added parser for multiboot OS header

src/firmware/multiboot.c

@@ -37,19 +37,104 @@ static struct {
 	char *modules[16];
 } config;
 
-void
-multiboot_init(char *kernel_path, char *initrd_path, char *cmdline) {
-	config.kernel = kernel_path;
-	config.cmdline = cmdline;
-
-	int i = 0;
-	config.modules[i++] = initrd_path;
-	config.modules[i++] = NULL;
+static
+int
+multiboot_parse_image(const char *image, struct multiboot_header *hdr) {
+	FILE *f;
+	uint32_t *head;
+	size_t bytes;
+	int i, ret = -1;
+
+	f = fopen(image, "r");
+	if (!f) {
+		fprintf(stderr, "Failed to load kernel image: %s", strerror(errno));
+		return -1;
+	}
+
+	head = malloc(MULTIBOOT_SEARCH);
+	if (!head)
+		return -2;
+
+	bytes = fread(head, 1, MULTIBOOT_SEARCH, f);
+
+	/* Search Multiboot magic */
+	for (i = 0; i < bytes / sizeof(*head); i++) {
+		if (head[i] == MULTIBOOT_HEADER_MAGIC) {
+			memcpy(hdr, &head[i]);
+
+			/* Verify checksum */
+			ret = (hdr->magic + hdr->flags + hdr->checksum == 0) ? 0 : -3;
+
+			break;
+		}
+	}
+
+	free(head);
+	fclose(f);
+
+	return ret;
+}
+
+int
+multiboot_init(char *opts[]) {
+	config.kernel = opts[0];
+	config.cmdline = opts[1];
+	config.modules = &opts[2];
+
+	return 0;
 }
 
 uint64_t
 multiboot(void)
 {
+	int ret, i;
+	char *module;
+	struct multiboot_header hdr;
 
-	return 0;
+	/* Check integrity and load header of multiboot image */
+	ret = multiboot_parse_image(config.kernel, &hdr);
+	if (ret)
+		abort();
+
+	/* Load OS image (kernel) */
+	ret = multiboot_load_kernel(config.kernel, hdr.load_addr, hdr.load_end_addr);
+	if (ret)
+		abort();
+
+	/* Load modules (initrd..) */
+	for (i = 0; i < 16 && module = config.modules[i]; i++) {
+		FILE *f = fopen(module, "r");
+		if (f) {
+			multiboot_load_module(module);
+		}
+		else {
+			fprintf(stderr, "Failed to open module: %s\n", module);
+		}
+	}
+
+	/* Prepare machine state. See: Section 3.2 of Multiboot spec 0.6 */
+	xh_vcpu_reset(0);
+
+	xh_vm_set_desc(0, VM_REG_GUEST_GDTR, BASE_GDT, 0x1f, 0);
+	xh_vm_set_desc(0, VM_REG_GUEST_CS, 0, 0xffffffff, 0xc09b);
+	xh_vm_set_desc(0, VM_REG_GUEST_DS, 0, 0xffffffff, 0xc093);
+	xh_vm_set_desc(0, VM_REG_GUEST_ES, 0, 0xffffffff, 0xc093);
+	xh_vm_set_desc(0, VM_REG_GUEST_SS, 0, 0xffffffff, 0xc093);
+
+	xh_vm_set_register(0, VM_REG_GUEST_CS, 0x10);
+	xh_vm_set_register(0, VM_REG_GUEST_DS, 0x18);
+	xh_vm_set_register(0, VM_REG_GUEST_ES, 0x18);
+	xh_vm_set_register(0, VM_REG_GUEST_SS, 0x18);
+
+	xh_vm_set_register(0, VM_REG_GUEST_CR0, CR0_PE);
+	xh_vm_set_register(0, VM_REG_GUEST_RFLAGS, 0);
+
+	xh_vm_set_register(0, VM_REG_GUEST_RBP, 0);
+	xh_vm_set_register(0, VM_REG_GUEST_RDI, 0);
+	xh_vm_set_register(0, VM_REG_GUEST_RBX, /* MB info struct */);
+	xh_vm_set_register(0, VM_REG_GUEST_RSI, );
+	xh_vm_set_register(0, VM_REG_GUEST_RIP, );
+	xh_vm_set_register(0, VM_REG_GUEST_RAX, 0x2BADB002);
+
+	return kernel.base;
 }