iris/source/elfrun.ccp

#pypp 0
// Iris: micro-kernel for a capability-based operating system.
// source/elfrun.ccp: Process creation server.
// Copyright 2009 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>

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::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 Iris::Memory parent_memory
static Iris::Cap parent
static unsigned slot
static char *mapping
static unsigned pages
static Iris::Caps pages_caps
static Iris::Memory mem
static unsigned *bss_mapping
static Iris::Page bss_page

static Iris::Caps map_string (Iris::String data):
	// Get the size.
	Iris::Num size = data.get_size ()
	if size.value () == 0:
		Iris::panic (0, "data string is empty")
	// Allocate a caps with all the pages.
	pages = (size.value () + PAGE_SIZE - 1) >> PAGE_BITS
	pages_caps = Iris::my_memory.create_caps (pages)
	slot = pages_caps.use ()
	// Map them into the address space as well.
	mapping = alloc_space (pages)
	// Create a memory for the program.
	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))
		data.get_page (p << PAGE_BITS)
		Iris::my_memory.map (Iris::Cap (slot, p), (unsigned)&mapping[p << PAGE_BITS])

static Iris::Caps map_caps (Iris::Caps data, unsigned p):
	// Get the size.
	if p == 0:
		Iris::panic (0, "data caps is empty")
	// Allocate a new caps with all the pages for mapping locally.
	pages = p
	pages_caps = Iris::my_memory.create_caps (pages)
	slot = pages_caps.use ()
	unsigned src_slot = data.use ()
	// Map them into the address space as well.
	mapping = alloc_space (pages)
	// Create a memory for the program.
	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::Page page = Iris::Cap (slot, p)
		Iris::set_recv_arg (page)
		Iris::my_memory.create_page ()
		Iris::Page (Iris::Cap (src_slot, p)).share (page)
		Iris::my_memory.map (page, (unsigned)&mapping[p << PAGE_BITS])
	Iris::free_slot (src_slot)

static Iris::Caps run (Iris::Caps data, Iris::Memory parent_memory, Iris::Cap parent, unsigned num_slots, unsigned num_caps):
	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 Iris::Caps ()
	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 Iris::Caps ()
	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:
			//kdebug ("loading ")
			//kdebug_num (shdr->sh_addr)
			//kdebug ("+")
			//kdebug_num (shdr->sh_size)
			//kdebug ("\n")
			unsigned file_offset = shdr->sh_offset >> PAGE_BITS
			if (file_offset + ((shdr->sh_size + PAGE_SIZE - 1) >> PAGE_BITS)) >= (PAGE_SIZE >> 2):
				kdebug ("thread size: ")
				kdebug_num (file_offset)
				kdebug (",")
				kdebug_num (shdr->sh_size)
				kdebug ("\n")
				Iris::panic (shdr->sh_size, "thread too large")
				return Iris::Caps ()
			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, 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::Caps ()
				Iris::free_cap (page)
		else:
			if readonly:
				Iris::panic (0, "unwritable bss section")
				return Iris::Caps ()
			//kdebug ("clearing ")
			//kdebug_num (shdr->sh_addr)
			//kdebug ("+")
			//kdebug_num (shdr->sh_size)
			//kdebug ("\n")
			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::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)
	//kdebug ("start of program:\n")
	//for unsigned i = 0; i < 0x40; i += 4:
	//	kdebug_num ((unsigned)mapping + 4 * i, 3)
	//	kdebug (" ==>")
	//	for unsigned j = 0; j < 4; j += 1:
	//		kdebug (" ")
	//		kdebug_num (((unsigned *)mapping)[i + j])
	//	kdebug ("\n")
	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::free_cap (pages_caps)
	Iris::Page stackpage = mem.create_page ()
	stackpage.set_flags (Iris::Page::PAYING | Iris::Page::FRAME, 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.copy ())
	Iris::free_cap (receiver)
	Iris::free_cap (thread)
	Iris::free_cap (mem)
	Iris::free_cap (call)
	return caps

Iris::Num start ():
	kdebug ("elfrun started.\n")
	init_alloc ()
	Iris::Elfrun dev = Iris::my_receiver.create_capability (0)
	Iris::my_parent.provide_capability <Iris::Elfrun> (dev.copy ())
	Iris::free_cap (dev)
	bss_mapping = (unsigned *)alloc_space (1)
	bss_page = Iris::my_memory.create_page ()
	Iris::my_memory.map (bss_page, (unsigned)bss_mapping)

	while true:
		Iris::wait ()
		Iris::Cap reply = Iris::get_reply ()
		Iris::Cap arg = Iris::get_arg ()
		switch Iris::recv.data[0].l:
			case Iris::Elfrun::RUN_STRING:
				unsigned num_slots = Iris::recv.data[1].l
				unsigned num_caps = Iris::recv.data[1].h
				parent_memory = Iris::Caps (arg).get (Iris::Elfrun::PARENT_MEMORY)
				parent = Iris::Caps (arg).get (Iris::Elfrun::PARENT)
				Iris::String data = Iris::Caps (arg).get (Iris::Elfrun::DATA)
				map_string (data)
				Iris::Caps ret = run (data, parent_memory, parent, num_slots, num_caps)
				reply.invoke (0, 0, ret.copy ())
				free_cap (ret)
				free_cap (parent_memory)
				free_cap (parent)
				free_cap (data)
				break
			case Iris::Elfrun::RUN_CAPS:
				unsigned num_slots = Iris::recv.data[1].l
				unsigned num_caps = Iris::recv.data[1].h
				unsigned p = Iris::recv.data[0].h
				parent_memory = Iris::Caps (arg).get (Iris::Elfrun::PARENT_MEMORY)
				parent = Iris::Caps (arg).get (Iris::Elfrun::PARENT)
				Iris::Caps data = Iris::Caps (arg).get (Iris::Elfrun::DATA)
				map_caps (data, p)
				Iris::Caps ret = run (data, parent_memory, parent, num_slots, num_caps)
				reply.invoke (0, 0, ret.copy ())
				free_cap (ret)
				free_cap (parent_memory)
				free_cap (parent)
				free_cap (data)
				break
			default:
				Iris::panic (0, "invalid operation for elfrun")
				reply.invoke (~0)
				break
		Iris::free_cap (arg)
		Iris::free_cap (reply)