diff --git a/kernel/include/apic/timer.h b/kernel/include/apic/timer.h index 73510b1..b0cffb0 100644 --- a/kernel/include/apic/timer.h +++ b/kernel/include/apic/timer.h @@ -1,11 +1,19 @@ #pragma once #include "acpi/madt.h" +#include "util/optional.h" namespace apic { -struct lapic_timer_calibration_t {}; +struct lapic_timer_calibration_t { + uint64_t tsc_frequency_hz; +}; -lapic_timer_calibration_t calibrateTimer(const acpi::Madt& madt); +optional calibrateTimer(const acpi::Madt& madt); + +// TODO: when dynamic allocation and lists are available +// struct Timer {}; +// +// Timer getCoreTimerInstance(); } // namespace apic diff --git a/kernel/include/util/cpuid.h b/kernel/include/util/cpuid.h new file mode 100644 index 0000000..a40d2b8 --- /dev/null +++ b/kernel/include/util/cpuid.h @@ -0,0 +1,21 @@ +#pragma once + +#include +#include + +#include "util/optional.h" + +struct cpuid_result_t { + uint32_t eax; + uint32_t ebx; + uint32_t ecx; + uint32_t edx; +}; + +inline optional cpuid(uint32_t leaf, uint32_t subleaf = 0) { + cpuid_result_t result{}; + if (__get_cpuid_count(leaf, subleaf, &result.eax, &result.ebx, &result.ecx, &result.edx) == 0) { + return {}; + } + return result; +} diff --git a/kernel/include/util/function.h b/kernel/include/util/function.h index 2b5ae0b..b346920 100644 --- a/kernel/include/util/function.h +++ b/kernel/include/util/function.h @@ -1,5 +1,7 @@ #pragma once +#include "util/utility.h" + template struct overloaded : Ts... { using Ts::operator()...; @@ -7,3 +9,17 @@ struct overloaded : Ts... { template overloaded(Ts...) -> overloaded; + +template +auto partial(Func func, BoundArgs... bound_args) { + return [func, bound_args...](auto&&... call_args) { + return func(bound_args..., forward(call_args)...); + }; +} + +template +auto construct() { + return [](auto&&... args) { + return Type{forward(args)...}; + }; +} diff --git a/kernel/include/util/optional.h b/kernel/include/util/optional.h index 183b45d..e69f107 100644 --- a/kernel/include/util/optional.h +++ b/kernel/include/util/optional.h @@ -9,6 +9,9 @@ // instead of . The CrackOS3 value_or_panic() helper is omitted because // there is no global panic() in this tree yet. +struct nullopt_t {}; +inline constexpr nullopt_t nullopt{}; + template struct optional { private: @@ -26,6 +29,7 @@ public: using value_type = T; constexpr optional() : initialized(false) {} + constexpr optional(nullopt_t) : initialized(false) {} optional(const T& value) : initialized(true) { new (buffer) T(value); } @@ -135,10 +139,45 @@ public: return !initialized; } - template - optional map(Func func, ArgT... args) { + template + auto map(Func&& func) -> optional { if (initialized) { - return func(value(), forward(args)...); + return func(value()); + } else { + return {}; + } + } + + template + auto map(Func&& func) const -> optional { + if (initialized) { + return func(value()); + } else { + return {}; + } + } + + template + optional or_else(Func&& func) const { + if (initialized) { + return *this; + } + return func(); + } + + template + auto bind(Func&& func) -> decltype(func(value())) { + if (initialized) { + return func(value()); + } else { + return {}; + } + } + + template + auto bind(Func&& func) const -> decltype(func(value())) { + if (initialized) { + return func(value()); } else { return {}; } diff --git a/kernel/src/apic/timer.cpp b/kernel/src/apic/timer.cpp new file mode 100644 index 0000000..cbc3d38 --- /dev/null +++ b/kernel/src/apic/timer.cpp @@ -0,0 +1,55 @@ +#include "apic/timer.h" + +#include "util/cpuid.h" +#include "util/function.h" + +namespace { + +constexpr uint32_t feature_info_leaf = 0x1; +constexpr uint32_t tsc_crystal_ratio_leaf = 0x15; +constexpr uint32_t processor_frequency_leaf = 0x16; + +constexpr uint32_t feature_edx_tsc = 1u << 4; + +bool isTscSupported() { + return cpuid(feature_info_leaf) + .map([](const cpuid_result_t& features) { + return (features.edx & feature_edx_tsc) != 0; + }) + .value_or(false); +} + +optional tscFrequencyFromCrystalRatio() { + return cpuid(tsc_crystal_ratio_leaf).bind([](const cpuid_result_t& ratio) -> optional { + uint64_t denominator = ratio.eax; + uint64_t numerator = ratio.ebx; + uint64_t crystal_frequency_hz = ratio.ecx; + if (denominator == 0 || numerator == 0 || crystal_frequency_hz == 0) { + return nullopt; + } + return crystal_frequency_hz * numerator / denominator; + }); +} + +optional tscFrequencyFromProcessorBase() { + return cpuid(processor_frequency_leaf).bind([](const cpuid_result_t& frequency_info) -> optional { + uint64_t base_frequency_mhz = frequency_info.eax & 0xFFFF; + if (base_frequency_mhz == 0) { + return nullopt; + } + return base_frequency_mhz * 1'000'000; + }); +} + +optional tscFrequency() { + return tscFrequencyFromCrystalRatio().or_else(tscFrequencyFromProcessorBase); +} + +} // namespace + +optional apic::calibrateTimer(const acpi::Madt&) { + if (!isTscSupported()) { + return {}; + } + return tscFrequency().map(construct()); +}