[Crash-utility] [PATCH] crash-gcore-command extension module: ARM64 support

[HATAYAMA Daisuke]

From: Dave Anderson <anderson at redhat.com>
Subject: [PATCH] crash-gcore-command extension module: ARM64 support
Date: Thu, 17 Jul 2014 12:04:45 -0400

> 
> 
> Hello Daisuke,
> 

Hello Dave,

Sorry for very late responce....

> Attached is a patch to introduce support for the ARM64 architecture
> for the gcore extension module.   
> 
> The patch is fairly straight-forward other than the fact that on
> ARM64 machines, the chain of headers included from the crash utility's
> "defs.h" looks like this:
> 
>   /usr/include/crash/defs.h 
>     /usr/include/signal.h 
>       /usr/include/sys/ucontext.h 
>         /usr/include/sys/procfs.h 
> 
> The <sys/procfs.h> file defines several of the ELF-related structures that
> are hard-coded in gcore_defs.h, causing compile failures due to duplicate 
> structure declarations.
> 
> Note that the <sys/ucontext.h> file on the other three architectures does 
> not #include <sys/procfs.h> so there are no conflicts.  It would be possible
> to move all architectures to include <sys/procfs.h>, but for example, that 
> would also bring in the <sys/user.h> definition of the user_regs_struct,
> which in turn causes a myriad of register name mismatches in gcore_x86.c.
> So for the sake of simplicity, wherever there is an ARM64-only duplicate
> structure or definition in gcore_defs.h, I've encapsulated them by:
> 
>   #if defined(X86) || defined(X86_64) || defined(ARM)
> 

Thanks for this explanation. I'll also try to investigate this.

> Also, there are two generic fixes, one where the gcore module fails on
> Linux 3.11 and later kernels due to a structure member name change,
> and another that changes the getopt() return variable to an "int" instead
> of a "char".
> 
> Here are the details:
>   
>   gcore.mk:
>   
>     - Introduce ARM64 as a supported architecture
>     - Add libgcore/gcore_arm64 to GCORE_CFILES
>   
>   gcore.c:
>   
>     - In cmd_gcore() change "c" type to "int" to correctly match
>       the return type of getopt(); without it, the while loop
>       spins indefinitely on ARM64.

>     - In gcore_offset_table_init(), account for the Linux 3.11 
>       structure member name-change from ns_proxy.pid_ns to 
>       ns_proxy.pid_ns_for_children; without it, the gcore command
>       fails during initialization.

I've already dealt with this locally, but thanks.

>   
>   libgcore/gcore_defs.h:
>   
>     - Add ARM64 ELF- and REGSET_VIEW-related #defines required for
>       each architecture.
>     - Account for variable page sizes in ARM64.
>     - Restrict the hard-coded ELF_NGREG, elf_siginfo, elf_prstatus, 
>       __kernel_old_uid_t and __kernel_old_gid_t, and elf_prsinfo 
>       definitions to X86, X86_64 and ARM architectures.
>     - Add ARM64 thread_struct_fpsmid_state and thread_struct_tp_value
>       offsets to gcore_offset_table.
>   
>   libgcore/gcore_coredump.c:
>   
>     - In fill_prstatus_note(), account for the ARM64 usage of 
>       "user_pt_regs" structure instead of the "user_regs_struct" 
>       used by the other architectures.
>   
>   libgcore/gcore_arm64.c:
>   
>     - Implement ARM64-specific user_regset and user_regset_view
>       structures and all required support functions.
>   
> Please accept these changes into an new package version.
>   

I'll commit these into my local repository with some changes for ease
of my maintainance purpose. Maybe, I'll ask you to review the changed
version.

--
Thanks.
HATAYAMA, Daisuke