Implemented GDT initialisation

arch/x86_64/cpu.c

@@ -0,0 +1,14 @@
+#include <socks/machine/cpu.h>
+#include <socks/machine/_gdt.h>
+
+int ml_cpu_block_init(ml_cpu_block *p)
+{
+	gdt_init(&p->c_gdt, &p->c_gdt_ptr);
+	return 0;
+}
+
+int ml_cpu_block_use(ml_cpu_block *p)
+{
+	gdt_load(&p->c_gdt_ptr);
+	return 0;
+}

arch/x86_64/gdt.c

@@ -0,0 +1,27 @@
+#include <socks/libc/string.h>
+#include <socks/machine/_gdt.h>
+
+static void init_entry(struct gdt_entry *entry, int access, int flags)
+{
+	entry->ge_limit_low = 0xFFFF;
+	entry->ge_base_low = 0x00;
+	entry->ge_base_mid = 0x00;
+	entry->ge_access = access;
+	entry->ge_gran = flags;
+	entry->ge_base_hi = 0x00;
+}
+
+int gdt_init(struct gdt *gdt, struct gdt_ptr *gdtp)
+{
+	memset(&gdt->g_entries[0], 0x0, sizeof gdt->g_entries[0]);
+
+	init_entry(&gdt->g_entries[1], GDT_A_PRESENT | GDT_A_CODEREAD | GDT_A_CODE, GDT_F_64BIT);
+	init_entry(&gdt->g_entries[2], GDT_A_PRESENT | GDT_A_DATAWRITE | GDT_A_DATA, GDT_F_64BIT);
+	init_entry(&gdt->g_entries[3], GDT_A_PRESENT | GDT_A_USER | GDT_A_CODEREAD | GDT_A_CODE, GDT_F_64BIT);
+	init_entry(&gdt->g_entries[4], GDT_A_PRESENT | GDT_A_USER | GDT_A_DATAWRITE | GDT_A_DATA, GDT_F_64BIT);
+
+	gdtp->g_ptr = (uint64_t)gdt;
+	gdtp->g_limit = sizeof(*gdt) - 1;
+
+	return 0;
+}

arch/x86_64/gdt_load.S

@@ -0,0 +1,28 @@
+.section .text
+
+.global gdt_load
+.type gdt_load, @function
+
+gdt_load:
+	pushq %rbp
+	movq %rsp, %rbp
+
+	lgdt (%rdi)
+
+	mov $0x10, %ax
+	mov %ax, %ss
+	mov %ax, %ds
+	mov %ax, %es
+	mov %ax, %fs
+	mov %ax, %gs
+
+	movabsq $(gdt_load2), %rax
+
+	push $0x08
+	push %rax
+
+	lretq
+
+gdt_load2:
+	popq %rbp
+	ret

arch/x86_64/include/socks/machine/_gdt.h

@@ -0,0 +1,42 @@
+#ifndef SOCKS_X86_64__GDT_H_
+#define SOCKS_X86_64__GDT_H_
+
+#include <socks/compiler.h>
+#include <stdint.h>
+
+#define NR_GDT_ENTRIES 5
+
+#define GDT_A_PRESENT		(1 << 7)
+#define GDT_A_USER		(3 << 5)
+#define GDT_A_CODE		(3 << 3)
+#define GDT_A_DATA		(8 << 1)
+#define GDT_A_RPLK		(1 << 5)
+#define GDT_A_CODEREAD		(1 << 1)
+#define GDT_A_DATAWRITE		(1 << 1)
+#define GDT_A_GROWUP		(1 << 5)
+#define GDT_F_64BIT		(0x2F)
+#define GDT_F_32BIT		(0x4F)
+#define GDT_F_16BIT		(0xF)
+
+struct gdt_entry {
+	uint16_t ge_limit_low;
+	uint16_t ge_base_low;
+	uint8_t ge_base_mid;
+	uint8_t ge_access;
+	uint8_t ge_gran;
+	uint8_t ge_base_hi;
+} __packed;
+
+struct gdt {
+	struct gdt_entry g_entries[NR_GDT_ENTRIES];
+} __packed;
+
+struct gdt_ptr {
+	uint16_t g_limit;
+	uint64_t g_ptr;
+} __packed;
+
+extern int gdt_init(struct gdt *gdt, struct gdt_ptr *gdtp);
+extern int gdt_load(struct gdt_ptr *gdtp);
+
+#endif

arch/x86_64/include/socks/machine/cpu.h

@@ -1,10 +1,15 @@
 #ifndef SOCKS_X86_64_CPU_H_
 #define SOCKS_X86_64_CPU_H_
 
-typedef struct ml_cpu_block {
+#include <socks/machine/_gdt.h>
 
+typedef struct ml_cpu_block {
+	struct gdt c_gdt;
+	struct gdt_ptr c_gdt_ptr;
 } ml_cpu_block;
 
+extern int ml_init_bootcpu(void);
+
 extern int ml_cpu_block_init(ml_cpu_block *p);
 extern int ml_cpu_block_use(ml_cpu_block *p);