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

[Michael Holzheu]

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.

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;
 	}
 }
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