[Crash-utility] [PATCH v2 2/3] crash_taget: fetch_registers support

[HAGIO KAZUHITO(萩尾 一仁)]

-----Original Message-----
> Provides API for crash_target to fetch registers of given
> CPU. It will allow gdb to perform such commands as "bt",
> "frame", "info locals".
> 
> Highlevel API is crash_get_cpu_reg (). It calls machine
> (architecture) specific function: machdep->get_cpu_reg().
> Input arguments such as register number and register size
> come from gdb arch information. So, get_cpu_regs()
> implementations in crash must understand it.
> 
> Signed-off-by: Alexey Makhalov <amakhalov at vmware.com>

I've not debugged this yet, but with this patch, the crash cannot
start the session.  Do you have any clue?

$ make 
TARGET: X86_64
 CRASH: 7.2.9++
   GDB: 10.1
...
gcc -c -g -DX86_64  -DGDB_10_1 -g -O2 vmware_guestdump.c -Wall -O2 -Wstrict-prototypes -Wmissing-prototypes -fstack-protector -Wformat-security
gcc -c -g -DX86_64  -DGDB_10_1 -g -O2 xen_dom0.c -Wall -O2 -Wstrict-prototypes -Wmissing-prototypes -fstack-protector -Wformat-security
gcc -c -g -DX86_64  -DGDB_10_1 -g -O2 kaslr_helper.c -Wall -O2 -Wstrict-prototypes -Wmissing-prototypes -fstack-protector -Wformat-security
ar -rs crashlib.a main.o tools.o global_data.o memory.o filesys.o help.o task.o build_data.o kernel.o test.o gdb_interface.o net.o dev.o bpf.o printk.o alpha.o x86.o ppc.o ia64.o s390.o s390x.o s390dbf.o ppc64.o x86_64.o arm.o arm64.o mips.o sparc64.o extensions.o remote.o va_server.o va_server_v1.o symbols.o cmdline.o lkcd_common.o lkcd_v1.o lkcd_v2_v3.o lkcd_v5.o lkcd_v7.o lkcd_v8.o lkcd_fix_mem.o s390_dump.o netdump.o diskdump.o makedumpfile.o xendump.o lkcd_x86_trace.o unwind_v1.o unwind_v2.o unwind_v3.o unwind_x86_32_64.o unwind_arm.o xen_hyper.o xen_hyper_command.o xen_hyper_global_data.o xen_hyper_dump_tables.o kvmdump.o qemu.o qemu-load.o sadump.o ipcs.o ramdump.o vmware_vmss.o vmware_guestdump.o xen_dom0.o kaslr_helper.o
ar: creating crashlib.a
  CXXLD  gdb
make[3]: Nothing to be done for `all-target'.

$ crash vmlinux-3.10.0-693.el7.x86_64 vmcore

crash 7.2.9++
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Reading symbols from vmlinux-3.10.0-693.el7.x86_64...
thread.c:95: internal-error: thread_info* inferior_thread(): Assertion `current_thread_ != nullptr' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)


Thanks,
Kazu