[PATCH v4] Fix max_mapnr issue on system has over 44-bit addressing.

This patch will fix a bug of makedumpfile doesn't work correctly on system
has over 44-bit addressing in compression dump mode.
This bug was posted here:
http://lists.infradead.org/pipermail/kexec/2013-September/009587.html

This patch will add 3 new fields in struct kdump_sub_header.
unsigned long long start_pfn_64;  /* header_version 6 and later */
unsigned long long end_pfn_64;    /* header_version 6 and later */
unsigned long long max_mapnr_64;  /* header_version 6 and later */

And the old "unsigned int max_mapnr" in struct disk_dump_header will
not be used anymore, but still be there for compatibility purpose.

The max_mapnr_64 only exists in strcut kdump_sub_header, and that only
for compressed kdump format, so for ELF format kdump files (non-compressed),
only the max_mapnr is available, so it still may be truncated for addresses
exceed 44bit (above 16TB).

This patch will change the header_version to 6.

The corresponding patch for crash utility can be found here:
http://lists.infradead.org/pipermail/kexec/2013-October/009750.html

This patch doesn't change sadump_header.

Changelog:
v4:
- Do not change max_mapnr_64 in kdump_sub_header in memory for old kernel.

v3:
- Change notes for max_mapnr, start_pfn and end_pfn as obsolete.
- Remove "(32bit)" from debug messages of max_mapnr, start_pfn and end_pfn.
- Set the 32bit start_pfn and end_pfn to UINT_MAX.
- Remove bitmap writting enhancement to another seperate patch.
- Change type of len_bitmap in struct DumpInfo back to unsigned long.

v2:
- Rename max_mapnr in struct kdump_sub_header to max_mapnr_64.
- Change type of max_mapnr_64 from unsigned long to unsigned long long.
  In x86 PAE mode on x86_32 kernel, the address may exceeds 44bit limit.
- Add start_pfn_64, end_pfn_64 for struct kdump_sub_header.
- Only print 64bit start_pfn_64, end_pfn_64 and max_mapnr_64
  debug messages for disk dump header version >= 6.
- Change type of bitmap_len in struct DumpInfo, from unsigned long to
  unsigned long long.
- Enhance bitmap writting function in reassemble_kdump_header().
  Prevent bitmap writting failure if the size of bitmap is too large to
  fit a sigle write.

v1:
- http://lists.infradead.org/pipermail/kexec/2013-September/009662.html

Signed-off-by: Jingbai Ma <jingbai.ma@hp.com>
Tested-by: Lisa Mitchell <lisa.mitchell@hp.com>

1 files changed, 12 insertions, 3 deletions

diff --git a/diskdump_mod.h b/diskdump_mod.h
index 00ab852..dd24eb2 100644
--- a/diskdump_mod.h
+++ b/diskdump_mod.h
@@ -52,7 +52,9 @@ struct disk_dump_header {
 						   header in blocks */
 	unsigned int		bitmap_blocks;	/* Size of Memory bitmap in
 						   block */
-	unsigned int		max_mapnr;	/* = max_mapnr */
+	unsigned int		max_mapnr;	/* = max_mapnr, OBSOLETE!
+						   32bit only, full 64bit
+						   in sub header. */
 	unsigned int		total_ram_blocks;/* Number of blocks should be
 						   written */
 	unsigned int		device_blocks;	/* Number of total blocks in
@@ -71,14 +73,21 @@ struct kdump_sub_header {
 	unsigned long	phys_base;
 	int		dump_level;	/* header_version 1 and later */
 	int		split;		/* header_version 2 and later */
-	unsigned long	start_pfn;	/* header_version 2 and later */
-	unsigned long	end_pfn;	/* header_version 2 and later */
+	unsigned long	start_pfn;	/* header_version 2 and later,
+					   OBSOLETE! 32bit only, full
+					   64bit in start_pfn_64. */
+	unsigned long	end_pfn;	/* header_version 2 and later,
+					   OBSOLETE! 32bit only, full
+					   64bit in end_pfn_64. */
 	off_t		offset_vmcoreinfo;/* header_version 3 and later */
 	unsigned long	size_vmcoreinfo;  /* header_version 3 and later */
 	off_t		offset_note;      /* header_version 4 and later */
 	unsigned long	size_note;        /* header_version 4 and later */
 	off_t		offset_eraseinfo; /* header_version 5 and later */
 	unsigned long	size_eraseinfo;   /* header_version 5 and later */
+	unsigned long long start_pfn_64;  /* header_version 6 and later */
+	unsigned long long end_pfn_64;	  /* header_version 6 and later */
+	unsigned long long max_mapnr_64;  /* header_version 6 and later */
 };
 
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