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 8007ae7c0d8..b75ee51b271 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 760f4bce7d1..2ab3d0d55ef 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 00000000000..e443c9c6914
--- /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");