linux/drivers/char/ramoops.c

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/*
* RAM Oops/Panic logger
*
* Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
*
* 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/kmsg_dump.h>
#include <linux/time.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/ramoops.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)");
static struct ramoops_context {
struct kmsg_dumper dump;
void *virt_addr;
phys_addr_t phys_addr;
unsigned long size;
unsigned long record_size;
int dump_oops;
int count;
int max_count;
} oops_cxt;
static struct platform_device *dummy;
static struct ramoops_platform_data *dummy_data;
static void ramoops_do_dump(struct kmsg_dumper *dumper,
enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
const char *s2, unsigned long l2)
{
struct ramoops_context *cxt = container_of(dumper,
struct ramoops_context, dump);
unsigned long s1_start, s2_start;
unsigned long l1_cpy, l2_cpy;
int res, hdr_size;
char *buf, *buf_orig;
struct timeval timestamp;
kmsg_dump: constrain mtdoops and ramoops to perform their actions only for KMSG_DUMP_PANIC This series aims to develop logging facility for enterprise use. It is important to save kernel messages reliably on enterprise system because they are helpful for diagnosing system. This series add kmsg_dump() to the paths loosing kernel messages. The use case is the following. [Use case of reboot/poweroff/halt/emergency_restart] My company has often experienced the followings in our support service. - Customer's system suddenly reboots. - Customers ask us to investigate the reason of the reboot. We recognize the fact itself because boot messages remain in /var/log/messages. However, we can't investigate the reason why the system rebooted, because the last messages don't remain. And off course we can't explain the reason. We can solve above problem with this patch as follows. Case1: reboot with command - We can see "Restarting system with command:" or ""Restarting system.". Case2: halt with command - We can see "System halted.". Case3: poweroff with command - We can see " Power down.". Case4: emergency_restart with sysrq. - We can see "Sysrq:" outputted in __handle_sysrq(). Case5: emergency_restart with softdog. - We can see "Initiating system reboot" in watchdog_fire(). So, we can distinguish the reason of reboot, poweroff, halt and emergency_restart. If customer executed reboot command, you may think the customer should know the fact. However, they often claim they don't execute the command when they rebooted system by mistake. No message remains on the current Linux kernel, so we can't show the proof to the customer. This patch improves this situation. This patch: Alters mtdoops and ramoops to perform their actions only for KMSG_DUMP_PANIC, KMSG_DUMP_OOPS and KMSG_DUMP_KEXEC because they would like to log crashes only. Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Marco Stornelli <marco.stornelli@gmail.com> Reviewed-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 00:59:29 +00:00
if (reason != KMSG_DUMP_OOPS &&
reason != KMSG_DUMP_PANIC &&
reason != KMSG_DUMP_KEXEC)
return;
/* Only dump oopses if dump_oops is set */
if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
return;
buf = cxt->virt_addr + (cxt->count * cxt->record_size);
buf_orig = buf;
memset(buf, '\0', cxt->record_size);
res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
buf += res;
do_gettimeofday(&timestamp);
res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
buf += res;
hdr_size = buf - buf_orig;
l2_cpy = min(l2, cxt->record_size - hdr_size);
l1_cpy = min(l1, cxt->record_size - hdr_size - l2_cpy);
s2_start = l2 - l2_cpy;
s1_start = l1 - l1_cpy;
memcpy(buf, s1 + s1_start, l1_cpy);
memcpy(buf + l1_cpy, s2 + s2_start, l2_cpy);
cxt->count = (cxt->count + 1) % cxt->max_count;
}
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;
if (!pdata->mem_size || !pdata->record_size) {
pr_err("The memory size and the record size must be "
"non-zero\n");
goto fail3;
}
rounddown_pow_of_two(pdata->mem_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, minium is %lu\n", MIN_MEM_SIZE);
goto fail3;
}
if (pdata->mem_size < pdata->record_size) {
pr_err("The memory size must be larger than the "
"records size\n");
goto fail3;
}
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;
/*
* 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;
if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
pr_err("request mem region failed\n");
err = -EINVAL;
goto fail3;
}
cxt->virt_addr = ioremap(cxt->phys_addr, cxt->size);
if (!cxt->virt_addr) {
pr_err("ioremap failed\n");
goto fail2;
}
cxt->dump.dump = ramoops_do_dump;
err = kmsg_dump_register(&cxt->dump);
if (err) {
pr_err("registering kmsg dumper failed\n");
goto fail1;
}
return 0;
fail1:
iounmap(cxt->virt_addr);
fail2:
release_mem_region(cxt->phys_addr, cxt->size);
fail3:
return err;
}
static int __exit ramoops_remove(struct platform_device *pdev)
{
struct ramoops_context *cxt = &oops_cxt;
if (kmsg_dump_unregister(&cxt->dump) < 0)
pr_warn("could not unregister kmsg_dumper\n");
iounmap(cxt->virt_addr);
release_mem_region(cxt->phys_addr, cxt->size);
return 0;
}
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");