x86, bts, hw-branch-tracer: add _noirq variants to the debug store interface

The hw-branch-tracer uses debug store functions from an on_each_cpu()
context, which is simply wrong since the functions may sleep.

Add _noirq variants for most functions, which  may be called with
interrupts disabled.

Separate per-cpu and per-task tracing and allow per-cpu tracing to be
controlled from any cpu.

Make the hw-branch-tracer use the new debug store interface, synchronize
with hotplug cpu event using get/put_online_cpus(), and remove the
unnecessary spinlock.

Make the ptrace bts and the ds selftest code use the new interface.

Defer the ds selftest.

Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Cc: roland@redhat.com
Cc: eranian@googlemail.com
Cc: oleg@redhat.com
Cc: juan.villacis@intel.com
Cc: ak@linux.jf.intel.com
LKML-Reference: <20090403144555.658136000@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 2 deletions

diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 7c21d1e8cae7..adbb24322d8f 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -800,8 +800,9 @@ static int ptrace_bts_config(struct task_struct *child,
         if (cfg.flags & PTRACE_BTS_O_SCHED)
                 flags |= BTS_TIMESTAMPS;
 
-        context->tracer = ds_request_bts(child, context->buffer, context->size,
-                                         NULL, (size_t)-1, flags);
+        context->tracer =
+                ds_request_bts_task(child, context->buffer, context->size,
+                                    NULL, (size_t)-1, flags);
         if (unlikely(IS_ERR(context->tracer))) {
                 int error = PTR_ERR(context->tracer);