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https://github.com/Mathewnd/Astral.git
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Matheus
84 lines
2.0 KiB
C
84 lines
2.0 KiB
C
#include <kernel/timekeeper.h>
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#include <arch/tsc.h>
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#include <arch/cpuid.h>
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#include <logging.h>
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#include <kernel/alloc.h>
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#include <arch/hpet.h>
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#include <kernel/cmdline.h>
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static bool tsc_probe(void) {
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if (cmdline_get("notsc"))
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return false;
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cpuid_results_t cpuid_results;
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uint32_t max_extended_leaf = cpuid_extended_max_leaf();
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if (max_extended_leaf < 0x80000007)
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return false;
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cpuid(0x80000007, &cpuid_results);
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return cpuid_results.edx & (1 << 8);
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}
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static MUTEX_DEFINE(init_mutex);
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// keeping this here in a multisocket machine could possibly result in completely wrong
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// tsc measurements for the other sokets. disable the tsc in these using the "notsc" commandline option.
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static time_t hz;
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static timekeeper_source_info_t *tsc_init(void) {
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MUTEX_ACQUIRE(&init_mutex);
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__assert(tsc_probe());
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timekeeper_source_info_t *timekeeper_source_info = alloc(sizeof(timekeeper_source_info_t));
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__assert(timekeeper_source_info);
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timekeeper_source_info->private = current_cpu();
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if (hz)
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goto leave;
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bool need_calibration = true;
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if (cpuid_base_max_leaf() >= 0x15) {
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cpuid_results_t cpuid_results;
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cpuid(0x15, &cpuid_results);
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if (cpuid_results.eax == 0 || cpuid_results.ebx == 0 || cpuid_results.ecx == 0)
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goto calibrate;
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uint64_t core_frequency = cpuid_results.ecx;
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uint64_t core_numerator = cpuid_results.ebx;
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uint64_t core_denominator = cpuid_results.eax;
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uint64_t tsc_frequency = core_frequency * core_numerator / core_denominator;
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hz = tsc_frequency;
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need_calibration = false;
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}
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calibrate:
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if (need_calibration) {
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hz = arch_hpet_calibrate_tsc(200) * 1000;
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__assert(hz);
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}
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leave:
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timekeeper_source_info->hz = hz;
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MUTEX_RELEASE(&init_mutex);
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return timekeeper_source_info;
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}
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// ran in at least IPL_DPC
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static time_t tsc_ticks(timekeeper_source_info_t *timekeeper_source_info) {
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__assert(timekeeper_source_info->private == current_cpu());
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return rdtsc_serialized();
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}
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TIMEKEEPER_SOURCE(kvmtimer_source,
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.name = "Invariant TSC",
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.priority = 990,
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.probe = tsc_probe,
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.init = tsc_init,
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.ticks = tsc_ticks,
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.flags = 0
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);
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