[Crash-utility] [PATCH 01/16] Add MIPS64 framework code support

[Youling Tang]

Hi Kazu,

On 03/12/2021 12:21 PM, HAGIO KAZUHITO(萩尾　一仁) wrote:

> -----Original Message-----
>>>> --- a/diskdump.c
>>>> +++ b/diskdump.c
>>>> @@ -594,6 +594,9 @@ restart:
>>>>    	else if (STRNEQ(header->utsname.machine, "mips") &&
>>>>    	    machine_type_mismatch(file, "MIPS", NULL, 0))
>>>>    		goto err;
>>>> +	else if (STRNEQ(header->utsname.machine, "mips64") &&
>>>> +	    machine_type_mismatch(file, "MIPS", NULL, 0))
>>>> +		goto err;
>>> Why do you make MACHINE_TYPE the same as the MIPS one?
>>> With this, doesn't a MIPS64 crash match a MIPS vmcore?
>> The value of the machine type e_machine in mips32 or mips64 is MIPS, which
>> corresponds to EM_MIPS.
>> The definition in gdb-7.6/include/elf/common.h:110 is as follows:
>>       #define EM_MIPS        8        /* MIPS R3000 */
>> But there is no related definition of EM_MIPS64 or other mips64, so both
>> mips32 and mips64 should use EM_MIPS, and the corresponding e_machine is
>> MIPS.
>>
>> If the MACHINE_TYPE of mips64 is defined as MIPS64, as follows:
>>       define MACHINE_TYPE     "MIPS64"
>>
>> The following error will appear when running crash:
>>       WARNING: machine type mismatch:
>>                 crash utility: MIPS64
>>                 vmcore: MIPS
> Then, is there any problem with this?
>    machine_type_mismatch(file, "MIPS64", NULL, 0))
>
> This can prevent a mips64 crash from trying to open a mips32 vmcore
> and the reverse.
Read the ELF header information of vmocre (whether it is mips32 or mips64),
and the obtained machine type is MIPS, not MIPS64. In mips64, if you use
machine_type_mismatch(file, "MIPS64", NULL, 0)), there will be a machine 
type
mismatch. You can only use machine_type_mismatch(file, "MIPS", NULL, 0)),
only then It can be successfully matched to the machine type.

Thanks,
Youling
> Thanks,
> Kazu
>
>> # readelf -h vmcore
>> ...
>>     Type:                              CORE (Core file)
>>     Machine:                           MIPS R3000
>> ...
>>
>> Therefore, the MACHINE_TYPE of mips32 and mips64 both define MIPS.
>>
>> Thanks,
>> Youling