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, 5 insertions, 4 deletions

diff --git a/arch/x86/kernel/ds_selftest.c b/arch/x86/kernel/ds_selftest.c
index 8c46fbf38c46..e5a263c8a14c 100644
--- a/arch/x86/kernel/ds_selftest.c
+++ b/arch/x86/kernel/ds_selftest.c
@@ -10,11 +10,12 @@
 
 #include <linux/kernel.h>
 #include <linux/string.h>
+#include <linux/smp.h>
 
 #include <asm/ds.h>
 
 
-#define DS_SELFTEST_BUFFER_SIZE 1021 /* Intentionally chose an odd size. */
+#define BUFFER_SIZE 1021 /* Intentionally chose an odd size. */
 
 
 static int ds_selftest_bts_consistency(const struct bts_trace *trace)
@@ -125,12 +126,12 @@ int ds_selftest_bts(void)
         struct bts_tracer *tracer;
         int error = 0;
         void *top;
-        unsigned char buffer[DS_SELFTEST_BUFFER_SIZE];
+        unsigned char buffer[BUFFER_SIZE];
 
         printk(KERN_INFO "[ds] bts selftest...");
 
-        tracer = ds_request_bts(NULL, buffer, DS_SELFTEST_BUFFER_SIZE,
-                                NULL, (size_t)-1, BTS_KERNEL);
+        tracer = ds_request_bts_cpu(smp_processor_id(), buffer, BUFFER_SIZE,
+                                    NULL, (size_t)-1, BTS_KERNEL);
         if (IS_ERR(tracer)) {
                 error = PTR_ERR(tracer);
                 tracer = NULL;