On Monday 16 June 2014 03:22 PM, bharat.bhus...@freescale.com wrote:
>
>
>> -----Original Message-----
>> From: qemu-ppc-bounces+bharat.bhushan=freescale....@nongnu.org
>> [mailto:qemu-ppc-
>> bounces+bharat.bhushan=freescale....@nongnu.org] On Behalf Of Madhavan
>> Srinivasan
>> Sent: Sunday, June 15, 2014 2:38 AM
>> To: ag...@suse.de; pau...@samba.org
>> Cc: Madhavan Srinivasan; qemu-...@nongnu.org; qemu-devel@nongnu.org
>> Subject: [Qemu-ppc] [PATCH] qemu/target-ppc: software breakpoint support
>>
>> This patch adds software breakpoint support for ppc. Patch
>> allows to insert and remove sw breakpoints using Qemu
>> gdbserver on ppc.
>>
>> Patch use "abs" instruction as sw breakpoint instruction.
>> This instruction with primary opcode 31 and extended opcode 360
>> has been dropped from PowerISA (in v2.01) and will generate an
>> Emulation assistance interrupt in hypervisor when executed.
>> KVM also has to be updated with this to make use of sw breakpoint.
>
> There are already a patch "ppc debug: Add debug stub support" in review which
> implements software breakpoint
My bad. Should have checked for it. Will look at the patchset posted.
> In addition this patch also implements h/w breakpoints/watchpoints for BOOKE.
> But I actually do not know how h/w breakpoints works on BOOK3S and you can
> help me figuring out what can be shared between booke and book3s.
>
Sure will update you on this soon.
>>
>> Signed-off-by: Madhavan Srinivasan <ma...@linux.vnet.ibm.com>
>> ---
>> target-ppc/kvm.c | 38 +++++++++++++++++++++++++++++++++++---
>> 1 file changed, 35 insertions(+), 3 deletions(-)
>>
>> diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
>> index 9974b10..fa4b4ec 100644
>> --- a/target-ppc/kvm.c
>> +++ b/target-ppc/kvm.c
>> @@ -1201,6 +1201,17 @@ static int kvmppc_handle_dcr_write(CPUPPCState *env,
>> uint32_t dcrn, uint32_t dat
>> return 0;
>> }
>>
>> +static int kvmppc_handle_debug(CPUState *cs, struct kvm_debug_exit_arch
>> *arch_info)
>> +{
>> + int ret = -1;
>> +
>> + if (kvm_find_sw_breakpoint(cs, arch_info->address)) {
>> + ret = EXCP_DEBUG;
>> + }
>> +
>> + return ret;
>> +}
>> +
>> int kvm_arch_handle_exit(CPUState *cs, struct kvm_run *run)
>> {
>> PowerPCCPU *cpu = POWERPC_CPU(cs);
>> @@ -1240,7 +1251,10 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run
>> *run)
>> watchdog_perform_action();
>> ret = 0;
>> break;
>> -
>> + case KVM_EXIT_DEBUG:
>> + DPRINTF("handle debug exit pc = 0x%lx\n", run->debug.arch.address);
>> + ret = kvmppc_handle_debug(cs, &run->debug.arch);
>> + break;
>> default:
>> fprintf(stderr, "KVM: unknown exit reason %d\n", run->exit_reason);
>> ret = -1;
>> @@ -1901,14 +1915,29 @@ void kvm_arch_init_irq_routing(KVMState *s)
>> {
>> }
>>
>> +static const uint8_t dbg_int[] = { 0x7c, 0x00, 0x02, 0xd0};
>
> This should not be hardcoded but we should get this from KVM. Please refer to
> patch "ppc debug: Add debug stub support" to know how to get debug
> instruction.
>
Sure Will do
> Thanks
> -Bharat
>
Thanks for review.
Regards
Maddy
>> int kvm_arch_insert_sw_breakpoint(CPUState *cpu, struct kvm_sw_breakpoint
>> *bp)
>> {
>> - return -EINVAL;
>> + if( cpu_memory_rw_debug(cpu, bp->pc, (uint8_t *)&bp->saved_insn,
>> sizeof(dbg_int), 0) ||
>> + cpu_memory_rw_debug(cpu, bp->pc, (uint8_t *)dbg_int,
>> sizeof(dbg_int),
>> 1) ){
>> + return -EINVAL;
>> + }
>> + return 0;
>> }
>>
>> int kvm_arch_remove_sw_breakpoint(CPUState *cpu, struct kvm_sw_breakpoint
>> *bp)
>> {
>> - return -EINVAL;
>> + uint8_t tmp[4];
>> +
>> + if (cpu_memory_rw_debug(cpu, bp->pc, tmp, sizeof(dbg_int), 0)) {
>> + return -EINVAL;
>> + } else if (memcmp(tmp, dbg_int, sizeof(dbg_int))) {
>> + return -EINVAL;
>> + } else if (cpu_memory_rw_debug(cpu, bp->pc, (uint8_t *)&bp->saved_insn,
>> sizeof(dbg_int), 1)) {
>> + return -EINVAL;
>> + }
>> +
>> + return 0;
>> }
>>
>> int kvm_arch_insert_hw_breakpoint(target_ulong addr, target_ulong len, int
>> type)
>> @@ -1927,6 +1956,9 @@ void kvm_arch_remove_all_hw_breakpoints(void)
>>
>> void kvm_arch_update_guest_debug(CPUState *cpu, struct kvm_guest_debug *dbg)
>> {
>> + if (kvm_sw_breakpoints_active(cpu)) {
>> + dbg->control |= KVM_GUESTDBG_USE_SW_BP;
>> + }
>> }
>>
>> struct kvm_get_htab_buf {
>> --
>> 1.8.3.1
>>
>
