[deliverable/linux.git] / arch / x86 / kernel / ldt_64.c

/*
 * Copyright (C) 1992 Krishna Balasubramanian and Linus Torvalds
 * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
 * Copyright (C) 2002 Andi Kleen
 * 
 * This handles calls from both 32bit and 64bit mode.
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/ldt.h>
#include <asm/desc.h>
#include <asm/proto.h>

#ifdef CONFIG_SMP /* avoids "defined but not used" warnig */
static void flush_ldt(void *null)
{
	if (current->active_mm)
               load_LDT(&current->active_mm->context);
}
#endif

static int alloc_ldt(mm_context_t *pc, unsigned mincount, int reload)
{
	void *oldldt;
	void *newldt;
	unsigned oldsize;

	if (mincount <= (unsigned)pc->size)
		return 0;
	oldsize = pc->size;
	mincount = (mincount+511)&(~511);
	if (mincount*LDT_ENTRY_SIZE > PAGE_SIZE)
		newldt = vmalloc(mincount*LDT_ENTRY_SIZE);
	else
		newldt = kmalloc(mincount*LDT_ENTRY_SIZE, GFP_KERNEL);

	if (!newldt)
		return -ENOMEM;

	if (oldsize)
		memcpy(newldt, pc->ldt, oldsize*LDT_ENTRY_SIZE);
	oldldt = pc->ldt;
	memset(newldt+oldsize*LDT_ENTRY_SIZE, 0, (mincount-oldsize)*LDT_ENTRY_SIZE);
	wmb();
	pc->ldt = newldt;
	wmb();
	pc->size = mincount;
	wmb();
	if (reload) {
#ifdef CONFIG_SMP
		cpumask_t mask;

		preempt_disable();
		mask = cpumask_of_cpu(smp_processor_id());
		load_LDT(pc);
		if (!cpus_equal(current->mm->cpu_vm_mask, mask))
			smp_call_function(flush_ldt, NULL, 1, 1);
		preempt_enable();
#else
		load_LDT(pc);
#endif
	}
	if (oldsize) {
		if (oldsize*LDT_ENTRY_SIZE > PAGE_SIZE)
			vfree(oldldt);
		else
			kfree(oldldt);
	}
	return 0;
}

static inline int copy_ldt(mm_context_t *new, mm_context_t *old)
{
	int err = alloc_ldt(new, old->size, 0);
	if (err < 0)
		return err;
	memcpy(new->ldt, old->ldt, old->size*LDT_ENTRY_SIZE);
	return 0;
}

/*
 * we do not have to muck with descriptors here, that is
 * done in switch_mm() as needed.
 */
int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
	struct mm_struct * old_mm;
	int retval = 0;

	init_MUTEX(&mm->context.sem);
	mm->context.size = 0;
	old_mm = current->mm;
	if (old_mm && old_mm->context.size > 0) {
		down(&old_mm->context.sem);
		retval = copy_ldt(&mm->context, &old_mm->context);
		up(&old_mm->context.sem);
	}
	return retval;
}

/*
 * 
 * Don't touch the LDT register - we're already in the next thread.
 */
void destroy_context(struct mm_struct *mm)
{
	if (mm->context.size) {
		if ((unsigned)mm->context.size*LDT_ENTRY_SIZE > PAGE_SIZE)
			vfree(mm->context.ldt);
		else
			kfree(mm->context.ldt);
		mm->context.size = 0;
	}
}

static int read_ldt(void __user * ptr, unsigned long bytecount)
{
	int err;
	unsigned long size;
	struct mm_struct * mm = current->mm;

	if (!mm->context.size)
		return 0;
	if (bytecount > LDT_ENTRY_SIZE*LDT_ENTRIES)
		bytecount = LDT_ENTRY_SIZE*LDT_ENTRIES;

	down(&mm->context.sem);
	size = mm->context.size*LDT_ENTRY_SIZE;
	if (size > bytecount)
		size = bytecount;

	err = 0;
	if (copy_to_user(ptr, mm->context.ldt, size))
		err = -EFAULT;
	up(&mm->context.sem);
	if (err < 0)
		goto error_return;
	if (size != bytecount) {
		/* zero-fill the rest */
		if (clear_user(ptr+size, bytecount-size) != 0) {
			err = -EFAULT;
			goto error_return;
		}
	}
	return bytecount;
error_return:
	return err;
}

static int read_default_ldt(void __user * ptr, unsigned long bytecount)
{
	/* Arbitrary number */ 
	/* x86-64 default LDT is all zeros */
	if (bytecount > 128) 
		bytecount = 128; 	
	if (clear_user(ptr, bytecount))
		return -EFAULT;
	return bytecount; 
}

static int write_ldt(void __user * ptr, unsigned long bytecount, int oldmode)
{
	struct task_struct *me = current;
	struct mm_struct * mm = me->mm;
	__u32 entry_1, entry_2, *lp;
	int error;
	struct user_desc ldt_info;

	error = -EINVAL;

	if (bytecount != sizeof(ldt_info))
		goto out;
	error = -EFAULT; 	
	if (copy_from_user(&ldt_info, ptr, bytecount))
		goto out;

	error = -EINVAL;
	if (ldt_info.entry_number >= LDT_ENTRIES)
		goto out;
	if (ldt_info.contents == 3) {
		if (oldmode)
			goto out;
		if (ldt_info.seg_not_present == 0)
			goto out;
	}

	down(&mm->context.sem);
	if (ldt_info.entry_number >= (unsigned)mm->context.size) {
		error = alloc_ldt(&current->mm->context, ldt_info.entry_number+1, 1);
		if (error < 0)
			goto out_unlock;
	}

	lp = (__u32 *) ((ldt_info.entry_number << 3) + (char *) mm->context.ldt);

   	/* Allow LDTs to be cleared by the user. */
   	if (ldt_info.base_addr == 0 && ldt_info.limit == 0) {
		if (oldmode || LDT_empty(&ldt_info)) {
			entry_1 = 0;
			entry_2 = 0;
			goto install;
		}
	}

	entry_1 = LDT_entry_a(&ldt_info);
	entry_2 = LDT_entry_b(&ldt_info);
	if (oldmode)
		entry_2 &= ~(1 << 20);

	/* Install the new entry ...  */
install:
	*lp	= entry_1;
	*(lp+1)	= entry_2;
	error = 0;

out_unlock:
	up(&mm->context.sem);
out:
	return error;
}

asmlinkage int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount)
{
	int ret = -ENOSYS;

	switch (func) {
	case 0:
		ret = read_ldt(ptr, bytecount);
		break;
	case 1:
		ret = write_ldt(ptr, bytecount, 1);
		break;
	case 2:
		ret = read_default_ldt(ptr, bytecount);
		break;
	case 0x11:
		ret = write_ldt(ptr, bytecount, 0);
		break;
	}
	return ret;
}
Commit	Line	Data
1da177e4	1	/*
1da177e4 LT	2	* Copyright (C) 1992 Krishna Balasubramanian and Linus Torvalds
	3	* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
	4	* Copyright (C) 2002 Andi Kleen
	5	*
	6	* This handles calls from both 32bit and 64bit mode.
	7	*/
	8
	9	#include <linux/errno.h>
	10	#include <linux/sched.h>
	11	#include <linux/string.h>
	12	#include <linux/mm.h>
	13	#include <linux/smp.h>
1da177e4 LT	14	#include <linux/vmalloc.h>
	15	#include <linux/slab.h>
	16
	17	#include <asm/uaccess.h>
	18	#include <asm/system.h>
	19	#include <asm/ldt.h>
	20	#include <asm/desc.h>
	21	#include <asm/proto.h>
	22
	23	#ifdef CONFIG_SMP /* avoids "defined but not used" warnig */
	24	static void flush_ldt(void *null)
	25	{
	26	if (current->active_mm)
	27	load_LDT(&current->active_mm->context);
	28	}
	29	#endif
	30
	31	static int alloc_ldt(mm_context_t *pc, unsigned mincount, int reload)
	32	{
	33	void *oldldt;
	34	void *newldt;
	35	unsigned oldsize;
	36
	37	if (mincount <= (unsigned)pc->size)
	38	return 0;
	39	oldsize = pc->size;
	40	mincount = (mincount+511)&(~511);
	41	if (mincount*LDT_ENTRY_SIZE > PAGE_SIZE)
	42	newldt = vmalloc(mincount*LDT_ENTRY_SIZE);
	43	else
	44	newldt = kmalloc(mincount*LDT_ENTRY_SIZE, GFP_KERNEL);
	45
	46	if (!newldt)
	47	return -ENOMEM;
	48
	49	if (oldsize)
	50	memcpy(newldt, pc->ldt, oldsize*LDT_ENTRY_SIZE);
	51	oldldt = pc->ldt;
	52	memset(newldt+oldsizeLDT_ENTRY_SIZE, 0, (mincount-oldsize)LDT_ENTRY_SIZE);
	53	wmb();
	54	pc->ldt = newldt;
	55	wmb();
	56	pc->size = mincount;
	57	wmb();
	58	if (reload) {
	59	#ifdef CONFIG_SMP
	60	cpumask_t mask;
	61
	62	preempt_disable();
	63	mask = cpumask_of_cpu(smp_processor_id());
	64	load_LDT(pc);
	65	if (!cpus_equal(current->mm->cpu_vm_mask, mask))
	66	smp_call_function(flush_ldt, NULL, 1, 1);
	67	preempt_enable();
	68	#else
	69	load_LDT(pc);
	70	#endif
	71	}
	72	if (oldsize) {
	73	if (oldsize*LDT_ENTRY_SIZE > PAGE_SIZE)
	74	vfree(oldldt);
	75	else
	76	kfree(oldldt);
	77	}
78	return 0;
79	}
80
81	static inline int copy_ldt(mm_context_t new, mm_context_t old)
82	{
83	int err = alloc_ldt(new, old->size, 0);
84	if (err < 0)
85	return err;
86	memcpy(new->ldt, old->ldt, old->size*LDT_ENTRY_SIZE);
87	return 0;
88	}
89
90	/*
91	* we do not have to muck with descriptors here, that is
92	* done in switch_mm() as needed.
93	*/
94	int init_new_context(struct task_struct tsk, struct mm_struct mm)
95	{
96	struct mm_struct * old_mm;
97	int retval = 0;
98
99	init_MUTEX(&mm->context.sem);
100	mm->context.size = 0;
101	old_mm = current->mm;
102	if (old_mm && old_mm->context.size > 0) {
103	down(&old_mm->context.sem);
104	retval = copy_ldt(&mm->context, &old_mm->context);
105	up(&old_mm->context.sem);
106	}
107	return retval;
108	}
109
110	/*
111	*
112	* Don't touch the LDT register - we're already in the next thread.
113	*/
114	void destroy_context(struct mm_struct *mm)
115	{
116	if (mm->context.size) {
117	if ((unsigned)mm->context.size*LDT_ENTRY_SIZE > PAGE_SIZE)
118	vfree(mm->context.ldt);
119	else
120	kfree(mm->context.ldt);
121	mm->context.size = 0;
122	}
123	}
124
125	static int read_ldt(void __user * ptr, unsigned long bytecount)
126	{
127	int err;
128	unsigned long size;
129	struct mm_struct * mm = current->mm;
130
131	if (!mm->context.size)
132	return 0;
133	if (bytecount > LDT_ENTRY_SIZE*LDT_ENTRIES)
134	bytecount = LDT_ENTRY_SIZE*LDT_ENTRIES;
135
136	down(&mm->context.sem);
137	size = mm->context.size*LDT_ENTRY_SIZE;
138	if (size > bytecount)
139	size = bytecount;
140
141	err = 0;
142	if (copy_to_user(ptr, mm->context.ldt, size))
143	err = -EFAULT;
144	up(&mm->context.sem);
145	if (err < 0)
146	goto error_return;
147	if (size != bytecount) {
148	/* zero-fill the rest */
149	if (clear_user(ptr+size, bytecount-size) != 0) {
150	err = -EFAULT;
151	goto error_return;
152	}
153	}
154	return bytecount;
155	error_return:
156	return err;
157	}
158
159	static int read_default_ldt(void __user * ptr, unsigned long bytecount)
160	{
161	/* Arbitrary number */
162	/* x86-64 default LDT is all zeros */
163	if (bytecount > 128)
164	bytecount = 128;
165	if (clear_user(ptr, bytecount))
166	return -EFAULT;
167	return bytecount;
168	}
169
170	static int write_ldt(void __user * ptr, unsigned long bytecount, int oldmode)
171	{
172	struct task_struct *me = current;
173	struct mm_struct * mm = me->mm;
174	__u32 entry_1, entry_2, *lp;
175	int error;
176	struct user_desc ldt_info;
177
178	error = -EINVAL;
179
180	if (bytecount != sizeof(ldt_info))
181	goto out;
182	error = -EFAULT;
183	if (copy_from_user(&ldt_info, ptr, bytecount))
184	goto out;
185
186	error = -EINVAL;
187	if (ldt_info.entry_number >= LDT_ENTRIES)
188	goto out;
189	if (ldt_info.contents == 3) {
190	if (oldmode)
191	goto out;
192	if (ldt_info.seg_not_present == 0)
193	goto out;
194	}
195
196	down(&mm->context.sem);
197	if (ldt_info.entry_number >= (unsigned)mm->context.size) {
198	error = alloc_ldt(&current->mm->context, ldt_info.entry_number+1, 1);
199	if (error < 0)
200	goto out_unlock;
201	}
202
203	lp = (__u32 ) ((ldt_info.entry_number << 3) + (char ) mm->context.ldt);
204
205	/* Allow LDTs to be cleared by the user. */
206	if (ldt_info.base_addr == 0 && ldt_info.limit == 0) {
207	if (oldmode \|\| LDT_empty(&ldt_info)) {
208	entry_1 = 0;
209	entry_2 = 0;
210	goto install;
211	}
212	}
213
214	entry_1 = LDT_entry_a(&ldt_info);
215	entry_2 = LDT_entry_b(&ldt_info);
216	if (oldmode)
217	entry_2 &= ~(1 << 20);
218
219	/* Install the new entry ... */
220	install:
221	*lp = entry_1;
222	*(lp+1) = entry_2;
223	error = 0;
224
225	out_unlock:
226	up(&mm->context.sem);
227	out:
228	return error;
229	}
230
231	asmlinkage int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount)
232	{
233	int ret = -ENOSYS;
234
235	switch (func) {
236	case 0:
237	ret = read_ldt(ptr, bytecount);
238	break;
239	case 1:
240	ret = write_ldt(ptr, bytecount, 1);
241	break;
242	case 2:
243	ret = read_default_ldt(ptr, bytecount);
244	break;
245	case 0x11:
246	ret = write_ldt(ptr, bytecount, 0);
247	break;
248	}
249	return ret;
250	}