feat/kernel: Re-added MADT

.vscode/settings.json

@@ -23,7 +23,8 @@
         "string_view": "c",
         "lapic.h": "c",
         "spinlock.h": "c",
-        "fb.h": "c"
+        "fb.h": "c",
+        "acpi.h": "c"
     },
     "editor.formatOnPaste": true,
     "editor.formatOnSave": true,

GNUmakefile

@@ -2,7 +2,7 @@
 MAKEFLAGS += -rR
 .SUFFIXES:
 
-QEMUFLAGS := -serial stdio -smp 4
+QEMUFLAGS := -smp 4
 USER_QEMUFLAGS ?=
 IMAGE_NAME := release/emk
 
@@ -15,7 +15,7 @@ all: $(IMAGE_NAME).iso
 .PHONY: run
 run: $(IMAGE_NAME).iso ovmf/ovmf-code-x86_64.fd
 	@qemu-system-x86_64 \
-		-M q35 \
+		-M q35 -serial stdio \
 		-drive if=pflash,unit=0,format=raw,file=ovmf/ovmf-code-x86_64.fd,readonly=on \
 		-cdrom $(IMAGE_NAME).iso \
 		$(QEMUFLAGS)

kernel/src/emk.c

@@ -19,6 +19,7 @@
 #endif // FLANTERM_SUPPORT
 #include <arch/smp.h>
 #include <sys/acpi.h>
+#include <sys/acpi/madt.h>
 
 __attribute__((used, section(".limine_requests"))) static volatile LIMINE_BASE_REVISION(3);
 __attribute__((used, section(".limine_requests"))) static volatile struct limine_memmap_request memmap_request = {
@@ -167,7 +168,7 @@ void emk_entry(void)
     *c = 32;
     kfree(c);
 
-    /* Setup ACPI (and TODO APIC) */
+    /* Setup ACPI */
     rsdp_response = rsdp_request.response;
     if (!rsdp_response)
     {
@@ -175,10 +176,16 @@ void emk_entry(void)
     }
     acpi_init();
 
+    /* Disable legacy PIC to prepare for APIC */
+    outb(0x21, 0xff);
+    outb(0xA1, 0xff);
+
+    /* Setup APIC */
+    madt_init();
+
     /* Finished */
     log_early("%s", LOG_SEPARATOR);
-    uint32_t uptime = 0;
+    log_early("Finished initializing EMK v1.0, took ? seconds"); /* Still not usermode, so keep using log_early */
-    log_early("Finished initializing EMK v1.0, took %d seconds", uptime); /* Still not usermode, so keep using log_early */
 
     hlt();
 }

kernel/src/sys/acpi/madt.c

@@ -0,0 +1,56 @@
+/* EMK 1.0 Copyright (c) 2025 Piraterna */
+#include <sys/acpi/madt.h>
+#include <sys/acpi.h>
+#include <sys/kpanic.h>
+#include <util/log.h>
+
+acpi_madt_ioapic_t *madt_ioapic_list[256] = {0};
+acpi_madt_ioapic_src_ovr_t *madt_iso_list[256] = {0};
+
+uint32_t madt_ioapic_len = 0;
+uint32_t madt_iso_len = 0;
+
+uint64_t lapic_addr = 0;
+
+void madt_init()
+{
+    acpi_madt_t *madt = (acpi_madt_t *)acpi_find_table("APIC");
+    if (!madt)
+    {
+        kpanic(NULL, "Failed to find MADT table");
+    }
+
+    if (madt->sdt.length < sizeof(acpi_madt_t))
+    {
+        kpanic(NULL, "MADT table is too small");
+    }
+
+    uint64_t offset = 0;
+    while (offset < madt->sdt.length - sizeof(acpi_madt_t))
+    {
+        acpi_madt_entry_t *entry = (acpi_madt_entry_t *)(madt->table + offset);
+
+        if (entry->length == 0 || offset + entry->length > madt->sdt.length - sizeof(acpi_madt_t))
+        {
+            kpanic(NULL, "Invalid MADT entry length or overflow");
+        }
+
+        if (entry->type == MADT_ENTRY_IOAPIC)
+        {
+            if (madt_ioapic_len < 256)
+                madt_ioapic_list[madt_ioapic_len++] = (acpi_madt_ioapic_t *)entry;
+        }
+        else if (entry->type == MADT_ENTRY_IOAPIC_SRC_OVR)
+        {
+            if (madt_iso_len < 256)
+                madt_iso_list[madt_iso_len++] = (acpi_madt_ioapic_src_ovr_t *)entry;
+        }
+        else if (entry->type == MADT_ENTRY_LAPIC_ADDR_OVR)
+        {
+            lapic_addr = ((acpi_madt_lapic_addr_ovr_t *)entry)->lapic_addr;
+        }
+
+        offset += entry->length;
+    }
+    log_early("MADT parsed: %u IOAPIC(s), %u ISO(s), LAPIC addr: 0x%lx", madt_ioapic_len, madt_iso_len, lapic_addr);
+}

kernel/src/sys/acpi/madt.h

@@ -0,0 +1,104 @@
+/* EMK 1.0 Copyright (c) 2025 Piraterna */
+#ifndef MADT_H
+#define MADT_H
+
+#include <stdint.h>
+#include <sys/acpi.h>
+
+#define MADT_ENTRY_LAPIC 0          /* Local APIC */
+#define MADT_ENTRY_IOAPIC 1         /* I/O APIC */
+#define MADT_ENTRY_IOAPIC_SRC_OVR 2 /* I/O APIC Interrupt Source Override */
+#define MADT_ENTRY_IOAPIC_NMI_SRC 3 /* I/O APIC Non-Maskable Interrupt Source */
+#define MADT_ENTRY_LAPIC_NMI 4      /* Local APIC Non-Maskable Interrupt */
+#define MADT_ENTRY_LAPIC_ADDR_OVR 5 /* Local APIC Address Override */
+#define MADT_ENTRY_LX2APIC 9        /* Local x2APIC */
+
+typedef struct acpi_madt
+{
+    acpi_sdt_header_t sdt;
+    uint32_t lapic_base;
+    uint32_t flags;
+    char table[];
+} __attribute__((packed)) acpi_madt_t;
+
+typedef struct acpi_madt_entry
+{
+    uint8_t type;
+    uint8_t length;
+} __attribute__((packed)) acpi_madt_entry_t;
+
+/* Entry Type 0: Processor Local APIC */
+typedef struct acpi_madt_lapic
+{
+    acpi_madt_entry_t header;
+    uint8_t acpi_proc_id; /* ACPI Processor ID */
+    uint8_t apic_id;      /* APIC ID */
+    uint32_t flags;       /* Bit 0: Processor Enabled, Bit 1: Online Capable */
+} __attribute__((packed)) acpi_madt_lapic_t;
+
+/* Entry Type 1: I/O APIC */
+typedef struct acpi_madt_ioapic
+{
+    acpi_madt_entry_t header;
+    uint8_t ioapic_id;    /* I/O APIC's ID */
+    uint8_t reserved;     /* Reserved (0) */
+    uint32_t ioapic_addr; /* I/O APIC Address */
+    uint32_t gsi_base;    /* Global System Interrupt Base */
+} __attribute__((packed)) acpi_madt_ioapic_t;
+
+/* Entry Type 2: I/O APIC Interrupt Source Override */
+typedef struct acpi_madt_ioapic_src_ovr
+{
+    acpi_madt_entry_t header;
+    uint8_t bus_source; /* Bus Source */
+    uint8_t irq_source; /* IRQ Source */
+    uint32_t gsi;       /* Global System Interrupt */
+    uint16_t flags;     /* Flags */
+} __attribute__((packed)) acpi_madt_ioapic_src_ovr_t;
+
+/* Entry Type 3: I/O APIC Non-Maskable Interrupt Source */
+typedef struct acpi_madt_ioapic_nmi_src
+{
+    acpi_madt_entry_t header;
+    uint8_t nmi_source; /* NMI Source */
+    uint8_t reserved;   /* Reserved */
+    uint16_t flags;     /* Flags */
+    uint32_t gsi;       /* Global System Interrupt */
+} __attribute__((packed)) acpi_madt_ioapic_nmi_src_t;
+
+/* Entry Type 4: Local APIC Non-Maskable Interrupt */
+typedef struct acpi_madt_lapic_nmi
+{
+    acpi_madt_entry_t header;
+    uint8_t acpi_proc_id; /* ACPI Processor ID (0xFF for all processors) */
+    uint16_t flags;       /* Flags */
+    uint8_t lint;         /* LINT# (0 or 1) */
+} __attribute__((packed)) acpi_madt_lapic_nmi_t;
+
+/* Entry Type 5: Local APIC Address Override */
+typedef struct acpi_madt_lapic_addr_ovr
+{
+    acpi_madt_entry_t header;
+    uint16_t reserved;   /* Reserved */
+    uint64_t lapic_addr; /* 64-bit Physical Address of Local APIC */
+} __attribute__((packed)) acpi_madt_lapic_addr_ovr_t;
+
+/* Entry Type 9: Processor Local x2APIC */
+typedef struct acpi_madt_lx2apic
+{
+    acpi_madt_entry_t header;
+    uint16_t reserved;
+    uint32_t x2apic_id; /* Processor's Local x2APIC ID */
+    uint32_t flags;     /* Flags (same as Local APIC) */
+    uint32_t acpi_id;   /* ACPI ID */
+} __attribute__((packed)) acpi_madt_lx2apic_t;
+
+extern acpi_madt_ioapic_t *madt_ioapic_list[256];
+extern acpi_madt_ioapic_src_ovr_t *madt_iso_list[256];
+extern uint32_t madt_ioapic_len;
+extern uint32_t madt_iso_len;
+extern uint64_t lapic_addr;
+
+void madt_init();
+
+#endif // MADT_H