Hi Doug,
On Tue, Jul 30, 2019 at 03:18:00PM -0700, Douglas Anderson wrote:
> diff --git a/arch/arm64/kernel/kgdb.c b/arch/arm64/kernel/kgdb.c
> index 43119922341f..b666210fbc75 100644
> --- a/arch/arm64/kernel/kgdb.c
> +++ b/arch/arm64/kernel/kgdb.c
> @@ -148,6 +148,45 @@ sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,
> struct task_struct *task)
> gdb_regs[32] = cpu_context->pc;
> }
>
> +void kgdb_call_nmi_hook(void *ignored)
> +{
> + struct pt_regs *regs;
> +
> + /*
> + * NOTE: get_irq_regs() is supposed to get the registers from
> + * before the IPI interrupt happened and so is supposed to
> + * show where the processor was. In some situations it's
> + * possible we might be called without an IPI, so it might be
> + * safer to figure out how to make kgdb_breakpoint() work
> + * properly here.
> + */
> + regs = get_irq_regs();
> +
> + /*
> + * Some commands (like 'btc') assume that they can find info about
> + * a task in the 'cpu_context'. Unfortunately that's only valid
> + * for sleeping tasks. ...but let's make it work anyway by just
> + * writing the registers to the right place. This is safe because
> + * nobody else is using the 'cpu_context' for a running task.
> + */
> + current->thread.cpu_context.x19 = regs->regs[19];
> + current->thread.cpu_context.x20 = regs->regs[20];
> + current->thread.cpu_context.x21 = regs->regs[21];
> + current->thread.cpu_context.x22 = regs->regs[22];
> + current->thread.cpu_context.x23 = regs->regs[23];
> + current->thread.cpu_context.x24 = regs->regs[24];
> + current->thread.cpu_context.x25 = regs->regs[25];
> + current->thread.cpu_context.x26 = regs->regs[26];
> + current->thread.cpu_context.x27 = regs->regs[27];
> + current->thread.cpu_context.x28 = regs->regs[28];
> + current->thread.cpu_context.fp = regs->regs[29];
> +
> + current->thread.cpu_context.sp = regs->sp;
> + current->thread.cpu_context.pc = regs->pc;
> +
> + kgdb_nmicallback(raw_smp_processor_id(), regs);
> +}
This is really gross... :/
Can you IPI the other CPUs instead and have them backtrace locally, like we
do for things like magic sysrq (sysrq_handle_showallcpus())?
Will
