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authorVivek Goyal <vgoyal@in.ibm.com>2005-06-25 17:58:24 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-25 19:24:54 -0400
commit315c215c0a7324894541d43b0e720f20cafca92e (patch)
treeebfc01b5d4e19622a192b11ff467a17f67b918be /drivers
parent50b1fdbd81edcc8bd343ca44aca2b87a29e2f15c (diff)
[PATCH] kdump: cleanups for dump file access in linear raw format
Removed the dependency on backup region. Now all the information is encoded in ELF format. /dev/oldmem is a dummy interface. User space tool need to be intelligent enough to parse the elf headers and read the relevant memory areas with the help of /dev/oldmem. Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/char/mem.c51
1 files changed, 15 insertions, 36 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 01b3c17ca851..b64108dd765b 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -26,6 +26,7 @@
26#include <linux/highmem.h> 26#include <linux/highmem.h>
27#include <linux/crash_dump.h> 27#include <linux/crash_dump.h>
28#include <linux/backing-dev.h> 28#include <linux/backing-dev.h>
29#include <linux/bootmem.h>
29 30
30#include <asm/uaccess.h> 31#include <asm/uaccess.h>
31#include <asm/io.h> 32#include <asm/io.h>
@@ -278,55 +279,33 @@ static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
278#ifdef CONFIG_CRASH_DUMP 279#ifdef CONFIG_CRASH_DUMP
279/* 280/*
280 * Read memory corresponding to the old kernel. 281 * Read memory corresponding to the old kernel.
281 * If we are reading from the reserved section, which is
282 * actually used by the current kernel, we just return zeroes.
283 * Or if we are reading from the first 640k, we return from the
284 * backed up area.
285 */ 282 */
286static ssize_t read_oldmem(struct file * file, char * buf, 283static ssize_t read_oldmem(struct file *file, char __user *buf,
287 size_t count, loff_t *ppos) 284 size_t count, loff_t *ppos)
288{ 285{
289 unsigned long pfn; 286 unsigned long pfn, offset;
290 unsigned backup_start, backup_end, relocate_start; 287 size_t read = 0, csize;
291 size_t read=0, csize; 288 int rc = 0;
292
293 backup_start = CRASH_BACKUP_BASE / PAGE_SIZE;
294 backup_end = backup_start + (CRASH_BACKUP_SIZE / PAGE_SIZE);
295 relocate_start = (CRASH_BACKUP_BASE + CRASH_BACKUP_SIZE) / PAGE_SIZE;
296 289
297 while(count) { 290 while(count) {
298 pfn = *ppos / PAGE_SIZE; 291 pfn = *ppos / PAGE_SIZE;
292 if (pfn > saved_max_pfn)
293 return read;
299 294
300 csize = (count > PAGE_SIZE) ? PAGE_SIZE : count; 295 offset = (unsigned long)(*ppos % PAGE_SIZE);
301 296 if (count > PAGE_SIZE - offset)
302 /* Perform translation (see comment above) */ 297 csize = PAGE_SIZE - offset;
303 if ((pfn >= backup_start) && (pfn < backup_end)) { 298 else
304 if (clear_user(buf, csize)) { 299 csize = count;
305 read = -EFAULT;
306 goto done;
307 }
308
309 goto copy_done;
310 } else if (pfn < (CRASH_RELOCATE_SIZE / PAGE_SIZE))
311 pfn += relocate_start;
312
313 if (pfn > saved_max_pfn) {
314 read = 0;
315 goto done;
316 }
317
318 if (copy_oldmem_page(pfn, buf, csize, 1)) {
319 read = -EFAULT;
320 goto done;
321 }
322 300
323copy_done: 301 rc = copy_oldmem_page(pfn, buf, csize, offset, 1);
302 if (rc < 0)
303 return rc;
324 buf += csize; 304 buf += csize;
325 *ppos += csize; 305 *ppos += csize;
326 read += csize; 306 read += csize;
327 count -= csize; 307 count -= csize;
328 } 308 }
329done:
330 return read; 309 return read;
331} 310}
332#endif 311#endif