[lkcd-devel] cross system lcrash - dump header, common structures

[Andreas H. <AHE...@de...>]

Some thoughts about the dump file format.

1) In order to make dump file format arch independend, we should
pack all needed structures (dump_header_t, dump_header_asm_t,
dump_page_t).

2) Furthermore arch independend types sould be used in those structures.
E.g. here is the dump-header as I have defined it in cross system
lcrash:


typedef struct kl_dump_header_s {
      uint64_t magic_number; /* dump magic number, unique to verify dump */
      uint32_t version;      /* version number of this dump */
      uint32_t header_size;  /* size of this header */
      uint32_t dump_level;   /* level of this dump */
      uint32_t page_size;    /* page size (e.g. 4K, 8K, 16K, etc.) */
      uint64_t memory_size;  /* size of entire physical memory */
      uint64_t memory_start; /* start of physical memory */
      uint64_t memory_end;      /* end of physical memory */
      uint32_t num_pages;       /* number of pages in this dump */
      char panic_string[KL_DUMP_PANIC_LEN]; /* panic string, if available*/
      struct {uint64_t tv_sec;
            uint64_t tv_usec;
      } time; /* the time of the system crash */
      /* the NEW utsname (uname) information -- in character form */
      /* we do this so we don't have to include utsname.h         */
      /* plus it helps us be more architecture independent        */
      char utsname_sysname[KL_UTS_LEN];
      char utsname_nodename[KL_UTS_LEN];
      char utsname_release[KL_UTS_LEN];
      char utsname_version[KL_UTS_LEN];
      char utsname_machine[KL_UTS_LEN];
      char utsname_domainname[KL_UTS_LEN];

      uint64_t current_task; /* fixme: better use uint64_t here */
      uint32_t dump_compress; /* compression type used in this dump */
      uint32_t dump_flags;       /* any additional flags */
      uint32_t dump_device;   /* any additional flags */
} __attribute__((packed)) kl_dump_header_t;


I even defined my own struct time. Of course before using tv_sec or tv_usec
those values might have to be casted or filled into another struct.

3) I discussed with Michael Holzheu, what endianess the common structures
of
a dump should have. Finally we mean that the endianess of the dump_header_t
and dump_page_t should be the same as in the dump. Having different
endianess
for the dump file format (dump_header_t, dump_page_t) and the file contents
(the dumped memory) whould make things worse for cross system lcrash.


What do you think about this issues?


Regards,

Andreas



--
Linux for eServer Development
Tel :  +49-7031-16-4640
Notes mail :  Andreas Herrmann/GERMANY/IBM@IBMDE
email :  ahe...@de...