Re: [Crash-utility] xencrash fixes for xen-3.3.0

[Dave Anderson <anderson@redhat.com>]

Itsuro ODA wrote:
> Hi,
> 
> This patch is for xen hypervisor analysis function of the
> crash command to apply to the xen-3.3.0 (the newest version of xen).
> 
> * PERCPU_SHIFT becomes 13 (from 12) in the xen-3.3.0.
>   This value is calculated from "__per_cpu_start" and "__per_cpu_data_end".
> * "jiffies" does not exist in the xen-3.3.0.
>   It was used to show the uptime. I found there is no altanernative
>   (i.e. the xen hypervisor does not have the uptime.).
>   Then if "jiffies" does not exist, "--:--:--" is showed as UPTIME in
>   the sys command.
>   (Is it better to eliminate the whole UPTIME line ?)
>   --- example ---
>   crash> sys
>      KERNEL: xen-syms
>    DUMPFILE: vmcore
>        CPUS: 4
>     DOMAINS: 5
>      UPTIME: --:--:--
>     MACHINE: Intel(R) Core(TM)2 Quad  CPU   Q9450  @ 2.66GHz  (2660 Mhz)
>      MEMORY: 2 GB
>   ----------------
> 
> This patch is for crash-4.0-7.2.
> 
> Thanks
> Itsuro Oda

The patch looks OK.  But just for sanity's sake, is it guaranteed that
the per_cpu data section will be greater than 4k on both architectures?
Or could there be some combination of xen CONFIG options that could
reduce the i386 per_cpu data section contents to less than 4K even though
PERCPU_SHIFT is 13?

Dave

> 
> ---
> --- xen_hyper_defs.h.org        2008-10-06 13:45:39.000000000 +0900
> +++ xen_hyper_defs.h    2008-10-06 13:44:44.000000000 +0900
> @@ -134,9 +134,8 @@
>  #endif
> 
>  #if defined(X86) || defined(X86_64)
> -#define XEN_HYPER_PERCPU_SHIFT 12
>  #define xen_hyper_per_cpu(var, cpu)  \
> -       ((ulong)(var) + (((ulong)(cpu))<<XEN_HYPER_PERCPU_SHIFT))
> +       ((ulong)(var) + (((ulong)(cpu))<<xht->percpu_shift))
>  #elif defined(IA64)
>  #define xen_hyper_per_cpu(var, cpu)  \
>         ((xht->flags & XEN_HYPER_SMP) ? \
> @@ -404,6 +403,7 @@
>         ulong *cpumask;
>         uint *cpu_idxs;
>         ulong *__per_cpu_offset;
> +       int percpu_shift;
>  };
> 
>  struct xen_hyper_dumpinfo_context {
> --- xen_hyper.c.org     2008-10-06 13:41:14.000000000 +0900
> +++ xen_hyper.c 2008-10-06 14:15:03.000000000 +0900
> @@ -71,6 +71,8 @@
>  #endif
> 
>  #if defined(X86) || defined(X86_64)
> +       xht->percpu_shift =
> +           (symbol_value("__per_cpu_data_end") - symbol_value("__per_cpu_start") > 4096) ? 13: 12;
>         member_offset = MEMBER_OFFSET("cpuinfo_x86", "x86_model_id");
>         buf = GETBUF(XEN_HYPER_SIZE(cpuinfo_x86));
>         if (xen_hyper_test_pcpu_id(XEN_HYPER_CRASHING_CPU())) {
> @@ -1746,9 +1748,11 @@
>                         tmp2 = (ulong)jiffies_64;
>                         jiffies_64 = (ulonglong)(tmp2 - tmp1);
>                 }
> -       } else {
> +       } else if (symbol_exists("jiffies")) {
>                 get_symbol_data("jiffies", sizeof(long), &jiffies);
>                 jiffies_64 = (ulonglong)jiffies;
> +       } else {
> +               jiffies_64 = 0; /* hypervisor does not have uptime */
>         }
> 
>         return jiffies_64;
> --- xen_hyper_command.c.org     2008-10-07 08:05:37.000000000 +0900
> +++ xen_hyper_command.c 2008-10-07 08:24:29.000000000 +0900
> @@ -1022,7 +1022,8 @@
>                 (buf1, "%d\n", XEN_HYPER_NR_DOMAINS()));
>         /* !!!Display a date here if it can be found. */
>         XEN_HYPER_PRI(fp, len, "UPTIME: ", buf1, flag,
> -               (buf1, "%s\n", convert_time(xen_hyper_get_uptime_hyper(), buf2)));
> +               (buf1, "%s\n", (xen_hyper_get_uptime_hyper() ?
> +                convert_time(xen_hyper_get_uptime_hyper(), buf2) : "--:--:--")));
>         /* !!!Display a version here if it can be found. */
>         XEN_HYPER_PRI_CONST(fp, len, "MACHINE: ", flag);
>         if (strlen(uts->machine)) {
> ---