* bootstub version 0.01

6 files changed, 497 insertions, 0 deletions

diff --git a/bootparam.h b/bootparam.h
new file mode 100644
index 0000000..bd50669
--- /dev/null
+++ b/bootparam.h
@@ -0,0 +1,274 @@
+/* bootparms.h base on Linux kernel include/asm-x86/bootparam.h */
+
+#include "types.h"
+
+#define EDD_MBR_SIG_MAX 16
+#define E820MAX 128
+#define EDDMAXNR 6
+
+/* extensible setup data list node */
+struct setup_data {
+	__u64 next;
+	__u32 type;
+	__u32 len;
+	__u8 data[0];
+};
+
+struct screen_info {
+	__u8  orig_x;	   /* 0x00 */
+	__u8  orig_y;	   /* 0x01 */
+	__u16 ext_mem_k;	/* 0x02 */
+	__u16 orig_video_page;  /* 0x04 */
+	__u8  orig_video_mode;  /* 0x06 */
+	__u8  orig_video_cols;  /* 0x07 */
+	__u16 unused2;	  /* 0x08 */
+	__u16 orig_video_ega_bx;/* 0x0a */
+	__u16 unused3;	  /* 0x0c */
+	__u8  orig_video_lines; /* 0x0e */
+	__u8  orig_video_isVGA; /* 0x0f */
+	__u16 orig_video_points;/* 0x10 */
+
+	/* VESA graphic mode -- linear frame buffer */
+	__u16 lfb_width;	/* 0x12 */
+	__u16 lfb_height;       /* 0x14 */
+	__u16 lfb_depth;	/* 0x16 */
+	__u32 lfb_base;	 /* 0x18 */
+	__u32 lfb_size;	 /* 0x1c */
+	__u16 cl_magic, cl_offset; /* 0x20 */
+	__u16 lfb_linelength;   /* 0x24 */
+	__u8  red_size;	 /* 0x26 */
+	__u8  red_pos;	  /* 0x27 */
+	__u8  green_size;       /* 0x28 */
+	__u8  green_pos;	/* 0x29 */
+	__u8  blue_size;	/* 0x2a */
+	__u8  blue_pos;	 /* 0x2b */
+	__u8  rsvd_size;	/* 0x2c */
+	__u8  rsvd_pos;	 /* 0x2d */
+	__u16 vesapm_seg;       /* 0x2e */
+	__u16 vesapm_off;       /* 0x30 */
+	__u16 pages;	    /* 0x32 */
+	__u16 vesa_attributes;  /* 0x34 */
+	__u32 capabilities;     /* 0x36 */
+	__u8  _reserved[6];     /* 0x3a */
+} __attribute__((packed));
+
+struct apm_bios_info {
+	__u16   version;
+	__u16   cseg;
+	__u32   offset;
+	__u16   cseg_16;
+	__u16   dseg;
+	__u16   flags;
+	__u16   cseg_len;
+	__u16   cseg_16_len;    
+	__u16   dseg_len;
+};
+
+struct ist_info {
+	__u32 signature;
+	__u32 command;
+	__u32 event;
+	__u32 perf_level;
+};
+
+struct sys_desc_table {
+	__u16 length;
+	__u8  table[14];
+};
+
+struct efi_info {
+	__u32 efi_loader_signature;
+	__u32 efi_systab;
+	__u32 efi_memdesc_size;
+	__u32 efi_memdesc_version;
+	__u32 efi_memmap;
+	__u32 efi_memmap_size;
+	__u32 efi_systab_hi;
+	__u32 efi_memmap_hi;
+};
+
+struct setup_header {
+	__u8	setup_sects;
+	__u16	root_flags;
+	__u32	syssize;
+	__u16	ram_size;
+	__u16	vid_mode;
+	__u16	root_dev;
+	__u16	boot_flag;
+	__u16	jump;
+	__u32	header;
+	__u16	version;
+	__u32	realmode_swtch;
+	__u16	start_sys;
+	__u16	kernel_version;
+	__u8	type_of_loader;
+	__u8	loadflags;
+	__u16	setup_move_size;
+	__u32	code32_start;
+	__u32	ramdisk_image;
+	__u32	ramdisk_size;
+	__u32	bootsect_kludge;
+	__u16	heap_end_ptr;
+	__u16	_pad1;
+	__u32	cmd_line_ptr;
+	__u32	initrd_addr_max;
+	__u32	kernel_alignment;
+	__u8	relocatable_kernel;
+	__u8	_pad2[3];
+	__u32	cmdline_size;
+	__u32	hardware_subarch;
+	__u64	hardware_subarch_data;
+	__u32	payload_offset;
+	__u32	payload_length;
+	__u64	setup_data;
+} __attribute__((packed));
+
+struct edid_info {
+	unsigned char dummy[128];
+};
+
+struct e820entry { 
+	__u64 addr;     /* start of memory segment */   
+	__u64 size;     /* size of memory segment */    
+	__u32 type;     /* type of memory segment */    
+} __attribute__((packed));
+
+struct edd_device_params {
+	__u16 length;
+	__u16 info_flags;
+	__u32 num_default_cylinders;
+	__u32 num_default_heads;
+	__u32 sectors_per_track;
+	__u64 number_of_sectors;
+	__u16 bytes_per_sector;
+	__u32 dpte_ptr;	 /* 0xFFFFFFFF for our purposes */
+	__u16 key;	      /* = 0xBEDD */
+	__u8 device_path_info_length;   /* = 44 */
+	__u8 reserved2;
+	__u16 reserved3;
+	__u8 host_bus_type[4];
+	__u8 interface_type[8];
+	union {
+		struct {
+			__u16 base_address;
+			__u16 reserved1;
+			__u32 reserved2;
+		} __attribute__ ((packed)) isa;
+		struct {
+			__u8 bus;
+			__u8 slot;
+			__u8 function;
+			__u8 channel;
+			__u32 reserved;
+		} __attribute__ ((packed)) pci;
+		/* pcix is same as pci */
+		struct {
+			__u64 reserved;
+		} __attribute__ ((packed)) ibnd;
+		struct {
+			__u64 reserved;
+		} __attribute__ ((packed)) xprs;
+		struct {
+			__u64 reserved;
+		} __attribute__ ((packed)) htpt;
+		struct {
+			__u64 reserved;
+		} __attribute__ ((packed)) unknown;
+	} interface_path;
+	union {
+		struct {
+			__u8 device;
+			__u8 reserved1;
+			__u16 reserved2;
+			__u32 reserved3;
+			__u64 reserved4;
+		} __attribute__ ((packed)) ata;
+		struct {
+			__u8 device;
+			__u8 lun;
+			__u8 reserved1;
+			__u8 reserved2;
+			__u32 reserved3;
+			__u64 reserved4;
+		} __attribute__ ((packed)) atapi;
+		struct {
+			__u16 id;
+			__u64 lun;
+			__u16 reserved1;
+			__u32 reserved2;
+		} __attribute__ ((packed)) scsi;
+		struct {
+			__u64 serial_number;
+			__u64 reserved;
+		} __attribute__ ((packed)) usb;
+		struct {
+			__u64 eui;
+			__u64 reserved;
+		} __attribute__ ((packed)) i1394;
+		struct {
+			__u64 wwid;
+			__u64 lun;
+		} __attribute__ ((packed)) fibre;
+		struct {
+			__u64 identity_tag;
+			__u64 reserved;
+		} __attribute__ ((packed)) i2o;
+	       struct {
+			__u32 array_number;
+			__u32 reserved1;
+			__u64 reserved2;
+		} __attribute__ ((packed)) raid;
+		struct {
+			__u8 device;
+			__u8 reserved1;
+			__u16 reserved2;
+			__u32 reserved3;
+			__u64 reserved4;
+		} __attribute__ ((packed)) sata;
+		struct {
+			__u64 reserved1;
+			__u64 reserved2;
+		} __attribute__ ((packed)) unknown;
+	} device_path;
+	__u8 reserved4;
+	__u8 checksum;
+} __attribute__ ((packed));
+
+struct edd_info {
+	__u8 device;
+	__u8 version;
+	__u16 interface_support;
+	__u16 legacy_max_cylinder;
+	__u8 legacy_max_head;
+	__u8 legacy_sectors_per_track;
+	struct edd_device_params params;		
+} __attribute__ ((packed)); 
+
+/* The so-called "zeropage" */
+struct boot_params {
+	struct screen_info screen_info;			/* 0x000 */
+	struct apm_bios_info apm_bios_info;		/* 0x040 */
+	__u8  _pad2[12];				/* 0x054 */
+	struct ist_info ist_info;			/* 0x060 */
+	__u8  _pad3[16];				/* 0x070 */
+	__u8  hd0_info[16];	/* obsolete! */		/* 0x080 */
+	__u8  hd1_info[16];	/* obsolete! */		/* 0x090 */
+	struct sys_desc_table sys_desc_table;		/* 0x0a0 */
+	__u8  _pad4[144];				/* 0x0b0 */
+	struct edid_info edid_info;			/* 0x140 */
+	struct efi_info efi_info;			/* 0x1c0 */
+	__u32 alt_mem_k;				/* 0x1e0 */
+	__u32 scratch;		/* Scratch field! */	/* 0x1e4 */
+	__u8  e820_entries;				/* 0x1e8 */
+	__u8  eddbuf_entries;				/* 0x1e9 */
+	__u8  edd_mbr_sig_buf_entries;			/* 0x1ea */
+	__u8  _pad6[6];					/* 0x1eb */
+	struct setup_header hdr;    /* setup header */	/* 0x1f1 */
+	__u8  _pad7[0x290-0x1f1-sizeof(struct setup_header)];
+	__u32 edd_mbr_sig_buffer[EDD_MBR_SIG_MAX];	/* 0x290 */
+	struct e820entry e820_map[E820MAX];		/* 0x2d0 */
+	__u8  _pad8[48];				/* 0xcd0 */
+	struct edd_info eddbuf[EDDMAXNR];		/* 0xd00 */
+	__u8  _pad9[276];				/* 0xeec */
+} __attribute__((packed));
+
diff --git a/bootstub.c b/bootstub.c
new file mode 100644
index 0000000..c2a1ebd
--- /dev/null
+++ b/bootstub.c
@@ -0,0 +1,80 @@
+/* bootstub.c for loading protected mode kernel
+ * Copyright (C) 2008 Alek Du <alek.du@intel.com>
+ */
+
+#include "types.h"
+#include "bootstub.h"
+#include "bootparam.h"
+
+struct gdt_ptr {
+        u16 len;
+        u32 ptr;
+} __attribute__((packed));
+
+static void setup_gdt(void)
+{
+        static const u64 boot_gdt[] __attribute__((aligned(16))) = {
+                /* CS: code, read/execute, 4 GB, base 0 */
+                [GDT_ENTRY_BOOT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff),
+                /* DS: data, read/write, 4 GB, base 0 */
+                [GDT_ENTRY_BOOT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff),
+        };
+        static struct gdt_ptr gdt;
+
+        gdt.len = sizeof(boot_gdt)-1;
+        gdt.ptr = (u32)&boot_gdt;
+
+        asm volatile("lgdtl %0" : : "m" (gdt));
+}
+
+static void setup_idt(void)
+{
+        static const struct gdt_ptr null_idt = {0, 0};
+        asm volatile("lidtl %0" : : "m" (null_idt));
+}
+
+static void *memcpy(void *dest, const void *src, size_t count)
+{
+        char *tmp = dest;
+        const char *s = src;
+
+        while (count--)
+                *tmp++ = *s++;
+        return dest;
+}
+
+static void *memset(void *s, int c, size_t count)
+{
+        char *xs = s;
+ 
+        while (count--)
+                *xs++ = c; 
+        return s;
+}
+
+static void setup_boot_params(struct boot_params *bp, struct setup_header *sh)
+{
+	memset(bp, 0, sizeof (struct boot_params));
+	memcpy(&bp->hdr, sh, sizeof (struct setup_header));	
+}
+
+static int get_32bit_entry(unsigned char *ptr)
+{
+	while (1){
+		if (*(u32 *)ptr == SETUP_SIGNATURE)
+			break;
+		ptr++;
+	}
+	ptr+=4;
+	return (((unsigned int)ptr+511)/512)*512;
+}
+
+int main(void)
+{
+	setup_idt();
+	setup_gdt();
+	setup_boot_params((struct boot_params *)BOOT_PARAMS_OFFSET, 
+		(struct setup_header*)SETUP_HEADER_OFFSET);
+	return get_32bit_entry((unsigned char *)BZIMAGE_OFFSET);
+}
+
diff --git a/bootstub.h b/bootstub.h
new file mode 100644
index 0000000..5978379
--- /dev/null
+++ b/bootstub.h
@@ -0,0 +1,28 @@
+/* define bootstub constrains here, like memory map etc. 
+ */
+
+#ifndef _BOOT_STUB_HEAD
+#define _BOOT_STUB_HEAD
+
+#define CMDLINE_OFFSET 0x100000
+#define BZIMAGE_OFFSET 0x102000
+#define STACK_OFFSET 0x101000
+#define SETUP_HEADER_OFFSET (BZIMAGE_OFFSET + 0x1F1)
+#define SETUP_HEADER_SIZE (0x0202 + *(unsigned char*)(0x0201+BZIMAGE_OFFSET))
+#define BOOT_PARAMS_OFFSET 0x8000
+#define SETUP_SIGNATURE 0x5a5aaa55
+
+#define GDT_ENTRY_BOOT_CS       2
+#define __BOOT_CS               (GDT_ENTRY_BOOT_CS * 8)
+
+#define GDT_ENTRY_BOOT_DS       (GDT_ENTRY_BOOT_CS + 1)
+#define __BOOT_DS               (GDT_ENTRY_BOOT_DS * 8)
+
+#define GDT_ENTRY(flags, base, limit)           \
+        (((u64)(base & 0xff000000) << 32) |     \
+         ((u64)flags << 40) |                   \
+         ((u64)(limit & 0x00ff0000) << 32) |    \
+         ((u64)(base & 0x00ffffff) << 16) |     \
+         ((u64)(limit & 0x0000ffff)))
+
+#endif
diff --git a/bootstub.lds b/bootstub.lds
new file mode 100644
index 0000000..4248c54
--- /dev/null
+++ b/bootstub.lds
@@ -0,0 +1,37 @@
+OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")

+OUTPUT_ARCH(i386)

+ENTRY(_start)

+SECTIONS

+{

+	. = 0x101000;		/* bootstub entry in DRAM */

+	.text.head : {

+		_head = . ;

+		*(.text.head)

+		_ehead = . ;

+	}

+	.text :	{

+		_text = .; 	/* Text */

+		*(.text)

+		*(.text.*)

+		_etext = . ;

+	}

+	.rodata : {

+		_rodata = . ;

+		*(.rodata)	 /* read-only data */

+		*(.rodata.*)

+		_erodata = . ;

+	}

+	.data :	{

+		_data = . ;

+		*(.data)

+		*(.data.*)

+		_edata = . ;

+	}

+	.bss : {

+		_bss = . ;

+		*(.bss)

+		*(.bss.*)

+		*(COMMON)

+		_end = . ;

+	}

+}

diff --git a/head.S b/head.S
new file mode 100644
index 0000000..7431584
--- /dev/null
+++ b/head.S
@@ -0,0 +1,58 @@
+/* head.S for bootstub to load protected mode kernel
+ * Copyright (C) 2008 Alek Du <alek.du@intel.com>
+ * 
+ * Note. When FW hand-off control to bootstub, the CPU is already in protected
+ * Mode with 1. GDT(8)=4G GDT(10)=4G
+ *           2. CS=8, DS=ES=FS=GS=10
+ *           3. Paging mode disabled
+ *           4. Interrupt ENABLED
+ */ 
+
+/* When bootstub get control, the memory map in DRAM is like:
+ *		~			~
+ * 0x102000	|	initramfs	|
+ *+bzImage size +-----------------------+
+ *		|	bzImage		|
+ * 0x102000	+-----------------------+
+ *		|	boot stub	|
+ * 0x101000	+-----------------------+
+ *		|	free space	|
+ *		|	used as stack   |
+ * 0x100100	+-----------------------+
+ *		|	kernel cmdline	|
+ * 0x100000	+-----------------------+
+*/
+
+#include "bootstub.h"
+
+.text
+
+.section ".text.head","ax",@progbits
+	.globl _start
+
+_start:
+	cld
+	cli
+	/* DS=ES=FS=GS=10 */
+	movl 0x2, %eax	
+	movl %eax, %ds
+	movl %eax, %es
+	movl %eax, %fs
+	movl %eax, %gs
+	movl %eax, %ss
+	/* setup stack, because we are heading off to "C" */
+	movl $STACK_OFFSET, %esp
+	/* after call main, GDT was set (0x10 and 0x18) IDT was clear
+	 * eax will store 32bit entry of bzImage
+         */
+	calll main
+	ljmp $__BOOT_CS,$1f
+1:	
+	/* tell kernel where is boot_param */
+	movl $(BOOT_PARAMS_OFFSET), %esi
+	xor %ebp, %ebp
+	xor %edi, %edi
+	xor %ebx, %ebx
+	
+	jmpl *%eax    # Jump to the 32-bit entrypoint
+	
diff --git a/types.h b/types.h
new file mode 100644
index 0000000..b84de8e
--- /dev/null
+++ b/types.h
@@ -0,0 +1,20 @@
+/* types.h
+ * very early types definition
+ */
+
+#ifndef _TYPES_
+#define _TYPES_
+
+typedef unsigned char  __u8;
+typedef unsigned short __u16;
+typedef unsigned int   __u32;
+typedef unsigned long long __u64;
+
+typedef __u8 u8;
+typedef __u16 u16;
+typedef __u32 u32;
+typedef __u64 u64;
+
+typedef unsigned int size_t;
+
+#endif