iris/alloc.ccp

#pypp 0
// Iris: micro-kernel for a capability-based operating system.
// alloc.ccp: Allocation of kernel structures.
// 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 "kernel.hh"

#define PREV(x) (((Object_base **)(x))[-2])
#define NEXT(x) (((Object_base **)(x))[-1])
#define SIZE (2 * sizeof (unsigned))

bool Memory::use ():
	// Go up to parents, incrementing used.
	for Memory *m = this; m; m = m->address_space:
		if used >= limit:
			// Not allowed.  Restore used for all children.
			for Memory *r = this; r != m; r = r->address_space:
				--r->used
			return false
		++m->used
	return true

void Memory::unuse ():
	for Memory *m = this; m; m = m->address_space:
		--m->used

unsigned raw_zalloc ():
	FreePage *ret = zero_pages
	if !ret:
		ret = junk_pages
		for unsigned i = 1; i < (PAGE_SIZE >> 2); ++i:
			((unsigned *)ret)[i] = 0
		junk_pages = ret->next
	else:
		zero_pages = ret->next
	ret->next = NULL
	return (unsigned)ret

void raw_pfree (unsigned page):
	FreePage *p = (FreePage *)page
	p->next = junk_pages
	junk_pages = p

unsigned Memory::palloc ():
	if !use ():
		return NULL
	FreePage *ret = junk_pages
	if !ret:
		ret = zero_pages
		zero_pages = ret->next
	else:
		junk_pages = ret->next
	return (unsigned)ret
	
unsigned Memory::zalloc ():
	if !use ():
		return NULL
	return raw_zalloc ()

void Memory::pfree (unsigned page):
	unuse ()
	return raw_pfree (page)

void Memory::zfree (unsigned page):
	unuse ()
	FreePage *p = (FreePage *)page
	p->next = zero_pages
	zero_pages = p

void *Memory::search_free (unsigned size, void **first):
	Free *f
	unsigned s = 0
	for f = frees; f; f = f->next:
		if NEXT (f):
			s = (unsigned)NEXT (f) - (unsigned)f
		else:
			s = PAGE_SIZE - ((unsigned)f & ~PAGE_MASK) + SIZE
		if s >= size + SIZE:
			break
	if !f:
		unsigned p = palloc ()
		if !p:
			return NULL
		f = (Free *)(p + SIZE)
		f->marker = ~0
		f->next = frees
		f->prev = NULL
		frees = f
		if f->next:
			f->next->prev = f
		NEXT (f) = NULL
		PREV (f) = NULL
		s = PAGE_SIZE
	// We have a free block, possibly too large.
	if s >= size + sizeof (Free) + SIZE:
		// Create the new object at the end and keep the Free.
		Free *obj = (Free *)((unsigned)f + s - size - SIZE)
		NEXT (obj) = NEXT (f)
		if NEXT (obj):
			PREV (NEXT (obj)) = obj
		PREV (obj) = f
		NEXT (f) = obj
		f = obj
	else:
		if f->prev:
			f->prev->next = f->next
		else:
			frees = f->next
		if f->next:
			f->next->prev = f->prev
	f->address_space = this
	f->refs = NULL
	f->next = (Free *)*first
	f->prev = NULL
	if f->next:
		f->next->prev = f
	*first = f
	return f

void Memory::free_obj (Object_base *obj):
	Free *self
	// Merge with previous, if it exists and is a Free.
	if PREV (obj) && PREV (obj)->is_free ():
		self = (Free *)PREV (obj)
		NEXT (self) = NEXT (obj)
		if NEXT (obj):
			PREV (NEXT (obj)) = self
	else:
		self = (Free *)obj
		self->next = frees
		self->prev = NULL
		if self->next:
			self->next->prev = self
		frees = self
		self->marker = ~0
	// Merge with next, if it exists and is a Free.
	if NEXT (self) && NEXT (self)->is_free ():
		NEXT (self) = NEXT (NEXT (self))
		if NEXT (self):
			PREV (NEXT (self)) = self
	// Free page if the resulting object is the only thing in it.
	if !PREV (self) && !NEXT (self):
		if self->next:
			self->next->prev = self->prev
		if self->prev:
			self->prev->next = self->next
		else:
			frees = self->next
		pfree ((unsigned)(self - SIZE))

Page *Memory::alloc_page ():
	Page *ret = (Page *)search_free (sizeof (Page), (void **)&pages)
	if !ret:
		return NULL
	ret->data.frame = 0
	ret->data.flags = 0
	return ret

Thread *Memory::alloc_thread ():
	Thread *ret = (Thread *)search_free (sizeof (Thread), (void **)&threads)
	if !ret:
		return NULL
	ret->address_space = this
	ret->pc = 0
	ret->sp = 0
	Thread_arch_init (ret)
	ret->flags = 0
	ret->schedule_prev = NULL
	ret->schedule_next = NULL
	ret->receivers = NULL
	return ret

Message *Memory::alloc_message (Receiver *target, unsigned protected_data):
	Message *ret = (Message *)search_free (sizeof (Message), (void **)&target->messages)
	if !ret:
		return NULL
	for unsigned i = 0; i < 4; ++i:
		ret->capabilities[i] = NULL
		ret->data[i] = 0
	ret->protected_data = protected_data
	return ret

Receiver *Memory::alloc_receiver ():
	Receiver *ret = (Receiver *)search_free (sizeof (Receiver), (void **)&receivers)
	if !ret:
		return NULL
	ret->owner = NULL
	ret->prev_owned = NULL
	ret->next_owned = NULL
	ret->capabilities = NULL
	ret->messages = NULL
	ret->reply_protected_data = ~0
	ret->protected_only = false
	return ret

Capability *Memory::alloc_capability (Receiver *target, Capability *parent, Capability **parent_ptr, unsigned protected_data, Capability *ret):
	if !ret:
		ret = (Capability *)search_free (sizeof (Capability), (void **)&capabilities)
		if !ret:
			return NULL
	ret->target = target
	ret->parent = parent
	ret->children = NULL
	ret->sibling_prev = NULL
	ret->sibling_next = parent_ptr ? *parent_ptr : NULL
	if ret->sibling_next:
		ret->sibling_next->sibling_prev = ret
	ret->protected_data = protected_data
	return ret

Capability *Memory::clone_capability (Capability *source, bool copy, Capability *ret):
	if copy:
		return alloc_capability (source->target, source->parent, source->parent ? &source->parent->children : &source->target->capabilities, source->protected_data, ret)
	else:
		return alloc_capability (source->target, source, &source->children, source->protected_data, ret)

Cappage *Memory::alloc_cappage ():
	Cappage *ret = (Cappage *)search_free (sizeof (Cappage), (void **)&cappages)
	if !ret:
		return NULL
	ret->data.frame = zalloc ()
	if !ret->data.frame:
		free_cappage (ret)
		return NULL
	ret->data.flags = 0
	return ret

Memory *Memory::alloc_memory ():
	Memory *ret = (Memory *)search_free (sizeof (Memory), (void **)&memories)
	if !ret:
		return NULL
	ret->frees = NULL
	ret->pages = NULL
	ret->threads = NULL
	ret->memories = NULL
	ret->limit = ~0
	ret->used = 0
	Memory_arch_init (ret)
	return ret

void Memory::free_page (Page *page):
	if page->prev:
		page->prev->next = page->next
	else:
		pages = page->next
	if page->next:
		page->next->prev = page->prev
	unuse ()
	if page->data.frame:
		pfree (page->data.frame)
	free_obj (page)

void Memory::free_thread (Thread *thread):
	if thread->prev:
		thread->prev->next = thread->next
	else:
		threads = thread->next
	if thread->next:
		thread->next->prev = thread->prev
	// Unschedule.
	if thread->schedule_prev:
		thread->schedule_prev->schedule_next = thread->schedule_next
	else if first_scheduled == thread:
		first_scheduled = thread->schedule_next
	if thread->schedule_next:
		thread->schedule_next->schedule_prev = thread->schedule_prev
	while thread->receivers:
		thread->receivers->orphan ()
	free_obj (thread)

void Memory::free_message (Message *message):
	for unsigned i = 0; i < 4; ++i:
		free_capability (message->capabilities[i])
	free_obj (message)

void Memory::free_receiver (Receiver *receiver):
	receiver->orphan ()
	while receiver->capabilities:
		receiver->capabilities->invalidate ()
	while receiver->messages:
		free_message (receiver->messages)
	free_obj (receiver)

void Receiver::orphan ():
	if prev_owned:
		prev_owned->next_owned = next_owned
	else:
		owner->receivers = next_owned
	if next_owned:
		next_owned->prev_owned = prev_owned
	owner = NULL

void Receiver::own (Thread *o):
	if owner:
		orphan ()
	owner = o
	next_owned = o->receivers
	if next_owned:
		next_owned->prev_owned = this
	o->receivers = this

void Memory::free_capability (Capability *capability):
	capability->invalidate ()
	free_obj (capability)

void Capability::invalidate ():
	if !target:
		return
	if sibling_prev:
		sibling_prev->sibling_next = sibling_next
	else if target:
		target->capabilities = sibling_next
	if sibling_next:
		sibling_next->sibling_prev = sibling_prev
	parent = NULL
	sibling_prev = NULL
	sibling_next = NULL
	Capability *c = this
	while c->children:
		c = c->children
	while c:
		Capability *next = c->sibling_next
		if !next:
			next = c->parent
		c->target = NULL
		c->parent = NULL
		c->children = NULL
		c->sibling_prev = NULL
		c->sibling_next = NULL
		c->protected_data = 0
		c = next

void Memory::free_cappage (Cappage *p):
	for unsigned i = 0; i < CAPPAGE_SIZE; ++i:
		((Capability *)p->data.frame)[i].invalidate ()
	zfree (p->data.frame)
	free_obj (p)

void Memory::free_memory (Memory *mem):
	if mem->prev:
		mem->prev->next = mem->next
	else:
		memories = mem->next
	if mem->next:
		mem->next->prev = mem->prev
	while mem->pages:
		free_page (mem->pages)
	while mem->threads:
		free_thread (mem->threads)
	while mem->memories:
		free_memory (mem->memories)
	Memory_arch_free (mem)
	free_obj (mem)

void Page::forget ():
	if data.share_prev || data.share_next:
		if data.share_prev:
			((Page *)data.share_prev)->data.share_next = data.share_next
		if data.share_next:
			((Page *)data.share_next)->data.share_prev = data.share_prev
		data.share_prev = NULL
		data.share_next = NULL
	else:
		raw_pfree (data.frame)
	data.frame = 0
	data.flags &= ~(PAGE_FLAG_FRAME | PAGE_FLAG_SHARED)
	Page_arch_update_mapping (this)

void Cappage::forget ():
	if data.share_prev || data.share_next:
		if data.share_prev:
			((Cappage *)data.share_prev)->data.share_next = data.share_next
		if data.share_next:
			((Cappage *)data.share_next)->data.share_prev = data.share_prev
		data.share_prev = NULL
		data.share_next = NULL
	else:
		for unsigned i = 0; i < CAPPAGE_SIZE; ++i:
			((Capability *)data.frame)[i].invalidate ()
		raw_pfree (data.frame)
	data.frame = 0
	data.flags &= ~(PAGE_FLAG_FRAME | PAGE_FLAG_SHARED)