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Fix HPET unaligned read/writes on bochs

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This commit is contained in:
Kamil Kowalczyk
2025-12-22 21:06:48 +01:00
parent 69feceaaae
commit 849df9c27d
5 changed files with 43 additions and 12 deletions
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36
kernel/amd64/hpet.c
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@@ -1,6 +1,7 @@
#include <amd64/hpet.h>
#include <libk/std.h>
#include <limine/requests.h>
#include <sync/spin_lock.h>
#include <sys/debug.h>
#include <sys/mm.h>
#include <uacpi/acpi.h>
@@ -15,9 +16,12 @@
static bool hpet_32bits = 1;
static uintptr_t hpet_paddr;
static uint64_t hpet_clock_nano;
static spin_lock_t hpet_lock = SPIN_LOCK_INIT;
extern void amd64_spin (void);
/* These functions assume hpet_lock is held by the caller! */
static uint64_t amd64_hpet_read (uint32_t reg) {
struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
uintptr_t hpet_vaddr = hpet_paddr + (uintptr_t)hhdm->offset;
@@ -36,13 +40,27 @@ static void amd64_hpet_write (uint32_t reg, uint64_t value) {
static uint64_t amd64_hpet_timestamp (void) { return amd64_hpet_read (HPET_MCVR); }
uint64_t amd64_hpet_current_nano (void) { return amd64_hpet_timestamp () * hpet_clock_nano; }
uint64_t amd64_hpet_current_nano (bool lock) {
if (lock)
spin_lock (&hpet_lock);
uint64_t t = amd64_hpet_timestamp () * hpet_clock_nano;
if (lock)
spin_unlock (&hpet_lock);
return t;
}
void amd64_hpet_sleep_micro (uint64_t us) {
spin_lock (&hpet_lock);
uint64_t start = amd64_hpet_timestamp ();
uint64_t conv = us * 1000;
while (((amd64_hpet_timestamp () - start) * hpet_clock_nano) < conv)
__asm__ volatile ("pause" ::: "memory");
spin_unlock (&hpet_lock);
}
void amd64_hpet_init (void) {
@@ -61,7 +79,19 @@ void amd64_hpet_init (void) {
hpet_32bits = (amd64_hpet_read (HPET_GCIDR) & (1 << 13)) ? 0 : 1;
amd64_hpet_write (HPET_GCR, amd64_hpet_read (HPET_GCR) | 0x01);
/* reset */
amd64_hpet_write (HPET_GCR, 0);
amd64_hpet_write (HPET_MCVR, 0);
amd64_hpet_write (HPET_GCR, 1);
hpet_clock_nano = amd64_hpet_read (HPET_GCIDR + 4) / 1000000;
uint64_t gcidr = amd64_hpet_read (HPET_GCIDR);
if (hpet_32bits) {
uint32_t low = (uint32_t)gcidr;
uint32_t high = (uint32_t)amd64_hpet_read (HPET_GCIDR + 4);
gcidr = (((uint64_t)high << 32) | low);
}
uint64_t period_fs = (gcidr >> 32);
hpet_clock_nano = period_fs / 1000000;
}