GDB can't fetch the PowerPC's FPSCR register: (gdb) print $fpscr reading register fpscr (#70): Input/output error. (gdb) as occures when GDB is doing an inferior function call. Version-Release number of selected component (if applicable): 2.6.9-rc4 strace shows: ptrace(PTRACE_PEEKUSER, 503, 0x288, 0xffffcdb0) = -1 EIO and grubbing the headers: #define PT_FPR0 48 define PT_FPSCR (PT_FPR0 + 32 + 1) (gdb) print/x (48 + 32 + 1) * 8 $1 = 0x288 suggests that the value is correct.
See bug #91727. The value of PT_FPSCR for 64-bit userspace is different to the value for 32-bit. This is because a 'double' is worth two longs for 32-bit code, and only one for 64-bit code. I think the kernel is doing the right thing -- if there's a kernel bug it's purely the evilness of the way the interface is done. If we're going to start criticising the ptrace interface... :) Closing NOTABUG. Feel free to argue if you feel strongly ;)
*** This bug has been marked as a duplicate of 91727 ***
Changed to 'CLOSED' state since 'RESOLVED' has been deprecated.