Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263778AbUIONDv (ORCPT ); Wed, 15 Sep 2004 09:03:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266117AbUIOM7t (ORCPT ); Wed, 15 Sep 2004 08:59:49 -0400 Received: from e34.co.us.ibm.com ([32.97.110.132]:46055 "EHLO e34.co.us.ibm.com") by vger.kernel.org with ESMTP id S266096AbUIOM5V (ORCPT ); Wed, 15 Sep 2004 08:57:21 -0400 Date: Wed, 15 Sep 2004 18:27:28 +0530 From: Hariprasad Nellitheertha To: akpm@osdl.org, linux-kernel@vger.kernel.org, fastboot@osdl.org Cc: Suparna Bhattacharya , mbligh@aracnet.com, ebiederm@xmission.com, litke@us.ibm.com Subject: Re: [PATCH][6/6]Linear/raw format dump file access Message-ID: <20040915125728.GG15450@in.ibm.com> Reply-To: hari@in.ibm.com References: <20040915125041.GA15450@in.ibm.com> <20040915125145.GB15450@in.ibm.com> <20040915125322.GC15450@in.ibm.com> <20040915125422.GD15450@in.ibm.com> <20040915125525.GE15450@in.ibm.com> <20040915125631.GF15450@in.ibm.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="b8GWCKCLzrXbuNet" Content-Disposition: inline In-Reply-To: <20040915125631.GF15450@in.ibm.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4751 Lines: 162 --b8GWCKCLzrXbuNet Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Regards, Hari -- Hariprasad Nellitheertha Linux Technology Center India Software Labs IBM India, Bangalore --b8GWCKCLzrXbuNet Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="kd-oldmem-269rc1-mm5.patch" This patch contains the code that enables us to access the previous kernel's memory as /dev/oldmem. Signed off by Hariprasad Nellitheertha Signed off by Adam Litke --- linux-2.6.9-rc1-hari/Documentation/devices.txt | 1 linux-2.6.9-rc1-hari/drivers/char/mem.c | 66 +++++++++++++++++++++++++ 2 files changed, 67 insertions(+) diff -puN Documentation/devices.txt~kd-oldmem-269rc1-mm5 Documentation/devices.txt --- linux-2.6.9-rc1/Documentation/devices.txt~kd-oldmem-269rc1-mm5 2004-09-15 17:36:57.000000000 +0530 +++ linux-2.6.9-rc1-hari/Documentation/devices.txt 2004-09-15 17:36:57.000000000 +0530 @@ -100,6 +100,7 @@ Your cooperation is appreciated. 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 kexec-ed crash dump 1 block RAM disk 0 = /dev/ram0 First RAM disk 1 = /dev/ram1 Second RAM disk diff -puN drivers/char/mem.c~kd-oldmem-269rc1-mm5 drivers/char/mem.c --- linux-2.6.9-rc1/drivers/char/mem.c~kd-oldmem-269rc1-mm5 2004-09-15 17:36:57.000000000 +0530 +++ linux-2.6.9-rc1-hari/drivers/char/mem.c 2004-09-15 17:36:57.000000000 +0530 @@ -23,6 +23,8 @@ #include #include #include +#include +#include #include #include @@ -231,6 +233,60 @@ static int mmap_mem(struct file *file, s return 0; } +/* + * 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; +} + extern long vread(char *buf, char *addr, unsigned long count); extern long vwrite(char *buf, char *addr, unsigned long count); @@ -535,6 +591,7 @@ static int open_port(struct inode * inod #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, @@ -579,6 +636,11 @@ static struct file_operations full_fops .write = write_full, }; +static struct file_operations oldmem_fops = { + .read = read_oldmem, + .open = open_oldmem, +}; + static ssize_t kmsg_write(struct file * file, const char __user * buf, size_t count, loff_t *ppos) { @@ -633,6 +695,9 @@ static int memory_open(struct inode * in case 11: filp->f_op = &kmsg_fops; break; + case 12: + filp->f_op = &oldmem_fops; + break; default: return -ENXIO; } @@ -662,6 +727,7 @@ 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}, + {12,"oldmem", S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops}, }; static struct class_simple *mem_class; _ --b8GWCKCLzrXbuNet-- - 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/