kernel: string.h, gdt, msr, cpu and ist

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

@@ -0,0 +1,55 @@
+#include <arch/cpu.h>
+#include <arch/ist.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+#include <printf.h>
+
+static uint64_t template[7] = {
+	0, // NULL 0x0
+	0x00af9b000000ffff, // code64 0x8
+	0x00af93000000ffff, // data64 0x10
+	0x00affb000000ffff, // ucode64 0x18
+	0x00aff3000000ffff, // udata64 0x20
+	0x0020890000000000, // low ist 0x28
+	0x0000000000000000  // high ist
+};
+
+typedef struct {
+	uint16_t size;
+	uint64_t address;
+} __attribute__((packed)) gdtr_t;
+
+void arch_gdt_reload() {
+	memcpy(_cpu()->gdt, template, sizeof(template));
+	uintptr_t istaddr = (uintptr_t)&_cpu()->ist;
+
+	// add ist to gdt
+	_cpu()->gdt[5] |= ((istaddr & 0xff000000) << 32) | ((istaddr & 0xff0000) << 16) | ((istaddr & 0xffff) << 16) | sizeof(ist_t);
+	_cpu()->gdt[6] = (istaddr >> 32) & 0xffffffff;
+
+	// reload gdt and ist
+
+	gdtr_t gdtr = {
+		.size = sizeof(template) - 1,
+		.address = (uintptr_t)&_cpu()->gdt
+	};
+
+	asm volatile("lgdt (%%rax)" : : "a"(&gdtr) : "memory");
+	asm volatile("ltr %%ax" : : "a"(0x28));
+	asm volatile(
+		"swapgs;"
+		"mov $0, %%ax;"
+		"mov %%ax, %%gs;"
+		"mov %%ax, %%fs;"
+		"swapgs;"
+		"mov $0x10, %%ax;"
+		"mov %%ax, %%ds;"
+		"mov %%ax, %%es;"
+		"mov %%ax, %%ss;"
+		"pushq $0x8;"
+		"pushq $.reload;"
+		"retfq;"
+		".reload:"
+		: : : "ax");
+}

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

@@ -1,7 +1,12 @@
 #include <arch/e9.h>
 #include <logging.h>
+#include <arch/cpu.h>
+
+static cpu_t bsp_cpu;
 
 void kernel_entry() {
+	cpu_set(&bsp_cpu);
 	logging_sethook(arch_e9_putc);
+	arch_gdt_reload();
 	__assert(!"kernel entry end");
 }