powerpc: Add virtual processor dispatch trace log

pseries SPLPAR machines are able to retrieve a log of dispatch and
preempt events from the hypervisor. With this information, we can
see when and why each dispatch & preempt is occuring.

This change adds a set of debugfs files allowing userspace to read this
dispatch log.

Based on initial patches from Nishanth Aravamudan <nacc@us.ibm.com>.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/pseries/plpar_wrappers.h b/arch/powerpc/platforms/pseries/plpar_wrappers.h
index d967c1893ab5..a24a6b2333b2 100644
--- a/arch/powerpc/platforms/pseries/plpar_wrappers.h
+++ b/arch/powerpc/platforms/pseries/plpar_wrappers.h
@@ -43,6 +43,16 @@ static inline long register_slb_shadow(unsigned long cpu, unsigned long vpa)
 	return vpa_call(0x3, cpu, vpa);
 }
 
+static inline long unregister_dtl(unsigned long cpu, unsigned long vpa)
+{
+	return vpa_call(0x6, cpu, vpa);
+}
+
+static inline long register_dtl(unsigned long cpu, unsigned long vpa)
+{
+	return vpa_call(0x2, cpu, vpa);
+}
+
 static inline long plpar_page_set_loaned(unsigned long vpa)
 {
 	unsigned long cmo_page_sz = cmo_get_page_size();