Endian issues on T4240 Powerpc:e6500

[Ed Liversidge <ed at harmonicss dot co dot uk>]

Hi,

I am trying to get gdb 7.12.1 (build from source tried --target=powerpc64-linux-gdb and --target=powerpc64-elf-gdb), to allow me to remotely debug a T4240 PowerPC target.

When I connect to a bdi3000 emulator, gdb reports the program counter to be 32bit word swapped to the actual program counter, reported by the emulator:

(gdb) target remote 192.168.1.70:2001

(gdb) show architecture
The target architecture is assumed to be powerpc:e6500
(gdb) show endian
The target endianness is set automatically (currently big endian)
(gdb) i r pc
pc             0x801080f8ffffffff         0x801080f8ffffffff
(gdb) x $pc
0x801080f8ffffffff:           Cannot access memory at address 0x801080f8ffffffff
T4240#0>info
    Target CPU        : T4/B4 Thread#0 (e6500)
    Core state        : halted
    Debug entry cause : single step
    Current PC        : 0xffffffff_801080f8
    Current CR        : 0x00000000
    Current MSR       : 0x80000200
    Current LR        : 0xffffffff_8021bee4
    Current CCSRBAR   : 0xf_fe000000

As you can see, the BDI reports the PC as 0xffffffff801080f8, and gdb reports it as 0x801080f8ffffffff. I thought perhaps this was a display issue, but the read of the instruction at $pc is also incorrect.

Is this a bug, or am I missing something?

I have also tried the very latest git 8.0, with different results:
  (gdb) target remote 192.168.1.70:2001
  Remote debugging using 192.168.1.70:2001
  warning: No executable has been specified and target does not support
  determining executable automatically.  Try using the "file" command.
  0x7ff7bef0 in ?? ()
  (gdb) i r $pc
  pc             0x7ff7bef0     0x7ff7bef0
  (gdb) show architecture
  The target architecture is set automatically (currently rs6000:6000)
  (gdb) set architecture powerpc:common64
  The target architecture is assumed to be powerpc:common64
  Truncated register 51 in remote 'g' packet
  (gdb) show architecture
  The target architecture is assumed to be powerpc:common64
  Truncated register 51 in remote 'g' packet
  (gdb) i r $pc
  Truncated register 51 in remote 'g' packet

Can anyone help me to get this working?

Thanks in advance for any help,

Ed Liversidge
Director, Harmonic Software Systems Ltd.