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

-----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? 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