APIC, HPET, virtual memory

2025-12-22 19:36:43 +01:00
parent 741d0fb9b0
commit 7b33d0757a
13 changed files with 495 additions and 3 deletions
--- a/kernel/amd64/apic.c
+++ b/kernel/amd64/apic.c
@@ -0,0 +1,158 @@
+#include <amd64/apic.h>
+#include <libk/std.h>
+#include <limine/requests.h>
+#include <sys/debug.h>
+#include <sys/mm.h>
+#include <uacpi/acpi.h>
+#include <uacpi/status.h>
+#include <uacpi/tables.h>
+#include <uacpi/uacpi.h>
+
+#define IOAPICS_MAX                 24
+#define INTERRUPT_SRC_OVERRIDES_MAX 24
+
+static struct acpi_madt_ioapic apics[IOAPICS_MAX];
+/* clang-format off */
+static struct acpi_madt_interrupt_source_override intr_src_overrides[INTERRUPT_SRC_OVERRIDES_MAX];
+/* clang-format on */
+static size_t ioapic_entries = 0;
+static size_t intr_src_override_entries = 0;
+
+extern void amd64_spin (void);
+
+static uint32_t amd64_ioapic_read (uintptr_t vaddr, uint32_t reg) {
+  *(volatile uint32_t*)vaddr = reg;
+  return *(volatile uint32_t*)(vaddr + 0x10);
+}
+
+static void amd64_ioapic_write (uintptr_t vaddr, uint32_t reg, uint32_t value) {
+  *(volatile uint32_t*)vaddr = reg;
+  *(volatile uint32_t*)(vaddr + 0x10) = value;
+}
+
+static struct acpi_madt_ioapic* amd64_ioapic_find (uint8_t irq) {
+  struct acpi_madt_ioapic* apic = NULL;
+  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
+
+  for (size_t i = 0; i < ioapic_entries; i++) {
+    apic = &apics[i];
+    uint32_t version = amd64_ioapic_read (
+        (uintptr_t)hhdm->offset + (uintptr_t)apic->address, 1);
+    uint32_t max = (version >> 16);
+
+    if ((apic->gsi_base <= irq) && ((apic->gsi_base + max) > irq))
+      break;
+  }
+
+  return apic;
+}
+
+void amd64_ioapic_route_irq (uint8_t vec, uint8_t irq, uint64_t flags,
+                             uint64_t lapic_id) {
+  struct acpi_madt_ioapic* apic;
+  struct acpi_madt_interrupt_source_override* override;
+  bool found_override = false;
+  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
+
+  for (size_t i = 0; i < intr_src_override_entries; i++) {
+    override = &intr_src_overrides[i];
+    if (override->source == irq) {
+      found_override = true;
+      break;
+    }
+  }
+
+  uint64_t calc_flags = (lapic_id << 56) | (flags) | (vec & 0xFF);
+
+  if (found_override) {
+    uint8_t polarity = ((override->flags & 0x03) == 0x03) ? 1 : 0;
+    uint8_t mode = (((override->flags >> 2) & 0x03) == 0x03) ? 1 : 0;
+    calc_flags = (lapic_id << 56) | (mode << 15) | (polarity << 14) |
+        (vec & 0xFF) | flags;
+  }
+
+  apic = amd64_ioapic_find (irq);
+
+  if (apic == NULL)
+    return;
+
+  uint32_t irq_reg = ((irq - apic->gsi_base) * 2) + 0x10;
+
+  amd64_ioapic_write ((uintptr_t)hhdm->offset + (uintptr_t)apic->address,
+                      irq_reg, (uint32_t)calc_flags);
+
+  amd64_ioapic_write ((uintptr_t)hhdm->offset + (uintptr_t)apic->address,
+                      irq_reg + 1, (uint32_t)(calc_flags >> 32));
+}
+
+void amd64_ioapic_mask (uint8_t irq) {
+  struct acpi_madt_ioapic* apic;
+  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
+
+  apic = amd64_ioapic_find (irq);
+
+  if (apic == NULL)
+    return;
+
+  uint32_t irq_reg = ((irq - apic->gsi_base) * 2) + 0x10;
+
+  uint32_t value = amd64_ioapic_read (
+      (uintptr_t)hhdm->offset + (uintptr_t)apic->address, irq_reg);
+  amd64_ioapic_write ((uintptr_t)hhdm->offset + (uintptr_t)apic->address,
+                      irq_reg, value | (1 << 16));
+}
+
+void amd64_ioapic_unmask (uint8_t irq) {
+  struct acpi_madt_ioapic* apic;
+  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
+
+  apic = amd64_ioapic_find (irq);
+
+  if (apic == NULL)
+    return;
+
+  uint32_t irq_reg = ((irq - apic->gsi_base) * 2) + 0x10;
+
+  uint32_t value = amd64_ioapic_read (
+      (uintptr_t)hhdm->offset + (uintptr_t)apic->address, irq_reg);
+  amd64_ioapic_write ((uintptr_t)hhdm->offset + (uintptr_t)apic->address,
+                      irq_reg, value & ~(1 << 16));
+}
+
+void amd64_ioapic_init (void) {
+  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
+
+  struct uacpi_table apic_table;
+  uacpi_status status =
+      uacpi_table_find_by_signature (ACPI_MADT_SIGNATURE, &apic_table);
+  if (status != UACPI_STATUS_OK) {
+    DEBUG ("Could not find MADT table!\n");
+    amd64_spin ();
+  }
+
+  struct acpi_madt* apic = (struct acpi_madt*)apic_table.virt_addr;
+  struct acpi_entry_hdr* current = (struct acpi_entry_hdr*)apic->entries;
+
+  for (;;) {
+    if ((uintptr_t)current >= ((uintptr_t)apic->entries + apic->hdr.length -
+                               sizeof (struct acpi_madt)))
+      break;
+
+    switch (current->type) {
+    case ACPI_MADT_ENTRY_TYPE_IOAPIC: {
+      struct acpi_madt_ioapic* ioapic = (struct acpi_madt_ioapic*)current;
+      mm_map_kernel_page ((uintptr_t)ioapic->address,
+                          (uintptr_t)hhdm->offset + (uintptr_t)ioapic->address,
+                          MM_PG_USER | MM_PG_RW);
+      apics[ioapic_entries++] = *ioapic;
+    } break;
+    case ACPI_MADT_ENTRY_TYPE_INTERRUPT_SOURCE_OVERRIDE: {
+      struct acpi_madt_interrupt_source_override* override =
+          (struct acpi_madt_interrupt_source_override*)current;
+      intr_src_overrides[intr_src_override_entries++] = *override;
+    } break;
+    }
+
+    current = (struct acpi_entry_hdr*)((uintptr_t)current + current->length);
+  }
+}