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This commit is contained in:
Marvin
2026-09-19 21:57:06 +02:00
parent 1e9a1ebf4d
commit 831308b2ad
61 changed files with 777 additions and 837 deletions
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arch/x86_64/tsc.c
+43 -13
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@@ -1,17 +1,52 @@
#include <zinnia/clock.h>
#include <zinnia/cmdline.h>
#include <zinnia/print.h>
#include <zinnia/utils.h>
#include <stdint.h>
#include <x86_64/asm.h>
#include <x86_64/defs.h>
static bool use_tsc = true;
static void tsc_option(bool opt) {
use_tsc = opt;
}
CMDLINE_OPTION("x86_64.tsc", "Enable timestamp counter", tsc_option);
constexpr uint64_t nanos_per_sec = 1'000'000'000;
static uint64_t tsc_freq = 0;
static uint64_t tsc_base_cycles = 0;
static uint64_t cycles_to_ns(uint64_t cycles, uint64_t freq) {
uint64_t seconds = cycles / freq;
uint64_t remaining_cycles = cycles % freq;
uint64_t fractional_ns = (uint64_t)((__uint128_t)remaining_cycles * (__uint128_t)nanos_per_sec / (__uint128_t)freq);
uint64_t ns = seconds * nanos_per_sec + fractional_ns;
return MIN(ns, UINT64_MAX);
}
static void tsc_reset(struct clock* clock) {
tsc_base_cycles = asm_rdtsc();
}
static uint64_t tsc_get_elapsed_ns(struct clock* clock) {
uint64_t cycles = asm_rdtsc() - tsc_base_cycles;
return cycles_to_ns(cycles, tsc_freq);
}
static struct clock tsc_clock = {
.name = "tsc",
.priority = 255,
.reset = tsc_reset,
.get_elapsed_ns = tsc_get_elapsed_ns,
};
void tsc_init() {
if (!use_tsc)
return;
if (!(asm_cpuid(1, 0).edx & CPUID_1D_TSC) || !(asm_cpuid(0x8000'0007, 0).edx & (1 << 8))) {
log("x86_64/tsc", "No invariant TSC detected!\n");
log("x86_64/tsc: No invariant TSC detected!\n");
return;
}
@@ -22,33 +57,28 @@ void tsc_init() {
tsc_leaf = asm_cpuid(0x15, 0);
}
uint64_t freq = 0;
if (clock_available()) {
// Calibrate using existing clock.
uint64_t t1 = asm_rdtsc();
clock_spin_ns(10'000'000);
uint64_t t2 = asm_rdtsc();
freq = (t2 - t1) * 100;
tsc_freq = (t2 - t1) * 100;
} else if (has_tsc_leaf) {
// If we have no timer (yet), the only way we can calibrate the TSC is if CPUID gives us the frequency.
// On a normal system, this should usually never be called and is a last resort
// since at this point we have at least the HPET timer.
if (tsc_leaf.ecx != 0 && tsc_leaf.ebx != 0 && tsc_leaf.eax != 0) {
log("x86_64/tsc", "Calibrating TSC using CPUID 0x15");
freq = tsc_leaf.ecx * tsc_leaf.ebx / tsc_leaf.eax;
log("x86_64/tsc: Calibrating TSC using CPUID 0x15");
tsc_freq = tsc_leaf.ecx * tsc_leaf.ebx / tsc_leaf.eax;
} else {
log("x86_64/tsc", "Unable to calibrate TSC using CPUID frequency information");
log("x86_64/tsc: Unable to calibrate TSC using CPUID frequency information");
return;
}
} else {
log("x86_64/tsc", "Unable to calibrate the TSC without a clock or static frequency info!\n");
log("x86_64/tsc: Unable to calibrate the TSC without a clock or static frequency info!\n");
return;
}
log("x86_64/tsc", "Timer frequency is %lu MHz\n", freq / 1'000'000);
log("x86_64/tsc: Timer frequency is %lu MHz\n", tsc_freq / 1'000'000);
clock_switch(&tsc_clock);
}
static void tsc_option(bool opt) {
use_tsc = opt;
}
CMDLINE_OPTION("x86_64.tsc", tsc_option);