fernlader2/src/main.c

#include "std.h"

#include <bootboot.h>

#define COM1_BASE_PORT 0x3F8

static inline uint8_t
inb(uint16_t port)
{
	uint8_t data;
	__asm__ ("inb %%dx, %%al" : "=a"(data) : "d"(port));
	return data;
}

static inline void
outb(uint16_t port, uint8_t data)
{
	__asm__ ("outb %%al, %%dx" :: "a"(data), "d"(port));
}

extern void bios_write(const char *msg);
extern void *bios_getmap(void *buffer);

void
debug_write(const char *msg)
{
	for (const char *c = msg; *c; c++) {
		outb(0xE9, *c);
	}
	bios_write(msg);
}

extern BOOTBOOT bootboot;

#define E820_TYPE_FREE        0x1
#define E820_TYPE_RESERVED    0x2
#define E820_TYPE_RECLAIMABLE 0x3
#define E820_TYPE_NONVOLATILE 0x4
#define E820_TYPE_BADMEM      0x5

struct e820_entry {
	uint64_t base;
	uint64_t length;
	uint32_t type;
	uint32_t xattr;
};

struct e820_entry memmap[128];

struct vesa_info {
	char signature[4];
	uint16_t version;
	uint16_t oem_name[2];
	uint8_t capab[4];
	uint16_t video_mode_offset;
	uint16_t video_mode_segment;
	uint16_t num_64k_blocks;
	uint8_t reserved[492];
};

extern uint16_t bios_func(uint8_t inum, uint32_t reg[]);

void
blank_screen(uint16_t attr)
{
	uint32_t reg[7];
	reg[0] = (0x06 << 8);
	reg[1] = 0;
	reg[2] = 0xFFFF;
	reg[3] = attr << 8;
	reg[4] = 0;
	reg[5] = 0;
	reg[6] = 0;
	bios_func(0x10, reg);
}

void
move_cursor(uint8_t row, uint8_t col)
{
	uint32_t reg[7];
	reg[0] = (0x02 << 8);
	reg[1] = 0;
	reg[2] = (row << 8) | col;
	reg[3] = 0;
	reg[4] = 0;
	reg[5] = 0;
	reg[6] = 0;
	bios_func(0x10, reg);
}

void
display_string(uint16_t attr, const char *str)
{
	uint32_t reg[7];
	reg[0] = (0x13 << 8) | 0x01;
	reg[1] = strlen(str);
	reg[2] = 0xFFFF;
	reg[3] = attr;
	reg[4] = (uint32_t)str;
	reg[5] = 0;
	reg[6] = 0;
	bios_func(0x10, reg);
}

void
debug_write_uint(unsigned v)
{
	char buf[20], *p = buf + sizeof buf;
	p--;
	*p = 0;
	do {
		p--;
		*p = (v % 10) + '0';
		v /= 10;
	} while (v);
	debug_write(p);
}

#define PG_PRESENT 0x001
#define PG_WRITE   0x002
#define PG_USER    0x004
#define PG_SIZE    0x080
#define PG_GLOBAL  0x100

__attribute__((aligned(4096))) uint64_t pml4[512];
__attribute__((aligned(4096))) uint64_t pdp[512];
__attribute__((aligned(4096))) uint64_t pd[512];

uint64_t
pg_setup()
{
	pml4[0] = (uint64_t)(uint32_t)pdp | PG_WRITE | PG_PRESENT;
	pdp[0] = (uint64_t)(uint32_t)pd | PG_WRITE | PG_PRESENT;
	for (unsigned i = 0; i < 512; i++) {
		pd[i] = (i * (uint64_t)0x200000) | PG_WRITE | PG_PRESENT | PG_SIZE;
	}
	uint64_t cr3 = (uint64_t)(uint32_t)pml4;
	return cr3;
}

struct PXENV {
	uint8_t  signature[6];
	uint16_t version;
	uint8_t  length;
	uint8_t  checksum;
	uint32_t rmentry;
	uint32_t pmoffset;
};

struct exPXE {
	uint8_t  signature[4];
	uint8_t  length;
	uint8_t  checksum;
	uint8_t  revision;
	uint8_t  reserved;
	uint32_t undiromid;
	uint32_t bcromid;
	uint32_t rmentry;
	uint32_t pmentry;
};

struct bootph {
	uint8_t  opcode;
	uint8_t  hardware;
	uint8_t  hardlen;
	uint8_t  gatehops;
	uint32_t ident;
	uint16_t seconds;
	uint16_t flags;
	uint32_t cip;
	uint32_t yip;
	uint32_t sip;
	uint32_t gip;
	uint8_t  caddr[16];
	uint8_t  sname[64];
	uint8_t  bootfile[128];
	uint8_t  vendor[64];
};

extern uint32_t pxe_entry;
extern uint32_t pxe_call(uint16_t func, uint16_t segment, uint16_t offset);

extern unsigned char pxe_cmd_buf[512];
extern struct PXENV *PXENV;
extern struct exPXE *exPXE;

#define PXENV_GET_CACHED 0x0071
#define PXENV_TFTP_OPEN  0x0020

typedef struct __attribute__((packed)) s_PXENV_GET_CACHED {
	uint16_t      status;
	uint16_t      packet_type;
	uint16_t      buffer_size;
	uint16_t      buffer_offset;
	uint16_t      buffer_seg;
	uint16_t      buffer_limit;
} t_PXENV_GET_CACHED;

typedef struct __attribute__((packed)) s_PXENV_TFTP_OPEN {
	uint16_t      status;
	uint32_t      server_ip;
	uint32_t      gateway_ip;
	unsigned char filename[128];
	uint16_t      tftp_port;
	uint16_t      packet_size;
} t_PXENV_TFTP_OPEN;

void
main()
{
	blank_screen(0x10);
	move_cursor(0, 0);
	//display_string(0x14, "Netboot via fernlader v2 ...\r\n");
	debug_write("Going well ...\r\n");

	if (memcmp(PXENV->signature, "PXENV+", 6) != 0) {
		debug_write("missing PXENV+ signature\r\n");
	}
	if (PXENV->version >= 0x0201) {
		debug_write("!PXE version\r\n");
		if (memcmp(exPXE->signature, "!PXE", 4) != 0) {
			debug_write("missing !PXE signature\r\n");
		}
		pxe_entry = exPXE->rmentry;
	}

	memcpy(bootboot.magic, BOOTBOOT_MAGIC, sizeof bootboot.magic);
	bootboot.size = 128;
	bootboot.protocol = PROTOCOL_MINIMAL | LOADER_BIOS;
	bootboot.numcores = 1;

	//display_string(0x0E, "init\r\n");
	struct e820_entry *end = bios_getmap(memmap);
	//display_string(0x0E, "karlos\r\n");
	for (int i = 0; ; i++) {
		if (&memmap[i] >= end) break;
		char buf[2];
		buf[0] = memmap[i].type < 10 ? memmap[i].type + '0' : '?';
		buf[1] = 0;
		debug_write(buf);
	}

	pg_setup();

#if 1
	t_PXENV_GET_CACHED *t_get = (void *)pxe_cmd_buf;
	t_get->status = 0;
	t_get->packet_type = 2;
	t_get->buffer_size = 0;
	t_get->buffer_offset = 0;
	t_get->buffer_seg = 0;
	t_get->buffer_limit = 0xFFFFu;
	debug_write("Performing PXE call\r\n");
	unsigned ret = pxe_call(PXENV_GET_CACHED, (uint16_t)(uintptr_t)pxe_cmd_buf, 0x0000);
	debug_write("Still alive!\r\n");
	debug_write("ret=");
	debug_write_uint(ret);
	debug_write("\r\nstatus=");
	debug_write_uint(t_get->status);
	debug_write("\r\n");
#endif

	debug_write("buffer_off=");
	debug_write_uint(t_get->buffer_offset);
	debug_write("\r\nbuffer_seg=");
	debug_write_uint(t_get->buffer_seg);
	struct bootph *bootph = (void *)(t_get->buffer_offset + 16 * t_get->buffer_seg);
	uint32_t sip = bootph->sip;
	uint32_t gip = bootph->gip;
	debug_write("\r\nsip=");
	debug_write_uint(sip);
	debug_write("\r\ngip=");
	debug_write_uint(gip);
	debug_write("\r\n");

#if 1
	t_PXENV_TFTP_OPEN *t_open = (void *)pxe_cmd_buf;
	t_open->status = 0;
	t_open->server_ip = sip;
	t_open->gateway_ip = gip;
	memcpy(t_open->filename, "/initrd", 8);
	t_open->tftp_port = 69 << 8;
	t_open->packet_size = 512;
	debug_write("Performing PXE OPEN call\r\n");
	ret = pxe_call(PXENV_TFTP_OPEN, (uint16_t)(uintptr_t)pxe_cmd_buf, 0x0000);
	debug_write("Still alive!\r\n");
	debug_write("ret=");
	debug_write_uint(ret);
	debug_write("\r\nstatus=");
	debug_write_uint(t_open->status);
	debug_write("\r\n");
#endif

#if 0
	uint32_t reg[7];
	reg[0] = (0x0E << 8) + 'J';
	reg[1] = 0;
	reg[2] = 0;
	reg[3] = 0;
	reg[4] = 0;
	reg[5] = 0;
	reg[6] = 0;
	bios_func(0x10, reg);

	debug_write("what?\r\n");
#endif

	for (;;) {
		__asm__ ("hlt");
	}
}