Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261623AbVASHxR (ORCPT ); Wed, 19 Jan 2005 02:53:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261656AbVASHxJ (ORCPT ); Wed, 19 Jan 2005 02:53:09 -0500 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:51135 "EHLO ebiederm.dsl.xmission.com") by vger.kernel.org with ESMTP id S261624AbVASHdT (ORCPT ); Wed, 19 Jan 2005 02:33:19 -0500 From: "Eric W. Biederman" To: Andrew Morton Cc: , Subject: [PATCH 29/29] crashdump-linear-raw-format-dump-file-access Date: Wed, 19 Jan 2005 0:31:37 -0700 Message-ID: X-Mailer: patch-bomb.pl@ebiederm.dsl.xmission.com In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4604 Lines: 149 From: Hariprasad Nellitheertha This patch contains the code that enables us to access the previous kernel's memory as /dev/oldmem. Signed-off-by: Eric Biederman --- Documentation/devices.txt | 1 drivers/char/mem.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 75 insertions(+) diff -uNr linux-2.6.11-rc1-mm1-nokexec-crashdump-elf-format-dump-file-access/Documentation/devices.txt linux-2.6.11-rc1-mm1-nokexec-crashdump-linear-raw-format-dump-file-access/Documentation/devices.txt --- linux-2.6.11-rc1-mm1-nokexec-crashdump-elf-format-dump-file-access/Documentation/devices.txt Fri Jan 14 04:32:22 2005 +++ linux-2.6.11-rc1-mm1-nokexec-crashdump-linear-raw-format-dump-file-access/Documentation/devices.txt Tue Jan 18 23:17:15 2005 @@ -100,6 +100,7 @@ 9 = /dev/urandom Faster, less secure random number gen. 10 = /dev/aio Asyncronous I/O notification interface 11 = /dev/kmsg Writes to this come out as printk's + 12 = /dev/oldmem Access to crash dump from kexec kernel 1 block RAM disk 0 = /dev/ram0 First RAM disk 1 = /dev/ram1 Second RAM disk diff -uNr linux-2.6.11-rc1-mm1-nokexec-crashdump-elf-format-dump-file-access/drivers/char/mem.c linux-2.6.11-rc1-mm1-nokexec-crashdump-linear-raw-format-dump-file-access/drivers/char/mem.c --- linux-2.6.11-rc1-mm1-nokexec-crashdump-elf-format-dump-file-access/drivers/char/mem.c Fri Jan 14 04:32:23 2005 +++ linux-2.6.11-rc1-mm1-nokexec-crashdump-linear-raw-format-dump-file-access/drivers/char/mem.c Tue Jan 18 23:17:15 2005 @@ -23,6 +23,8 @@ #include #include #include +#include +#include #include #include @@ -226,6 +228,62 @@ return 0; } +#ifdef CONFIG_CRASH_DUMP +/* + * Read memory corresponding to the old kernel. + * If we are reading from the reserved section, which is + * actually used by the current kernel, we just return zeroes. + * Or if we are reading from the first 640k, we return from the + * backed up area. + */ +static ssize_t read_oldmem(struct file * file, char * buf, + size_t count, loff_t *ppos) +{ + unsigned long pfn; + unsigned backup_start, backup_end, relocate_start; + size_t read=0, csize; + + backup_start = CRASH_BACKUP_BASE / PAGE_SIZE; + backup_end = backup_start + (CRASH_BACKUP_SIZE / PAGE_SIZE); + relocate_start = (CRASH_BACKUP_BASE + CRASH_BACKUP_SIZE) / PAGE_SIZE; + + while(count) { + pfn = *ppos / PAGE_SIZE; + + csize = (count > PAGE_SIZE) ? PAGE_SIZE : count; + + /* Perform translation (see comment above) */ + if ((pfn >= backup_start) && (pfn < backup_end)) { + if (clear_user(buf, csize)) { + read = -EFAULT; + goto done; + } + + goto copy_done; + } else if (pfn < (CRASH_RELOCATE_SIZE / PAGE_SIZE)) + pfn += relocate_start; + + if (pfn > saved_max_pfn) { + read = 0; + goto done; + } + + if (copy_oldmem_page(pfn, buf, csize, 1)) { + read = -EFAULT; + goto done; + } + +copy_done: + buf += csize; + *ppos += csize; + read += csize; + count -= csize; + } +done: + return read; +} +#endif + extern long vread(char *buf, char *addr, unsigned long count); extern long vwrite(char *buf, char *addr, unsigned long count); @@ -530,6 +588,7 @@ #define read_full read_zero #define open_mem open_port #define open_kmem open_mem +#define open_oldmem open_mem #ifndef ARCH_HAS_DEV_MEM static struct file_operations mem_fops = { @@ -578,6 +637,13 @@ .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) { @@ -632,6 +698,11 @@ case 11: filp->f_op = &kmsg_fops; break; +#ifdef CONFIG_CRASH_DUMP + case 12: + filp->f_op = &oldmem_fops; + break; +#endif default: return -ENXIO; } @@ -661,6 +732,9 @@ {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_simple *mem_class; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/