syscall_emul: implement clock_gettime system call

src/arch/x86/linux/process.cc

@@ -446,7 +446,7 @@ static SyscallDesc syscallDescs64[] = {
     /* 225 */ SyscallDesc("timer_getoverrun", unimplementedFunc),
     /* 226 */ SyscallDesc("timer_delete", unimplementedFunc),
     /* 227 */ SyscallDesc("clock_settime", unimplementedFunc),
-    /* 228 */ SyscallDesc("clock_gettime", unimplementedFunc),
+    /* 228 */ SyscallDesc("clock_gettime", clock_gettimeFunc<X86Linux64>),
     /* 229 */ SyscallDesc("clock_getres", unimplementedFunc),
     /* 230 */ SyscallDesc("clock_nanosleep", unimplementedFunc),
     /* 231 */ SyscallDesc("exit_group", exitGroupFunc),
@@ -806,7 +806,7 @@ static SyscallDesc syscallDescs32[] = {
     /* 262 */ SyscallDesc("timer_getoverrun", unimplementedFunc),
     /* 263 */ SyscallDesc("timer_delete", unimplementedFunc),
     /* 264 */ SyscallDesc("clock_settime", unimplementedFunc),
-    /* 265 */ SyscallDesc("clock_gettime", unimplementedFunc),
+    /* 265 */ SyscallDesc("clock_gettime", clock_gettimeFunc<X86Linux32>),
     /* 266 */ SyscallDesc("clock_getres", unimplementedFunc),
     /* 267 */ SyscallDesc("clock_nanosleep", unimplementedFunc),
     /* 268 */ SyscallDesc("statfs64", unimplementedFunc),

src/kern/linux/linux.hh

@@ -130,6 +130,12 @@ class Linux : public OperatingSystem
         int64_t tv_usec;        //!< microseconds
     };
 
+    /// For clock_gettime().
+    struct timespec {
+        time_t tv_sec;         //!< seconds
+        int64_t tv_nsec;        //!< nanoseconds
+    };
+
     /// Clock ticks per second, for times().
     static const int M5_SC_CLK_TCK = 100;
 

src/sim/syscall_emul.hh

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2012-2013 ARM Limited
+ * Copyright (c) 2015 Advanced Micro Devices, Inc.
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -397,6 +398,8 @@ SyscallReturn getgidPseudoFunc(SyscallDesc *desc, int num,
 
 /// A readable name for 1,000,000, for converting microseconds to seconds.
 const int one_million = 1000000;
+/// A readable name for 1,000,000,000, for converting nanoseconds to seconds.
+const int one_billion = 1000000000;
 
 /// Approximate seconds since the epoch (1/1/1970).  About a billion,
 /// by my reckoning.  We want to keep this a constant (not use the
@@ -407,13 +410,24 @@ const unsigned seconds_since_epoch = 1000000000;
 /// microseconds.
 template <class T1, class T2>
 void
-getElapsedTime(T1 &sec, T2 &usec)
+getElapsedTimeMicro(T1 &sec, T2 &usec)
 {
-    int elapsed_usecs = curTick() / SimClock::Int::us;
+    uint64_t elapsed_usecs = curTick() / SimClock::Int::us;
     sec = elapsed_usecs / one_million;
     usec = elapsed_usecs % one_million;
 }
 
+/// Helper function to convert current elapsed time to seconds and
+/// nanoseconds.
+template <class T1, class T2>
+void
+getElapsedTimeNano(T1 &sec, T2 &nsec)
+{
+    uint64_t elapsed_nsecs = curTick() / SimClock::Int::ns;
+    sec = elapsed_nsecs / one_billion;
+    nsec = elapsed_nsecs % one_billion;
+}
+
 //////////////////////////////////////////////////////////////////////
 //
 // The following emulation functions are generic, but need to be
@@ -1283,6 +1297,25 @@ getrlimitFunc(SyscallDesc *desc, int callnum, LiveProcess *process,
     return 0;
 }
 
+/// Target clock_gettime() function.
+template <class OS>
+SyscallReturn
+clock_gettimeFunc(SyscallDesc *desc, int num, LiveProcess *p, ThreadContext *tc)
+{
+    int index = 1;
+    //int clk_id = p->getSyscallArg(tc, index);
+    TypedBufferArg<typename OS::timespec> tp(p->getSyscallArg(tc, index));
+
+    getElapsedTimeNano(tp->tv_sec, tp->tv_nsec);
+    tp->tv_sec += seconds_since_epoch;
+    tp->tv_sec = TheISA::htog(tp->tv_sec);
+    tp->tv_nsec = TheISA::htog(tp->tv_nsec);
+
+    tp.copyOut(tc->getMemProxy());
+
+    return 0;
+}
+
 /// Target gettimeofday() handler.
 template <class OS>
 SyscallReturn
@@ -1292,7 +1325,7 @@ gettimeofdayFunc(SyscallDesc *desc, int callnum, LiveProcess *process,
     int index = 0;
     TypedBufferArg<typename OS::timeval> tp(process->getSyscallArg(tc, index));
 
-    getElapsedTime(tp->tv_sec, tp->tv_usec);
+    getElapsedTimeMicro(tp->tv_sec, tp->tv_usec);
     tp->tv_sec += seconds_since_epoch;
     tp->tv_sec = TheISA::htog(tp->tv_sec);
     tp->tv_usec = TheISA::htog(tp->tv_usec);
@@ -1369,7 +1402,7 @@ getrusageFunc(SyscallDesc *desc, int callnum, LiveProcess *process,
 
     switch (who) {
       case OS::TGT_RUSAGE_SELF:
-        getElapsedTime(rup->ru_utime.tv_sec, rup->ru_utime.tv_usec);
+        getElapsedTimeMicro(rup->ru_utime.tv_sec, rup->ru_utime.tv_usec);
         rup->ru_utime.tv_sec = TheISA::htog(rup->ru_utime.tv_sec);
         rup->ru_utime.tv_usec = TheISA::htog(rup->ru_utime.tv_usec);
         break;
@@ -1423,7 +1456,7 @@ timeFunc(SyscallDesc *desc, int callnum, LiveProcess *process,
            ThreadContext *tc)
 {
     typename OS::time_t sec, usec;
-    getElapsedTime(sec, usec);
+    getElapsedTimeMicro(sec, usec);
     sec += seconds_since_epoch;
 
     int index = 0;