[Crash-utility] [RFC/PATCH] s390x: Add live dump detection

[Dave Anderson]

----- Original Message -----
> Hello Dave,
> 
> On Thu, 19 Apr 2012 14:44:43 -0400 (EDT)
> Dave Anderson <anderson at redhat.com> wrote:
> 
> [snip]
> 
> > I would have no problem with adding a new LIVE_DUMP flag to
> > pc->flags2, and just checking it in display_sys_stats() and
> > non_matching_kernel() as you've done below.  In dealing with
> > dumpfiles generated from snap.so, the "bt" command is pretty
> > much the only command that probably should be restricted.
> > However, I don't restrict "bt" with snap.so vmcores because
> > currently there's no magic/signature/whatever that indicates
> > what kind of dump it is.  But if you implement a new LIVE_DUMP
> > flag, I might do it there as well so we've got some consistency.
> > 
> > What do you think about that?
> 
> Sounds good. So what about introducing a new macro LIVE() that
> indicates that the dump or live system is inconsistent.

Good idea -- queued for crash-6.0.6.

I'll also put some kind of indicator in the snap.so ELF header.

Thanks,
  Dave
 
> Something like the following:
> ---
>  defs.h   |    2 ++
>  kernel.c |    9 +++++++--
>  main.c   |    2 ++
>  s390x.c  |   12 ++++++++++++
>  4 files changed, 23 insertions(+), 2 deletions(-)
> 
> --- a/defs.h
> +++ b/defs.h
> @@ -203,6 +203,7 @@ struct number_option {
>  
>  #define ACTIVE()            (pc->flags & LIVE_SYSTEM)
>  #define DUMPFILE()          (!(pc->flags & LIVE_SYSTEM))
> +#define LIVE()              (pc->flags2 & LIVE_DUMP || pc->flags &
> LIVE_SYSTEM)
>  #define MEMORY_SOURCES
>  (NETDUMP|KDUMP|MCLXCD|LKCD|DEVMEM|S390D|MEMMOD|DISKDUMP|XENDUMP|CRASHBUILTIN|KVMDUMP|PROC_KCORE|SADUMP)
>  #define DUMPFILE_TYPES
>       (DISKDUMP|NETDUMP|KDUMP|MCLXCD|LKCD|S390D|XENDUMP|KVMDUMP|SADUMP)
>  #define REMOTE()            (pc->flags2 & REMOTE_DAEMON)
> @@ -446,6 +447,7 @@ struct program_context {
>  #define REMOTE_DAEMON  (0x08ULL)
>  #define ERASEINFO_DATA (0x10ULL)
>  #define GDB_CMD_MODE   (0x20ULL)
> +#define LIVE_DUMP      (0x40ULL)
>  #define FLAT_FORMAT() (pc->flags2 & FLAT)
>  #define ELF_NOTES_VALID() (pc->flags2 & ELF_NOTES)
>  	char *cleanup;
> --- a/kernel.c
> +++ b/kernel.c
> @@ -992,6 +992,8 @@ non_matching_kernel(void)
>                          else
>                                  fprintf(fp, "%s", pc->dumpfile);
>                  }
> +		if (LIVE())
> +			fprintf(fp, " [LIVE DUMP]");
>          }
>  
>  	fprintf(fp, "\n\n");
> @@ -2072,9 +2074,9 @@ else
>  	}
>  
>  	if (active) {
> -		if (ACTIVE())
> +		if (LIVE())
>  			error(FATAL,
> -			    "-a option not supported on a live system\n");
> +			    "-a option not supported on a live system or live dump\n");
>  
>  		if (bt->flags & BT_THREAD_GROUP)
>  			error(FATAL,
> @@ -4098,6 +4100,9 @@ display_sys_stats(void)
>                  		fprintf(fp, "%s", pc->dumpfile);
>  		}
>  
> +		if (LIVE())
> +			fprintf(fp, "  [LIVE DUMP]");
> +
>  		if (NETDUMP_DUMPFILE() && is_partial_netdump())
>  			fprintf(fp, "  [PARTIAL DUMP]");
>  
> --- a/main.c
> +++ b/main.c
> @@ -1110,6 +1110,8 @@ dump_program_context(void)
>  	if (pc->flags & LIVE_SYSTEM)
>  		sprintf(&buf[strlen(buf)], "%sLIVE_SYSTEM",
>  			others++ ? "|" : "");
> +	if (pc->flags2 & LIVE_DUMP)
> +		sprintf(&buf[strlen(buf)], "%sLIVE_DUMP", others++ ? "|" : "");
>  	if (pc->flags & TTY)
>  		sprintf(&buf[strlen(buf)], "%sTTY", others++ ? "|" : "");
>          if (pc->flags & IN_FOREACH)
> --- a/s390x.c
> +++ b/s390x.c
> @@ -328,6 +328,17 @@ static void s390x_process_elf_notes(void
>  	}
>  }
>  
> +static void s390x_check_live(void)
> +{
> +	unsigned long long live_magic;
> +
> +	readmem(0, KVADDR, &live_magic, sizeof(live_magic), "live_magic",
> +		RETURN_ON_ERROR | QUIET);
> +
> +	if (live_magic == 0x4c49564544554d50ULL)
> +		pc->flags2 |= LIVE_DUMP;
> +}
> +
>  /*
>   *  Do all necessary machine-specific setup here.  This is called
>   several
>   *  times during initialization.
> @@ -402,6 +413,7 @@ s390x_init(int when)
>  		break;
>  
>  	case POST_INIT:
> +		s390x_check_live();
>  		break;
>  	}
>  }
>