[linux-2.6-block.git] / arch / s390 / mm / mmap.c

/*
 *  flexible mmap layout support
 *
 * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
 * All Rights Reserved.
 *
 * 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 2 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *
 * Started by Ingo Molnar <mingo@elte.hu>
 */

#include <linux/personality.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/compat.h>
#include <linux/security.h>
#include <asm/pgalloc.h>

unsigned long mmap_rnd_mask;
unsigned long mmap_align_mask;

static unsigned long stack_maxrandom_size(void)
{
	if (!(current->flags & PF_RANDOMIZE))
		return 0;
	if (current->personality & ADDR_NO_RANDOMIZE)
		return 0;
	return STACK_RND_MASK << PAGE_SHIFT;
}

/*
 * Top of mmap area (just below the process stack).
 *
 * Leave at least a ~32 MB hole.
 */
#define MIN_GAP (32*1024*1024)
#define MAX_GAP (STACK_TOP/6*5)

static inline int mmap_is_legacy(void)
{
	if (current->personality & ADDR_COMPAT_LAYOUT)
		return 1;
	if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
		return 1;
	return sysctl_legacy_va_layout;
}

unsigned long arch_mmap_rnd(void)
{
	if (is_32bit_task())
		return (get_random_int() & 0x7ff) << PAGE_SHIFT;
	else
		return (get_random_int() & mmap_rnd_mask) << PAGE_SHIFT;
}

static unsigned long mmap_base_legacy(unsigned long rnd)
{
	return TASK_UNMAPPED_BASE + rnd;
}

static inline unsigned long mmap_base(unsigned long rnd)
{
	unsigned long gap = rlimit(RLIMIT_STACK);

	if (gap < MIN_GAP)
		gap = MIN_GAP;
	else if (gap > MAX_GAP)
		gap = MAX_GAP;
	gap &= PAGE_MASK;
	return STACK_TOP - stack_maxrandom_size() - rnd - gap;
}

unsigned long
arch_get_unmapped_area(struct file *filp, unsigned long addr,
		unsigned long len, unsigned long pgoff, unsigned long flags)
{
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	struct vm_unmapped_area_info info;
	int do_color_align;

	if (len > TASK_SIZE - mmap_min_addr)
		return -ENOMEM;

	if (flags & MAP_FIXED)
		return addr;

	if (addr) {
		addr = PAGE_ALIGN(addr);
		vma = find_vma(mm, addr);
		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
		    (!vma || addr + len <= vma->vm_start))
			return addr;
	}

	do_color_align = 0;
	if (filp || (flags & MAP_SHARED))
		do_color_align = !is_32bit_task();

	info.flags = 0;
	info.length = len;
	info.low_limit = mm->mmap_base;
	info.high_limit = TASK_SIZE;
	info.align_mask = do_color_align ? (mmap_align_mask << PAGE_SHIFT) : 0;
	info.align_offset = pgoff << PAGE_SHIFT;
	return vm_unmapped_area(&info);
}

unsigned long
arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
			  const unsigned long len, const unsigned long pgoff,
			  const unsigned long flags)
{
	struct vm_area_struct *vma;
	struct mm_struct *mm = current->mm;
	unsigned long addr = addr0;
	struct vm_unmapped_area_info info;
	int do_color_align;

	/* requested length too big for entire address space */
	if (len > TASK_SIZE - mmap_min_addr)
		return -ENOMEM;

	if (flags & MAP_FIXED)
		return addr;

	/* requesting a specific address */
	if (addr) {
		addr = PAGE_ALIGN(addr);
		vma = find_vma(mm, addr);
		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
				(!vma || addr + len <= vma->vm_start))
			return addr;
	}

	do_color_align = 0;
	if (filp || (flags & MAP_SHARED))
		do_color_align = !is_32bit_task();

	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
	info.length = len;
	info.low_limit = max(PAGE_SIZE, mmap_min_addr);
	info.high_limit = mm->mmap_base;
	info.align_mask = do_color_align ? (mmap_align_mask << PAGE_SHIFT) : 0;
	info.align_offset = pgoff << PAGE_SHIFT;
	addr = vm_unmapped_area(&info);

	/*
	 * A failed mmap() very likely causes application failure,
	 * so fall back to the bottom-up function here. This scenario
	 * can happen with large stack limits and large mmap()
	 * allocations.
	 */
	if (addr & ~PAGE_MASK) {
		VM_BUG_ON(addr != -ENOMEM);
		info.flags = 0;
		info.low_limit = TASK_UNMAPPED_BASE;
		info.high_limit = TASK_SIZE;
		addr = vm_unmapped_area(&info);
	}

	return addr;
}

unsigned long randomize_et_dyn(void)
{
	unsigned long base;

	base = STACK_TOP / 3 * 2;
	if (!is_32bit_task())
		/* Align to 4GB */
		base &= ~((1UL << 32) - 1);

	if (current->flags & PF_RANDOMIZE)
		base += arch_mmap_rnd();

	return base;
}

#ifndef CONFIG_64BIT

/*
 * This function, called very early during the creation of a new
 * process VM image, sets up which VM layout function to use:
 */
void arch_pick_mmap_layout(struct mm_struct *mm)
{
	unsigned long random_factor = 0UL;

	if (current->flags & PF_RANDOMIZE)
		random_factor = arch_mmap_rnd();

	/*
	 * Fall back to the standard layout if the personality
	 * bit is set, or if the expected stack growth is unlimited:
	 */
	if (mmap_is_legacy()) {
		mm->mmap_base = mmap_base_legacy(random_factor);
		mm->get_unmapped_area = arch_get_unmapped_area;
	} else {
		mm->mmap_base = mmap_base(random_factor);
		mm->get_unmapped_area = arch_get_unmapped_area_topdown;
	}
}

#else

int s390_mmap_check(unsigned long addr, unsigned long len, unsigned long flags)
{
	if (is_compat_task() || (TASK_SIZE >= (1UL << 53)))
		return 0;
	if (!(flags & MAP_FIXED))
		addr = 0;
	if ((addr + len) >= TASK_SIZE)
		return crst_table_upgrade(current->mm, 1UL << 53);
	return 0;
}

static unsigned long
s390_get_unmapped_area(struct file *filp, unsigned long addr,
		unsigned long len, unsigned long pgoff, unsigned long flags)
{
	struct mm_struct *mm = current->mm;
	unsigned long area;
	int rc;

	area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
	if (!(area & ~PAGE_MASK))
		return area;
	if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < (1UL << 53)) {
		/* Upgrade the page table to 4 levels and retry. */
		rc = crst_table_upgrade(mm, 1UL << 53);
		if (rc)
			return (unsigned long) rc;
		area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
	}
	return area;
}

static unsigned long
s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr,
			  const unsigned long len, const unsigned long pgoff,
			  const unsigned long flags)
{
	struct mm_struct *mm = current->mm;
	unsigned long area;
	int rc;

	area = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags);
	if (!(area & ~PAGE_MASK))
		return area;
	if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < (1UL << 53)) {
		/* Upgrade the page table to 4 levels and retry. */
		rc = crst_table_upgrade(mm, 1UL << 53);
		if (rc)
			return (unsigned long) rc;
		area = arch_get_unmapped_area_topdown(filp, addr, len,
						      pgoff, flags);
	}
	return area;
}
/*
 * This function, called very early during the creation of a new
 * process VM image, sets up which VM layout function to use:
 */
void arch_pick_mmap_layout(struct mm_struct *mm)
{
	unsigned long random_factor = 0UL;

	if (current->flags & PF_RANDOMIZE)
		random_factor = arch_mmap_rnd();

	/*
	 * Fall back to the standard layout if the personality
	 * bit is set, or if the expected stack growth is unlimited:
	 */
	if (mmap_is_legacy()) {
		mm->mmap_base = mmap_base_legacy(random_factor);
		mm->get_unmapped_area = s390_get_unmapped_area;
	} else {
		mm->mmap_base = mmap_base(random_factor);
		mm->get_unmapped_area = s390_get_unmapped_area_topdown;
	}
}

static int __init setup_mmap_rnd(void)
{
	struct cpuid cpu_id;

	get_cpu_id(&cpu_id);
	switch (cpu_id.machine) {
	case 0x9672:
	case 0x2064:
	case 0x2066:
	case 0x2084:
	case 0x2086:
	case 0x2094:
	case 0x2096:
	case 0x2097:
	case 0x2098:
	case 0x2817:
	case 0x2818:
	case 0x2827:
	case 0x2828:
		mmap_rnd_mask = 0x7ffUL;
		mmap_align_mask = 0UL;
		break;
	case 0x2964:	/* z13 */
	default:
		mmap_rnd_mask = 0x3ff80UL;
		mmap_align_mask = 0x7fUL;
		break;
	}
	return 0;
}
early_initcall(setup_mmap_rnd);

#endif
Commit	Line	Data
1da177e4	1	/*
1da177e4 LT	2	* flexible mmap layout support
	3	*
	4	* Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
	5	* All Rights Reserved.
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation; either version 2 of the License, or
	10	* (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	20	*
	21	*
	22	* Started by Ingo Molnar <mingo@elte.hu>
	23	*/
	24
	25	#include <linux/personality.h>
	26	#include <linux/mm.h>
638ad34a	27	#include <linux/mman.h>
1da177e4	28	#include <linux/module.h>
df1ca53c	29	#include <linux/random.h>
048cd4e5	30	#include <linux/compat.h>
1f6b83e5	31	#include <linux/security.h>
6252d702	32	#include <asm/pgalloc.h>
1da177e4	33
1f6b83e5 MS	34	unsigned long mmap_rnd_mask;
	35	unsigned long mmap_align_mask;
	36
9046e401 HC	37	static unsigned long stack_maxrandom_size(void)
	38	{
	39	if (!(current->flags & PF_RANDOMIZE))
	40	return 0;
	41	if (current->personality & ADDR_NO_RANDOMIZE)
	42	return 0;
	43	return STACK_RND_MASK << PAGE_SHIFT;
	44	}
	45
1da177e4 LT	46	/*
	47	* Top of mmap area (just below the process stack).
	48	*
9e78a13b	49	* Leave at least a ~32 MB hole.
1da177e4	50	*/
9e78a13b	51	#define MIN_GAP (3210241024)
f481bfaf	52	#define MAX_GAP (STACK_TOP/6*5)
1da177e4	53
1060f62e HC	54	static inline int mmap_is_legacy(void)
	55	{
	56	if (current->personality & ADDR_COMPAT_LAYOUT)
	57	return 1;
	58	if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
	59	return 1;
	60	return sysctl_legacy_va_layout;
	61	}
	62
2b68f6ca	63	unsigned long arch_mmap_rnd(void)
df1ca53c	64	{
1f6b83e5 MS	65	if (is_32bit_task())
	66	return (get_random_int() & 0x7ff) << PAGE_SHIFT;
	67	else
	68	return (get_random_int() & mmap_rnd_mask) << PAGE_SHIFT;
df1ca53c HC	69	}
df1ca53c HC	70
8e89a356	71	static unsigned long mmap_base_legacy(unsigned long rnd)
7aba842f	72	{
8e89a356	73	return TASK_UNMAPPED_BASE + rnd;
7aba842f HC	74	}
7aba842f HC	75
8e89a356	76	static inline unsigned long mmap_base(unsigned long rnd)
1da177e4	77	{
a58c26bb	78	unsigned long gap = rlimit(RLIMIT_STACK);
1da177e4 LT	79
	80	if (gap < MIN_GAP)
	81	gap = MIN_GAP;
	82	else if (gap > MAX_GAP)
	83	gap = MAX_GAP;
df1ca53c	84	gap &= PAGE_MASK;
8e89a356	85	return STACK_TOP - stack_maxrandom_size() - rnd - gap;
1da177e4 LT	86	}
1da177e4 LT	87
1f6b83e5 MS	88	unsigned long
	89	arch_get_unmapped_area(struct file *filp, unsigned long addr,
	90	unsigned long len, unsigned long pgoff, unsigned long flags)
	91	{
	92	struct mm_struct *mm = current->mm;
	93	struct vm_area_struct *vma;
	94	struct vm_unmapped_area_info info;
	95	int do_color_align;
	96
	97	if (len > TASK_SIZE - mmap_min_addr)
	98	return -ENOMEM;
	99
	100	if (flags & MAP_FIXED)
	101	return addr;
	102
	103	if (addr) {
	104	addr = PAGE_ALIGN(addr);
	105	vma = find_vma(mm, addr);
	106	if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
	107	(!vma \|\| addr + len <= vma->vm_start))
	108	return addr;
	109	}
	110
	111	do_color_align = 0;
	112	if (filp \|\| (flags & MAP_SHARED))
	113	do_color_align = !is_32bit_task();
	114
	115	info.flags = 0;
	116	info.length = len;
	117	info.low_limit = mm->mmap_base;
	118	info.high_limit = TASK_SIZE;
	119	info.align_mask = do_color_align ? (mmap_align_mask << PAGE_SHIFT) : 0;
	120	info.align_offset = pgoff << PAGE_SHIFT;
	121	return vm_unmapped_area(&info);
	122	}
	123
	124	unsigned long
	125	arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
	126	const unsigned long len, const unsigned long pgoff,
	127	const unsigned long flags)
	128	{
	129	struct vm_area_struct *vma;
	130	struct mm_struct *mm = current->mm;
	131	unsigned long addr = addr0;
	132	struct vm_unmapped_area_info info;
	133	int do_color_align;
	134
	135	/* requested length too big for entire address space */
	136	if (len > TASK_SIZE - mmap_min_addr)
	137	return -ENOMEM;
	138
	139	if (flags & MAP_FIXED)
	140	return addr;
	141
	142	/* requesting a specific address */
	143	if (addr) {
	144	addr = PAGE_ALIGN(addr);
	145	vma = find_vma(mm, addr);
	146	if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
	147	(!vma \|\| addr + len <= vma->vm_start))
	148	return addr;
	149	}
	150
	151	do_color_align = 0;
152	if (filp \|\| (flags & MAP_SHARED))
153	do_color_align = !is_32bit_task();
154
155	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
156	info.length = len;
157	info.low_limit = max(PAGE_SIZE, mmap_min_addr);
158	info.high_limit = mm->mmap_base;
159	info.align_mask = do_color_align ? (mmap_align_mask << PAGE_SHIFT) : 0;
160	info.align_offset = pgoff << PAGE_SHIFT;
161	addr = vm_unmapped_area(&info);
162
163	/*
164	* A failed mmap() very likely causes application failure,
165	* so fall back to the bottom-up function here. This scenario
166	* can happen with large stack limits and large mmap()
167	* allocations.
168	*/
169	if (addr & ~PAGE_MASK) {
170	VM_BUG_ON(addr != -ENOMEM);
171	info.flags = 0;
172	info.low_limit = TASK_UNMAPPED_BASE;
173	info.high_limit = TASK_SIZE;
174	addr = vm_unmapped_area(&info);
175	}
176
177	return addr;
178	}
179
180	unsigned long randomize_et_dyn(void)
181	{
182	unsigned long base;
183
4ba2815d MS	184	base = STACK_TOP / 3 * 2;
	185	if (!is_32bit_task())
	186	/* Align to 4GB */
	187	base &= ~((1UL << 32) - 1);
8e89a356 KC	188
8e89a356 KC	189	if (current->flags & PF_RANDOMIZE)
2b68f6ca	190	base += arch_mmap_rnd();
8e89a356 KC	191
8e89a356 KC	192	return base;
1f6b83e5 MS	193	}
1f6b83e5 MS	194
6252d702 MS	195	#ifndef CONFIG_64BIT
6252d702 MS	196
1da177e4 LT	197	/*
	198	* This function, called very early during the creation of a new
	199	* process VM image, sets up which VM layout function to use:
	200	*/
	201	void arch_pick_mmap_layout(struct mm_struct *mm)
	202	{
8e89a356 KC	203	unsigned long random_factor = 0UL;
	204
	205	if (current->flags & PF_RANDOMIZE)
2b68f6ca	206	random_factor = arch_mmap_rnd();
8e89a356	207
1da177e4 LT	208	/*
	209	* Fall back to the standard layout if the personality
	210	* bit is set, or if the expected stack growth is unlimited:
	211	*/
	212	if (mmap_is_legacy()) {
8e89a356	213	mm->mmap_base = mmap_base_legacy(random_factor);
1da177e4	214	mm->get_unmapped_area = arch_get_unmapped_area;
1da177e4	215	} else {
8e89a356	216	mm->mmap_base = mmap_base(random_factor);
1da177e4	217	mm->get_unmapped_area = arch_get_unmapped_area_topdown;
1da177e4 LT	218	}
1da177e4 LT	219	}
1da177e4	220
6252d702 MS	221	#else
6252d702 MS	222
486c0a0b	223	int s390_mmap_check(unsigned long addr, unsigned long len, unsigned long flags)
0fb1d9bc	224	{
486c0a0b HB	225	if (is_compat_task() \|\| (TASK_SIZE >= (1UL << 53)))
	226	return 0;
	227	if (!(flags & MAP_FIXED))
	228	addr = 0;
10607864 MS	229	if ((addr + len) >= TASK_SIZE)
10607864 MS	230	return crst_table_upgrade(current->mm, 1UL << 53);
0fb1d9bc MS	231	return 0;
	232	}
	233
6252d702 MS	234	static unsigned long
	235	s390_get_unmapped_area(struct file *filp, unsigned long addr,
	236	unsigned long len, unsigned long pgoff, unsigned long flags)
	237	{
	238	struct mm_struct *mm = current->mm;
0fb1d9bc	239	unsigned long area;
6252d702 MS	240	int rc;
6252d702 MS	241
0fb1d9bc MS	242	area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
	243	if (!(area & ~PAGE_MASK))
	244	return area;
7757591a	245	if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < (1UL << 53)) {
0fb1d9bc MS	246	/* Upgrade the page table to 4 levels and retry. */
0fb1d9bc MS	247	rc = crst_table_upgrade(mm, 1UL << 53);
6252d702 MS	248	if (rc)
6252d702 MS	249	return (unsigned long) rc;
0fb1d9bc	250	area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
6252d702	251	}
0fb1d9bc	252	return area;
6252d702 MS	253	}
	254
	255	static unsigned long
0fb1d9bc	256	s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr,
6252d702 MS	257	const unsigned long len, const unsigned long pgoff,
	258	const unsigned long flags)
	259	{
	260	struct mm_struct *mm = current->mm;
0fb1d9bc	261	unsigned long area;
6252d702 MS	262	int rc;
6252d702 MS	263
0fb1d9bc MS	264	area = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags);
	265	if (!(area & ~PAGE_MASK))
	266	return area;
7757591a	267	if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < (1UL << 53)) {
0fb1d9bc MS	268	/* Upgrade the page table to 4 levels and retry. */
0fb1d9bc MS	269	rc = crst_table_upgrade(mm, 1UL << 53);
6252d702 MS	270	if (rc)
6252d702 MS	271	return (unsigned long) rc;
0fb1d9bc MS	272	area = arch_get_unmapped_area_topdown(filp, addr, len,
0fb1d9bc MS	273	pgoff, flags);
6252d702	274	}
0fb1d9bc	275	return area;
6252d702 MS	276	}
	277	/*
	278	* This function, called very early during the creation of a new
	279	* process VM image, sets up which VM layout function to use:
	280	*/
	281	void arch_pick_mmap_layout(struct mm_struct *mm)
	282	{
8e89a356 KC	283	unsigned long random_factor = 0UL;
	284
	285	if (current->flags & PF_RANDOMIZE)
2b68f6ca	286	random_factor = arch_mmap_rnd();
8e89a356	287
6252d702 MS	288	/*
	289	* Fall back to the standard layout if the personality
	290	* bit is set, or if the expected stack growth is unlimited:
	291	*/
	292	if (mmap_is_legacy()) {
8e89a356	293	mm->mmap_base = mmap_base_legacy(random_factor);
6252d702	294	mm->get_unmapped_area = s390_get_unmapped_area;
6252d702	295	} else {
8e89a356	296	mm->mmap_base = mmap_base(random_factor);
6252d702	297	mm->get_unmapped_area = s390_get_unmapped_area_topdown;
6252d702 MS	298	}
6252d702 MS	299	}
6252d702	300
1f6b83e5 MS	301	static int __init setup_mmap_rnd(void)
	302	{
	303	struct cpuid cpu_id;
	304
	305	get_cpu_id(&cpu_id);
	306	switch (cpu_id.machine) {
	307	case 0x9672:
	308	case 0x2064:
	309	case 0x2066:
	310	case 0x2084:
	311	case 0x2086:
	312	case 0x2094:
	313	case 0x2096:
	314	case 0x2097:
	315	case 0x2098:
	316	case 0x2817:
	317	case 0x2818:
	318	case 0x2827:
	319	case 0x2828:
	320	mmap_rnd_mask = 0x7ffUL;
	321	mmap_align_mask = 0UL;
	322	break;
	323	case 0x2964: /* z13 */
	324	default:
	325	mmap_rnd_mask = 0x3ff80UL;
	326	mmap_align_mask = 0x7fUL;
	327	break;
	328	}
	329	return 0;
	330	}
	331	early_initcall(setup_mmap_rnd);
	332
6252d702	333	#endif