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

-----Original Message----- > -----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". > > This is wrong? e.g. mips32 also can use an ELF64 kernel/module binary? If there is such a case, maybe we can also use these?: machine_type_mismatch(file, "MIPS", "MIPS64", 0) machine_type("MIPS") || machine_type("MIPS64") I'm thinking that as we define the values/functions for mips64 separately from mips32, it would be reasonable to make crash's MACHINE_TYPE different from mips32 as well, and we can remove some unusual ifdefs.

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 > > -- > Crash-utility mailing list > Crash-utility(a)redhat.com > https://listman.redhat.com/mailman/listinfo/crash-utility