Hello all, Lately, I've been experimenting with KGDB to do some kernel debugging. While doing this, a doubt arised while using the "set" command, trying to change the value of some registers. I've been able to successfully change the value of all the registers provided by the "info registers" command (i. e., in my case $eax, $ecx, $edx, $ebx, $esp, $ebp, $esi, $edi, $eip, $eflags, $cs, $ss, $ds, $es, $fs and $gs) *except* for $esp, $ss, $fs and $gs. Why is it so? I've been making these tests after hitting a hardware breakpoint, then I set the values with e. g. "set $es = 0xf1c2007c", and verifiy the assignemt with "info reg $es". As I've pointed out, it works with the majority of the registers, except for that four (in this particular case, the first command doesn't output any error, but the second command shows me that the registers remain with the initial value). By the way, I've started GDB with the -write option (checked it inside GDb with the "show write" command). My GDB version is 7.2. I have a practical example below the end of this message, with "set debug remote 1" option enabled. Still regarding this exxample, from what I've been told in the GDB mailing list, it seems KGDB is ignoring the value change on $ss.
Anyone here knows why? If someone knows something about this situation and can share it with me, it would be great. Best regards, João Example: (gdb) info reg $es es 0x7b 123 (gdb) set $es = 0x7c Sending packet: $Pd=7c000000#ab...Ack Packet received: Packet P (set-register) is NOT supported Sending packet: $G14000000ccb59cc00000000067000000089fcbf10c9fcbf1ac309dc00000000079154ac09600000060000000680000007b009dc07c000000ffff0000ffff0000#61...Ack Packet received: OK Sending packet: $g#67...Ack Packet received: 14000000ccb59cc00000000067000000089fcbf10c9fcbf1ac309dc00000000079154ac09600000060000000680000007b009dc07c000000ffff0000ffff0000 (gdb) info reg $es es 0x7c 124 (gdb) info reg $ssPedro ss 0x68 104 (gdb) set $ss = 0x69 Sending packet: $G14000000ccb59cc00000000067000000089fcbf10c9fcbf1ac309dc00000000079154ac09600000060000000690000007b009dc07c000000ffff0000ffff0000#62...Ack Packet received: OK Sending packet: $g#67...Ack Packet received: 14000000ccb59cc00000000067000000089fcbf10c9fcbf1ac309dc00000000079154ac09600000060000000680000007b009dc07c000000ffff0000ffff0000 (gdb) info reg $ss ss 0x68 104 Best regards, João ------------------------------------------------------------------------------ _______________________________________________ Kgdb-bugreport mailing list Kgdb-bugreport@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kgdb-bugreport
