ARM: Detect and skip udelay() functions in linux kernel.

This change speeds up booting, especially in MP cases, by not executing
udelay() on the core but instead skipping ahead tha amount of time that is being
delayed.

1 files changed, 25 insertions, 0 deletions

diff --git a/src/kern/linux/events.cc b/src/kern/linux/events.cc
index 60aa857ac..75c2b6f7f 100644
--- a/src/kern/linux/events.cc
+++ b/src/kern/linux/events.cc
@@ -44,11 +44,13 @@
 #include <sstream>
 
 #include "base/trace.hh"
+#include "arch/utility.hh"
 #include "cpu/thread_context.hh"
 #include "kern/linux/events.hh"
 #include "kern/linux/printk.hh"
 #include "kern/system_events.hh"
 #include "sim/arguments.hh"
+#include "sim/pseudo_inst.hh"
 #include "sim/system.hh"
 
 namespace Linux {
@@ -66,4 +68,27 @@ DebugPrintkEvent::process(ThreadContext *tc)
     SkipFuncEvent::process(tc);
 }
 
+void
+UDelayEvent::process(ThreadContext *tc)
+{
+    int arg_num  = 0;
+
+    // Get the time in native size
+    uint64_t time = TheISA::getArgument(tc, arg_num,  (uint16_t)-1, false);
+
+    // convert parameter to ns
+    if (argDivToNs)
+        time /= argDivToNs;
+
+    time *= argMultToNs;
+
+    // Convert ns to ticks
+    time *= SimClock::Int::ns;
+
+    SkipFuncEvent::process(tc);
+
+    PseudoInst::quiesceNs(tc, time);
+}
+
+
 } // namespace linux