iris/source/bootinit.ccp

#pypp 0
// Iris: micro-kernel for a capability-based operating system.
// source/bootinit.ccp: Bootstrapping code.
// Copyright 2009-2010 Bas Wijnen <wijnen@debian.org>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

#include "devices.hh"
#include "iris.hh"
#include <elf.h>

#define ELFRUN_NAME "elfrun.elf"
#define INIT_NAME "init.elf"

// These numbers are only used for elfrun.
#define NUM_SLOTS 8
#define NUM_CAPS 32

static unsigned _free
extern unsigned _end

void init_alloc ():
	_free = ((unsigned)&_end + PAGE_SIZE - 1) & PAGE_MASK

char *alloc_space (unsigned pages):
	unsigned ret = (_free + PAGE_SIZE - 1) & PAGE_MASK
	_free = ret + (pages << PAGE_BITS)
	return (char *)ret

void *operator new[] (unsigned size):
	//kdebug ("new ")
	void *ret = (void *)_free
	size = (size + 3) & ~3
	unsigned rest = PAGE_SIZE - (((_free - 1) & ~PAGE_MASK) + 1)
	if rest < size:
		unsigned pages = ((size - rest) + PAGE_SIZE - 1) >> PAGE_BITS
		for unsigned p = 0; p < pages; ++p:
			Iris::Page page = Iris::my_memory.create_page ()
			page.set_flags (Iris::Page::PAYING | Iris::Page::FRAME)
			Iris::my_memory.map (page, _free + rest + (p << PAGE_BITS))
			Iris::free_cap (page)
	_free += size
	//kdebug_num ((unsigned)ret)
	//kdebug ("+")
	//kdebug_num (size)
	//kdebug ("\n")
	return ret

void *operator new (unsigned size):
	return new char[size]

static unsigned *bss_mapping
static Iris::Page bss_page

// Get the initial block device and filesystem.
static Iris::Directory receive_devices ():
	Iris::String device
	bool have_device = false
	Iris::Cap reply[2]
	bool have_reply[2]
	have_reply[0] = false
	have_reply[1] = false
	unsigned next = 2
	while true:
		Iris::wait ()
		kdebug_num (Iris::recv.protected_data.l, 1)
		kdebug (": ")
		if Iris::recv.protected_data.l == 0:
			kdebug ("sd detect event device request\n")
			// SD detection event device request.
			// Ignore all; that will result in the driver thinking there is a card.
			Iris::recv.reply.invoke ()
			continue
		switch Iris::recv.data[0].l:
			case Iris::Parent::PROVIDE_CAPABILITY:
				switch Iris::recv.data[1].l:
					case Iris::String::ID:
					case Iris::WString::ID:
						// Ignore other partitions.
						Iris::Cap r = Iris::get_reply ()
						if Iris::recv.data[0].h != 0:
							kdebug ("ignoring non-0 partition\n")
						else:
							if have_device:
								Iris::panic (0, "double device provided")
							device = Iris::get_arg ()
							if have_reply[next - 2]:
								kdebug ("string provided (used)\n")
								reply[next++ - 2].invoke (0, 0, device.copy ())
								Iris::free_cap (device)
							else:
								kdebug ("string provided (stored)\n")
								have_device = true
						r.invoke ()
						Iris::free_cap (r)
						break
					case Iris::Directory::ID:
						kdebug ("directory provided\n")
						Iris::Directory ret = Iris::get_arg ()
						Iris::recv.reply.invoke ()
						return ret
					default:
						Iris::panic (Iris::recv.data[1].l, "invalid capability type provided by boot thread")
				break
			case Iris::Parent::GET_CAPABILITY:
				if Iris::recv.data[1].l == Iris::Event::ID:
					kdebug ("event requested\n")
					// Detection of sd card.
					Iris::Cap reply = Iris::get_reply ()
					Iris::Cap event = Iris::my_receiver.create_capability (0)
					reply.invoke (0, 0, event.copy ())
					Iris::free_cap (event)
					Iris::free_cap (reply)
					break
				if Iris::recv.data[1].l != Iris::String::ID && Iris::recv.data[1].l != Iris::WString::ID:
					Iris::panic (Iris::recv.data[1].l, "invalid capability type requested by boot thread")
				if next == Iris::recv.protected_data.l && have_device:
					kdebug ("string requested (sent)\n")
					Iris::recv.reply.invoke (0, 0, device.copy ())
					Iris::free_cap (device)
					have_device = false
					++next
				else:
					kdebug ("string requested (not sent)\n")
					reply[Iris::recv.protected_data.l - 2] = Iris::get_reply ()
					have_reply[Iris::recv.protected_data.l - 2] = true
				break
			case Iris::Parent::INIT_DONE:
				kdebug ("init done\n")
				// Ignore.
				Iris::recv.reply.invoke ()
				break
			case Iris::Parent::EXIT:
				Iris::panic (Iris::recv.protected_data.l, "boot thread exits")
			default:
				Iris::panic (Iris::recv.protected_data.l, "invalid boot request")

static bool stringcmp (char const *s1, char const *s2, unsigned size):
	for unsigned t = 0; t < size; ++t:
		if s1[t] != s2[t]:
			return false
	return true

static Iris::String find (Iris::Directory root, char const *name):
	unsigned size = 0
	while name[size]:
		++size
	Iris::Num num_files = root.get_size ()
	for Iris::Num i = 0; i.value () < num_files.value (); i = i.value () + 1:
		Iris::String n = root.get_name (i)
		char current_name[16]
		n.get_chars (0, current_name)
		Iris::free_cap (n)
		if !stringcmp (current_name, name, size):
			continue
		// Found elfrun.
		Iris::String ret = root.get_file_ro (i)
		return ret
	Iris::panic (0, "bootfile not found")

static void run (Iris::String data, Iris::Memory parent_memory, Iris::Cap parent):
	// Get the size.
	Iris::Num size = data.get_size ()
	if size.value () == 0:
		Iris::panic (0, "elfrun is empty")
	// Allocate a caps with all the pages.
	unsigned pages = (size.value () + PAGE_SIZE - 1) >> PAGE_BITS
	Iris::Caps pages_caps = Iris::my_memory.create_caps (pages)
	unsigned slot = pages_caps.use ()
	// Map them into the address space as well.
	char *mapping = alloc_space (pages)
	// Create a memory for the program.
	Iris::Memory mem = parent_memory.create_memory ()
	// Load the file into memory and map it.
	for unsigned p = 0; p < pages; ++p:
		//kdebug_num (p)
		//kdebug ("/")
		//kdebug_num (pages)
		//kdebug ("\n")
		Iris::set_recv_arg (Iris::Cap (slot, p))
		Iris::my_memory.create_page ()
		Iris::Page (slot, p).set_flags (Iris::Page::PAYING)
		data.get_block (p << PAGE_BITS, PAGE_SIZE, 0, Iris::Cap (slot, p))
		Iris::my_memory.map (Iris::Cap (slot, p), (unsigned)&mapping[p << PAGE_BITS])
	Iris::Thread thread = mem.create_thread (NUM_SLOTS)
	Elf32_Ehdr *header = (Elf32_Ehdr *)mapping
	for unsigned j = 0; j < SELFMAG; ++j:
		if header->e_ident[j] != ELFMAG[j]:
			Iris::panic (header->e_ident[j], "invalid ELF magic")
			return
	if header->e_ident[EI_CLASS] != ELFCLASS32:
		kdebug ("invalid ELF class:")
		kdebug_num (header->e_ident[EI_CLASS])
		kdebug (" != ")
		kdebug_num (ELFCLASS32)
		kdebug ("\n")
		Iris::panic (0)
		return
	if header->e_ident[EI_DATA] != ELFDATA2LSB:
		Iris::panic (header->e_ident[EI_DATA], "invalid ELF data")
	if header->e_ident[EI_VERSION] != EV_CURRENT:
		Iris::panic (header->e_ident[EI_VERSION], "invalid ELF version")
	if header->e_type != ET_EXEC:
		Iris::panic (header->e_type, "invalid ELF type")
	if header->e_machine != EM_MIPS_RS3_LE && header->e_machine != EM_MIPS:
		Iris::panic (header->e_machine, "invalid ELF machine")
	thread.set_pc (header->e_entry)
	thread.set_sp (0x80000000)
	for unsigned section = 0; section < header->e_shnum; ++section:
		Elf32_Shdr *shdr = (Elf32_Shdr *)((unsigned)mapping + header->e_shoff + section * header->e_shentsize)
		if ~shdr->sh_flags & SHF_ALLOC:
			continue
		bool readonly = !(shdr->sh_flags & SHF_WRITE)
		//bool executable = shdr->sh_flags & SHF_EXEC_INSTR
		if shdr->sh_type != SHT_NOBITS:
			unsigned file_offset = shdr->sh_offset >> PAGE_BITS
			if (file_offset + ((shdr->sh_size + PAGE_SIZE - 1) >> PAGE_BITS)) >= (PAGE_SIZE >> 2):
				Iris::panic (shdr->sh_size, "thread too large")
				return
			for unsigned p = (shdr->sh_addr & PAGE_MASK); p < shdr->sh_addr + shdr->sh_size; p += PAGE_SIZE:
				unsigned section_offset = (p - (shdr->sh_addr & PAGE_MASK)) >> PAGE_BITS
				unsigned idx = file_offset + section_offset
				Iris::Page page = mem.mapping ((void *)p)
				if Iris::recv.data[0].l == Iris::NO_ERROR:
					// The address already has a mapping; assume that it is correct.
					Iris::free_cap (page)
					continue
				Iris::free_cap (page)
				page = mem.create_page ()
				unsigned f
				if readonly:
					f = Iris::Page::PAYING | Iris::Page::MAPPED_READONLY
				else:
					f = Iris::Page::PAYING
				page.set_flags (f)
				Iris::Page (slot, idx).share (page, 0)
				//kdebug ("mapping at ")
				//kdebug_num (p)
				//if readonly:
				//	kdebug (" (readonly)")
				//kdebug ("\n")
				if !mem.map (page, p):
					Iris::panic (0, "unable to map page")
					return
				Iris::free_cap (page)
		else:
			if readonly:
				Iris::panic (0, "unwritable bss section")
				return
			for unsigned p = (shdr->sh_addr & PAGE_MASK); p < shdr->sh_addr + shdr->sh_size; p += PAGE_SIZE:
				Iris::Page page = mem.mapping ((void *)p)
				if Iris::recv.data[0].l == Iris::NO_ERROR:
					// No error means there is a mapping.
					page.share (bss_page, 0)
					Iris::free_cap (page)
					for unsigned a = p; a < ((p + PAGE_SIZE) & PAGE_MASK); a += 4:
						if a >= shdr->sh_addr + shdr->sh_size:
							break
						if a < shdr->sh_addr:
							continue
						bss_mapping[(a & ~PAGE_MASK) >> 2] = 0
				else:
					Iris::free_cap (page)
					page = mem.create_page ()
					if Iris::recv.data[0].l != Iris::NO_ERROR:
						Iris::panic (Iris::recv.data[0].l, "out of memory")
					if !page.set_flags (Iris::Page::PAYING | Iris::Page::FRAME):
						Iris::panic (0, "out of memory")
					if !mem.map (page, p):
						Iris::panic (0, "unable to map bss page")
					Iris::free_cap (page)
	for unsigned p = 0; p < pages; ++p:
		Iris::my_memory.destroy (Iris::Page (slot, p))
	Iris::my_memory.destroy (pages_caps)
	Iris::free_slot (slot)
	Iris::Page stackpage = mem.create_page ()
	stackpage.set_flags (Iris::Page::PAYING | Iris::Page::FRAME)
	if Iris::recv.data[0].l != Iris::NO_ERROR || !mem.map (stackpage, 0x7ffff000):
		Iris::panic (Iris::recv.data[0].l, "unable to map initial stack page")
	Iris::free_cap (stackpage)
	Iris::Caps caps = mem.create_caps (NUM_CAPS)
	thread.use (caps, 0)
	thread.set_info (Iris::Thread::A0, NUM_SLOTS)
	thread.set_info (Iris::Thread::A1, NUM_CAPS)
	Iris::Receiver receiver = mem.create_receiver ()
	receiver.set_owner (thread.copy ())
	Iris::Cap call = receiver.create_call_capability ()
	caps.set (__caps_num, caps.copy ())
	caps.set (__receiver_num, receiver.copy ())
	caps.set (__thread_num, thread.copy ())
	caps.set (__memory_num, mem.copy ())
	caps.set (__call_num, call.copy ())
	caps.set (__parent_num, parent)
	thread.run ()
	Iris::free_cap (receiver)
	Iris::free_cap (thread)
	Iris::free_cap (call)
	Iris::free_cap (caps)

Iris::Num start ():
	// Wait for the debugging device to be active, in case there is one.
	Iris::schedule ()
	kdebug ("Starting bootinit\n")
	init_alloc ()
	bss_mapping = (unsigned *)alloc_space (1)
	bss_page = Iris::my_memory.create_page ()
	Iris::my_memory.map (bss_page, (unsigned)bss_mapping)

	Iris::Memory top_memory = Iris::get_top_memory ()
	Iris::Directory root = receive_devices ()
	root.lock_ro ()
	Iris::String run_string = find (root, ELFRUN_NAME)
	Iris::Cap parent_cap = Iris::my_receiver.create_capability (0)
	run (run_string, top_memory, parent_cap)
	Iris::wait ()
	if Iris::recv.data[0].l != Iris::Parent::PROVIDE_CAPABILITY || Iris::recv.data[1].l != Iris::Elfrun::ID:
		Iris::panic (0, "elfrun doesn't provide correct capability")
	Iris::Cap reply = Iris::get_reply ()
	Iris::Elfrun elfrun = Iris::get_arg ()
	Iris::my_caps.set (parent_cap.idx (), Iris::Cap (CAP_NONE))
	Iris::free_cap (parent_cap)
	reply.invoke ()
	Iris::free_cap (reply)

	parent_cap = Iris::my_receiver.create_capability (0)
	Iris::String init_string = find (root, INIT_NAME)
	Iris::Caps init_caps = elfrun.run_string (top_memory.copy (), init_string.copy (), parent_cap.copy (), 8, 63)

	Iris::Thread init = init_caps.get (__thread_num)
	init.make_priv ()
	init.run ()
	Iris::free_cap (init)
	Iris::free_cap (init_caps)

	bool have_root = false
	bool have_elfrun = false
	while true:
		Iris::wait ()
		switch Iris::recv.data[0].l:
			case Iris::Parent::GET_CAPABILITY:
				switch Iris::recv.data[1].l:
					case Iris::Directory::ID:
						if have_root:
							Iris::panic (0, "Init requests root directory twice")
						Iris::recv.reply.invoke (0, 0, root.copy ())
						have_root = true
						break
					case Iris::Elfrun::ID:
						if have_elfrun:
							Iris::panic (0, "Init requests elfrun twice")
						Iris::recv.reply.invoke (0, 0, elfrun.copy ())
						have_elfrun = true
						break
					default:
						Iris::panic (0, "Invalid device requested by init")
				break
			case Iris::Parent::INIT_DONE:
				if Iris::recv.data[1].value () != 0:
					Iris::recv.reply.invoke ()
					break
				// Special response: kill boot threads.
				Iris::Cap reply = Iris::get_reply ()
				root.unlock_ro ()
				reply.invoke ()
				Iris::free_cap (reply)
				top_memory.destroy (Iris::my_memory)
				Iris::panic (0, "bootinit should be destroyed")
			default:
				Iris::panic (Iris::recv.data[0].l, "invalid operation from init")