libc/test/src/__support/OSUtil/linux/vdso_test.cpp

   1 //===-- Unittests for VDSO ------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "hdr/signal_macros.h"
  10 #include "hdr/time_macros.h"
  11 #include "hdr/types/clockid_t.h"
  12 #include "hdr/types/struct_sigaction.h"
  13 #include "hdr/types/struct_timespec.h"
  14 #include "hdr/types/struct_timeval.h"
  15 #include "hdr/types/time_t.h"
  16 #include "src/__support/OSUtil/linux/vdso.h"
  17 #include "src/__support/OSUtil/syscall.h"
  18 #include "src/__support/macros/properties/architectures.h"
  19 #include "src/signal/raise.h"
  20 #include "src/signal/sigaction.h"
  21 #include "test/UnitTest/ErrnoSetterMatcher.h"
  22 #include "test/UnitTest/Test.h"
  23 #include <linux/time_types.h>
  24 #include <sys/syscall.h>
  25
  26 struct riscv_hwprobe {
  27   int64_t key;
  28   uint64_t value;
  29 };
  30
  31 namespace LIBC_NAMESPACE_DECL {
  32 // For x86_64, we explicitly test some traditional vdso symbols are indeed
  33 // available.
  34
  35 TEST(LlvmLibcOSUtilVDSOTest, GetTimeOfDay) {
  36   vdso::TypedSymbol<vdso::VDSOSym::GetTimeOfDay> symbol;
  37   if (!symbol)
  38     return;
  39   timeval tv;
  40   EXPECT_EQ(symbol(&tv, nullptr), 0);
  41   // hopefully people are not building time machines using our libc.
  42   EXPECT_GT(tv.tv_sec, static_cast<decltype(tv.tv_sec)>(0));
  43 }
  44
  45 TEST(LlvmLibcOSUtilVDSOTest, Time) {
  46   vdso::TypedSymbol<vdso::VDSOSym::Time> symbol;
  47   if (!symbol)
  48     return;
  49   time_t a, b;
  50   EXPECT_GT(symbol(&a), static_cast<time_t>(0));
  51   EXPECT_GT(symbol(&b), static_cast<time_t>(0));
  52   EXPECT_GE(b, a);
  53 }
  54
  55 TEST(LlvmLibcOSUtilVDSOTest, ClockGetTime) {
  56   vdso::TypedSymbol<vdso::VDSOSym::ClockGetTime> symbol;
  57   if (!symbol)
  58     return;
  59   timespec a, b;
  60   EXPECT_EQ(symbol(CLOCK_MONOTONIC, &a), 0);
  61   EXPECT_EQ(symbol(CLOCK_MONOTONIC, &b), 0);
  62   if (a.tv_sec == b.tv_sec) {
  63     EXPECT_LT(a.tv_nsec, b.tv_nsec);
  64   } else {
  65     EXPECT_LT(a.tv_sec, b.tv_sec);
  66   }
  67 }
  68
  69 TEST(LlvmLibcOSUtilVDSOTest, ClockGetTime64) {
  70   vdso::TypedSymbol<vdso::VDSOSym::ClockGetTime64> symbol;
  71   if (!symbol)
  72     return;
  73   // See kernel API at
  74   // https://elixir.bootlin.com/linux/latest/source/tools/testing/selftests/vDSO/vdso_test_correctness.c#L155
  75   __kernel_timespec a, b;
  76   EXPECT_EQ(symbol(CLOCK_MONOTONIC, &a), 0);
  77   EXPECT_EQ(symbol(CLOCK_MONOTONIC, &b), 0);
  78   if (a.tv_sec == b.tv_sec) {
  79     EXPECT_LT(a.tv_nsec, b.tv_nsec);
  80   } else {
  81     EXPECT_LT(a.tv_sec, b.tv_sec);
  82   }
  83 }
  84
  85 TEST(LlvmLibcOSUtilVDSOTest, ClockGetRes) {
  86   vdso::TypedSymbol<vdso::VDSOSym::ClockGetRes> symbol;
  87   if (!symbol)
  88     return;
  89   timespec res{};
  90   EXPECT_EQ(symbol(CLOCK_MONOTONIC, &res), 0);
  91   EXPECT_TRUE(res.tv_sec > 0 || res.tv_nsec > 0);
  92 }
  93
  94 TEST(LlvmLibcOSUtilVDSOTest, GetCpu) {
  95   // The kernel system call has a third argument, which should be passed as
  96   // nullptr.
  97   vdso::TypedSymbol<vdso::VDSOSym::GetCpu> symbol;
  98   if (!symbol)
  99     return;
 100   unsigned cpu = static_cast<unsigned>(-1), node = static_cast<unsigned>(-1);
 101   EXPECT_EQ(symbol(&cpu, &node, nullptr), 0);
 102   EXPECT_GE(cpu, 0u);
 103   EXPECT_GE(node, 0u);
 104 }
 105
 106 static bool flag = false;
 107 static void sigprof_handler [[gnu::used]] (int) { flag = true; }
 108
 109 TEST(LlvmLibcOSUtilVDSOTest, RtSigReturn) {
 110   using namespace testing::ErrnoSetterMatcher;
 111   // must use struct since there is a function of the same name in the same
 112   // scope.
 113   struct sigaction sa {};
 114   struct sigaction old_sa {};
 115   sa.sa_handler = sigprof_handler;
 116   sa.sa_flags = SA_RESTORER;
 117   vdso::TypedSymbol<vdso::VDSOSym::RTSigReturn> symbol;
 118   if (!symbol)
 119     return;
 120   sa.sa_restorer = symbol;
 121   ASSERT_THAT(LIBC_NAMESPACE::sigaction(SIGPROF, &sa, &old_sa), Succeeds());
 122   raise(SIGPROF);
 123   ASSERT_TRUE(flag);
 124   flag = false;
 125   ASSERT_THAT(LIBC_NAMESPACE::sigaction(SIGPROF, &old_sa, nullptr), Succeeds());
 126 }
 127
 128 TEST(LlvmLibcOSUtilVDSOTest, FlushICache) {
 129   vdso::TypedSymbol<vdso::VDSOSym::FlushICache> symbol;
 130   if (!symbol)
 131     return;
 132   char buf[512];
 133   // we just check that the flush will not panic the program.
 134   // the flags part only take 0/1 as up to kernel 6.10, which is used to
 135   // indicate whether the flush is local to the core or global.
 136   symbol(buf, buf + sizeof(buf), 0);
 137   symbol(buf, buf + sizeof(buf), 1);
 138 }
 139
 140 // https://docs.kernel.org/6.5/riscv/hwprobe.html
 141 TEST(LlvmLibcOSUtilVDSOTest, RiscvHwProbe) {
 142   using namespace testing::ErrnoSetterMatcher;
 143   vdso::TypedSymbol<vdso::VDSOSym::RiscvHwProbe> symbol;
 144   if (!symbol)
 145     return;
 146   // If a key is unknown to the kernel, its key field will be cleared to -1, and
 147   // its value set to 0. We expect probes.value are all 0.
 148   // Usermode can supply NULL for cpus and 0 for cpu_count as a shortcut for all
 149   // online CPUs
 150   riscv_hwprobe probes[2] = {{-1, 1}, {-1, 1}};
 151   ASSERT_THAT(symbol(/*pairs=*/probes, /*count=*/2, /*cpusetsize=*/0,
 152                      /*cpuset=*/nullptr,
 153                      /*flags=*/0),
 154               Succeeds());
 155   for (auto &probe : probes) {
 156     EXPECT_EQ(probe.key, static_cast<decltype(probe.key)>(-1));
 157     EXPECT_EQ(probe.value, static_cast<decltype(probe.value)>(0));
 158   }
 159 }
 160
 161 } // namespace LIBC_NAMESPACE_DECL