[PATCH v8 1/1] wineboot: Compute and write the TSC frequency to registry ~Mhz.

[Rémi Bernon]

From: Rémi Bernon

In HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor

Some games such as Horizon Zero Dawn use this registry value to
correlate values from rtdsc to real time.

Returning the nominal/maximum cpu frequency here causes the game to run
in slow motion as it may not match the tsc frequency of the processor.

Based on patches from Arkadiusz Hiler and Joshua Ashton.
---
 programs/wineboot/wineboot.c | 114 ++++++++++++++++++++++++++++++++++-
 1 file changed, 113 insertions(+), 1 deletion(-)

diff --git a/programs/wineboot/wineboot.c b/programs/wineboot/wineboot.c
index 728c41fffa9..03b37d055d1 100644
--- a/programs/wineboot/wineboot.c
+++ b/programs/wineboot/wineboot.c
@@ -240,12 +240,120 @@ static void initialize_xstate_features(struct _KUSER_SHARED_DATA *data)
     TRACE("XSAVE feature 2 %#x, %#x, %#x, %#x.\n", regs[0], regs[1], regs[2], regs[3]);
 }

+static BOOL is_tsc_trusted_by_the_kernel(void)
+{
+    char buf[4] = {0};
+    DWORD num_read;
+    HANDLE handle;
+    BOOL ret = TRUE;
+
+    /* Darwin for x86-64 uses the TSC internally for timekeeping, so it can always
+     * be trusted.
+     * For BSDs there seems to be no unified interface to query TSC quality.
+     * If there is a sysfs entry with clocksource information, use it to check though. */
+    handle = CreateFileW( L"\??\unix\sys\bus\clocksource\devices\clocksource0\current_clocksource",
+                          GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, 0 );
+    if (handle == INVALID_HANDLE_VALUE) return TRUE;
+
+    if (ReadFile( handle, buf, sizeof(buf) - 1, &num_read, NULL ) && strcmp( "tsc", buf ))
+        ret = FALSE;
+
+    CloseHandle( handle );
+    return ret;
+}
+
+static UINT64 read_tsc_frequency(void)
+{
+    UINT64 freq = 0;
+    LONGLONG time0, time1, tsc0, tsc1, tsc2, tsc3, freq0, freq1, error;
+    BOOL has_rdtscp = FALSE;
+    unsigned int aux;
+    UINT retries = 50;
+    int regs[4];
+
+    if (!is_tsc_trusted_by_the_kernel())
+    {
+        WARN( "Failed to compute TSC frequency, not trusted by the kernel.\n" );
+        return 0;
+    }
+
+    __cpuid(regs, 1);
+    if (!(regs[3] & (1 << 4)))
+    {
+        WARN( "Failed to compute TSC frequency, RDTSC instruction not supported.\n" );
+        return 0;
+    }
+
+    __cpuid( regs, 0x80000000 );
+    if (regs[0] < 0x80000007)
+    {
+        WARN( "Failed to compute TSC frequency, unable to check invariant TSC.\n" );
+        return 0;
+    }
+
+    /* check for invariant tsc bit */
+    __cpuid( regs, 0x80000007 );
+    if (!(regs[3] & (1 << 8)))
+    {
+        WARN( "Failed to compute TSC frequency, no invariant TSC.\n" );
+        return 0;
+    }
+
+    /* check for rdtscp support bit */
+    __cpuid( regs, 0x80000001 );
+    if ((regs[3] & (1 << 27))) has_rdtscp = TRUE;
+
+    /* FIXME: implement a better frequency measurement here. */
+    do
+    {
+        if (has_rdtscp)
+        {
+            tsc0 = __rdtscp( &aux );
+            time0 = RtlGetSystemTimePrecise();
+            tsc1 = __rdtscp( &aux );
+            Sleep( 1 );
+            tsc2 = __rdtscp( &aux );
+            time1 = RtlGetSystemTimePrecise();
+            tsc3 = __rdtscp( &aux );
+        }
+        else
+        {
+            tsc0 = __rdtsc(); __cpuid( regs, 0 );
+            time0 = RtlGetSystemTimePrecise();
+            tsc1 = __rdtsc(); __cpuid( regs, 0 );
+            Sleep(1);
+            tsc2 = __rdtsc(); __cpuid( regs, 0 );
+            time1 = RtlGetSystemTimePrecise();
+            tsc3 = __rdtsc(); __cpuid( regs, 0 );
+        }
+
+        freq0 = (tsc2 - tsc0) * 10000000 / (time1 - time0);
+        freq1 = (tsc3 - tsc1) * 10000000 / (time1 - time0);
+        error = llabs( (freq1 - freq0) * 1000000 / min( freq1, freq0 ) );
+    }
+    while (error > 500 && --retries);
+
+    if (!retries) WARN( "TSC frequency calibration failed, unstable TSC?\n" );
+    else
+    {
+        freq = (freq0 + freq1) / 2;
+        TRACE( "TSC frequency calibration complete, found %I64u Hz\n", freq );
+    }
+
+    return freq;
+}
+
 #else

static void initialize_xstate_features(struct _KUSER_SHARED_DATA *data)
 {
 }

+static UINT64 read_tsc_frequency(void)
+{
+    return 0;
+}
+
 #endif

static void create_user_shared_data(void)
@@ -736,13 +844,17 @@ static void create_hardware_registry_keys(void)
         if (!RegCreateKeyExW( cpu_key, numW, 0, NULL, REG_OPTION_VOLATILE,
                               KEY_ALL_ACCESS, NULL, &hkey, NULL ))
         {
+            UINT64 tsc_frequency = read_tsc_frequency();
+            DWORD tsc_freq_mhz = (DWORD)(tsc_frequency / 1000000ull); /* Hz -> Mhz */
+            if (!tsc_freq_mhz) tsc_freq_mhz = power_info[i].MaxMhz;
+
             RegSetValueExW( hkey, L"FeatureSet", 0, REG_DWORD, (BYTE *)&sci.ProcessorFeatureBits, sizeof(DWORD) );
             set_reg_value( hkey, L"Identifier", id );
             /* TODO: report ARM properly */
             RegSetValueExA( hkey, "ProcessorNameString", 0, REG_SZ, (const BYTE *)name_buffer,
                             strlen( (char *)name_buffer ) + 1 );
             set_reg_value( hkey, L"VendorIdentifier", vendorid );
-            RegSetValueExW( hkey, L"~MHz", 0, REG_DWORD, (BYTE *)&power_info[i].MaxMhz, sizeof(DWORD) );
+            RegSetValueExW( hkey, L"~MHz", 0, REG_DWORD, (BYTE *)&tsc_freq_mhz, sizeof(DWORD) );
             RegCloseKey( hkey );
         }
         if (sci.ProcessorArchitecture != PROCESSOR_ARCHITECTURE_ARM &&