mckernel/kernel/process.c

/**
 * \file process.c
 *  License details are found in the file LICENSE.
 * \brief
 *  process, thread, and, virtual memory management
 * \author Taku Shimosawa  <shimosawa@is.s.u-tokyo.ac.jp> \par
 * 	Copyright (C) 2011 - 2012  Taku Shimosawa
 * \author Balazs Gerofi  <bgerofi@riken.jp> \par
 * 	Copyright (C) 2012  RIKEN AICS
 * \author Masamichi Takagi  <m-takagi@ab.jp.nec.com> \par
 * 	Copyright (C) 2012 - 2013  NEC Corporation
 * \author Balazs Gerofi  <bgerofi@is.s.u-tokyo.ac.jp> \par
 * 	Copyright (C) 2013  The University of Tokyo
 * \author Gou Nakamura  <go.nakamura.yw@hitachi-solutions.com> \par
 * 	Copyright (C) 2013  Hitachi, Ltd.
 * \author Tomoki Shirasawa  <tomoki.shirasawa.kk@hitachi-solutions.com> \par
 * 	Copyright (C) 2013  Hitachi, Ltd.
 */
/*
 * HISTORY:
 */

#include <process.h>
#include <string.h>
#include <errno.h>
#include <kmalloc.h>
#include <cls.h>
#include <ihk/debug.h>
#include <page.h>
#include <cpulocal.h>
#include <auxvec.h>
#include <timer.h>
#include <mman.h>

//#define DEBUG_PRINT_PROCESS

#ifdef DEBUG_PRINT_PROCESS
#define dkprintf(...) kprintf(__VA_ARGS__)
#define ekprintf(...) kprintf(__VA_ARGS__)
#else
#define dkprintf(...)
#define ekprintf(...) kprintf(__VA_ARGS__)
#endif


#define USER_STACK_NR_PAGES 8192
#define KERNEL_STACK_NR_PAGES 25

extern long do_arch_prctl(unsigned long code, unsigned long address);
static void insert_vm_range_list(struct process_vm *vm, 
		struct vm_range *newrange);
static int copy_user_ranges(struct process *proc, struct process *org);


void hold_fork_tree_node(struct fork_tree_node *ftn)
{
	ihk_atomic_inc(&ftn->refcount);
	dkprintf("hold ftn(%d): %d\n", 
			ftn->pid, ihk_atomic_read(&ftn->refcount));
}

void release_fork_tree_node(struct fork_tree_node *ftn)
{
	dkprintf("release ftn(%d): %d\n", 
			ftn->pid, ihk_atomic_read(&ftn->refcount));
	
	if (!ihk_atomic_dec_and_test(&ftn->refcount)) {
		return;
	}
	
	dkprintf("dealloc ftn(%d): %d\n", 
			ftn->pid, ihk_atomic_read(&ftn->refcount));
	
	/* Dealloc */
	kfree(ftn);
}


void init_fork_tree_node(struct fork_tree_node *ftn, 
		struct fork_tree_node *parent, struct process *owner)
{
	ihk_mc_spinlock_init(&ftn->lock);
	/* Only the process/thread holds a reference at this point */
	ihk_atomic_set(&ftn->refcount, 1);
	
	ftn->owner = owner;

	/* These will be filled out when changing status */
	ftn->pid = -1;
	ftn->exit_status = -1;
	ftn->status = PS_RUNNING;

	ftn->parent = NULL;
	if (parent) {
		ftn->parent = parent;
	}

	INIT_LIST_HEAD(&ftn->children);
	INIT_LIST_HEAD(&ftn->siblings_list);
	
	waitq_init(&ftn->waitpid_q);
}

static int init_process_vm(struct process *owner, struct process_vm *vm)
{
	void *pt = ihk_mc_pt_create(IHK_MC_AP_NOWAIT);

	if(pt == NULL)
		return -ENOMEM;

	ihk_mc_spinlock_init(&vm->memory_range_lock);
	ihk_mc_spinlock_init(&vm->page_table_lock);

	ihk_atomic_set(&vm->refcount, 1);
	INIT_LIST_HEAD(&vm->vm_range_list);
	vm->page_table = pt;
	hold_process(owner);
	vm->owner_process = owner;
	
	return 0;
}

struct process *create_process(unsigned long user_pc)
{
	struct process *proc;

	proc = ihk_mc_alloc_pages(KERNEL_STACK_NR_PAGES, IHK_MC_AP_NOWAIT);
	if (!proc)
		return NULL;

	memset(proc, 0, sizeof(struct process));
	ihk_atomic_set(&proc->refcount, 2);	

	proc->sighandler = kmalloc(sizeof(struct sig_handler), IHK_MC_AP_NOWAIT);
	if(!proc->sighandler){
		goto err_free_process;
	}
	proc->sigshared = kmalloc(sizeof(struct sig_shared), IHK_MC_AP_NOWAIT);
	if(!proc->sigshared){
		goto err_free_sighandler;
	}
	memset(proc->sighandler, '\0', sizeof(struct sig_handler));
	ihk_atomic_set(&proc->sighandler->use, 1);
	ihk_mc_spinlock_init(&proc->sighandler->lock);
	ihk_atomic_set(&proc->sigshared->use, 1);
	ihk_mc_spinlock_init(&proc->sigshared->lock);
	INIT_LIST_HEAD(&proc->sigshared->sigpending);
	ihk_mc_spinlock_init(&proc->sigpendinglock);
	INIT_LIST_HEAD(&proc->sigpending);

	ihk_mc_init_user_process(&proc->ctx, &proc->uctx,
	                         ((char *)proc) + 
							 KERNEL_STACK_NR_PAGES * PAGE_SIZE, user_pc, 0);

	proc->vm = (struct process_vm *)(proc + 1);

	proc->ftn = kmalloc(sizeof(struct fork_tree_node), IHK_MC_AP_NOWAIT);
	if (!proc->ftn) {
		goto err_free_sigshared;
	}

	init_fork_tree_node(proc->ftn, NULL, proc);

	if(init_process_vm(proc, proc->vm) != 0){
		goto err_free_sigshared;
	}

	ihk_mc_spinlock_init(&proc->spin_sleep_lock);
	proc->spin_sleep = 0;

	return proc;

err_free_sigshared:
	kfree(proc->sigshared);

err_free_sighandler:
	kfree(proc->sighandler);

err_free_process:
	ihk_mc_free_pages(proc, KERNEL_STACK_NR_PAGES);
	
	return NULL;
}

struct process *clone_process(struct process *org, unsigned long pc,
                              unsigned long sp, int clone_flags)
{
	struct process *proc;

	if ((proc = ihk_mc_alloc_pages(KERNEL_STACK_NR_PAGES, 
					IHK_MC_AP_NOWAIT)) == NULL) {
		return NULL;
	}

	memset(proc, 0, sizeof(struct process));
	ihk_atomic_set(&proc->refcount, 2);	

	/* NOTE: sp is the user mode stack! */
	ihk_mc_init_user_process(&proc->ctx, &proc->uctx,
	                         ((char *)proc) + 
							 KERNEL_STACK_NR_PAGES * PAGE_SIZE, pc, sp);

	memcpy(proc->uctx, org->uctx, sizeof(*org->uctx));
	ihk_mc_modify_user_context(proc->uctx, IHK_UCR_STACK_POINTER, sp);
	ihk_mc_modify_user_context(proc->uctx, IHK_UCR_PROGRAM_COUNTER, pc);

	proc->rlimit_stack = org->rlimit_stack;
	
	proc->ftn = kmalloc(sizeof(struct fork_tree_node), IHK_MC_AP_NOWAIT);
	if (!proc->ftn) {
		goto err_free_sigshared;
	}

	init_fork_tree_node(proc->ftn, (clone_flags & CLONE_VM) ? NULL : org->ftn,
			proc);

	/* clone() */
	if (clone_flags & CLONE_VM) {
		ihk_atomic_inc(&org->vm->refcount);
		proc->vm = org->vm;
		
		proc->sighandler = org->sighandler;
		ihk_atomic_inc(&org->sighandler->use);

		proc->sigshared = org->sigshared;
		ihk_atomic_inc(&org->sigshared->use);

		ihk_mc_spinlock_init(&proc->sigpendinglock);
		INIT_LIST_HEAD(&proc->sigpending);
	}
	/* fork() */
	else {
		dkprintf("fork(): sighandler\n");
		proc->sighandler = kmalloc(sizeof(struct sig_handler), 
				IHK_MC_AP_NOWAIT);
		
		if (!proc->sighandler) {
			goto err_free_proc;
		}

		dkprintf("fork(): sigshared\n");
		proc->sigshared = kmalloc(sizeof(struct sig_shared), IHK_MC_AP_NOWAIT);
		
		if (!proc->sigshared) {
			goto err_free_sighandler;
		}

		memset(proc->sighandler, '\0', sizeof(struct sig_handler));
		ihk_atomic_set(&proc->sighandler->use, 1);
		ihk_mc_spinlock_init(&proc->sighandler->lock);
		ihk_atomic_set(&proc->sigshared->use, 1);
		ihk_mc_spinlock_init(&proc->sigshared->lock);
		INIT_LIST_HEAD(&proc->sigshared->sigpending);
		ihk_mc_spinlock_init(&proc->sigpendinglock);
		INIT_LIST_HEAD(&proc->sigpending);

		proc->vm = (struct process_vm *)(proc + 1);
		
		dkprintf("fork(): init_process_vm()\n");
		if (init_process_vm(proc, proc->vm) != 0) {
			goto err_free_sigshared;
		}

		memcpy(&proc->vm->region, &org->vm->region, sizeof(struct vm_regions));
		
		dkprintf("fork(): copy_user_ranges()\n");
		/* Copy user-space mappings.
		 * TODO: do this with COW later? */	
		if (copy_user_ranges(proc, org) != 0) {
			goto err_free_sigshared;
		}
		
		dkprintf("fork(): copy_user_ranges() OK\n");
		
		/* Add proc's fork_tree_node to parent's children list */
		ihk_mc_spinlock_lock_noirq(&org->ftn->lock);
		list_add_tail(&proc->ftn->siblings_list, &org->ftn->children);
		ihk_mc_spinlock_unlock_noirq(&org->ftn->lock);	

		/* We hold a reference to parent */
		hold_fork_tree_node(proc->ftn->parent);
		
		/* Parent holds a reference to us */
		hold_fork_tree_node(proc->ftn);
	}

	ihk_mc_spinlock_init(&proc->spin_sleep_lock);
	proc->spin_sleep = 0;

	return proc;

err_free_sigshared:
	kfree(proc->sigshared);

err_free_sighandler:
	ihk_mc_free_pages(proc->sighandler, KERNEL_STACK_NR_PAGES);

err_free_proc:
	ihk_mc_free_pages(proc, KERNEL_STACK_NR_PAGES);
	release_process(org);
	return NULL;
}

static int copy_user_ranges(struct process *proc, struct process *org) 
{
	struct vm_range *src_range;
	struct vm_range *range;	
	
	ihk_mc_spinlock_lock_noirq(&org->vm->memory_range_lock);

	/* Iterate original process' vm_range list and take a copy one-by-one */
	list_for_each_entry(src_range, &org->vm->vm_range_list, list) {
		void *ptepgaddr;
		size_t ptepgsize;
		int ptep2align;
		void *pg_vaddr;
		size_t pgsize;
		void *vaddr;
		int p2align;
		enum ihk_mc_pt_attribute attr;
		pte_t *ptep;

		range = kmalloc(sizeof(struct vm_range), IHK_MC_AP_NOWAIT);
		if (!range) {
			goto err_rollback;
		}

		INIT_LIST_HEAD(&range->list);
		range->start = src_range->start;
		range->end = src_range->end;
		range->flag = src_range->flag;
		range->memobj = src_range->memobj;
		range->objoff = src_range->objoff;
		if (range->memobj) {
			memobj_ref(range->memobj);
		}

		/* Copy actual mappings */
		vaddr = (void *)range->start; 
		while ((unsigned long)vaddr < range->end) {
			/* Get source PTE */
			ptep = ihk_mc_pt_lookup_pte(org->vm->page_table, vaddr,
					&ptepgaddr, &ptepgsize, &ptep2align);

			if (!ptep || pte_is_null(ptep) || !pte_is_present(ptep)) {
				vaddr += PAGE_SIZE;
				continue;
			}

			dkprintf("copy_user_ranges(): 0x%lx PTE found\n", vaddr);
			
			/* Page size */
			if (arch_get_smaller_page_size(NULL, -1, &ptepgsize, 
						&ptep2align)) {

				kprintf("ERROR: copy_user_ranges() "
						"(%p,%lx-%lx %lx,%lx):"
						"get pgsize failed\n", org->vm,
						range->start, range->end,
						range->flag, vaddr);

				goto err_free_range_rollback;
			}
			
			pgsize = ptepgsize;
			p2align = ptep2align;
			dkprintf("copy_user_ranges(): page size: %d\n", pgsize);
			
			/* Get physical page */
			pg_vaddr = ihk_mc_alloc_aligned_pages(1, p2align, IHK_MC_AP_NOWAIT);

			if (!pg_vaddr) {
				kprintf("ERROR: copy_user_ranges() allocating new page\n");
				goto err_free_range_rollback;
			}
			dkprintf("copy_user_ranges(): phys page allocated\n", pgsize);

			/* Copy content */
			memcpy(pg_vaddr, vaddr, pgsize);
			dkprintf("copy_user_ranges(): memcpy OK\n", pgsize);

			/* Set up new PTE */
			attr = arch_vrflag_to_ptattr(range->flag, PF_POPULATE, NULL);
			if (ihk_mc_pt_set_range(proc->vm->page_table, vaddr,
						vaddr + pgsize, virt_to_phys(pg_vaddr), attr)) {
				kprintf("ERROR: copy_user_ranges() "
						"(%p,%lx-%lx %lx,%lx):"
						"set range failed.\n",
						org->vm, range->start, range->end,
						range->flag, vaddr);

				goto err_free_range_rollback;
			}
			dkprintf("copy_user_ranges(): new PTE set\n", pgsize);
			
			vaddr += pgsize;
		}

		insert_vm_range_list(proc->vm, range);
	}

	ihk_mc_spinlock_unlock_noirq(&org->vm->memory_range_lock);
	
	return 0;

err_free_range_rollback:
	kfree(range);

err_rollback:

	/* TODO: implement rollback */


	ihk_mc_spinlock_unlock_noirq(&org->vm->memory_range_lock);

	return -1;
}

int update_process_page_table(struct process *process,
                          struct vm_range *range, uint64_t phys,
			  enum ihk_mc_pt_attribute flag)
{
	unsigned long p, pa = phys;
	unsigned long pp;
	unsigned long flags = ihk_mc_spinlock_lock(&process->vm->page_table_lock);
	enum ihk_mc_pt_attribute attr;

	attr = flag | PTATTR_USER | PTATTR_FOR_USER;
	attr |= (range->flag & VR_PROT_WRITE)? PTATTR_WRITABLE: 0;
	attr |= (range->flag & VR_PROT_EXEC)? 0: PTATTR_NO_EXECUTE;

	p = range->start;
	while (p < range->end) {
#ifdef USE_LARGE_PAGES
		/* Use large PTE if both virtual and physical addresses are large page 
		 * aligned and more than LARGE_PAGE_SIZE is left from the range */
		if ((p & (LARGE_PAGE_SIZE - 1)) == 0 && 
				(pa & (LARGE_PAGE_SIZE - 1)) == 0 &&
				(range->end - p) >= LARGE_PAGE_SIZE) {

			if (ihk_mc_pt_set_large_page(process->vm->page_table, (void *)p,
					pa, attr) != 0) {
				goto err;
			}

			dkprintf("large page set for 0x%lX -> 0x%lX\n", p, pa);

			pa += LARGE_PAGE_SIZE;
			p += LARGE_PAGE_SIZE;
		}
		else {
#endif		
			if(ihk_mc_pt_set_page(process->vm->page_table, (void *)p,
			      pa, attr) != 0){
				goto err;
			}

			pa += PAGE_SIZE;
			p += PAGE_SIZE;
#ifdef USE_LARGE_PAGES
		}
#endif
	}
	ihk_mc_spinlock_unlock(&process->vm->page_table_lock, flags);
	return 0;

err:
	pp = range->start;
	pa = phys;
	while(pp < p){
#ifdef USE_LARGE_PAGES
		if ((p & (LARGE_PAGE_SIZE - 1)) == 0 && 
				(pa & (LARGE_PAGE_SIZE - 1)) == 0 &&
				(range->end - p) >= LARGE_PAGE_SIZE) {
			ihk_mc_pt_clear_large_page(process->vm->page_table, (void *)pp);
			pa += LARGE_PAGE_SIZE;
			pp += LARGE_PAGE_SIZE;
		}
		else{
#endif
			ihk_mc_pt_clear_page(process->vm->page_table, (void *)pp);
			pa += PAGE_SIZE;
			pp += PAGE_SIZE;
#ifdef USE_LARGE_PAGES
		}
#endif
	}

	ihk_mc_spinlock_unlock(&process->vm->page_table_lock, flags);
	return -ENOMEM;
}

int split_process_memory_range(struct process *proc, struct vm_range *range,
		uintptr_t addr, struct vm_range **splitp)
{
	int error;
	struct vm_range *newrange = NULL;

	dkprintf("split_process_memory_range(%p,%lx-%lx,%lx,%p)\n",
			proc, range->start, range->end, addr, splitp);

	newrange = kmalloc(sizeof(struct vm_range), IHK_MC_AP_NOWAIT);
	if (!newrange) {
		ekprintf("split_process_memory_range(%p,%lx-%lx,%lx,%p):"
				"kmalloc failed\n",
				proc, range->start, range->end, addr, splitp);
		error = -ENOMEM;
		goto out;
	}

	newrange->start = addr;
	newrange->end = range->end;
	newrange->flag = range->flag;

	if (range->memobj) {
		memobj_ref(range->memobj);
		newrange->memobj = range->memobj;
		newrange->objoff = range->objoff + (addr - range->start);
	}
	else {
		newrange->memobj = NULL;
		newrange->objoff = 0;
	}

	range->end = addr;

	list_add(&newrange->list, &range->list);

	error = 0;
	if (splitp != NULL) {
		*splitp = newrange;
	}

out:
	dkprintf("split_process_memory_range(%p,%lx-%lx,%lx,%p): %d %p %lx-%lx\n",
			proc, range->start, range->end, addr, splitp,
			error, newrange,
			newrange? newrange->start: 0, newrange? newrange->end: 0);
	return error;
}

int join_process_memory_range(struct process *proc,
		struct vm_range *surviving, struct vm_range *merging)
{
	int error;

	dkprintf("join_process_memory_range(%p,%lx-%lx,%lx-%lx)\n",
			proc, surviving->start, surviving->end,
			merging->start, merging->end);

	if ((surviving->end != merging->start)
			|| (surviving->flag != merging->flag)
			|| (surviving->memobj != merging->memobj)) {
		error = -EINVAL;
		goto out;
	}
	if (surviving->memobj != NULL) {
		size_t len;
		off_t endoff;

		len = surviving->end - surviving->start;
		endoff = surviving->objoff + len;
		if (endoff != merging->objoff) {
			return -EINVAL;
		}
	}

	surviving->end = merging->end;

	if (merging->memobj) {
		memobj_release(merging->memobj);
	}
	list_del(&merging->list);
	ihk_mc_free(merging);

	error = 0;
out:
	dkprintf("join_process_memory_range(%p,%lx-%lx,%p): %d\n",
			proc, surviving->start, surviving->end, merging, error);
	return error;
}

int free_process_memory_range(struct process_vm *vm, struct vm_range *range)
{
	const intptr_t start0 = range->start;
	const intptr_t end0 = range->end;
	int error;
	intptr_t start;
	intptr_t end;
#ifdef USE_LARGE_PAGES
	struct vm_range *neighbor;
	intptr_t lpstart;
	intptr_t lpend;
#endif /* USE_LARGE_PAGES */

	dkprintf("free_process_memory_range(%p,%lx-%lx)\n",
			vm, start0, end0);

	start = range->start;
	end = range->end;
	if (!(range->flag & (VR_REMOTE | VR_IO_NOCACHE | VR_RESERVED))) {
#ifdef USE_LARGE_PAGES
		lpstart = start & LARGE_PAGE_MASK;
		lpend = (end + LARGE_PAGE_SIZE - 1) & LARGE_PAGE_MASK;


		if (lpstart < start) {
			neighbor = previous_process_memory_range(vm, range);
			if ((neighbor == NULL) || (neighbor->end <= lpstart)) {
				start = lpstart;
			}
		}

		if (end < lpend) {
			neighbor = next_process_memory_range(vm, range);
			if ((neighbor == NULL) || (lpend <= neighbor->start)) {
				end = lpend;
			}
		}
#endif /* USE_LARGE_PAGES */

		ihk_mc_spinlock_lock_noirq(&vm->page_table_lock);
		if (range->memobj) {
			memobj_lock(range->memobj);
		}
		error = ihk_mc_pt_free_range(vm->page_table,
				(void *)start, (void *)end,
				(range->flag & VR_PRIVATE)? NULL: range->memobj);
		if (range->memobj) {
			memobj_unlock(range->memobj);
		}
		ihk_mc_spinlock_unlock_noirq(&vm->page_table_lock);
		if (error && (error != -ENOENT)) {
			ekprintf("free_process_memory_range(%p,%lx-%lx):"
					"ihk_mc_pt_free_range(%lx-%lx,%p) failed. %d\n",
					vm, start0, end0, start, end, range->memobj, error);
			/* through */
		}
	}
	else {
		ihk_mc_spinlock_lock_noirq(&vm->page_table_lock);
		error = ihk_mc_pt_clear_range(vm->page_table,
				(void *)start, (void *)end);
		ihk_mc_spinlock_unlock_noirq(&vm->page_table_lock);
		if (error && (error != -ENOENT)) {
			ekprintf("free_process_memory_range(%p,%lx-%lx):"
					"ihk_mc_pt_clear_range(%lx-%lx) failed. %d\n",
					vm, start0, end0, start, end, error);
			/* through */
		}
	}

	if (range->memobj) {
		memobj_release(range->memobj);
	}
	list_del(&range->list);
	ihk_mc_free(range);

	dkprintf("free_process_memory_range(%p,%lx-%lx): 0\n",
			vm, start0, end0);
	return 0;
}

int remove_process_memory_range(struct process *process,
		unsigned long start, unsigned long end, int *ro_freedp)
{
	struct process_vm * const vm = process->vm;
	struct vm_range *range;
	struct vm_range *next;
	int error;
	struct vm_range *freerange;
	int ro_freed = 0;

	dkprintf("remove_process_memory_range(%p,%lx,%lx)\n",
			process, start, end);

	list_for_each_entry_safe(range, next, &vm->vm_range_list, list) {
		if ((range->end <= start) || (end <= range->start)) {
			/* no overlap */
			continue;
		}
		freerange = range;

		if (freerange->start < start) {
			error = split_process_memory_range(process,
					freerange, start, &freerange);
			if (error) {
				ekprintf("remove_process_memory_range(%p,%lx,%lx):"
						"split failed %d\n",
						process, start, end, error);
				return error;
			}
		}

		if (end < freerange->end) {
			error = split_process_memory_range(process,
					freerange, end, NULL);
			if (error) {
				ekprintf("remove_process_memory_range(%p,%lx,%lx):"
						"split failed %d\n",
						process, start, end, error);
				return error;
			}
		}

		if (!(freerange->flag & VR_PROT_WRITE)) {
			ro_freed = 1;
		}

		error = free_process_memory_range(process->vm, freerange);
		if (error) {
			ekprintf("remove_process_memory_range(%p,%lx,%lx):"
					"free failed %d\n",
					process, start, end, error);
			return error;
		}

	}

	if (ro_freedp) {
		*ro_freedp = ro_freed;
	}
	dkprintf("remove_process_memory_range(%p,%lx,%lx): 0 %d\n",
			process, start, end, ro_freed);
	return 0;
}

static void insert_vm_range_list(struct process_vm *vm, struct vm_range *newrange)
{
	struct list_head *next;
	struct vm_range *range;

	next = &vm->vm_range_list;
	list_for_each_entry(range, &vm->vm_range_list, list) {
		if ((newrange->start < range->end) && (range->start < newrange->end)) {
			ekprintf("insert_vm_range_list(%p,%lx-%lx %lx):overlap %lx-%lx %lx\n",
					vm, newrange->start, newrange->end, newrange->flag,
					range->start, range->end, range->flag);
			panic("insert_vm_range_list\n");
		}

		if (newrange->end <= range->start) {
			next = &range->list;
			break;
		}
	}

	list_add_tail(&newrange->list, next);
	return;
}

enum ihk_mc_pt_attribute common_vrflag_to_ptattr(unsigned long flag, uint64_t fault, pte_t *ptep)
{
	enum ihk_mc_pt_attribute attr;

	attr = PTATTR_USER | PTATTR_FOR_USER;

	if (flag & VR_REMOTE) {
		attr |= IHK_PTA_REMOTE;
	}
	else if (flag & VR_IO_NOCACHE) {
		attr |= PTATTR_UNCACHABLE;
	}

	if ((flag & VR_PROT_MASK) != VR_PROT_NONE) {
		attr |= PTATTR_ACTIVE;
	}

	if (flag & VR_PROT_WRITE) {
		attr |= PTATTR_WRITABLE;
	}

	if (!(flag & VR_PROT_EXEC)) {
		attr |= PTATTR_NO_EXECUTE;
	}

	return attr;
}

int add_process_memory_range(struct process *process,
                             unsigned long start, unsigned long end,
                             unsigned long phys, unsigned long flag,
			     struct memobj *memobj, off_t offset)
{
	struct vm_range *range;
	int rc;
#if 0
	extern void __host_update_process_range(struct process *process,
						struct vm_range *range);
#endif

	if ((start < process->vm->region.user_start)
			|| (process->vm->region.user_end < end)) {
		kprintf("range(%#lx - %#lx) is not in user avail(%#lx - %#lx)\n",
				start, end, process->vm->region.user_start,
				process->vm->region.user_end);
		return -EINVAL;
	}

	range = kmalloc(sizeof(struct vm_range), IHK_MC_AP_NOWAIT);
	if (!range) {
		return -ENOMEM;
	}
	INIT_LIST_HEAD(&range->list);
	range->start = start;
	range->end = end;
	range->flag = flag;
	range->memobj = memobj;
	range->objoff = offset;

    if(range->flag & VR_DEMAND_PAGING) {
	dkprintf("range: 0x%lX - 0x%lX => physicall memory area is allocated on demand (%ld) [%lx]\n",
	        range->start, range->end, range->end - range->start,
		range->flag);
    } else {
		dkprintf("range: 0x%lX - 0x%lX (%ld) [%lx]\n",
				range->start, range->end, range->end - range->start,
				range->flag);
    }

	if (flag & VR_REMOTE) {
		rc = update_process_page_table(process, range, phys, IHK_PTA_REMOTE);
	} else if (flag & VR_IO_NOCACHE) {
		rc = update_process_page_table(process, range, phys, PTATTR_UNCACHABLE);
	} else if(flag & VR_DEMAND_PAGING){
	  //demand paging no need to update process table now
	  dkprintf("demand paging do not update process page table\n");
      rc = 0;
	} else if ((range->flag & VR_PROT_MASK) == VR_PROT_NONE) {
		rc = 0;
	} else {
		rc = update_process_page_table(process, range, phys, 0);
	}
	if(rc != 0){
		kfree(range);
		return rc;
	}

#if 0 // disable __host_update_process_range() in add_process_memory_range(), because it has no effect on the actual mapping on the MICs side. 
	if (!(flag & VR_REMOTE)) {
		__host_update_process_range(process, range);
	}
#endif
	
	insert_vm_range_list(process->vm, range);
	
	/* Clear content! */
	if (!(flag & (VR_REMOTE | VR_DEMAND_PAGING))
			&& ((flag & VR_PROT_MASK) != VR_PROT_NONE)) {
		memset((void*)phys_to_virt(phys), 0, end - start);
	}

	return 0;
}

struct vm_range *lookup_process_memory_range(
		struct process_vm *vm, uintptr_t start, uintptr_t end)
{
	struct vm_range *range = NULL;

	dkprintf("lookup_process_memory_range(%p,%lx,%lx)\n", vm, start, end);

	if (end <= start) {
		goto out;
	}

	list_for_each_entry(range, &vm->vm_range_list, list) {
		if (end <= range->start) {
			break;
		}
		if ((start < range->end) && (range->start < end)) {
			goto out;
		}
	}

	range = NULL;
out:
	dkprintf("lookup_process_memory_range(%p,%lx,%lx): %p %lx-%lx\n",
			vm, start, end, range,
			range? range->start: 0, range? range->end: 0);
	return range;
}

struct vm_range *next_process_memory_range(
		struct process_vm *vm, struct vm_range *range)
{
	struct vm_range *next;

	dkprintf("next_process_memory_range(%p,%lx-%lx)\n",
			vm, range->start, range->end);

	if (list_is_last(&range->list, &vm->vm_range_list)) {
		next = NULL;
	}
	else {
		next = list_entry(range->list.next, struct vm_range, list);
	}

	dkprintf("next_process_memory_range(%p,%lx-%lx): %p %lx-%lx\n",
			vm, range->start, range->end, next,
			next? next->start: 0, next? next->end: 0);
	return next;
}

struct vm_range *previous_process_memory_range(
		struct process_vm *vm, struct vm_range *range)
{
	struct vm_range *prev;

	dkprintf("previous_process_memory_range(%p,%lx-%lx)\n",
			vm, range->start, range->end);

	if (list_first_entry(&vm->vm_range_list, struct vm_range, list) == range) {
		prev = NULL;
	}
	else {
		prev = list_entry(range->list.prev, struct vm_range, list);
	}

	dkprintf("previous_process_memory_range(%p,%lx-%lx): %p %lx-%lx\n",
			vm, range->start, range->end, prev,
			prev? prev->start: 0, prev? prev->end: 0);
	return prev;
}

int change_prot_process_memory_range(struct process *proc,
		struct vm_range *range, unsigned long protflag)
{
	unsigned long newflag;
	int error;
	enum ihk_mc_pt_attribute oldattr;
	enum ihk_mc_pt_attribute newattr;
	enum ihk_mc_pt_attribute clrattr;
	enum ihk_mc_pt_attribute setattr;

	dkprintf("change_prot_process_memory_range(%p,%lx-%lx,%lx)\n",
			proc, range->start, range->end, protflag);

	newflag = (range->flag & ~VR_PROT_MASK) | (protflag & VR_PROT_MASK);
	if (range->flag == newflag) {
		/* nothing to do */
		error = 0;
		goto out;
	}

	oldattr = arch_vrflag_to_ptattr(range->flag, PF_POPULATE, NULL);
	newattr = arch_vrflag_to_ptattr(newflag, PF_POPULATE, NULL);

	clrattr = oldattr & ~newattr;
	setattr = newattr & ~oldattr;

	ihk_mc_spinlock_lock_noirq(&proc->vm->page_table_lock);
	error = ihk_mc_pt_change_attr_range(proc->vm->page_table,
			(void *)range->start, (void *)range->end,
			clrattr, setattr);
	ihk_mc_spinlock_unlock_noirq(&proc->vm->page_table_lock);
	if (error && (error != -ENOENT)) {
		ekprintf("change_prot_process_memory_range(%p,%lx-%lx,%lx):"
				"ihk_mc_pt_change_attr_range failed: %d\n",
				proc, range->start, range->end, protflag, error);
		goto out;
	}

	if (((range->flag & VR_PROT_MASK) == PROT_NONE)
			&& !(range->flag & VR_DEMAND_PAGING)) {
		ihk_mc_spinlock_lock_noirq(&proc->vm->page_table_lock);
		error = ihk_mc_pt_alloc_range(proc->vm->page_table,
				(void *)range->start, (void *)range->end,
				newattr);
		ihk_mc_spinlock_unlock_noirq(&proc->vm->page_table_lock);
		if (error) {
			ekprintf("change_prot_process_memory_range(%p,%lx-%lx,%lx):"
					"ihk_mc_pt_alloc_range failed: %d\n",
					proc, range->start, range->end, protflag, error);
			goto out;
		}
	}

	range->flag = newflag;
	error = 0;
out:
	dkprintf("change_prot_process_memory_range(%p,%lx-%lx,%lx): %d\n",
			proc, range->start, range->end, protflag, error);
	return error;
}

static int page_fault_process_memory_range(struct process_vm *vm, struct vm_range *range, uintptr_t fault_addr, uint64_t reason)
{
	int error;
	pte_t *ptep;
	void *pgaddr;
	size_t pgsize;
	int p2align;
	enum ihk_mc_pt_attribute attr;
	uintptr_t phys;
	struct page *page = NULL;

	dkprintf("page_fault_process_memory_range(%p,%lx-%lx %lx,%lx,%lx)\n", vm, range->start, range->end, range->flag, fault_addr, reason);
	ihk_mc_spinlock_lock_noirq(&vm->page_table_lock);
	/*****/
	ptep = ihk_mc_pt_lookup_pte(vm->page_table, (void *)fault_addr, &pgaddr, &pgsize, &p2align);
	if (!(reason & PF_PROT) && ptep && !pte_is_null(ptep)) {
		if (!pte_is_present(ptep)) {
			error = -EFAULT;
			kprintf("page_fault_process_memory_range(%p,%lx-%lx %lx,%lx,%lx):PROT_NONE. %d\n", vm, range->start, range->end, range->flag, fault_addr, reason, error);
			goto out;
		}
		error = 0;
		goto out;
	}
	if ((reason & PF_PROT) && (!ptep || !pte_is_present(ptep))) {
		flush_tlb_single(fault_addr);
		error = 0;
		goto out;
	}
	/*****/
	if (!ptep || (pgsize != PAGE_SIZE)) {
		ptep = NULL;
		pgsize = PAGE_SIZE;
		p2align = PAGE_P2ALIGN;
	}
	attr = arch_vrflag_to_ptattr(range->flag, reason, ptep);
	pgaddr = (void *)(fault_addr & ~(pgsize - 1));
	if (!ptep || pte_is_null(ptep)) {
		if (range->memobj) {
			off_t off;

			off = range->objoff + ((uintptr_t)pgaddr - range->start);
			error = memobj_get_page(range->memobj, off, p2align, &phys);
			if (error) {
				if (error != -ERESTART) {
				}
				goto out;
			}
		}
		else {
			void *virt;
			size_t npages;

			npages = pgsize / PAGE_SIZE;
			virt = ihk_mc_alloc_aligned_pages(npages, p2align, IHK_MC_AP_NOWAIT);
			if (!virt) {
				error = -ENOMEM;
				kprintf("page_fault_process_memory_range(%p,%lx-%lx %lx,%lx,%lx):cannot allocate new page. %d\n", vm, range->start, range->end, range->flag, fault_addr, reason, error);
				goto out;
			}
			memset(virt, 0, pgsize);
			phys = virt_to_phys(virt);
			page_map(phys_to_page(phys));
		}
	}
	else {
		phys = pte_get_phys(ptep);
	}
	page = phys_to_page(phys);
	/*****/
	if ((range->flag & VR_PRIVATE) && (!page || page_is_in_memobj(page) || page_is_multi_mapped(page))) {
		if (!(attr & PTATTR_DIRTY)) {
			attr &= ~PTATTR_WRITABLE;
		}
		else {
			void *virt;
			size_t npages;

			npages = pgsize / PAGE_SIZE;
			virt = ihk_mc_alloc_aligned_pages(npages, p2align, IHK_MC_AP_NOWAIT);
			if (!virt) {
				error = -ENOMEM;
				kprintf("page_fault_process_memory_range(%p,%lx-%lx %lx,%lx,%lx):cannot allocate copy page. %d\n", vm, range->start, range->end, range->flag, fault_addr, reason, error);
				goto out;
			}
			memcpy(virt, phys_to_virt(phys), pgsize);

			phys = virt_to_phys(virt);
			if (page) {
				page_unmap(page);
			}
			page = phys_to_page(phys);
		}
	}
	/*****/
	if (ptep) {
		error = ihk_mc_pt_set_pte(vm->page_table, ptep, pgsize, phys, attr);
		if (error) {
			kprintf("page_fault_process_memory_range(%p,%lx-%lx %lx,%lx,%lx):set_pte failed. %d\n", vm, range->start, range->end, range->flag, fault_addr, reason, error);
			goto out;
		}
	}
	else {
		error = ihk_mc_pt_set_range(vm->page_table, pgaddr, pgaddr+pgsize, phys, attr);
		if (error) {
			kprintf("page_fault_process_memory_range(%p,%lx-%lx %lx,%lx,%lx):set_range failed. %d\n", vm, range->start, range->end, range->flag, fault_addr, reason, error);
			goto out;
		}
	}
	flush_tlb_single(fault_addr);
	error = 0;
	page = NULL;
out:
	ihk_mc_spinlock_unlock_noirq(&vm->page_table_lock);
	if (page) {
		page_unmap(page);
	}
	dkprintf("page_fault_process_memory_range(%p,%lx-%lx %lx,%lx,%lx): %d\n", vm, range->start, range->end, range->flag, fault_addr, reason, error);
	return error;
}

static int do_page_fault_process(struct process *proc, void *fault_addr0, uint64_t reason)
{
	struct process_vm *vm = proc->vm;
	int error;
	const uintptr_t fault_addr = (uintptr_t)fault_addr0;
	struct vm_range *range;

	dkprintf("[%d]do_page_fault_process(%p,%lx,%lx)\n",
			ihk_mc_get_processor_id(), proc, fault_addr0, reason);

	ihk_mc_spinlock_lock_noirq(&vm->memory_range_lock);

	range = lookup_process_memory_range(vm, fault_addr, fault_addr+1);
	if (range == NULL) {
		error = -EFAULT;
		kprintf("[%d]do_page_fault_process(%p,%lx,%lx):"
				"out of range. %d\n",
				ihk_mc_get_processor_id(), proc,
				fault_addr0, reason, error);
		goto out;
	}

	if (((range->flag & VR_PROT_MASK) == VR_PROT_NONE)
			|| ((reason & PF_WRITE)
				&& !(range->flag & VR_PROT_WRITE))
			|| ((reason & PF_INSTR)
				&& !(range->flag & VR_PROT_EXEC))) {
		error = -EFAULT;
		kprintf("[%d]do_page_fault_process(%p,%lx,%lx):"
				"access denied. %d\n",
				ihk_mc_get_processor_id(), proc,
				fault_addr0, reason, error);
		goto out;
	}

	error = page_fault_process_memory_range(vm, range, fault_addr, reason);
	if (error == -ERESTART) {
		goto out;
	}
	if (error) {
		kprintf("[%d]do_page_fault_process(%p,%lx,%lx):"
				"fault range failed. %d\n",
				ihk_mc_get_processor_id(), proc,
				fault_addr0, reason, error);
		goto out;
	}

	error = 0;
out:
	ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
	dkprintf("[%d]do_page_fault_process(%p,%lx,%lx): %d\n",
			ihk_mc_get_processor_id(), proc, fault_addr0,
			reason, error);
	return error;
}

int page_fault_process(struct process *proc, void *fault_addr, uint64_t reason)
{
	int error;

	if (proc != cpu_local_var(current)) {
		panic("page_fault_process: other process");
	}

	for (;;) {
		error = do_page_fault_process(proc, fault_addr, reason);
		if (error != -ERESTART) {
			break;
		}

		if (proc->pgio_fp) {
			(*proc->pgio_fp)(proc->pgio_arg);
			proc->pgio_fp = NULL;
		}
	}

	return error;
}

int init_process_stack(struct process *process, struct program_load_desc *pn,
                        int argc, char **argv, 
                        int envc, char **env)
{
	int s_ind = 0;
	int arg_ind;
	unsigned long size;
	unsigned long end = process->vm->region.user_end;
	unsigned long start;
	int rc;
	unsigned long vrflag;
	char *stack;
	int error;
	unsigned long *p;
	unsigned long minsz;

	/* create stack range */
	minsz = PAGE_SIZE;
	size = process->rlimit_stack.rlim_cur & PAGE_MASK;
	if (size > (USER_END / 2)) {
		size = USER_END / 2;
	}
	else if (size < minsz) {
		size = minsz;
	}
	start = end - size;

	vrflag = VR_STACK | VR_DEMAND_PAGING;
	vrflag |= PROT_TO_VR_FLAG(pn->stack_prot);
	vrflag |= VR_MAXPROT_READ | VR_MAXPROT_WRITE | VR_MAXPROT_EXEC;
#define	NOPHYS	((uintptr_t)-1)
	if ((rc = add_process_memory_range(process, start, end, NOPHYS,
					vrflag, NULL, 0)) != 0) {
		return rc;
	}

	/* map physical pages for initial stack frame */
	stack = ihk_mc_alloc_pages(minsz >> PAGE_SHIFT, IHK_MC_AP_NOWAIT);
	if (!stack) {
		return -ENOMEM;
	}
	memset(stack, 0, minsz);
	error = ihk_mc_pt_set_range(process->vm->page_table,
			(void *)(end-minsz), (void *)end,
			virt_to_phys(stack),
			arch_vrflag_to_ptattr(vrflag, PF_POPULATE, NULL));
	if (error) {
		kprintf("init_process_stack:"
				"set range %lx-%lx %lx failed. %d\n",
				(end-minsz), end, stack, error);
		ihk_mc_free_pages(stack, minsz >> PAGE_SHIFT);
		return error;
	}

	/* set up initial stack frame */
	p = (unsigned long *)(stack + minsz);
	s_ind = -1;
	p[s_ind--] = 0;     /* AT_NULL */
	p[s_ind--] = 0;
	p[s_ind--] = pn->at_entry; /* AT_ENTRY */
	p[s_ind--] = AT_ENTRY;
	p[s_ind--] = pn->at_phnum; /* AT_PHNUM */
	p[s_ind--] = AT_PHNUM;
	p[s_ind--] = pn->at_phent;  /* AT_PHENT */
	p[s_ind--] = AT_PHENT;
	p[s_ind--] = pn->at_phdr;  /* AT_PHDR */
	p[s_ind--] = AT_PHDR;	
	p[s_ind--] = 4096; /* AT_PAGESZ */
	p[s_ind--] = AT_PAGESZ;
	p[s_ind--] = 0;     /* envp terminating NULL */
	/* envp */
	for (arg_ind = envc - 1; arg_ind > -1; --arg_ind) {
		p[s_ind--] = (unsigned long)env[arg_ind];
	}
	
	p[s_ind--] = 0; /* argv terminating NULL */
	/* argv */
	for (arg_ind = argc - 1; arg_ind > -1; --arg_ind) {
		p[s_ind--] = (unsigned long)argv[arg_ind];
	}
	/* argc */
	p[s_ind] = argc;

	ihk_mc_modify_user_context(process->uctx, IHK_UCR_STACK_POINTER,
	                           end + sizeof(unsigned long) * s_ind);
	process->vm->region.stack_end = end;
	process->vm->region.stack_start = start;
	return 0;
}


unsigned long extend_process_region(struct process *proc,
                                    unsigned long start, unsigned long end,
                                    unsigned long address, unsigned long flag)
{
	unsigned long aligned_end, aligned_new_end;
	void *p;
	int rc;

	if (!address || address < start || address >= USER_END) {
		return end;
	}

	aligned_end = ((end + PAGE_SIZE - 1) & PAGE_MASK);

	if (aligned_end >= address) {
		return address;
	}

	aligned_new_end = (address + PAGE_SIZE - 1) & PAGE_MASK;

#ifdef USE_LARGE_PAGES
	if (aligned_new_end - aligned_end >= LARGE_PAGE_SIZE) {
	  if(flag & VR_DEMAND_PAGING){panic("demand paging for large page is not available!");}
		unsigned long p_aligned;
		unsigned long old_aligned_end = aligned_end;

		if ((aligned_end & (LARGE_PAGE_SIZE - 1)) != 0) {

			aligned_end = (aligned_end + (LARGE_PAGE_SIZE - 1)) & LARGE_PAGE_MASK;
			/* Fill in the gap between old_aligned_end and aligned_end
			 * with regular pages */
			if((p = allocate_pages((aligned_end - old_aligned_end) >> PAGE_SHIFT,
                                 IHK_MC_AP_NOWAIT)) == NULL){
				return end;
			}
			if((rc = add_process_memory_range(proc, old_aligned_end,
                                        aligned_end, virt_to_phys(p), flag)) != 0){
				free_pages(p, (aligned_end - old_aligned_end) >> PAGE_SHIFT);
				return end;
			}
			
			dkprintf("filled in gap for LARGE_PAGE_SIZE aligned start: 0x%lX -> 0x%lX\n",
					old_aligned_end, aligned_end);
		}
	
		/* Add large region for the actual mapping */
		aligned_new_end = (aligned_new_end + (aligned_end - old_aligned_end) +
				(LARGE_PAGE_SIZE - 1)) & LARGE_PAGE_MASK;
		address = aligned_new_end;

		if((p = allocate_pages((aligned_new_end - aligned_end + LARGE_PAGE_SIZE) >> PAGE_SHIFT,
                            IHK_MC_AP_NOWAIT)) == NULL){
			return end;
		}

		p_aligned = ((unsigned long)p + (LARGE_PAGE_SIZE - 1)) & LARGE_PAGE_MASK;

		if (p_aligned > (unsigned long)p) {
			free_pages(p, (p_aligned - (unsigned long)p) >> PAGE_SHIFT);
		}
		free_pages(
			(void *)(p_aligned + aligned_new_end - aligned_end),
			(LARGE_PAGE_SIZE - (p_aligned - (unsigned long)p)) >> PAGE_SHIFT);

		if((rc = add_process_memory_range(proc, aligned_end,
                               aligned_new_end, virt_to_phys((void *)p_aligned),
                               flag)) != 0){
			free_pages(p, (aligned_new_end - aligned_end + LARGE_PAGE_SIZE) >> PAGE_SHIFT);
			return end;
		}

		dkprintf("largePTE area: 0x%lX - 0x%lX (s: %lu) -> 0x%lX - \n",
				aligned_end, aligned_new_end, 
				(aligned_new_end - aligned_end), 
				virt_to_phys((void *)p_aligned));

		return address;
	}
#endif
	if(flag & VR_DEMAND_PAGING){
	  // demand paging no need to allocate page now
	  kprintf("demand page do not allocate page\n");
	  p=0;
	}else{

	p = allocate_pages((aligned_new_end - aligned_end) >> PAGE_SHIFT, IHK_MC_AP_NOWAIT);

	if (!p) {
		return end;
	}
    }	
	if((rc = add_process_memory_range(proc, aligned_end, aligned_new_end,
                                      (p==0?0:virt_to_phys(p)), flag, NULL, 0)) != 0){
		free_pages(p, (aligned_new_end - aligned_end) >> PAGE_SHIFT);
		return end;
	}
	
	return address;
}

// Original version retained because dcfa (src/mccmd/client/ibmic/main.c) calls this 
int remove_process_region(struct process *proc,
                          unsigned long start, unsigned long end)
{
	if ((start & (PAGE_SIZE - 1)) || (end & (PAGE_SIZE - 1))) {
		return -EINVAL;
	}

	ihk_mc_spinlock_lock_noirq(&proc->vm->page_table_lock);
	/* We defer freeing to the time of exit */
	// XXX: check error
	ihk_mc_pt_clear_range(proc->vm->page_table, (void *)start, (void *)end);
	ihk_mc_spinlock_unlock_noirq(&proc->vm->page_table_lock);

	return 0;
}

void flush_process_memory(struct process *proc)
{
	struct process_vm *vm = proc->vm;
	struct vm_range *range;
	struct vm_range *next;
	int error;

	dkprintf("flush_process_memory(%p)\n", proc);
	ihk_mc_spinlock_lock_noirq(&vm->memory_range_lock);
	list_for_each_entry_safe(range, next, &vm->vm_range_list, list) {
		if (range->memobj) {
			// XXX: temporary of temporary
			error = free_process_memory_range(vm, range);
			if (error) {
				ekprintf("flush_process_memory(%p):"
						"free range failed. %lx-%lx %d\n",
						proc, range->start, range->end, error);
				/* through */
			}
		}
	}
	ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
	dkprintf("flush_process_memory(%p):\n", proc);
	return;
}

void free_process_memory(struct process *proc)
{
	struct vm_range *range, *next;
	struct process_vm *vm = proc->vm;
	int error;

	if (vm == NULL) {
		return;
	}

	proc->vm = NULL;
	if (!ihk_atomic_dec_and_test(&vm->refcount)) {
		return;
	}

	ihk_mc_spinlock_lock_noirq(&vm->memory_range_lock);
	list_for_each_entry_safe(range, next, &vm->vm_range_list, list) {
		error = free_process_memory_range(vm, range);
		if (error) {
			ekprintf("free_process_memory(%p):"
					"free range failed. %lx-%lx %d\n",
					proc, range->start, range->end, error);
			/* through */
		}
	}
	ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);

	ihk_mc_pt_destroy(vm->page_table);
	release_process(vm->owner_process);
}

int populate_process_memory(struct process *proc, void *start, size_t len)
{
	int error;
	const int reason = PF_USER | PF_POPULATE;
	uintptr_t end;
	uintptr_t addr;

	end = (uintptr_t)start + len;
	for (addr = (uintptr_t)start; addr < end; addr += PAGE_SIZE) {
		error = page_fault_process(proc, (void *)addr, reason);
		if (error) {
			ekprintf("populate_process_range:page_fault_process"
					"(%p,%lx,%lx) failed %d\n",
					proc, addr, reason, error);
			goto out;
		}
	}

	error = 0;
out:
	return error;
}

void hold_process(struct process *proc)
{
	if (proc->status & (PS_ZOMBIE | PS_EXITED)) {
		panic("hold_process: already exited process");
	}

	ihk_atomic_inc(&proc->refcount);
	return;
}

void destroy_process(struct process *proc)
{
	struct sig_pending *pending;
	struct sig_pending *next;

	free_process_memory(proc);	

	if(ihk_atomic_dec_and_test(&proc->sighandler->use)){
		kfree(proc->sighandler);
	}
	if(ihk_atomic_dec_and_test(&proc->sigshared->use)){
		list_for_each_entry_safe(pending, next, &proc->sigshared->sigpending, list){
			list_del(&pending->list);
			kfree(pending);
		}
		list_del(&proc->sigshared->sigpending);
		kfree(proc->sigshared);
	}
	list_for_each_entry_safe(pending, next, &proc->sigpending, list){
		list_del(&pending->list);
		kfree(pending);
	}
	ihk_mc_free_pages(proc, KERNEL_STACK_NR_PAGES);
}

void release_process(struct process *proc)
{
	if (!ihk_atomic_dec_and_test(&proc->refcount)) {
		return;
	}

	destroy_process(proc);
}

static void idle(void)
{
	//unsigned int	flags;
	//flags = ihk_mc_spinlock_lock(&cpu_status_lock);
	//ihk_mc_spinlock_unlock(&cpu_status_lock, flags);
	cpu_local_var(status) = CPU_STATUS_IDLE;

	while (1) {
		cpu_enable_interrupt();
		schedule();
		//cpu_local_var(status) = CPU_STATUS_IDLE;
		cpu_halt();
	}
}

void sched_init(void)
{
	struct process *idle_process = &cpu_local_var(idle);

	memset(idle_process, 0, sizeof(struct process));
	memset(&cpu_local_var(idle_vm), 0, sizeof(struct process_vm));

	idle_process->vm = &cpu_local_var(idle_vm);

	ihk_mc_init_context(&idle_process->ctx, NULL, idle);
	idle_process->pid = 0;
	idle_process->tid = ihk_mc_get_processor_id();

	INIT_LIST_HEAD(&cpu_local_var(runq));
	cpu_local_var(runq_len) = 0;
	ihk_mc_spinlock_init(&cpu_local_var(runq_lock));

#ifdef TIMER_CPU_ID
	if (ihk_mc_get_processor_id() == TIMER_CPU_ID) {
		init_timers();
		wake_timers_loop();
	}
#endif
}

void schedule(void)
{
	struct cpu_local_var *v = get_this_cpu_local_var();
	struct process *next, *prev, *proc, *tmp = NULL;
	int switch_ctx = 0;
	unsigned long irqstate;
	struct process *last;

	irqstate = ihk_mc_spinlock_lock(&(v->runq_lock));

	next = NULL;
	prev = v->current;

	/* All runnable processes are on the runqueue */
	if (prev && prev != &cpu_local_var(idle)) {
		list_del(&prev->sched_list);
		--v->runq_len;	
		
		/* Round-robin if not exited yet */
		if (!(prev->status & (PS_ZOMBIE | PS_EXITED))) {
			list_add_tail(&prev->sched_list, &(v->runq));
			++v->runq_len;
		}

		if (!v->runq_len) {
			v->status = CPU_STATUS_IDLE;
		}
	}

	/* Pick a new running process */
	list_for_each_entry_safe(proc, tmp, &(v->runq), sched_list) {
		if (proc->status == PS_RUNNING) {
			next = proc;
			break;
		}
	}

	/* No process? Run idle.. */
	if (!next) {
		next = &cpu_local_var(idle);
	}

	if (prev != next) {
		switch_ctx = 1;
		v->current = next;
	}
	
	if (switch_ctx) {
		dkprintf("[%d] schedule: %d => %d \n",
		        ihk_mc_get_processor_id(),
		        prev ? prev->tid : 0, next ? next->tid : 0);

		ihk_mc_load_page_table(next->vm->page_table);
		
		dkprintf("[%d] schedule: tlsblock_base: 0x%lX\n", 
		         ihk_mc_get_processor_id(), next->thread.tlsblock_base); 

		/* Set up new TLS.. */
		do_arch_prctl(ARCH_SET_FS, next->thread.tlsblock_base);
		
		ihk_mc_spinlock_unlock(&(v->runq_lock), irqstate);
		
		if (prev) {
			last = ihk_mc_switch_context(&prev->ctx, &next->ctx, prev);
		} 
		else {
			last = ihk_mc_switch_context(NULL, &next->ctx, prev);
		}

		if ((last != NULL) && (last->status & (PS_ZOMBIE | PS_EXITED))) {
			free_process_memory(last);
			release_process(last);
		}
	}
	else {
		ihk_mc_spinlock_unlock(&(v->runq_lock), irqstate);
	}
}


int sched_wakeup_process(struct process *proc, int valid_states)
{
	int status;
	int spin_slept = 0;
	unsigned long irqstate;
	struct cpu_local_var *v = get_cpu_local_var(proc->cpu_id);
	
	irqstate = ihk_mc_spinlock_lock(&(proc->spin_sleep_lock));
	if (proc->spin_sleep) {
		dkprintf("sched_wakeup_process() spin wakeup: cpu_id: %d\n", 
				proc->cpu_id);

		spin_slept = 1;
		proc->spin_sleep = 0;
		status = 0;	
	}
	ihk_mc_spinlock_unlock(&(proc->spin_sleep_lock), irqstate);
	
	if (spin_slept)
		return status;

	irqstate = ihk_mc_spinlock_lock(&(v->runq_lock));
	
	if (proc->status & valid_states) {
		xchg4((int *)(&proc->status), PS_RUNNING);
		status = 0;
	} 
	else {
		status = -EINVAL;
	}

	ihk_mc_spinlock_unlock(&(v->runq_lock), irqstate);

	if (!status && (proc->cpu_id != ihk_mc_get_processor_id())) {
		ihk_mc_interrupt_cpu(get_x86_cpu_local_variable(proc->cpu_id)->apic_id,
		                     0xd1);
	}

	return status;
}



/* Runq lock must be held here */
void __runq_add_proc(struct process *proc, int cpu_id)
{
	struct cpu_local_var *v = get_cpu_local_var(cpu_id);
	list_add_tail(&proc->sched_list, &v->runq);
	++v->runq_len;
	proc->cpu_id = cpu_id;
	proc->status = PS_RUNNING;
	get_cpu_local_var(cpu_id)->status = CPU_STATUS_RUNNING;

	dkprintf("runq_add_proc(): tid %d added to CPU[%d]'s runq\n", 
             proc->tid, cpu_id);
}

void runq_add_proc(struct process *proc, int cpu_id)
{
	struct cpu_local_var *v = get_cpu_local_var(cpu_id);
	unsigned long irqstate;
	
	irqstate = ihk_mc_spinlock_lock(&(v->runq_lock));
	__runq_add_proc(proc, cpu_id);
	ihk_mc_spinlock_unlock(&(v->runq_lock), irqstate);

	/* Kick scheduler */
	if (cpu_id != ihk_mc_get_processor_id())
		ihk_mc_interrupt_cpu(
		         get_x86_cpu_local_variable(cpu_id)->apic_id, 0xd1);
}

/* NOTE: shouldn't remove a running process! */
void runq_del_proc(struct process *proc, int cpu_id)
{
	struct cpu_local_var *v = get_cpu_local_var(cpu_id);
	unsigned long irqstate;
	
	irqstate = ihk_mc_spinlock_lock(&(v->runq_lock));
	list_del(&proc->sched_list);
	--v->runq_len;
	
	if (!v->runq_len)
		get_cpu_local_var(cpu_id)->status = CPU_STATUS_IDLE;

	ihk_mc_spinlock_unlock(&(v->runq_lock), irqstate);
}