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Implement detection of timer capabilities
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This commit is contained in:
Aiken Harris
2026-04-12 23:58:48 +02:00
parent a08e07e515
commit cec5e8b16b
10 changed files with 289 additions and 95 deletions
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3
xtoskrnl/hl/data.cc
View File

@@ -42,5 +42,8 @@ APIC_MODE HL::Pic::ApicMode;
/* Kernel profiling interval */
ULONG HL::Timer::ProfilingInterval;
/* Timer capabilities */
TIMER_CAPABILITIES HL::Timer::TimerCapabilities = {0};
/* APIC timer frequency */
ULONG HL::Timer::TimerFrequency;

4
xtoskrnl/hl/x86/cpu.cc
View File

@@ -45,6 +45,6 @@ HL::Cpu::InitializeProcessor(VOID)
/* Set the APIC running level */
HL::RunLevel::SetRunLevel(KE::Processor::GetCurrentProcessorBlock()->RunLevel);
/* Initialize APIC timer */
HL::Timer::InitializeApicTimer();
/* Initialize timer */
HL::Timer::InitializeTimer();
}

238
xtoskrnl/hl/x86/timer.cc
View File

@@ -21,11 +21,14 @@ XTSTATUS
HL::Timer::CalibrateApicTimer()
{
ULONG CurrentCount, Frequency, InitialCount;
XTSTATUS Status;
/* Get APIC timer frequency from the Core Crystal Clock */
Status = GetApicTimerFrequency(&Frequency);
if(Status != STATUS_SUCCESS || !Frequency)
if(TimerCapabilities.Art && TimerCapabilities.TimerFrequency != 0)
{
/* CCC available, use it as the source of APIC timer frequency */
Frequency = TimerCapabilities.TimerFrequency;
}
else
{
/* CCC unavailable, fallback to PIT calibration */
InitialCount = 0xFFFFFFFF;
@@ -59,76 +62,6 @@ HL::Timer::CalibrateApicTimer()
return STATUS_SUCCESS;
}
/**
* Retrieves the APIC timer frequency from the Core Crystal Clock.
*
* @param Frequency
* Supplies a pointer to a variable that will receive the nominal APIC timer frequency in Hz.
*
* @return This routine returns a status code.
*
* @since XT 1.0
*/
XTAPI
XTSTATUS
HL::Timer::GetApicTimerFrequency(OUT PULONG Frequency)
{
CPUID_REGISTERS CpuRegisters;
/* Verify input parameter */
if(!Frequency)
{
/* Invalid parameter passed */
return STATUS_INVALID_PARAMETER;
}
/* Initialize output parameter to 0 */
*Frequency = 0;
/* Get maximum supported standard CPUID leaf */
CpuRegisters.Leaf = 0;
CpuRegisters.SubLeaf = 0;
CpuRegisters.Eax = 0;
CpuRegisters.Ebx = 0;
CpuRegisters.Ecx = 0;
CpuRegisters.Edx = 0;
AR::CpuFunc::CpuId(&CpuRegisters);
/* Check if leaf 0x15 is supported by the CPU */
if(CpuRegisters.Eax < 0x15)
{
/* Processor is too old, return error */
return STATUS_NOT_SUPPORTED;
}
/* Query Time Stamp Counter and Core Crystal Clock information */
CpuRegisters.Leaf = 0x15;
CpuRegisters.SubLeaf = 0;
CpuRegisters.Eax = 0;
CpuRegisters.Ebx = 0;
CpuRegisters.Ecx = 0;
CpuRegisters.Edx = 0;
AR::CpuFunc::CpuId(&CpuRegisters);
/* Check if the leaf is properly enumerated */
if(CpuRegisters.Eax == 0 || CpuRegisters.Ebx == 0)
{
/* Intel SDM: EAX or EBX is 0, the leaf is not properly enumerated, return error */
return STATUS_NOT_SUPPORTED;
}
/* Check if ECX contains the nominal frequency of the core crystal clock */
if(CpuRegisters.Ecx == 0)
{
/* Hardware did not provide the exact frequency, return error */
return STATUS_NOT_FOUND;
}
/* Save the base frequency for the APIC Timer and return success */
*Frequency = CpuRegisters.Ecx;
return STATUS_SUCCESS;
}
/**
* Initializes and calibrates the Local APIC Timer.
*
@@ -160,6 +93,24 @@ HL::Timer::InitializeApicTimer(VOID)
StopProfileInterrupt(ProfileXtKernel);
}
/**
* Performs a basic Timer initialization.
*
* @return This routine does not return any value.
*
* @since XT 1.0
*/
XTAPI
VOID
HL::Timer::InitializeTimer(VOID)
{
/* Query timer capabilities */
QueryTimerCapabilities();
/* Initialize the APIC timer */
InitializeApicTimer();
}
/**
* Stalls the CPU execution for a specified duration (maximum 3 seconds) using the legacy PIT timer.
*
@@ -221,6 +172,147 @@ HL::Timer::PitStallExecution(IN ULONG MicroSeconds)
}
}
/**
* Probes the processor via CPUID to detect available modern timing and clock generation features.
*
* @return This routine does not return any value.
*
* @since XT 1.0
*/
XTAPI
VOID
HL::Timer::QueryTimerCapabilities(VOID)
{
CPUID_REGISTERS CpuRegisters;
ULONG MaxStandardLeaf;
ULONG MaxExtendedLeaf;
/* Query maximum standard CPUID leaf */
CpuRegisters.Leaf = CPUID_GET_VENDOR_STRING;
CpuRegisters.SubLeaf = 0;
CpuRegisters.Eax = 0;
CpuRegisters.Ebx = 0;
CpuRegisters.Ecx = 0;
CpuRegisters.Edx = 0;
AR::CpuFunc::CpuId(&CpuRegisters);
/* Save maximum supported standard CPUID leaf */
MaxStandardLeaf = CpuRegisters.Eax;
/* Query maximum extended CPUID leaf */
CpuRegisters.Leaf = CPUID_GET_EXTENDED_MAX;
CpuRegisters.SubLeaf = 0;
CpuRegisters.Eax = 0;
CpuRegisters.Ebx = 0;
CpuRegisters.Ecx = 0;
CpuRegisters.Edx = 0;
AR::CpuFunc::CpuId(&CpuRegisters);
/* Save maximum supported extended CPUID leaf */
MaxExtendedLeaf = CpuRegisters.Eax;
/* Check TSC-Deadline mode if leaf supported */
if(MaxStandardLeaf >= CPUID_GET_STANDARD1_FEATURES)
{
CpuRegisters.Leaf = CPUID_GET_STANDARD1_FEATURES;
CpuRegisters.SubLeaf = 0;
CpuRegisters.Eax = 0;
CpuRegisters.Ebx = 0;
CpuRegisters.Ecx = 0;
CpuRegisters.Edx = 0;
AR::CpuFunc::CpuId(&CpuRegisters);
/* Verify TSC-Deadline support */
if(CpuRegisters.Ecx & CPUID_FEATURES_ECX_TSC_DEADLINE)
{
TimerCapabilities.TscDeadline = TRUE;
}
}
/* Check Always Running APIC Timer - ARAT if leaf supported */
if(MaxStandardLeaf >= CPUID_GET_POWER_MANAGEMENT)
{
CpuRegisters.Leaf = CPUID_GET_POWER_MANAGEMENT;
CpuRegisters.SubLeaf = 0;
CpuRegisters.Eax = 0;
CpuRegisters.Ebx = 0;
CpuRegisters.Ecx = 0;
CpuRegisters.Edx = 0;
AR::CpuFunc::CpuId(&CpuRegisters);
/* Verify ARAT support */
if(CpuRegisters.Eax & CPUID_FEATURES_EAX_ARAT)
{
TimerCapabilities.Arat = TRUE;
}
}
/* Check Always Running Timer - ART if leaf supported */
if(MaxStandardLeaf >= CPUID_GET_TSC_CRYSTAL_CLOCK)
{
CpuRegisters.Leaf = CPUID_GET_TSC_CRYSTAL_CLOCK;
CpuRegisters.SubLeaf = 0;
CpuRegisters.Eax = 0;
CpuRegisters.Ebx = 0;
CpuRegisters.Ecx = 0;
CpuRegisters.Edx = 0;
AR::CpuFunc::CpuId(&CpuRegisters);
/* Verify ART support */
if(CpuRegisters.Eax != 0 && CpuRegisters.Ebx != 0)
{
TimerCapabilities.Art = TRUE;
/* Save the TSC scaling ratios */
TimerCapabilities.TscDenominator = CpuRegisters.Eax;
TimerCapabilities.TscNumerator = CpuRegisters.Ebx;
/* Check if ECX contains the nominal frequency of the core crystal clock */
if(CpuRegisters.Ecx != 0)
{
/* Save the base frequency for the APIC Timer */
TimerCapabilities.TimerFrequency = CpuRegisters.Ecx;
}
}
}
/* Check RDTSCP instruction support if leaf supported */
if(MaxExtendedLeaf >= CPUID_GET_EXTENDED_FEATURES)
{
CpuRegisters.Leaf = CPUID_GET_EXTENDED_FEATURES;
CpuRegisters.SubLeaf = 0;
CpuRegisters.Eax = 0;
CpuRegisters.Ebx = 0;
CpuRegisters.Ecx = 0;
CpuRegisters.Edx = 0;
AR::CpuFunc::CpuId(&CpuRegisters);
/* Verify RDTSCP support */
if(CpuRegisters.Edx & CPUID_FEATURES_EDX_RDTSCP)
{
TimerCapabilities.RDTSCP = TRUE;
}
}
/* Check Invariant TSC if leaf supported */
if(MaxExtendedLeaf >= CPUID_GET_ADVANCED_POWER_MANAGEMENT)
{
CpuRegisters.Leaf = CPUID_GET_ADVANCED_POWER_MANAGEMENT;
CpuRegisters.SubLeaf = 0;
CpuRegisters.Eax = 0;
CpuRegisters.Ebx = 0;
CpuRegisters.Ecx = 0;
CpuRegisters.Edx = 0;
AR::CpuFunc::CpuId(&CpuRegisters);
/* Verify Invariant TSC support */
if(CpuRegisters.Edx & CPUID_FEATURES_EDX_TSCI)
{
TimerCapabilities.InvariantTsc = TRUE;
}
}
}
/**
* Sets the profile interrupt interval. The interval may be bounded by hardware capabilities.
*

6
xtoskrnl/includes/hl/timer.hh
View File

@@ -19,18 +19,20 @@ namespace HL
{
private:
STATIC ULONG ProfilingInterval;
STATIC TIMER_CAPABILITIES TimerCapabilities;
STATIC ULONG TimerFrequency;
public:
STATIC XTAPI VOID InitializeApicTimer(VOID);
STATIC XTAPI VOID InitializeTimer(VOID);
STATIC XTAPI ULONG_PTR SetProfileInterval(IN ULONG_PTR Interval);
STATIC XTAPI VOID StartProfileInterrupt(IN KPROFILE_SOURCE ProfileSource);
STATIC XTAPI VOID StopProfileInterrupt(IN KPROFILE_SOURCE ProfileSource);
private:
STATIC XTAPI XTSTATUS CalibrateApicTimer();
STATIC XTAPI XTSTATUS GetApicTimerFrequency(OUT PULONG Frequency);
STATIC XTAPI VOID InitializeApicTimer(VOID);
STATIC XTAPI VOID PitStallExecution(IN ULONG MicroSeconds);
STATIC XTAPI VOID QueryTimerCapabilities(VOID);
STATIC XTAPI VOID StallExecution(IN ULONG MicroSeconds);
};
}