From 71630b9fb04196db183de9a75a5656aa7c7607c5 Mon Sep 17 00:00:00 2001
From: Kevin Alavik <kevin@alavik.se>
Date: Fri, 16 May 2025 19:17:10 +0200
Subject: [PATCH] feat/kernel: Added MADT header for kernel

---
 kernel/src/arch/cpu.h      |  14 +++++
 kernel/src/sys/acpi.c      |   2 -
 kernel/src/sys/acpi/madt.h | 103 +++++++++++++++++++++++++++++++++++++
 3 files changed, 117 insertions(+), 2 deletions(-)
 create mode 100644 kernel/src/sys/acpi/madt.h

diff --git a/kernel/src/arch/cpu.h b/kernel/src/arch/cpu.h
index b8f2e68..fb9378f 100644
--- a/kernel/src/arch/cpu.h
+++ b/kernel/src/arch/cpu.h
@@ -17,4 +17,18 @@ static inline noreturn void hcf()
         __asm__ volatile("hlt");
 }
 
+static inline void wrmsr(uint64_t msr, uint64_t value)
+{
+    uint32_t low = value & 0xFFFFFFFF;
+    uint32_t high = value >> 32;
+    asm volatile("wrmsr" : : "c"(msr), "a"(low), "d"(high));
+}
+
+static inline uint64_t rdmsr(uint64_t msr)
+{
+    uint32_t low, high;
+    asm volatile("rdmsr" : "=a"(low), "=d"(high) : "c"(msr));
+    return ((uint64_t)high << 32) | low;
+}
+
 #endif // CPU_H
\ No newline at end of file
diff --git a/kernel/src/sys/acpi.c b/kernel/src/sys/acpi.c
index 8bf7d7d..1f36ac0 100644
--- a/kernel/src/sys/acpi.c
+++ b/kernel/src/sys/acpi.c
@@ -21,8 +21,6 @@ void acpi_init(void)
     if (memcmp(rsdp->signature, "RSD PTR", 7) != 0)
         kpanic(NULL, "Invalid RSDP signature!");
 
-    log_early("RSDP Signature: %.*s", 7, rsdp->signature);
-
     if (rsdp->revision != 0)
     {
         acpi_uses_xsdt = 1;
diff --git a/kernel/src/sys/acpi/madt.h b/kernel/src/sys/acpi/madt.h
new file mode 100644
index 0000000..f540868
--- /dev/null
+++ b/kernel/src/sys/acpi/madt.h
@@ -0,0 +1,103 @@
+/* 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
+{
+    uint8_t type; /* 0 */
+    uint8_t length;
+    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
+{
+    uint8_t type;
+    uint8_t length;
+    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
+{
+    uint8_t type;
+    uint8_t length;
+    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
+{
+    uint8_t type;
+    uint8_t length;
+    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
+{
+    uint8_t type;
+    uint8_t length;
+    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
+{
+    uint8_t type;
+    uint8_t length;
+    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
+{
+    uint8_t type;
+    uint8_t length;
+    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;
+
+#endif // MADT_H
\ No newline at end of file