[Crash-utility] [PATCH 01/16] Add MIPS64 framework code support
Youling Tang
tangyouling at loongson.cn
Sat Mar 13 04:01:54 UTC 2021
On 03/12/2021 04:04 PM, HAGIO KAZUHITO(萩尾 一仁) wrote:
> -----Original Message-----
>> 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.
> Probably I misunderstand something, but then need to know it..
>
> The machine_type_mismatch() doesn't use the ELF's EM_MIPS value.
> Why do we need to match crash's MACHINE_TYPE with ELF's EM_MIPS?
>
> int
> machine_type(char *type)
> {
> return STREQ(MACHINE_TYPE, type);
> }
>
> int
> machine_type_mismatch(char *file, char *e_machine, char *alt, ulong query)
> {
> if (machine_type(e_machine) || machine_type(alt))
> return FALSE;
>
> if (query == KDUMP_LOCAL) /* already printed by NETDUMP_LOCAL */
> return TRUE;
>
> error(WARNING, "machine type mismatch:\n");
>
> fprintf(fp, " crash utility: %s\n", MACHINE_TYPE);
> fprintf(fp, " %s: %s%s%s\n\n", file, e_machine,
> alt ? " or " : "", alt ? alt : "");
>
> return TRUE;
> }
>
> Without the following hunk, EM_MIPS has been used only for ELF32 in symbols.c.
>
> --- a/symbols.c
> +++ b/symbols.c
> @@ -3636,6 +3636,11 @@ is_kernel(char *file)
> goto bailout;
> break;
>
> + case EM_MIPS:
> + if (machine_type_mismatch(file, "MIPS", NULL, 0))
> + goto bailout;
> + break;
> +
> default:
> if (machine_type_mismatch(file, "(unknown)", NULL, 0))
> goto bailout;
> @@ -3890,6 +3895,11 @@ is_shared_object(char *file)
> if (machine_type("SPARC64"))
> return TRUE;
> break;
> +
> + case EM_MIPS:
> + if (machine_type("MIPS"))
> + return TRUE;
> + break;
> }
>
> So I thought that meybe we can also change these ELF64 cases to "MIPS64"
> with defining MACHINE_TYPE as "MIPS64".
If based on the original patch, make the following modifications:
(That is, the mips64 part still uses EM_MIPS, but MACHINE_TYPE is defined as
MIPS64, and the case EM_MIPS processing of the mips64 part is changed to
machine_type_mismatch(file, "MIPS64", NULL, 0)).
--- a/defs.h
+++ b/defs.h
@@ -6376,7 +6376,7 @@ void s390x_dump_machdep_table(ulong);
#endif
#ifdef __mips__ /* MIPS & MIPS64 */
-#define MACHINE_TYPE "MIPS"
+#define MACHINE_TYPE "MIPS64"
#endif
/*
diff --git a/diskdump.c b/diskdump.c
index b4712ad..538d0ad 100644
--- a/diskdump.c
+++ b/diskdump.c
@@ -595,7 +595,7 @@ restart:
machine_type_mismatch(file, "MIPS", NULL, 0))
goto err;
else if (STRNEQ(header->utsname.machine, "mips64") &&
- machine_type_mismatch(file, "MIPS", NULL, 0))
+ machine_type_mismatch(file, "MIPS64", NULL, 0))
goto err;
else if (STRNEQ(header->utsname.machine, "s390x") &&
machine_type_mismatch(file, "S390X", NULL, 0))
diff --git a/symbols.c b/symbols.c
index b30b92c..3048de5 100644
--- a/symbols.c
+++ b/symbols.c
@@ -3634,7 +3634,7 @@ is_kernel(char *file)
break;
case EM_MIPS:
- if (machine_type_mismatch(file, "MIPS", NULL, 0))
+ if (machine_type_mismatch(file, "MIPS64", NULL, 0))
goto bailout;
break;
@@ -3894,7 +3894,7 @@ is_shared_object(char *file)
break;
case EM_MIPS:
- if (machine_type("MIPS"))
+ if (machine_type("MIPS64"))
return TRUE;
break;
}
The running error is as follows:
# crash vmcore vmlinux
WARNING: machine type mismatch:
crash utility: MIPS64
/home/tang/vmcore_4.19.161: MIPS
crash: /home/tang/vmcore_4.19.161: not a supported file format
Thanks,
Youling
>
> This is wrong? e.g. mips32 also can use an ELF64 kernel/module binary?
>
> 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
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