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      1 //===-- xray_tsc.h ----------------------------------------------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file is a part of XRay, a dynamic runtime instrumentation system.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 #ifndef XRAY_EMULATE_TSC_H
     14 #define XRAY_EMULATE_TSC_H
     15 
     16 #include "sanitizer_common/sanitizer_common.h"
     17 
     18 namespace __xray {
     19 static constexpr uint64_t NanosecondsPerSecond = 1000ULL * 1000 * 1000;
     20 }
     21 
     22 #if SANITIZER_FUCHSIA
     23 #include <zircon/syscalls.h>
     24 
     25 namespace __xray {
     26 
     27 inline bool probeRequiredCPUFeatures() XRAY_NEVER_INSTRUMENT { return true; }
     28 
     29 ALWAYS_INLINE uint64_t readTSC(uint8_t &CPU) XRAY_NEVER_INSTRUMENT {
     30   CPU = 0;
     31   return _zx_ticks_get();
     32 }
     33 
     34 inline uint64_t getTSCFrequency() XRAY_NEVER_INSTRUMENT {
     35   return _zx_ticks_per_second();
     36 }
     37 
     38 } // namespace __xray
     39 
     40 #else // SANITIZER_FUCHSIA
     41 
     42 #if defined(__x86_64__)
     43 #include "xray_x86_64.inc"
     44 #elif defined(__powerpc64__)
     45 #include "xray_powerpc64.inc"
     46 #elif defined(__arm__) || defined(__aarch64__) || defined(__mips__)
     47 // Emulated TSC.
     48 // There is no instruction like RDTSCP in user mode on ARM. ARM's CP15 does
     49 //   not have a constant frequency like TSC on x86(_64), it may go faster
     50 //   or slower depending on CPU turbo or power saving mode. Furthermore,
     51 //   to read from CP15 on ARM a kernel modification or a driver is needed.
     52 //   We can not require this from users of compiler-rt.
     53 // So on ARM we use clock_gettime() which gives the result in nanoseconds.
     54 //   To get the measurements per second, we scale this by the number of
     55 //   nanoseconds per second, pretending that the TSC frequency is 1GHz and
     56 //   one TSC tick is 1 nanosecond.
     57 #include "sanitizer_common/sanitizer_common.h"
     58 #include "sanitizer_common/sanitizer_internal_defs.h"
     59 #include "xray_defs.h"
     60 #include <cerrno>
     61 #include <cstdint>
     62 #include <time.h>
     63 
     64 namespace __xray {
     65 
     66 inline bool probeRequiredCPUFeatures() XRAY_NEVER_INSTRUMENT { return true; }
     67 
     68 ALWAYS_INLINE uint64_t readTSC(uint8_t &CPU) XRAY_NEVER_INSTRUMENT {
     69   timespec TS;
     70   int result = clock_gettime(CLOCK_REALTIME, &TS);
     71   if (result != 0) {
     72     Report("clock_gettime(2) returned %d, errno=%d.", result, int(errno));
     73     TS.tv_sec = 0;
     74     TS.tv_nsec = 0;
     75   }
     76   CPU = 0;
     77   return TS.tv_sec * NanosecondsPerSecond + TS.tv_nsec;
     78 }
     79 
     80 inline uint64_t getTSCFrequency() XRAY_NEVER_INSTRUMENT {
     81   return NanosecondsPerSecond;
     82 }
     83 
     84 } // namespace __xray
     85 
     86 #else
     87 #error Target architecture is not supported.
     88 #endif // CPU architecture
     89 #endif // SANITIZER_FUCHSIA
     90 
     91 #endif // XRAY_EMULATE_TSC_H
     92