[mirror_ubuntu-artful-kernel.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/elf-randomize.h>
#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>

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)
{
	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;

	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;
	}

	info.flags = 0;
	info.length = len;
	info.low_limit = mm->mmap_base;
	info.high_limit = TASK_SIZE;
	if (filp || (flags & MAP_SHARED))
		info.align_mask = MMAP_ALIGN_MASK << PAGE_SHIFT;
	else
		info.align_mask = 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;

	/* 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;
	}

	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
	info.length = len;
	info.low_limit = max(PAGE_SIZE, mmap_min_addr);
	info.high_limit = mm->mmap_base;
	if (filp || (flags & MAP_SHARED))
		info.align_mask = MMAP_ALIGN_MASK << PAGE_SHIFT;
	else
		info.align_mask = 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;
}

int s390_mmap_check(unsigned long addr, unsigned long len, unsigned long flags)
{
	if (is_compat_task() || TASK_SIZE >= TASK_MAX_SIZE)
		return 0;
	if (!(flags & MAP_FIXED))
		addr = 0;
	if ((addr + len) >= TASK_SIZE)
		return crst_table_upgrade(current->mm);
	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 < TASK_MAX_SIZE) {
		/* Upgrade the page table to 4 levels and retry. */
		rc = crst_table_upgrade(mm);
		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 < TASK_MAX_SIZE) {
		/* Upgrade the page table to 4 levels and retry. */
		rc = crst_table_upgrade(mm);
		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;
	}
}
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
ca21872e	25	#include <linux/elf-randomize.h>
1da177e4 LT	26	#include <linux/personality.h>
1da177e4 LT	27	#include <linux/mm.h>
638ad34a	28	#include <linux/mman.h>
1da177e4	29	#include <linux/module.h>
df1ca53c	30	#include <linux/random.h>
048cd4e5	31	#include <linux/compat.h>
1f6b83e5	32	#include <linux/security.h>
6252d702	33	#include <asm/pgalloc.h>
1da177e4	34
9046e401 HC	35	static unsigned long stack_maxrandom_size(void)
	36	{
	37	if (!(current->flags & PF_RANDOMIZE))
	38	return 0;
	39	if (current->personality & ADDR_NO_RANDOMIZE)
	40	return 0;
	41	return STACK_RND_MASK << PAGE_SHIFT;
	42	}
	43
1da177e4 LT	44	/*
	45	* Top of mmap area (just below the process stack).
	46	*
9e78a13b	47	* Leave at least a ~32 MB hole.
1da177e4	48	*/
9e78a13b	49	#define MIN_GAP (3210241024)
f481bfaf	50	#define MAX_GAP (STACK_TOP/6*5)
1da177e4	51
1060f62e HC	52	static inline int mmap_is_legacy(void)
	53	{
	54	if (current->personality & ADDR_COMPAT_LAYOUT)
	55	return 1;
	56	if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
	57	return 1;
	58	return sysctl_legacy_va_layout;
	59	}
	60
2b68f6ca	61	unsigned long arch_mmap_rnd(void)
df1ca53c	62	{
c7e8b2c2	63	return (get_random_int() & MMAP_RND_MASK) << PAGE_SHIFT;
df1ca53c HC	64	}
df1ca53c HC	65
8e89a356	66	static unsigned long mmap_base_legacy(unsigned long rnd)
7aba842f	67	{
8e89a356	68	return TASK_UNMAPPED_BASE + rnd;
7aba842f HC	69	}
7aba842f HC	70
8e89a356	71	static inline unsigned long mmap_base(unsigned long rnd)
1da177e4	72	{
a58c26bb	73	unsigned long gap = rlimit(RLIMIT_STACK);
1da177e4 LT	74
	75	if (gap < MIN_GAP)
	76	gap = MIN_GAP;
	77	else if (gap > MAX_GAP)
	78	gap = MAX_GAP;
df1ca53c	79	gap &= PAGE_MASK;
8e89a356	80	return STACK_TOP - stack_maxrandom_size() - rnd - gap;
1da177e4 LT	81	}
1da177e4 LT	82
1f6b83e5 MS	83	unsigned long
	84	arch_get_unmapped_area(struct file *filp, unsigned long addr,
	85	unsigned long len, unsigned long pgoff, unsigned long flags)
	86	{
	87	struct mm_struct *mm = current->mm;
	88	struct vm_area_struct *vma;
	89	struct vm_unmapped_area_info info;
1f6b83e5 MS	90
	91	if (len > TASK_SIZE - mmap_min_addr)
	92	return -ENOMEM;
	93
	94	if (flags & MAP_FIXED)
	95	return addr;
	96
	97	if (addr) {
	98	addr = PAGE_ALIGN(addr);
	99	vma = find_vma(mm, addr);
	100	if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
	101	(!vma \|\| addr + len <= vma->vm_start))
	102	return addr;
	103	}
	104
1f6b83e5 MS	105	info.flags = 0;
	106	info.length = len;
	107	info.low_limit = mm->mmap_base;
	108	info.high_limit = TASK_SIZE;
c7e8b2c2 MS	109	if (filp \|\| (flags & MAP_SHARED))
	110	info.align_mask = MMAP_ALIGN_MASK << PAGE_SHIFT;
	111	else
	112	info.align_mask = 0;
1f6b83e5 MS	113	info.align_offset = pgoff << PAGE_SHIFT;
	114	return vm_unmapped_area(&info);
	115	}
	116
	117	unsigned long
	118	arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
	119	const unsigned long len, const unsigned long pgoff,
	120	const unsigned long flags)
	121	{
	122	struct vm_area_struct *vma;
	123	struct mm_struct *mm = current->mm;
	124	unsigned long addr = addr0;
	125	struct vm_unmapped_area_info info;
1f6b83e5 MS	126
	127	/* requested length too big for entire address space */
	128	if (len > TASK_SIZE - mmap_min_addr)
	129	return -ENOMEM;
	130
	131	if (flags & MAP_FIXED)
	132	return addr;
	133
	134	/* requesting a specific address */
	135	if (addr) {
	136	addr = PAGE_ALIGN(addr);
	137	vma = find_vma(mm, addr);
	138	if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
	139	(!vma \|\| addr + len <= vma->vm_start))
	140	return addr;
	141	}
	142
1f6b83e5 MS	143	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
	144	info.length = len;
	145	info.low_limit = max(PAGE_SIZE, mmap_min_addr);
	146	info.high_limit = mm->mmap_base;
c7e8b2c2 MS	147	if (filp \|\| (flags & MAP_SHARED))
	148	info.align_mask = MMAP_ALIGN_MASK << PAGE_SHIFT;
	149	else
	150	info.align_mask = 0;
1f6b83e5 MS	151	info.align_offset = pgoff << PAGE_SHIFT;
	152	addr = vm_unmapped_area(&info);
	153
	154	/*
	155	* A failed mmap() very likely causes application failure,
	156	* so fall back to the bottom-up function here. This scenario
	157	* can happen with large stack limits and large mmap()
	158	* allocations.
	159	*/
	160	if (addr & ~PAGE_MASK) {
	161	VM_BUG_ON(addr != -ENOMEM);
	162	info.flags = 0;
	163	info.low_limit = TASK_UNMAPPED_BASE;
	164	info.high_limit = TASK_SIZE;
	165	addr = vm_unmapped_area(&info);
	166	}
	167
	168	return addr;
	169	}
	170
486c0a0b	171	int s390_mmap_check(unsigned long addr, unsigned long len, unsigned long flags)
0fb1d9bc	172	{
a9d7ab97	173	if (is_compat_task() \|\| TASK_SIZE >= TASK_MAX_SIZE)
486c0a0b HB	174	return 0;
	175	if (!(flags & MAP_FIXED))
	176	addr = 0;
10607864	177	if ((addr + len) >= TASK_SIZE)
723cacbd	178	return crst_table_upgrade(current->mm);
0fb1d9bc MS	179	return 0;
	180	}
	181
6252d702 MS	182	static unsigned long
	183	s390_get_unmapped_area(struct file *filp, unsigned long addr,
	184	unsigned long len, unsigned long pgoff, unsigned long flags)
	185	{
	186	struct mm_struct *mm = current->mm;
0fb1d9bc	187	unsigned long area;
6252d702 MS	188	int rc;
6252d702 MS	189
0fb1d9bc MS	190	area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
	191	if (!(area & ~PAGE_MASK))
	192	return area;
a9d7ab97	193	if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < TASK_MAX_SIZE) {
0fb1d9bc	194	/* Upgrade the page table to 4 levels and retry. */
723cacbd	195	rc = crst_table_upgrade(mm);
6252d702 MS	196	if (rc)
6252d702 MS	197	return (unsigned long) rc;
0fb1d9bc	198	area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
6252d702	199	}
0fb1d9bc	200	return area;
6252d702 MS	201	}
	202
	203	static unsigned long
0fb1d9bc	204	s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr,
6252d702 MS	205	const unsigned long len, const unsigned long pgoff,
	206	const unsigned long flags)
	207	{
	208	struct mm_struct *mm = current->mm;
0fb1d9bc	209	unsigned long area;
6252d702 MS	210	int rc;
6252d702 MS	211
0fb1d9bc MS	212	area = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags);
	213	if (!(area & ~PAGE_MASK))
	214	return area;
a9d7ab97	215	if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < TASK_MAX_SIZE) {
0fb1d9bc	216	/* Upgrade the page table to 4 levels and retry. */
723cacbd	217	rc = crst_table_upgrade(mm);
6252d702 MS	218	if (rc)
6252d702 MS	219	return (unsigned long) rc;
0fb1d9bc MS	220	area = arch_get_unmapped_area_topdown(filp, addr, len,
0fb1d9bc MS	221	pgoff, flags);
6252d702	222	}
0fb1d9bc	223	return area;
6252d702 MS	224	}
	225	/*
	226	* This function, called very early during the creation of a new
	227	* process VM image, sets up which VM layout function to use:
	228	*/
	229	void arch_pick_mmap_layout(struct mm_struct *mm)
	230	{
8e89a356 KC	231	unsigned long random_factor = 0UL;
	232
	233	if (current->flags & PF_RANDOMIZE)
2b68f6ca	234	random_factor = arch_mmap_rnd();
8e89a356	235
6252d702 MS	236	/*
	237	* Fall back to the standard layout if the personality
	238	* bit is set, or if the expected stack growth is unlimited:
	239	*/
	240	if (mmap_is_legacy()) {
8e89a356	241	mm->mmap_base = mmap_base_legacy(random_factor);
6252d702	242	mm->get_unmapped_area = s390_get_unmapped_area;
6252d702	243	} else {
8e89a356	244	mm->mmap_base = mmap_base(random_factor);
6252d702	245	mm->get_unmapped_area = s390_get_unmapped_area_topdown;
6252d702 MS	246	}
6252d702 MS	247	}