----- Original Message -----
> At 02/28/2012 04:52 PM, HATAYAMA Daisuke Wrote:
> >>> In general, such characteristic should not be used. You should prepare
> >>> a solid interface. Even if using them, it should be limited to as
> >>> workaround to avoid some issue.
> >>>
> >>> Why not use qemu's CPU state? Include it as note information with good
> >>> name, and we can use it to distinguish which. Like:
> >>>
> >>> $ readelf -n vmcore
> >>>
> >>> Notes at offset 0x000001c8 with length 0x00000838:
> >>> Owner Data size Description
> >>> CORE 0x00000150 NT_PRSTATUS (prstatus structure)
> >>> CORE 0x00000150 NT_PRSTATUS (prstatus structure)
> >>> QEMU 0x00000557 Unknown note type: (0x00000000)
> >>>
> >>> Or QEMUCPUState is better?
> >>
> >> Good idea. I will try it, and hope gdb can also work.
> >>
> >
> > Tools basically ignore unknown notes. Looking into gdb, it appears to
> > ignore unknown information.
> >
> > static bfd_boolean
> > elfcore_grok_note (bfd *abfd, Elf_Internal_Note *note)
> > {
> > const struct elf_backend_data *bed = get_elf_backend_data (abfd);
> >
> > switch (note->type)
> > {
> > default:
> > return TRUE;
> > <cut>
> >
> > You might need to add new command to output contents of new note if
> > it's necessary.
>
> My goal is:
> 1. gdb uses NT_PRSTATUS, and can work well
> 2. crash uses unknown notes, and can get phys_base from it.
>
> Another question:
>
> What is QEMUCPUState? I donot find its definition?
It's just the note's name character string. Either "QEMU", "QEMUCPUState",
or whatever unique character string you prefer would suffice.
> What note->type shoule be for "QEMU"? If we choose an unused value, the
> value may be used in the future.
Why not do the same thing as the "VMCOREINFO" note, and leave it
as an "illegal/unknown" type of 0::
$ cat /usr/include/elf.h
... [ cut ] ...
/* Legal values for note segment descriptor types for core files. */
#define NT_PRSTATUS 1 /* Contains copy of prstatus struct */
#define NT_FPREGSET 2 /* Contains copy of fpregset struct */
#define NT_PRPSINFO 3 /* Contains copy of prpsinfo struct */
...
$
$ readelf -a vmcore
... [ cut ] ...
Notes at offset 0x00000190 with length 0x00000f1c:
Owner Data size Description
CORE 0x00000150 NT_PRSTATUS (prstatus structure)
CORE 0x00000150 NT_PRSTATUS (prstatus structure)
CORE 0x00000150 NT_PRSTATUS (prstatus structure)
CORE 0x00000150 NT_PRSTATUS (prstatus structure)
CORE 0x00000150 NT_PRSTATUS (prstatus structure)
CORE 0x00000150 NT_PRSTATUS (prstatus structure)
CORE 0x00000150 NT_PRSTATUS (prstatus structure)
CORE 0x00000150 NT_PRSTATUS (prstatus structure)
VMCOREINFO 0x000003e4 Unknown note type: (0x00000000)
$
Dave
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