The kmdb debugger can display machine registers as a group or individually. To display all registers as a group, use $r as shown in the following example.
[0]: $r g0 0 l0 0 g1 100130a4 debug_enter l1 edd00028 g2 10411c00 tsbmiss_area+0xe00 l2 10449c90 g3 10442000 ti_statetbl+0x1ba l3 1b g4 3000061a004 l4 10474400 ecc_syndrome_tab+0x80 g5 0 l5 3b9aca00 g6 0 l6 0 g7 2a10001fd40 l7 0 o0 0 i0 0 o1 c i1 10449e50 o2 20 i2 0 o3 300006b2d08 i3 10 o4 0 i4 0 o5 0 i5 b0 sp 2a10001b451 fp 2a10001b521 o7 1001311c debug_enter+0x78 i7 1034bb24 zsa_xsint+0x2c4 y 0 tstate: 1604 (ccr=0x0, asi=0x0, pstate=0x16, cwp=0x4) pstate: ag:0 ie:1 priv:1 am:0 pef:1 mm:0 tle:0 cle:0 mg:0 ig:0 winreg: cur:4 other:0 clean:7 cansave:1 canrest:5 wstate:14 tba 0x10000000 pc edd000d8 edd000d8: ta %icc,%g0 + 125 npc edd000dc edd000dc: nop |
The debugger exports each register value to a variable with the same name as the register. If you read the variable, the current value of the register is returned. If you write to the variable, the value of the associated machine register is changed. The following example changes the value of the %o0 register from 0 to 1 on an x86 machine.
[0]> &<eax=K c1e6e0f0 [0]> 0>eax [0]> &<eax=K 0 [0]> c1e6e0f0>eax |
If you need to inspect the registers of a different processor, you can use the ::cpuregs dcmd. The ID of the processor to be examined can be supplied as either the address to the dcmd or as the value of the -c option, as shown in the following example.
[0]> 0::cpuregs %cs = 0x0158 %eax = 0xc1e6e0f0 kmdbmod`kaif_dvec %ds = 0x0160 %ebx = 0x00000000 |
The following example switches from processor 0 to processor 3 on a SPARC machine. The %g3 register is inspected and then cleared. To confirm the new value, %g3 is read again.
[0]> 3::switch [3]> <g3=K 24 [3]> 0>g3 [3]> <g3 0 |