kernel: i/o apic initialisation and abstractions

kernel-src/arch/x86-64/apic.c

@@ -0,0 +1,143 @@
+#include <arch/acpi.h>
+#include <logging.h>
+#include <kernel/vmm.h>
+#include <arch/mmu.h>
+#include <kernel/alloc.h>
+
+#define IOAPIC_REG_ID 0
+#define IOAPIC_REG_ENTRYCOUNT 1
+#define IOAPIC_REG_PRIORITY 2
+#define IOAPIC_REG_ENTRY 0x10
+
+typedef struct {
+	uint8_t type;
+	uint8_t length;
+} __attribute__((packed)) listheader_t;
+
+typedef struct {
+	listheader_t header;
+	uint16_t reserved;
+	uint64_t addr;
+} __attribute__((packed)) lapicoverride_t;
+
+typedef struct {
+	listheader_t header;
+	uint8_t id;
+	uint8_t reserved;
+	uint32_t addr;
+	uint32_t intbase;
+} __attribute__((packed)) ioentry_t;
+
+typedef struct {
+	void *addr;
+	int base;
+	int top;
+} ioapicdesc_t;
+
+static ioapicdesc_t *ioapics;
+
+static madt_t *madt;
+static listheader_t *liststart;
+static listheader_t *listend;
+static void *lapicaddr;
+
+static size_t overridecount;
+static size_t iocount;
+
+static inline listheader_t *getnext(listheader_t *header) {
+	uintptr_t ptr = (uintptr_t)header;
+	return (listheader_t *)(ptr + header->length);
+}
+
+static inline void *getentry(int type, int n) {
+	listheader_t *entry = liststart;
+
+	while (entry < listend) {
+		if (entry->type == type) {
+			if (n-- == 0)
+				return entry;
+		}
+		entry = getnext(entry);
+	}
+
+	return NULL;
+}
+
+static int getcount(int type) {
+	listheader_t *entry = liststart;
+	int count = 0;
+
+	while (entry < listend) {
+		if (entry->type == type)
+			++count;
+		entry = getnext(entry);
+	}
+
+	return count;
+}
+
+static uint32_t readioapic(void *ioapic, int reg) {
+	volatile uint32_t *apic = ioapic;
+	*apic = reg & 0xff;
+	return *(apic + 4);
+}
+
+static void writeioapic(void *ioapic, int reg, uint32_t v) {
+	volatile uint32_t *apic = ioapic;
+	*apic = reg & 0xff;
+	*(apic + 4) = v;
+}
+
+static void writeiored(void *ioapic, uint8_t entry, uint8_t vector, uint8_t delivery, uint8_t destmode, uint8_t polarity, uint8_t mode, uint8_t mask, uint8_t dest){
+	uint32_t val = vector;
+	val |= (delivery & 0b111) << 8;
+	val |= (destmode & 1) << 11;
+	val |= (polarity & 1) << 13;
+	val |= (mode & 1) << 15;
+	val |= (mask & 1) << 16;
+
+	writeioapic(ioapic, 0x10 + entry * 2, val);
+	writeioapic(ioapic, 0x11 + entry * 2, (uint32_t)dest << 24);
+}
+
+void apic_init() {
+	madt = acpi_findtable("APIC", 0);
+	__assert(madt);
+
+	liststart = (void *)((uintptr_t)madt + sizeof(madt_t));
+	listend   = (void *)((uintptr_t)madt + madt->header.length);
+
+	overridecount = getcount(ACPI_MADT_TYPE_OVERRIDE);
+	iocount = getcount(ACPI_MADT_TYPE_IOAPIC);
+
+	// map LAPIC to virtual memory
+
+	lapicoverride_t *lapic64 = getentry(ACPI_MADT_TYPE_64BITADDR, 0);
+
+	void *paddr = lapic64 ? (void *)lapic64->addr : (void *)(uint64_t)madt->addr;
+
+	if (lapic64)
+		printf("\e[94mUsing 64 bit override for the local APIC address\n\e[0m");
+
+	lapicaddr = vmm_map(NULL, PAGE_SIZE, VMM_FLAGS_PHYSICAL, ARCH_MMU_FLAGS_READ | ARCH_MMU_FLAGS_WRITE | ARCH_MMU_FLAGS_NOEXEC, paddr);
+	__assert(lapicaddr);
+
+	// map I/O apics to memory
+
+	ioapics = alloc(sizeof(ioapicdesc_t) * iocount);
+	__assert(ioapics);
+
+	for (int i = 0; i < iocount; ++i) {
+		ioentry_t *entry = getentry(ACPI_MADT_TYPE_IOAPIC, i);
+
+		__assert((entry->addr % PAGE_SIZE) == 0);
+		ioapics[i].addr = vmm_map(NULL, PAGE_SIZE, VMM_FLAGS_PHYSICAL, ARCH_MMU_FLAGS_READ | ARCH_MMU_FLAGS_WRITE | ARCH_MMU_FLAGS_NOEXEC, (void *)(uint64_t)entry->addr);
+		__assert(ioapics[i].addr);
+		ioapics[i].base = entry->intbase;
+		ioapics[i].top = ioapics[i].base + ((readioapic(ioapics[i].addr, IOAPIC_REG_ENTRYCOUNT) >> 16) & 0xff) + 1;
+		printf("ioapic: addr %p base %lu top %lu\n", entry->addr, entry->intbase, ioapics[i].top);
+		for (int j = ioapics[i].base; j < ioapics[i].top; ++j)
+			writeiored(ioapics[i].addr, j - ioapics[i].base, 0xfe, 0, 0, 0, 0, 1, 0);
+			
+	}
+}

kernel-src/arch/x86-64/main.c

@@ -10,6 +10,7 @@
 #include <kernel/slab.h>
 #include <kernel/alloc.h>
 #include <arch/acpi.h>
+#include <arch/apic.h>
 
 static cpu_t bsp_cpu;
 
@@ -26,5 +27,6 @@ void kernel_entry() {
 	vmm_init();
 	alloc_init();
 	acpi_init();
+	apic_init();
 	__assert(!"kernel entry end");
 }

kernel-src/include/x86-64/arch/apic.h

@@ -0,0 +1,6 @@
+#ifndef _APIC_H
+#define _APIC_H
+
+void apic_init();
+
+#endif