e820 memory info

arch/Makefile

@@ -12,7 +12,7 @@ $(TARGET_ISO): clean $(kernel_target)
 	$(HIDE)mkdir -p build_dir/boot/grub
 	$(HIDE)cp $(kernel_target) build_dir/boot
 
-	$(HIDE)echo 'set timeout=1' > build_dir/boot/grub/grub.cfg
+	$(HIDE)echo 'set timeout=0' > build_dir/boot/grub/grub.cfg
 	$(HIDE)echo 'set default=0' >> build_dir/boot/grub/grub.cfg
 	$(HIDE)echo 'menuentry "HelloOS" {' >> build_dir/boot/grub/grub.cfg
 	$(HIDE)echo '	multiboot2 /boot/kernel.elf "HelloOS"' >> build_dir/boot/grub/grub.cfg

arch/x86/kernel/e820.c

@@ -0,0 +1,85 @@
+#include <asm/e820.h>
+#include <asm/bootparam.h>
+
+#include <os/types.h>
+#include <os/kernel.h>
+
+struct e820map e820;
+
+static void early_panic(char *msg) {
+	early_printk(msg);
+	early_printk("\npanic in e820");
+    __asm__("hlt");
+}
+
+static void e820_print_map(char *who) {
+	int i;
+
+	for (i = 0; i < e820.nr_map; i++) {
+		printk(KERN_INFO " %s: %016Lx - %016Lx ", who,
+		       (unsigned long long) e820.map[i].addr,
+		       (unsigned long long)
+		       (e820.map[i].addr + e820.map[i].size));
+		switch (e820.map[i].type) {
+		case E820_RAM:
+			printk(KERN_CONT "(usable)\n");
+			break;
+		case E820_RESERVED:
+			printk(KERN_CONT "(reserved)\n");
+			break;
+		case E820_ACPI:
+			printk(KERN_CONT "(ACPI data)\n");
+			break;
+		case E820_NVS:
+			printk(KERN_CONT "(ACPI NVS)\n");
+			break;
+		default:
+			printk(KERN_CONT "type %u\n", e820.map[i].type);
+			break;
+		}
+	}
+}
+
+static int copy_e820_map(struct e820entry *biosmap, int nr_map) {
+    if (nr_map < 2) {
+        return -1;
+    }
+
+    do {
+        uint64_t start = biosmap->addr;
+		uint64_t size = biosmap->size;
+		uint64_t end = start + size;
+		uint32_t type = biosmap->type;
+
+		/* Overflow in 64 bits? Ignore the memory map. */
+		if (start > end)
+			return -1;
+        int x = e820.nr_map;
+
+        if (x == E820MAX) {
+            printk(KERN_ERR "Ooops! Too many entries in the memory map!\n");
+            return;
+        }
+
+        e820.map[x].addr = start;
+        e820.map[x].size = size;
+        e820.map[x].type = type;
+        e820.nr_map++;
+    } while (biosmap++, --nr_map);
+    return 0;
+}
+
+char *machine_specific_memory_setup() {
+    char *who = "BIOS-e820";
+
+    // e820 数组中，可能存在某些内存段重复，需要将重复的部分分离；
+    // 而我们暂不处理这种情况，认为 multiboot2 中的内存段不存在重复。
+    // 复制 e820 信息
+    if (copy_e820_map(boot_params.e820_map, boot_params.e820_entries) < 0) {
+        early_panic("Cannot find a valid memory map");
+    }
+    printk(KERN_INFO "BIOS-provided physical RAM map:\n");
+
+    e820_print_map(who);
+    return who;
+}

arch/x86/kernel/head64.c

@@ -4,17 +4,53 @@
 #include <os/start_kernel.h>
 #include <os/kernel.h>
 
+#include <asm/bootparam.h>
+#include <asm/multiboot2.h>
+
+extern uint64_t mb2_info;
+
 void clear_bss() {
     memset(__bss_start, 0,
 	       (unsigned long) __bss_stop - (unsigned long) __bss_start);
 }
 
+static void mem_info(struct multiboot_tag *tag) {
+    struct multiboot_tag_mmap *mmap = (struct multiboot_tag_mmap*) tag;
+    struct multiboot_mmap_entry *entry = mmap->entries;
 
-void x86_64_start_kernel() {
-    early_printk("x86_64_start_kernel running...");
+    uint32_t i = 0;
+    while ((uint8_t*)entry < (uint8_t*)mmap + mmap->size) {
+        boot_params.e820_map[i].addr = entry->addr;
+        boot_params.e820_map[i].size = entry->len;
+        boot_params.e820_map[i].type = entry->type;
+
+        i++;
+        entry = (struct multiboot_mmap_entry*)((uint8_t*)entry + mmap->entry_size);
+    }
+    boot_params.e820_entries = i;
+}
+
+void parse_sys_info() {
+    struct multiboot_tag *tag;
+    for (tag = (struct multiboot_tag*)(mb2_info + MULTIBOOT_TAG_ALIGN);
+         tag->type != MULTIBOOT_TAG_TYPE_END;
+         tag = (struct multiboot_tag*)((multiboot_uint8_t *)tag + ((tag->size + 7) & ~7))) {
+        switch (tag->type) {
+        case MULTIBOOT_TAG_TYPE_MMAP:
+            mem_info(tag);
+            break;
+        default:
+            break;
+        }
+    }
+}
 
+void x86_64_start_kernel() {
+    early_printk("x86_64_start_kernel running\n");
     // bss 段清零
     clear_bss();
+    // 解析系统信息
+    parse_sys_info();
 
     start_kernel();
 }

arch/x86/kernel/head_64.S

@@ -8,6 +8,8 @@
 .global startup_64
 .extern print
 startup_64:
+	mov 	%ebx, mb2_info
+
 	/* 开启 PAE */
 	movl 	%cr4, %eax
 	btsl	$5, %eax
@@ -63,6 +65,8 @@ secondary_startup_64:
 
 ENTRY(init_rsp)
 	.quad  init_thread_union+THREAD_SIZE-8
+ENTRY(mb2_info)
+	.quad 0x00
 
 .text
 .code64

arch/x86/kernel/setup.c

@@ -0,0 +1,13 @@
+#include <asm/bootparam.h>
+
+#include <os/init.h>
+
+struct boot_params boot_params;
+
+void memory_setup() {
+    machine_specific_memory_setup();
+}
+
+void setup_arch() {
+    memory_setup();
+}

include/asm/bootparam.h

@@ -0,0 +1,13 @@
+#ifndef _ASM_X86_BOOTPARAM_H
+#define _ASM_X86_BOOTPARAM_H
+
+#include <asm/e820.h>
+
+struct boot_params {
+    __u32  e820_entries;
+    struct e820entry e820_map[E820MAX];
+};
+
+extern struct boot_params boot_params;
+
+#endif

include/asm/desc.h

@@ -0,0 +1,67 @@
+#ifndef _ASM_X86_DESC_H
+#define _ASM_X86_DESC_H
+
+#include <os/types.h>
+#include <os/string.h>
+
+#include <asm/segment.h>
+
+#define PTR_LOW(x) ((unsigned long long)(x) & 0xFFFF)
+#define PTR_MIDDLE(x) (((unsigned long long)(x) >> 16) & 0xFFFF)
+#define PTR_HIGH(x) ((unsigned long long)(x) >> 32)
+
+extern gate_desc idt_table[];
+
+struct gate_struct64 {
+	uint16_t offset_low;
+	uint16_t segment;
+	unsigned ist : 3, zero0 : 5, type : 5, dpl : 2, p : 1;
+	uint16_t offset_middle;
+	uint32_t offset_high;
+	uint32_t zero1;
+} __attribute__((packed));
+
+typedef struct gate_struct64 gate_desc;
+
+enum {
+	GATE_INTERRUPT = 0xE,
+	GATE_TRAP = 0xF,
+	GATE_CALL = 0xC,
+	GATE_TASK = 0x5,
+};
+
+static inline void pack_gate(gate_desc *gate, unsigned type, unsigned long func,
+			     unsigned dpl, unsigned ist, unsigned seg) {
+	gate->offset_low = PTR_LOW(func);
+	gate->segment = __KERNEL_CS;
+	gate->ist = ist;
+	gate->p = 1;
+	gate->dpl = dpl;
+	gate->zero0 = 0;
+	gate->zero1 = 0;
+	gate->type = type;
+	gate->offset_middle = PTR_MIDDLE(func);
+	gate->offset_high = PTR_HIGH(func);
+}
+
+static inline void write_idt_entry(gate_desc *idt, int entry,
+					  const gate_desc *gate) {
+	memcpy(&idt[entry], gate, sizeof(*gate));
+}
+
+static inline void _set_gate(int gate, unsigned type, void *addr,
+			     unsigned dpl, unsigned ist, unsigned seg) {
+	gate_desc s;
+	pack_gate(&s, type, (unsigned long)addr, dpl, ist, seg);
+	/*
+	 * does not need to be atomic because it is only done once at
+	 * setup time
+	 */
+	write_idt_entry(idt_table, gate, &s);
+}
+
+static inline void set_intr_gate(unsigned int n, void *addr) {
+	_set_gate(n, GATE_INTERRUPT, addr, 0, 0, __KERNEL_CS);
+}
+
+#endif

include/asm/e820.h

@@ -3,12 +3,23 @@
 
 #include <os/ioport.h>
 
+#define E820MAX	128
+
+#define E820_RAM	1
+#define E820_RESERVED	2
+#define E820_ACPI	3
+#define E820_NVS	4
+
 struct e820entry {
 	__u64 addr;	/* start of memory segment */
 	__u64 size;	/* size of memory segment */
 	__u32 type;	/* type of memory segment */
 } __attribute__((packed));
 
+struct e820map {
+	__u32 nr_map;
+	struct e820entry map[E820MAX];
+};
 
-
+extern struct e820map e820;
 #endif

include/asm/page.h

@@ -29,6 +29,8 @@
 #define KERNEL_IMAGE_SIZE	(512 * 1024 * 1024)
 #define KERNEL_IMAGE_START	_AC(0xffffffff80000000, UL)
 
+#define __pa(x)		((unsigned long)(x)-PAGE_OFFSET)
+#define __va(x)			((void *)((unsigned long)(x)+PAGE_OFFSET))
 
 
 #endif

include/asm/setup.h

@@ -0,0 +1,6 @@
+#ifndef _ASM_X86_SETUP_H
+#define _ASM_X86_SETUP_H
+
+char *machine_specific_memory_setup();
+
+#endif

include/os/init.h

@@ -0,0 +1,7 @@
+#ifndef _OS_INIT_H
+#define _OS_INIT_H
+
+void setup_arch();
+
+
+#endif

include/os/kernel.h

@@ -4,6 +4,17 @@
 #include <stdarg.h>
 #include <os/types.h>
 
+#define	KERN_EMERG	"<0>"	/* system is unusable			*/
+#define	KERN_ALERT	"<1>"	/* action must be taken immediately	*/
+#define	KERN_CRIT	"<2>"	/* critical conditions			*/
+#define	KERN_ERR	"<3>"	/* error conditions			*/
+#define	KERN_WARNING	"<4>"	/* warning conditions			*/
+#define	KERN_NOTICE	"<5>"	/* normal but significant condition	*/
+#define	KERN_INFO	"<6>"	/* informational			*/
+#define	KERN_DEBUG	"<7>"	/* debug-level messages			*/
+
+#define	KERN_CONT	""
+
 extern void __attribute__((format(printf, 1, 2)))
 	early_printk(const char *fmt, ...);
 
@@ -13,4 +24,10 @@ extern int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
 extern int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
 	__attribute__ ((format (printf, 3, 0)));
 
+// extern int printk(const char * fmt, ...)
+// 	__attribute__((format (printf, 1, 2)));
+#define printk(...) { \
+	early_printk(__VA_ARGS__); \
+}
+
 #endif

include/os/string.h

@@ -10,4 +10,8 @@ extern void *memset(void *,int,__kernel_size_t);
 extern __kernel_size_t strnlen(const char *,__kernel_size_t);
 #endif
 
+#ifndef __HAVE_ARCH_MEMCPY
+extern void* memcpy(void *dest, const void *src, size_t count);
+#endif
+
 #endif

init/main.c

@@ -1,6 +1,9 @@
-
+#include <os/init.h>
 
 void start_kernel() {
+
+    setup_arch();
+
     __asm__ __volatile__("hlt");
 }
 

kernel/printk.c

@@ -0,0 +1 @@
+#include <os/kernel.h>

lib/string.c

@@ -18,4 +18,16 @@ __kernel_size_t strnlen(const char *s, __kernel_size_t count) {
 		/* nothing */;
 	return sc - s;
 }
+#endif
+
+#ifndef __HAVE_ARCH_MEMCPY
+void *memcpy(void *dest, const void *src, size_t count)
+{
+	char *tmp = dest;
+	const char *s = src;
+
+	while (count--)
+		*tmp++ = *s++;
+	return dest;
+}
 #endif