.
 	   If you don't have a platform persistent store driver,
 	   say N.
+
+config PSTORE_RAM
+	tristate "Log panic/oops to a RAM buffer"
+	depends on HAS_IOMEM
+	depends on PSTORE
+	default n
+	help
+	  This enables panic and oops messages to be logged to a circular
+	  buffer in RAM where it can be read back at some later point.
+
+	  Note that for historical reasons, the module will be named
+	  "ramoops.ko".
+
+	  For more information, see Documentation/ramoops.txt.
diff --git a/fs/pstore/Makefile b/fs/pstore/Makefile
index 760f4bc..2ab3d0d 100644
--- a/fs/pstore/Makefile
+++ b/fs/pstore/Makefile
@@ -5,3 +5,6 @@
 obj-y += pstore.o
 
 pstore-objs += inode.o platform.o
+
+ramoops-objs += ram.o
+obj-$(CONFIG_PSTORE_RAM)	+= ramoops.o
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
new file mode 100644
index 0000000..e443c9c
--- /dev/null
+++ b/fs/pstore/ram.c
@@ -0,0 +1,362 @@
+/*
+ * RAM Oops/Panic logger
+ *
+ * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
+ * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/pstore.h>
+#include <linux/time.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/pstore_ram.h>
+
+#define RAMOOPS_KERNMSG_HDR "===="
+#define MIN_MEM_SIZE 4096UL
+
+static ulong record_size = MIN_MEM_SIZE;
+module_param(record_size, ulong, 0400);
+MODULE_PARM_DESC(record_size,
+		"size of each dump done on oops/panic");
+
+static ulong mem_address;
+module_param(mem_address, ulong, 0400);
+MODULE_PARM_DESC(mem_address,
+		"start of reserved RAM used to store oops/panic logs");
+
+static ulong mem_size;
+module_param(mem_size, ulong, 0400);
+MODULE_PARM_DESC(mem_size,
+		"size of reserved RAM used to store oops/panic logs");
+
+static int dump_oops = 1;
+module_param(dump_oops, int, 0600);
+MODULE_PARM_DESC(dump_oops,
+		"set to 1 to dump oopses, 0 to only dump panics (default 1)");
+
+struct ramoops_context {
+	void *virt_addr;
+	phys_addr_t phys_addr;
+	unsigned long size;
+	size_t record_size;
+	int dump_oops;
+	unsigned int count;
+	unsigned int max_count;
+	unsigned int read_count;
+	struct pstore_info pstore;
+};
+
+static struct platform_device *dummy;
+static struct ramoops_platform_data *dummy_data;
+
+static int ramoops_pstore_open(struct pstore_info *psi)
+{
+	struct ramoops_context *cxt = psi->data;
+
+	cxt->read_count = 0;
+	return 0;
+}
+
+static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
+				   struct timespec *time,
+				   char **buf,
+				   struct pstore_info *psi)
+{
+	ssize_t size;
+	char *rambuf;
+	struct ramoops_context *cxt = psi->data;
+
+	if (cxt->read_count >= cxt->max_count)
+		return -EINVAL;
+	*id = cxt->read_count++;
+	/* Only supports dmesg output so far. */
+	*type = PSTORE_TYPE_DMESG;
+	/* TODO(kees): Bogus time for the moment. */
+	time->tv_sec = 0;
+	time->tv_nsec = 0;
+
+	rambuf = cxt->virt_addr + (*id * cxt->record_size);
+	size = strnlen(rambuf, cxt->record_size);
+	*buf = kmalloc(size, GFP_KERNEL);
+	if (*buf == NULL)
+		return -ENOMEM;
+	memcpy(*buf, rambuf, size);
+
+	return size;
+}
+
+static int ramoops_pstore_write(enum pstore_type_id type,
+				enum kmsg_dump_reason reason,
+				u64 *id,
+				unsigned int part,
+				size_t size, struct pstore_info *psi)
+{
+	char *buf;
+	size_t res;
+	struct timeval timestamp;
+	struct ramoops_context *cxt = psi->data;
+	size_t available = cxt->record_size;
+
+	/* Currently ramoops is designed to only store dmesg dumps. */
+	if (type != PSTORE_TYPE_DMESG)
+		return -EINVAL;
+
+	/* Out of the various dmesg dump types, ramoops is currently designed
+	 * to only store crash logs, rather than storing general kernel logs.
+	 */
+	if (reason != KMSG_DUMP_OOPS &&
+	    reason != KMSG_DUMP_PANIC)
+		return -EINVAL;
+
+	/* Skip Oopes when configured to do so. */
+	if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
+		return -EINVAL;
+
+	/* Explicitly only take the first part of any new crash.
+	 * If our buffer is larger than kmsg_bytes, this can never happen,
+	 * and if our buffer is smaller than kmsg_bytes, we don't want the
+	 * report split across multiple records.
+	 */
+	if (part != 1)
+		return -ENOSPC;
+
+	buf = cxt->virt_addr + (cxt->count * cxt->record_size);
+
+	res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
+	buf += res;
+	available -= res;
+
+	do_gettimeofday(&timestamp);
+	res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
+	buf += res;
+	available -= res;
+
+	if (size > available)
+		size = available;
+
+	memcpy(buf, cxt->pstore.buf, size);
+	memset(buf + size, '\0', available - size);
+
+	cxt->count = (cxt->count + 1) % cxt->max_count;
+
+	return 0;
+}
+
+static int ramoops_pstore_erase(enum pstore_type_id type, u64 id,
+				struct pstore_info *psi)
+{
+	char *buf;
+	struct ramoops_context *cxt = psi->data;
+
+	if (id >= cxt->max_count)
+		return -EINVAL;
+
+	buf = cxt->virt_addr + (id * cxt->record_size);
+	memset(buf, '\0', cxt->record_size);
+
+	return 0;
+}
+
+static struct ramoops_context oops_cxt = {
+	.pstore = {
+		.owner	= THIS_MODULE,
+		.name	= "ramoops",
+		.open	= ramoops_pstore_open,
+		.read	= ramoops_pstore_read,
+		.write	= ramoops_pstore_write,
+		.erase	= ramoops_pstore_erase,
+	},
+};
+
+static int __init ramoops_probe(struct platform_device *pdev)
+{
+	struct ramoops_platform_data *pdata = pdev->dev.platform_data;
+	struct ramoops_context *cxt = &oops_cxt;
+	int err = -EINVAL;
+
+	/* Only a single ramoops area allowed at a time, so fail extra
+	 * probes.
+	 */
+	if (cxt->max_count)
+		goto fail_out;
+
+	if (!pdata->mem_size || !pdata->record_size) {
+		pr_err("The memory size and the record size must be "
+			"non-zero\n");
+		goto fail_out;
+	}
+
+	pdata->mem_size = rounddown_pow_of_two(pdata->mem_size);
+	pdata->record_size = rounddown_pow_of_two(pdata->record_size);
+
+	/* Check for the minimum memory size */
+	if (pdata->mem_size < MIN_MEM_SIZE &&
+			pdata->record_size < MIN_MEM_SIZE) {
+		pr_err("memory size too small, minimum is %lu\n",
+			MIN_MEM_SIZE);
+		goto fail_out;
+	}
+
+	if (pdata->mem_size < pdata->record_size) {
+		pr_err("The memory size must be larger than the "
+			"records size\n");
+		goto fail_out;
+	}
+
+	cxt->max_count = pdata->mem_size / pdata->record_size;
+	cxt->count = 0;
+	cxt->size = pdata->mem_size;
+	cxt->phys_addr = pdata->mem_address;
+	cxt->record_size = pdata->record_size;
+	cxt->dump_oops = pdata->dump_oops;
+
+	cxt->pstore.data = cxt;
+	cxt->pstore.bufsize = cxt->record_size;
+	cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
+	spin_lock_init(&cxt->pstore.buf_lock);
+	if (!cxt->pstore.buf) {
+		pr_err("cannot allocate pstore buffer\n");
+		goto fail_clear;
+	}
+
+	if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
+		pr_err("request mem region (0x%lx@0x%llx) failed\n",
+			cxt->size, (unsigned long long)cxt->phys_addr);
+		err = -EINVAL;
+		goto fail_buf;
+	}
+
+	cxt->virt_addr = ioremap(cxt->phys_addr,  cxt->size);
+	if (!cxt->virt_addr) {
+		pr_err("ioremap failed\n");
+		goto fail_mem_region;
+	}
+
+	err = pstore_register(&cxt->pstore);
+	if (err) {
+		pr_err("registering with pstore failed\n");
+		goto fail_iounmap;
+	}
+
+	/*
+	 * Update the module parameter variables as well so they are visible
+	 * through /sys/module/ramoops/parameters/
+	 */
+	mem_size = pdata->mem_size;
+	mem_address = pdata->mem_address;
+	record_size = pdata->record_size;
+	dump_oops = pdata->dump_oops;
+
+	pr_info("attached 0x%lx@0x%llx (%ux0x%zx)\n",
+		cxt->size, (unsigned long long)cxt->phys_addr,
+		cxt->max_count, cxt->record_size);
+
+	return 0;
+
+fail_iounmap:
+	iounmap(cxt->virt_addr);
+fail_mem_region:
+	release_mem_region(cxt->phys_addr, cxt->size);
+fail_buf:
+	kfree(cxt->pstore.buf);
+fail_clear:
+	cxt->pstore.bufsize = 0;
+	cxt->max_count = 0;
+fail_out:
+	return err;
+}
+
+static int __exit ramoops_remove(struct platform_device *pdev)
+{
+#if 0
+	/* TODO(kees): We cannot unload ramoops since pstore doesn't support
+	 * unregistering yet.
+	 */
+	struct ramoops_context *cxt = &oops_cxt;
+
+	iounmap(cxt->virt_addr);
+	release_mem_region(cxt->phys_addr, cxt->size);
+	cxt->max_count = 0;
+
+	/* TODO(kees): When pstore supports unregistering, call it here. */
+	kfree(cxt->pstore.buf);
+	cxt->pstore.bufsize = 0;
+
+	return 0;
+#endif
+	return -EBUSY;
+}
+
+static struct platform_driver ramoops_driver = {
+	.remove		= __exit_p(ramoops_remove),
+	.driver		= {
+		.name	= "ramoops",
+		.owner	= THIS_MODULE,
+	},
+};
+
+static int __init ramoops_init(void)
+{
+	int ret;
+	ret = platform_driver_probe(&ramoops_driver, ramoops_probe);
+	if (ret == -ENODEV) {
+		/*
+		 * If we didn't find a platform device, we use module parameters
+		 * building platform data on the fly.
+		 */
+		pr_info("platform device not found, using module parameters\n");
+		dummy_data = kzalloc(sizeof(struct ramoops_platform_data),
+				     GFP_KERNEL);
+		if (!dummy_data)
+			return -ENOMEM;
+		dummy_data->mem_size = mem_size;
+		dummy_data->mem_address = mem_address;
+		dummy_data->record_size = record_size;
+		dummy_data->dump_oops = dump_oops;
+		dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
+			NULL, 0, dummy_data,
+			sizeof(struct ramoops_platform_data));
+
+		if (IS_ERR(dummy))
+			ret = PTR_ERR(dummy);
+		else
+			ret = 0;
+	}
+
+	return ret;
+}
+
+static void __exit ramoops_exit(void)
+{
+	platform_driver_unregister(&ramoops_driver);
+	kfree(dummy_data);
+}
+
+module_init(ramoops_init);
+module_exit(ramoops_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
+MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");