PERF_CONTEXT_KERNEL
perf_callchain_store_context(entry, PERF_CONTEXT_KERNEL);
perf_callchain_store_context(&ctx, PERF_CONTEXT_KERNEL);
case PERF_CONTEXT_KERNEL:
case PERF_CONTEXT_KERNEL:
case PERF_CONTEXT_KERNEL:
case PERF_CONTEXT_KERNEL:
return ip < kernel_start ? PERF_CONTEXT_USER : PERF_CONTEXT_KERNEL;