[apple/xnu.git] / osfmk / i386 / user_ldt.c

/*
 * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code 
 * as defined in and that are subject to the Apple Public Source License 
 * Version 2.0 (the 'License'). You may not use this file except in 
 * compliance with the License.  The rights granted to you under the 
 * License may not be used to create, or enable the creation or 
 * redistribution of, unlawful or unlicensed copies of an Apple operating 
 * system, or to circumvent, violate, or enable the circumvention or 
 * violation of, any terms of an Apple operating system software license 
 * agreement.
 *
 * Please obtain a copy of the License at 
 * http://www.opensource.apple.com/apsl/ and read it before using this 
 * file.
 *
 * The Original Code and all software distributed under the License are 
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
 * Please see the License for the specific language governing rights and 
 * limitations under the License.
 *
 * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */
/* 
 * Mach Operating System
 * Copyright (c) 1991 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon 
 * the rights to redistribute these changes.
 */

/*
 */

/*
 * User LDT management.
 * Each thread in a task may have its own LDT.
 */

#include <kern/kalloc.h>
#include <kern/thread.h>
#include <kern/misc_protos.h>

#include <vm/vm_kern.h>

#include <i386/seg.h>
#include <i386/thread.h>
#include <i386/user_ldt.h>

char	acc_type[8][3] = {
    /*	code	stack	data */
    {	0,	0,	1	},	/* data */
    {	0,	1,	1	},	/* data, writable */
    {	0,	0,	1	},	/* data, expand-down */
    {	0,	1,	1	},	/* data, writable, expand-down */
    {	1,	0,	0	},	/* code */
    {	1,	0,	1	},	/* code, readable */
    {	1,	0,	0	},	/* code, conforming */
    {	1,	0,	1	},	/* code, readable, conforming */
};

#if 0
/* Forward */

extern boolean_t	selector_check(
				thread_t		thread,
				int			sel,
				int			type);

boolean_t
selector_check(
	thread_t		thread,
	int			sel,
	int			type)
{
	struct user_ldt	*ldt;
	int	access;

	ldt = thread->machine.pcb->ims.ldt;
	if (ldt == 0) {
	    switch (type) {
		case S_CODE:
		    return sel == USER_CS;
		case S_STACK:
		    return sel == USER_DS;
		case S_DATA:
		    return sel == 0 ||
			   sel == USER_CS ||
			   sel == USER_DS;
	    }
	}

	if (type != S_DATA && sel == 0)
	    return FALSE;
	if ((sel & (SEL_LDTS|SEL_PL)) != (SEL_LDTS|SEL_PL_U)
	  || sel > ldt->desc.limit_low)
		return FALSE;

	access = ldt->ldt[sel_idx(sel)].access;
	
	if ((access & (ACC_P|ACC_PL|ACC_TYPE_USER))
		!= (ACC_P|ACC_PL_U|ACC_TYPE_USER))
	    return FALSE;
		/* present, pl == pl.user, not system */

	return acc_type[(access & 0xe)>>1][type];
}

/*
 * Add the descriptors to the LDT, starting with
 * the descriptor for 'first_selector'.
 */

kern_return_t
i386_set_ldt(
	thread_t		thr_act,
	int			first_selector,
	descriptor_list_t	desc_list,
	mach_msg_type_number_t	count)
{
	user_ldt_t	new_ldt, old_ldt, temp;
	struct real_descriptor *dp;
	int		i;
	int		min_selector = 0;
	pcb_t		pcb;
	vm_size_t	ldt_size_needed;
	int		first_desc = sel_idx(first_selector);
	vm_map_copy_t	old_copy_object;
	thread_t		thread;

	if (first_desc < min_selector || first_desc > 8191)
	    return KERN_INVALID_ARGUMENT;
	if (first_desc + count >= 8192)
	    return KERN_INVALID_ARGUMENT;
	if (thr_act == THREAD_NULL)
	    return KERN_INVALID_ARGUMENT;
	if ((thread = act_lock_thread(thr_act)) == THREAD_NULL) {
		act_unlock_thread(thr_act);
	    return KERN_INVALID_ARGUMENT;
	}
	if (thread == current_thread())
		min_selector = LDTSZ;
	act_unlock_thread(thr_act);

	/*
	 * We must copy out desc_list to the kernel map, and wire
	 * it down (we touch it while the PCB is locked).
	 *
	 * We make a copy of the copyin object, and clear
	 * out the old one, so that the MIG stub will have a
	 * a empty (but valid) copyin object to discard.
	 */
	{
	    kern_return_t	kr;
	    vm_map_offset_t	dst_addr;

	    old_copy_object = (vm_map_copy_t) desc_list;

	    kr = vm_map_copyout(ipc_kernel_map, &dst_addr,
				vm_map_copy_copy(old_copy_object));
	    if (kr != KERN_SUCCESS)
		return kr;

	    (void) vm_map_wire(ipc_kernel_map,
			vm_map_trunc_page(dst_addr),
			vm_map_round_page(dst_addr + 
				count * sizeof(struct real_descriptor)),
			VM_PROT_READ|VM_PROT_WRITE, FALSE);
	    desc_list = CAST_DOWN(descriptor_list_t, dst_addr);
	}

	for (i = 0, dp = (struct real_descriptor *) desc_list;
	     i < count;
	     i++, dp++)
	{
	    switch (dp->access & ~ACC_A) {
		case 0:
		case ACC_P:
		    /* valid empty descriptor */
		    break;
		case ACC_P | ACC_CALL_GATE:
		    /* Mach kernel call */
		    *dp = *(struct real_descriptor *)
				&ldt[sel_idx(USER_SCALL)];
		    break;
		case ACC_P | ACC_PL_U | ACC_DATA:
		case ACC_P | ACC_PL_U | ACC_DATA_W:
		case ACC_P | ACC_PL_U | ACC_DATA_E:
		case ACC_P | ACC_PL_U | ACC_DATA_EW:
		case ACC_P | ACC_PL_U | ACC_CODE:
		case ACC_P | ACC_PL_U | ACC_CODE_R:
		case ACC_P | ACC_PL_U | ACC_CODE_C:
		case ACC_P | ACC_PL_U | ACC_CODE_CR:
		case ACC_P | ACC_PL_U | ACC_CALL_GATE_16:
		case ACC_P | ACC_PL_U | ACC_CALL_GATE:
		    break;
		default:
		    (void) vm_map_remove(ipc_kernel_map, 
					 vm_map_trunc_page(desc_list),
					 vm_map_round_page(&desc_list[count]),
					 VM_MAP_REMOVE_KUNWIRE);
		    return KERN_INVALID_ARGUMENT;
	    }
	}
	ldt_size_needed = sizeof(struct real_descriptor)
			* (first_desc + count);

	pcb = thr_act->machine.pcb;
	new_ldt = 0;
    Retry:
	simple_lock(&pcb->lock);
	old_ldt = pcb->ims.ldt;
	if (old_ldt == 0 ||
	    old_ldt->desc.limit_low + 1 < ldt_size_needed)
	{
	    /*
	     * No old LDT, or not big enough
	     */
	    if (new_ldt == 0) {
		simple_unlock(&pcb->lock);

		new_ldt = (user_ldt_t) kalloc(ldt_size_needed
					      + sizeof(struct real_descriptor));
		new_ldt->desc.limit_low   = ldt_size_needed - 1;
		new_ldt->desc.limit_high  = 0;
		new_ldt->desc.base_low    = 
				((vm_offset_t)&new_ldt->ldt[0]) & 0xffff;
		new_ldt->desc.base_med    = 
				(((vm_offset_t)&new_ldt->ldt[0]) >> 16)
						 & 0xff;
		new_ldt->desc.base_high   = 
				((vm_offset_t)&new_ldt->ldt[0]) >> 24;
		new_ldt->desc.access      = ACC_P | ACC_LDT;
		new_ldt->desc.granularity = 0;

		goto Retry;
	    }

	    /*
	     * Have new LDT.  If there was a an old ldt, copy descriptors
	     * from old to new.  Otherwise copy the default ldt.
	     */
	    if (old_ldt) {
		bcopy((char *)&old_ldt->ldt[0],
		      (char *)&new_ldt->ldt[0],
		      old_ldt->desc.limit_low + 1);
	    }
	    else if (thr_act == current_thread()) {
		struct real_descriptor template = {0, 0, 0, ACC_P, 0, 0 ,0};

		for (dp = &new_ldt->ldt[0], i = 0; i < first_desc; i++, dp++) {
		    if (i < LDTSZ)
		    	*dp = *(struct real_descriptor *) &ldt[i];
		    else
			*dp = template;
		}
	    }

	    temp = old_ldt;
	    old_ldt = new_ldt;	/* use new LDT from now on */
	    new_ldt = temp;	/* discard old LDT */

	    pcb->ims.ldt = old_ldt;	/* new LDT for thread */
	}

	/*
	 * Install new descriptors.
	 */
	bcopy((char *)desc_list,
	      (char *)&old_ldt->ldt[first_desc],
	      count * sizeof(struct real_descriptor));

	simple_unlock(&pcb->lock);

	if (new_ldt)
	    kfree((vm_offset_t)new_ldt,
		  new_ldt->desc.limit_low+1+sizeof(struct real_descriptor));

	/*
	 * Free the descriptor list.
	 */
	(void) vm_map_remove(ipc_kernel_map, vm_map_trunc_page(desc_list),
			     vm_map_round_page(&desc_list[count]),
			     VM_MAP_REMOVE_KUNWIRE);
	return KERN_SUCCESS;
}

kern_return_t
i386_get_ldt(
	thread_t		thr_act,
	int			first_selector,
	int			selector_count,	/* number wanted */
	descriptor_list_t	*desc_list,	/* in/out */
	mach_msg_type_number_t	*count)		/* in/out */
{
	struct user_ldt *user_ldt;
	pcb_t		pcb = thr_act->machine.pcb;
	int		first_desc = sel_idx(first_selector);
	unsigned int	ldt_count;
	vm_size_t	ldt_size;
	vm_size_t	size, size_needed;
	vm_offset_t	addr;
	thread_t		thread;

	if (thr_act == THREAD_NULL)
	    return KERN_INVALID_ARGUMENT;

	if (first_desc < 0 || first_desc > 8191)
	    return KERN_INVALID_ARGUMENT;
	if (first_desc + selector_count >= 8192)
	    return KERN_INVALID_ARGUMENT;

	addr = 0;
	size = 0;

	for (;;) {
	    simple_lock(&pcb->lock);
	    user_ldt = pcb->ims.ldt;
	    if (user_ldt == 0) {
		simple_unlock(&pcb->lock);
		if (addr)
		    kmem_free(ipc_kernel_map, addr, size);
		*count = 0;
		return KERN_SUCCESS;
	    }

	    /*
	     * Find how many descriptors we should return.
	     */
	    ldt_count = (user_ldt->desc.limit_low + 1) /
			sizeof (struct real_descriptor);
	    ldt_count -= first_desc;
	    if (ldt_count > selector_count)
		ldt_count = selector_count;

	    ldt_size = ldt_count * sizeof(struct real_descriptor);

	    /*
	     * Do we have the memory we need?
	     */
	    if (ldt_count <= *count)
		break;		/* fits in-line */

	    size_needed = round_page(ldt_size);
	    if (size_needed <= size)
		break;

	    /*
	     * Unlock the pcb and allocate more memory
	     */
	    simple_unlock(&pcb->lock);

	    if (size != 0)
		kmem_free(ipc_kernel_map, addr, size);

	    size = size_needed;

	    if (kmem_alloc(ipc_kernel_map, &addr, size)
			!= KERN_SUCCESS)
		return KERN_RESOURCE_SHORTAGE;
	}

	/*
	 * copy out the descriptors
	 */
	bcopy((char *)&user_ldt->ldt[first_desc],
	      (char *)addr,
	      ldt_size);
	*count = ldt_count;
	simple_unlock(&pcb->lock);

	if (addr) {
	    vm_size_t		size_used, size_left;
	    vm_map_copy_t	memory;

	    /*
	     * Free any unused memory beyond the end of the last page used
	     */
	    size_used = round_page(ldt_size);
	    if (size_used != size)
		kmem_free(ipc_kernel_map,
			addr + size_used, size - size_used);

	    /*
	     * Zero the remainder of the page being returned.
	     */
	    size_left = size_used - ldt_size;
	    if (size_left > 0)
		bzero((char *)addr + ldt_size, size_left);

	    /*
	     * Unwire the memory and make it into copyin form.
	     */
	    (void) vm_map_unwire(ipc_kernel_map, vm_map_trunc_page(addr),
				 vm_map_round_page(addr + size_used), FALSE);
	    (void) vm_map_copyin(ipc_kernel_map, (vm_map_address_t)addr, 
				 (vm_map_size_t)size_used, TRUE, &memory);
	    *desc_list = (descriptor_list_t) memory;
	}

	return KERN_SUCCESS;
}

#endif 
void
user_ldt_free(
	user_ldt_t	user_ldt)
{
	kfree(user_ldt,
		user_ldt->desc.limit_low+1+sizeof(struct real_descriptor));
}
Commit	Line	Data
1c79356b	1	/*
91447636	2	* Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
1c79356b	3	*
8ad349bb	4	* @APPLE_LICENSE_OSREFERENCE_HEADER_START@
1c79356b	5	*
8ad349bb A	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the
	10	* License may not be used to create, or enable the creation or
	11	* redistribution of, unlawful or unlicensed copies of an Apple operating
	12	* system, or to circumvent, violate, or enable the circumvention or
	13	* violation of, any terms of an Apple operating system software license
	14	* agreement.
	15	*
	16	* Please obtain a copy of the License at
	17	* http://www.opensource.apple.com/apsl/ and read it before using this
	18	* file.
	19	*
	20	* The Original Code and all software distributed under the License are
	21	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	22	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	23	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	24	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	25	* Please see the License for the specific language governing rights and
	26	* limitations under the License.
	27	*
	28	* @APPLE_LICENSE_OSREFERENCE_HEADER_END@
1c79356b A	29	*/
	30	/*
	31	* @OSF_COPYRIGHT@
	32	*/
	33	/*
	34	* Mach Operating System
	35	* Copyright (c) 1991 Carnegie Mellon University
	36	* All Rights Reserved.
	37	*
	38	* Permission to use, copy, modify and distribute this software and its
	39	* documentation is hereby granted, provided that both the copyright
	40	* notice and this permission notice appear in all copies of the
	41	* software, derivative works or modified versions, and any portions
	42	* thereof, and that both notices appear in supporting documentation.
	43	*
	44	* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
	45	* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
	46	* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
	47	*
	48	* Carnegie Mellon requests users of this software to return to
	49	*
	50	* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
	51	* School of Computer Science
	52	* Carnegie Mellon University
	53	* Pittsburgh PA 15213-3890
	54	*
	55	* any improvements or extensions that they make and grant Carnegie Mellon
	56	* the rights to redistribute these changes.
	57	*/
	58
	59	/*
	60	*/
	61
	62	/*
	63	* User LDT management.
8ad349bb	64	* Each thread in a task may have its own LDT.
1c79356b A	65	*/
	66
	67	#include <kern/kalloc.h>
	68	#include <kern/thread.h>
	69	#include <kern/misc_protos.h>
	70
	71	#include <vm/vm_kern.h>
	72
	73	#include <i386/seg.h>
	74	#include <i386/thread.h>
	75	#include <i386/user_ldt.h>
	76
8ad349bb A	77	char acc_type[8][3] = {
	78	/* code stack data */
	79	{ 0, 0, 1 }, /* data */
	80	{ 0, 1, 1 }, /* data, writable */
	81	{ 0, 0, 1 }, /* data, expand-down */
	82	{ 0, 1, 1 }, /* data, writable, expand-down */
	83	{ 1, 0, 0 }, /* code */
	84	{ 1, 0, 1 }, /* code, readable */
	85	{ 1, 0, 0 }, /* code, conforming */
	86	{ 1, 0, 1 }, /* code, readable, conforming */
	87	};
	88
	89	#if 0
	90	/* Forward */
	91
	92	extern boolean_t selector_check(
	93	thread_t thread,
	94	int sel,
	95	int type);
	96
	97	boolean_t
	98	selector_check(
	99	thread_t thread,
	100	int sel,
	101	int type)
	102	{
	103	struct user_ldt *ldt;
	104	int access;
	105
	106	ldt = thread->machine.pcb->ims.ldt;
	107	if (ldt == 0) {
	108	switch (type) {
	109	case S_CODE:
	110	return sel == USER_CS;
	111	case S_STACK:
	112	return sel == USER_DS;
	113	case S_DATA:
	114	return sel == 0 \|\|
	115	sel == USER_CS \|\|
	116	sel == USER_DS;
	117	}
	118	}
	119
	120	if (type != S_DATA && sel == 0)
	121	return FALSE;
	122	if ((sel & (SEL_LDTS\|SEL_PL)) != (SEL_LDTS\|SEL_PL_U)
	123	\|\| sel > ldt->desc.limit_low)
	124	return FALSE;
1c79356b	125
8ad349bb A	126	access = ldt->ldt[sel_idx(sel)].access;
	127
	128	if ((access & (ACC_P\|ACC_PL\|ACC_TYPE_USER))
	129	!= (ACC_P\|ACC_PL_U\|ACC_TYPE_USER))
	130	return FALSE;
	131	/* present, pl == pl.user, not system */
	132
	133	return acc_type[(access & 0xe)>>1][type];
	134	}
1c79356b A	135
	136	/*
	137	* Add the descriptors to the LDT, starting with
	138	* the descriptor for 'first_selector'.
	139	*/
	140
8ad349bb	141	kern_return_t
1c79356b	142	i386_set_ldt(
8ad349bb A	143	thread_t thr_act,
	144	int first_selector,
	145	descriptor_list_t desc_list,
	146	mach_msg_type_number_t count)
1c79356b	147	{
8ad349bb	148	user_ldt_t new_ldt, old_ldt, temp;
1c79356b	149	struct real_descriptor *dp;
8ad349bb A	150	int i;
	151	int min_selector = 0;
	152	pcb_t pcb;
	153	vm_size_t ldt_size_needed;
	154	int first_desc = sel_idx(first_selector);
	155	vm_map_copy_t old_copy_object;
	156	thread_t thread;
	157
	158	if (first_desc < min_selector \|\| first_desc > 8191)
	159	return KERN_INVALID_ARGUMENT;
	160	if (first_desc + count >= 8192)
	161	return KERN_INVALID_ARGUMENT;
	162	if (thr_act == THREAD_NULL)
	163	return KERN_INVALID_ARGUMENT;
	164	if ((thread = act_lock_thread(thr_act)) == THREAD_NULL) {
	165	act_unlock_thread(thr_act);
	166	return KERN_INVALID_ARGUMENT;
	167	}
	168	if (thread == current_thread())
	169	min_selector = LDTSZ;
	170	act_unlock_thread(thr_act);
c0fea474	171
8ad349bb A	172	/*
	173	* We must copy out desc_list to the kernel map, and wire
	174	* it down (we touch it while the PCB is locked).
	175	*
	176	* We make a copy of the copyin object, and clear
	177	* out the old one, so that the MIG stub will have a
	178	* a empty (but valid) copyin object to discard.
	179	*/
	180	{
	181	kern_return_t kr;
	182	vm_map_offset_t dst_addr;
	183
	184	old_copy_object = (vm_map_copy_t) desc_list;
	185
	186	kr = vm_map_copyout(ipc_kernel_map, &dst_addr,
	187	vm_map_copy_copy(old_copy_object));
	188	if (kr != KERN_SUCCESS)
	189	return kr;
	190
	191	(void) vm_map_wire(ipc_kernel_map,
	192	vm_map_trunc_page(dst_addr),
	193	vm_map_round_page(dst_addr +
	194	count * sizeof(struct real_descriptor)),
	195	VM_PROT_READ\|VM_PROT_WRITE, FALSE);
	196	desc_list = CAST_DOWN(descriptor_list_t, dst_addr);
	197	}
c0fea474	198
8ad349bb A	199	for (i = 0, dp = (struct real_descriptor *) desc_list;
	200	i < count;
	201	i++, dp++)
	202	{
	203	switch (dp->access & ~ACC_A) {
	204	case 0:
	205	case ACC_P:
	206	/* valid empty descriptor */
	207	break;
	208	case ACC_P \| ACC_CALL_GATE:
	209	/* Mach kernel call */
	210	dp = (struct real_descriptor *)
	211	&ldt[sel_idx(USER_SCALL)];
	212	break;
	213	case ACC_P \| ACC_PL_U \| ACC_DATA:
	214	case ACC_P \| ACC_PL_U \| ACC_DATA_W:
	215	case ACC_P \| ACC_PL_U \| ACC_DATA_E:
	216	case ACC_P \| ACC_PL_U \| ACC_DATA_EW:
	217	case ACC_P \| ACC_PL_U \| ACC_CODE:
	218	case ACC_P \| ACC_PL_U \| ACC_CODE_R:
	219	case ACC_P \| ACC_PL_U \| ACC_CODE_C:
	220	case ACC_P \| ACC_PL_U \| ACC_CODE_CR:
	221	case ACC_P \| ACC_PL_U \| ACC_CALL_GATE_16:
	222	case ACC_P \| ACC_PL_U \| ACC_CALL_GATE:
	223	break;
	224	default:
	225	(void) vm_map_remove(ipc_kernel_map,
	226	vm_map_trunc_page(desc_list),
	227	vm_map_round_page(&desc_list[count]),
	228	VM_MAP_REMOVE_KUNWIRE);
	229	return KERN_INVALID_ARGUMENT;
1c79356b A	230	}
1c79356b A	231	}
8ad349bb A	232	ldt_size_needed = sizeof(struct real_descriptor)
	233	* (first_desc + count);
	234
	235	pcb = thr_act->machine.pcb;
	236	new_ldt = 0;
	237	Retry:
	238	simple_lock(&pcb->lock);
	239	old_ldt = pcb->ims.ldt;
	240	if (old_ldt == 0 \|\|
	241	old_ldt->desc.limit_low + 1 < ldt_size_needed)
	242	{
1c79356b	243	/*
8ad349bb	244	* No old LDT, or not big enough
1c79356b	245	*/
8ad349bb A	246	if (new_ldt == 0) {
	247	simple_unlock(&pcb->lock);
	248
	249	new_ldt = (user_ldt_t) kalloc(ldt_size_needed
	250	+ sizeof(struct real_descriptor));
	251	new_ldt->desc.limit_low = ldt_size_needed - 1;
	252	new_ldt->desc.limit_high = 0;
	253	new_ldt->desc.base_low =
	254	((vm_offset_t)&new_ldt->ldt[0]) & 0xffff;
	255	new_ldt->desc.base_med =
	256	(((vm_offset_t)&new_ldt->ldt[0]) >> 16)
	257	& 0xff;
	258	new_ldt->desc.base_high =
	259	((vm_offset_t)&new_ldt->ldt[0]) >> 24;
	260	new_ldt->desc.access = ACC_P \| ACC_LDT;
	261	new_ldt->desc.granularity = 0;
	262
	263	goto Retry;
1c79356b A	264	}
	265
	266	/*
	267	* Have new LDT. If there was a an old ldt, copy descriptors
8ad349bb	268	* from old to new. Otherwise copy the default ldt.
1c79356b A	269	*/
1c79356b A	270	if (old_ldt) {
8ad349bb A	271	bcopy((char *)&old_ldt->ldt[0],
	272	(char *)&new_ldt->ldt[0],
	273	old_ldt->desc.limit_low + 1);
1c79356b	274	}
8ad349bb A	275	else if (thr_act == current_thread()) {
	276	struct real_descriptor template = {0, 0, 0, ACC_P, 0, 0 ,0};
	277
	278	for (dp = &new_ldt->ldt[0], i = 0; i < first_desc; i++, dp++) {
	279	if (i < LDTSZ)
	280	dp = (struct real_descriptor *) &ldt[i];
	281	else
	282	*dp = template;
1c79356b A	283	}
	284	}
	285
8ad349bb A	286	temp = old_ldt;
	287	old_ldt = new_ldt; /* use new LDT from now on */
	288	new_ldt = temp; /* discard old LDT */
1c79356b	289
8ad349bb A	290	pcb->ims.ldt = old_ldt; /* new LDT for thread */
8ad349bb A	291	}
c0fea474	292
1c79356b	293	/*
8ad349bb	294	* Install new descriptors.
1c79356b	295	*/
8ad349bb A	296	bcopy((char *)desc_list,
	297	(char *)&old_ldt->ldt[first_desc],
	298	count * sizeof(struct real_descriptor));
1c79356b	299
8ad349bb	300	simple_unlock(&pcb->lock);
1c79356b	301
8ad349bb A	302	if (new_ldt)
	303	kfree((vm_offset_t)new_ldt,
	304	new_ldt->desc.limit_low+1+sizeof(struct real_descriptor));
c0fea474	305
8ad349bb A	306	/*
	307	* Free the descriptor list.
	308	*/
	309	(void) vm_map_remove(ipc_kernel_map, vm_map_trunc_page(desc_list),
	310	vm_map_round_page(&desc_list[count]),
	311	VM_MAP_REMOVE_KUNWIRE);
	312	return KERN_SUCCESS;
1c79356b A	313	}
1c79356b A	314
8ad349bb	315	kern_return_t
1c79356b	316	i386_get_ldt(
8ad349bb A	317	thread_t thr_act,
	318	int first_selector,
	319	int selector_count, /* number wanted */
	320	descriptor_list_t desc_list, / in/out */
	321	mach_msg_type_number_t count) / in/out */
1c79356b	322	{
8ad349bb A	323	struct user_ldt *user_ldt;
	324	pcb_t pcb = thr_act->machine.pcb;
	325	int first_desc = sel_idx(first_selector);
1c79356b	326	unsigned int ldt_count;
8ad349bb A	327	vm_size_t ldt_size;
	328	vm_size_t size, size_needed;
	329	vm_offset_t addr;
	330	thread_t thread;
	331
	332	if (thr_act == THREAD_NULL)
	333	return KERN_INVALID_ARGUMENT;
	334
	335	if (first_desc < 0 \|\| first_desc > 8191)
	336	return KERN_INVALID_ARGUMENT;
	337	if (first_desc + selector_count >= 8192)
	338	return KERN_INVALID_ARGUMENT;
	339
	340	addr = 0;
	341	size = 0;
	342
	343	for (;;) {
	344	simple_lock(&pcb->lock);
	345	user_ldt = pcb->ims.ldt;
	346	if (user_ldt == 0) {
	347	simple_unlock(&pcb->lock);
	348	if (addr)
	349	kmem_free(ipc_kernel_map, addr, size);
	350	*count = 0;
	351	return KERN_SUCCESS;
	352	}
1c79356b	353
8ad349bb A	354	/*
	355	* Find how many descriptors we should return.
	356	*/
	357	ldt_count = (user_ldt->desc.limit_low + 1) /
	358	sizeof (struct real_descriptor);
	359	ldt_count -= first_desc;
	360	if (ldt_count > selector_count)
	361	ldt_count = selector_count;
1c79356b	362
8ad349bb	363	ldt_size = ldt_count * sizeof(struct real_descriptor);
1c79356b	364
8ad349bb A	365	/*
	366	* Do we have the memory we need?
	367	*/
	368	if (ldt_count <= *count)
	369	break; /* fits in-line */
c0fea474	370
8ad349bb A	371	size_needed = round_page(ldt_size);
	372	if (size_needed <= size)
	373	break;
1c79356b	374
8ad349bb A	375	/*
	376	* Unlock the pcb and allocate more memory
	377	*/
	378	simple_unlock(&pcb->lock);
1c79356b	379
8ad349bb A	380	if (size != 0)
8ad349bb A	381	kmem_free(ipc_kernel_map, addr, size);
1c79356b	382
8ad349bb	383	size = size_needed;
1c79356b	384
8ad349bb A	385	if (kmem_alloc(ipc_kernel_map, &addr, size)
	386	!= KERN_SUCCESS)
	387	return KERN_RESOURCE_SHORTAGE;
1c79356b A	388	}
1c79356b A	389
8ad349bb A	390	/*
	391	* copy out the descriptors
	392	*/
	393	bcopy((char *)&user_ldt->ldt[first_desc],
	394	(char *)addr,
	395	ldt_size);
	396	*count = ldt_count;
	397	simple_unlock(&pcb->lock);
1c79356b	398
8ad349bb A	399	if (addr) {
	400	vm_size_t size_used, size_left;
	401	vm_map_copy_t memory;
1c79356b	402
8ad349bb A	403	/*
	404	* Free any unused memory beyond the end of the last page used
	405	*/
	406	size_used = round_page(ldt_size);
	407	if (size_used != size)
	408	kmem_free(ipc_kernel_map,
	409	addr + size_used, size - size_used);
1c79356b	410
8ad349bb A	411	/*
	412	* Zero the remainder of the page being returned.
	413	*/
	414	size_left = size_used - ldt_size;
	415	if (size_left > 0)
	416	bzero((char *)addr + ldt_size, size_left);
1c79356b	417
8ad349bb A	418	/*
	419	* Unwire the memory and make it into copyin form.
	420	*/
	421	(void) vm_map_unwire(ipc_kernel_map, vm_map_trunc_page(addr),
	422	vm_map_round_page(addr + size_used), FALSE);
	423	(void) vm_map_copyin(ipc_kernel_map, (vm_map_address_t)addr,
	424	(vm_map_size_t)size_used, TRUE, &memory);
	425	*desc_list = (descriptor_list_t) memory;
1c79356b A	426	}
1c79356b A	427
8ad349bb	428	return KERN_SUCCESS;
1c79356b A	429	}
1c79356b A	430
8ad349bb	431	#endif
1c79356b	432	void
8ad349bb A	433	user_ldt_free(
8ad349bb A	434	user_ldt_t user_ldt)
1c79356b	435	{
8ad349bb A	436	kfree(user_ldt,
8ad349bb A	437	user_ldt->desc.limit_low+1+sizeof(struct real_descriptor));
1c79356b	438	}