diff options
Diffstat (limited to 'drivers/char/mem.c')
| -rw-r--r-- | drivers/char/mem.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index e3085b22a365..42187381506b 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -23,7 +23,10 @@ #include <linux/devfs_fs_kernel.h> #include <linux/ptrace.h> #include <linux/device.h> +#include <linux/highmem.h> +#include <linux/crash_dump.h> #include <linux/backing-dev.h> +#include <linux/bootmem.h> #include <asm/uaccess.h> #include <asm/io.h> @@ -273,6 +276,40 @@ static int mmap_kmem(struct file * file, struct vm_area_struct * vma) return mmap_mem(file, vma); } +#ifdef CONFIG_CRASH_DUMP +/* + * Read memory corresponding to the old kernel. + */ +static ssize_t read_oldmem(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + unsigned long pfn, offset; + size_t read = 0, csize; + int rc = 0; + + while (count) { + pfn = *ppos / PAGE_SIZE; + if (pfn > saved_max_pfn) + return read; + + offset = (unsigned long)(*ppos % PAGE_SIZE); + if (count > PAGE_SIZE - offset) + csize = PAGE_SIZE - offset; + else + csize = count; + + rc = copy_oldmem_page(pfn, buf, csize, offset, 1); + if (rc < 0) + return rc; + buf += csize; + *ppos += csize; + read += csize; + count -= csize; + } + return read; +} +#endif + extern long vread(char *buf, char *addr, unsigned long count); extern long vwrite(char *buf, char *addr, unsigned long count); @@ -721,6 +758,7 @@ static int open_port(struct inode * inode, struct file * filp) #define read_full read_zero #define open_mem open_port #define open_kmem open_mem +#define open_oldmem open_mem static struct file_operations mem_fops = { .llseek = memory_lseek, @@ -770,6 +808,13 @@ static struct file_operations full_fops = { .write = write_full, }; +#ifdef CONFIG_CRASH_DUMP +static struct file_operations oldmem_fops = { + .read = read_oldmem, + .open = open_oldmem, +}; +#endif + static ssize_t kmsg_write(struct file * file, const char __user * buf, size_t count, loff_t *ppos) { @@ -825,6 +870,11 @@ static int memory_open(struct inode * inode, struct file * filp) case 11: filp->f_op = &kmsg_fops; break; +#ifdef CONFIG_CRASH_DUMP + case 12: + filp->f_op = &oldmem_fops; + break; +#endif default: return -ENXIO; } @@ -854,6 +904,9 @@ static const struct { {8, "random", S_IRUGO | S_IWUSR, &random_fops}, {9, "urandom", S_IRUGO | S_IWUSR, &urandom_fops}, {11,"kmsg", S_IRUGO | S_IWUSR, &kmsg_fops}, +#ifdef CONFIG_CRASH_DUMP + {12,"oldmem", S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops}, +#endif }; static struct class *mem_class; |