blob: 7f09a56818009b8d56c421c298ce3ef6d8dd6c9c [file] [log] [blame]
/* Copyright (c) 2011-2012, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only 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.
*/
#include <linux/kernel.h>
#include <linux/workqueue.h>
#include <linux/io.h>
#include <linux/jiffies.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/uaccess.h>
#include <linux/elf.h>
#include <linux/wait.h>
#include "ramdump.h"
#define RAMDUMP_WAIT_MSECS 120000
struct ramdump_device {
char name[256];
unsigned int data_ready;
unsigned int consumer_present;
int ramdump_status;
struct completion ramdump_complete;
struct miscdevice device;
wait_queue_head_t dump_wait_q;
int nsegments;
struct ramdump_segment *segments;
size_t elfcore_size;
char *elfcore_buf;
};
static int ramdump_open(struct inode *inode, struct file *filep)
{
struct ramdump_device *rd_dev = container_of(filep->private_data,
struct ramdump_device, device);
rd_dev->consumer_present = 1;
rd_dev->ramdump_status = 0;
return 0;
}
static int ramdump_release(struct inode *inode, struct file *filep)
{
struct ramdump_device *rd_dev = container_of(filep->private_data,
struct ramdump_device, device);
rd_dev->consumer_present = 0;
rd_dev->data_ready = 0;
complete(&rd_dev->ramdump_complete);
return 0;
}
static unsigned long offset_translate(loff_t user_offset,
struct ramdump_device *rd_dev, unsigned long *data_left)
{
int i = 0;
for (i = 0; i < rd_dev->nsegments; i++)
if (user_offset >= rd_dev->segments[i].size)
user_offset -= rd_dev->segments[i].size;
else
break;
if (i == rd_dev->nsegments) {
pr_debug("Ramdump(%s): offset_translate returning zero\n",
rd_dev->name);
*data_left = 0;
return 0;
}
*data_left = rd_dev->segments[i].size - user_offset;
pr_debug("Ramdump(%s): Returning address: %llx, data_left = %ld\n",
rd_dev->name, rd_dev->segments[i].address + user_offset,
*data_left);
return rd_dev->segments[i].address + user_offset;
}
#define MAX_IOREMAP_SIZE SZ_1M
static int ramdump_read(struct file *filep, char __user *buf, size_t count,
loff_t *pos)
{
struct ramdump_device *rd_dev = container_of(filep->private_data,
struct ramdump_device, device);
void *device_mem = NULL;
unsigned long data_left = 0;
unsigned long addr = 0;
size_t copy_size = 0;
int ret = 0;
loff_t orig_pos = *pos;
if ((filep->f_flags & O_NONBLOCK) && !rd_dev->data_ready)
return -EAGAIN;
ret = wait_event_interruptible(rd_dev->dump_wait_q, rd_dev->data_ready);
if (ret)
return ret;
if (*pos < rd_dev->elfcore_size) {
copy_size = rd_dev->elfcore_size - *pos;
copy_size = min(copy_size, count);
if (copy_to_user(buf, rd_dev->elfcore_buf + *pos, copy_size)) {
ret = -EFAULT;
goto ramdump_done;
}
*pos += copy_size;
count -= copy_size;
buf += copy_size;
if (count == 0)
return copy_size;
}
addr = offset_translate(*pos - rd_dev->elfcore_size, rd_dev,
&data_left);
/* EOF check */
if (data_left == 0) {
pr_debug("Ramdump(%s): Ramdump complete. %lld bytes read.",
rd_dev->name, *pos);
rd_dev->ramdump_status = 0;
ret = 0;
goto ramdump_done;
}
copy_size = min(count, (size_t)MAX_IOREMAP_SIZE);
copy_size = min((unsigned long)copy_size, data_left);
device_mem = ioremap_nocache(addr, copy_size);
if (device_mem == NULL) {
pr_err("Ramdump(%s): Unable to ioremap: addr %lx, size %x\n",
rd_dev->name, addr, copy_size);
rd_dev->ramdump_status = -1;
ret = -ENOMEM;
goto ramdump_done;
}
if (copy_to_user(buf, device_mem, copy_size)) {
pr_err("Ramdump(%s): Couldn't copy all data to user.",
rd_dev->name);
iounmap(device_mem);
rd_dev->ramdump_status = -1;
ret = -EFAULT;
goto ramdump_done;
}
iounmap(device_mem);
*pos += copy_size;
pr_debug("Ramdump(%s): Read %d bytes from address %lx.",
rd_dev->name, copy_size, addr);
return *pos - orig_pos;
ramdump_done:
rd_dev->data_ready = 0;
*pos = 0;
complete(&rd_dev->ramdump_complete);
return ret;
}
static unsigned int ramdump_poll(struct file *filep,
struct poll_table_struct *wait)
{
struct ramdump_device *rd_dev = container_of(filep->private_data,
struct ramdump_device, device);
unsigned int mask = 0;
if (rd_dev->data_ready)
mask |= (POLLIN | POLLRDNORM);
poll_wait(filep, &rd_dev->dump_wait_q, wait);
return mask;
}
static const struct file_operations ramdump_file_ops = {
.open = ramdump_open,
.release = ramdump_release,
.read = ramdump_read,
.poll = ramdump_poll
};
void *create_ramdump_device(const char *dev_name, struct device *parent)
{
int ret;
struct ramdump_device *rd_dev;
if (!dev_name) {
pr_err("%s: Invalid device name.\n", __func__);
return NULL;
}
rd_dev = kzalloc(sizeof(struct ramdump_device), GFP_KERNEL);
if (!rd_dev) {
pr_err("%s: Couldn't alloc space for ramdump device!",
__func__);
return NULL;
}
snprintf(rd_dev->name, ARRAY_SIZE(rd_dev->name), "ramdump_%s",
dev_name);
init_completion(&rd_dev->ramdump_complete);
rd_dev->device.minor = MISC_DYNAMIC_MINOR;
rd_dev->device.name = rd_dev->name;
rd_dev->device.fops = &ramdump_file_ops;
rd_dev->device.parent = parent;
init_waitqueue_head(&rd_dev->dump_wait_q);
ret = misc_register(&rd_dev->device);
if (ret) {
pr_err("%s: misc_register failed for %s (%d)", __func__,
dev_name, ret);
kfree(rd_dev);
return NULL;
}
return (void *)rd_dev;
}
void destroy_ramdump_device(void *dev)
{
struct ramdump_device *rd_dev = dev;
if (IS_ERR_OR_NULL(rd_dev))
return;
misc_deregister(&rd_dev->device);
kfree(rd_dev);
}
static int _do_ramdump(void *handle, struct ramdump_segment *segments,
int nsegments, bool use_elf)
{
int ret, i;
struct ramdump_device *rd_dev = (struct ramdump_device *)handle;
Elf32_Phdr *phdr;
Elf32_Ehdr *ehdr;
unsigned long offset;
if (!rd_dev->consumer_present) {
pr_err("Ramdump(%s): No consumers. Aborting..\n", rd_dev->name);
return -EPIPE;
}
for (i = 0; i < nsegments; i++)
segments[i].size = PAGE_ALIGN(segments[i].size);
rd_dev->segments = segments;
rd_dev->nsegments = nsegments;
if (use_elf) {
rd_dev->elfcore_size = sizeof(*ehdr) +
sizeof(*phdr) * nsegments;
ehdr = kzalloc(rd_dev->elfcore_size, GFP_KERNEL);
rd_dev->elfcore_buf = (char *)ehdr;
if (!rd_dev->elfcore_buf)
return -ENOMEM;
memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
ehdr->e_ident[EI_CLASS] = ELFCLASS32;
ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
ehdr->e_ident[EI_VERSION] = EV_CURRENT;
ehdr->e_ident[EI_OSABI] = ELFOSABI_NONE;
ehdr->e_type = ET_CORE;
ehdr->e_version = EV_CURRENT;
ehdr->e_phoff = sizeof(*ehdr);
ehdr->e_ehsize = sizeof(*ehdr);
ehdr->e_phentsize = sizeof(*phdr);
ehdr->e_phnum = nsegments;
offset = rd_dev->elfcore_size;
phdr = (Elf32_Phdr *)(ehdr + 1);
for (i = 0; i < nsegments; i++, phdr++) {
phdr->p_type = PT_LOAD;
phdr->p_offset = offset;
phdr->p_vaddr = phdr->p_paddr = segments[i].address;
phdr->p_filesz = phdr->p_memsz = segments[i].size;
phdr->p_flags = PF_R | PF_W | PF_X;
offset += phdr->p_filesz;
}
}
rd_dev->data_ready = 1;
rd_dev->ramdump_status = -1;
INIT_COMPLETION(rd_dev->ramdump_complete);
/* Tell userspace that the data is ready */
wake_up(&rd_dev->dump_wait_q);
/* Wait (with a timeout) to let the ramdump complete */
ret = wait_for_completion_timeout(&rd_dev->ramdump_complete,
msecs_to_jiffies(RAMDUMP_WAIT_MSECS));
if (!ret) {
pr_err("Ramdump(%s): Timed out waiting for userspace.\n",
rd_dev->name);
ret = -EPIPE;
} else
ret = (rd_dev->ramdump_status == 0) ? 0 : -EPIPE;
rd_dev->data_ready = 0;
rd_dev->elfcore_size = 0;
kfree(rd_dev->elfcore_buf);
rd_dev->elfcore_buf = NULL;
return ret;
}
int do_ramdump(void *handle, struct ramdump_segment *segments, int nsegments)
{
return _do_ramdump(handle, segments, nsegments, false);
}
int
do_elf_ramdump(void *handle, struct ramdump_segment *segments, int nsegments)
{
return _do_ramdump(handle, segments, nsegments, true);
}