[people/ms/linux.git] / arch / arm / mm / mmap.c

/*
 *  linux/arch/arm/mm/mmap.c
 */
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/shm.h>
#include <linux/sched.h>
#include <linux/io.h>
#include <linux/personality.h>
#include <linux/random.h>
#include <asm/cachetype.h>

#define COLOUR_ALIGN(addr,pgoff)		\
	((((addr)+SHMLBA-1)&~(SHMLBA-1)) +	\
	 (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))

/* gap between mmap and stack */
#define MIN_GAP (128*1024*1024UL)
#define MAX_GAP ((TASK_SIZE)/6*5)

static 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;
}

static 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;

	return PAGE_ALIGN(TASK_SIZE - gap - rnd);
}

/*
 * We need to ensure that shared mappings are correctly aligned to
 * avoid aliasing issues with VIPT caches.  We need to ensure that
 * a specific page of an object is always mapped at a multiple of
 * SHMLBA bytes.
 *
 * We unconditionally provide this function for all cases, however
 * in the VIVT case, we optimise out the alignment rules.
 */
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;
	int do_align = 0;
	int aliasing = cache_is_vipt_aliasing();
	unsigned long offset = gr_rand_threadstack_offset(mm, filp, flags);
	struct vm_unmapped_area_info info;

	/*
	 * We only need to do colour alignment if either the I or D
	 * caches alias.
	 */
	if (aliasing)
		do_align = filp || (flags & MAP_SHARED);

	/*
	 * We enforce the MAP_FIXED case.
	 */
	if (flags & MAP_FIXED) {
		if (aliasing && flags & MAP_SHARED &&
		    (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
			return -EINVAL;
		return addr;
	}

	if (len > TASK_SIZE)
		return -ENOMEM;

#ifdef CONFIG_PAX_RANDMMAP
	if (!(mm->pax_flags & MF_PAX_RANDMMAP))
#endif

	if (addr) {
		if (do_align)
			addr = COLOUR_ALIGN(addr, pgoff);
		else
			addr = PAGE_ALIGN(addr);

		vma = find_vma(mm, addr);
		if (TASK_SIZE - len >= addr && check_heap_stack_gap(vma, addr, len, offset))
			return addr;
	}

	info.flags = 0;
	info.length = len;
	info.low_limit = mm->mmap_base;
	info.high_limit = TASK_SIZE;
	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
	info.align_offset = pgoff << PAGE_SHIFT;
	info.threadstack_offset = offset;
	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;
	int do_align = 0;
	int aliasing = cache_is_vipt_aliasing();
	unsigned long offset = gr_rand_threadstack_offset(mm, filp, flags);
	struct vm_unmapped_area_info info;

	/*
	 * We only need to do colour alignment if either the I or D
	 * caches alias.
	 */
	if (aliasing)
		do_align = filp || (flags & MAP_SHARED);

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

	if (flags & MAP_FIXED) {
		if (aliasing && flags & MAP_SHARED &&
		    (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
			return -EINVAL;
		return addr;
	}

#ifdef CONFIG_PAX_RANDMMAP
	if (!(mm->pax_flags & MF_PAX_RANDMMAP))
#endif

	/* requesting a specific address */
	if (addr) {
		if (do_align)
			addr = COLOUR_ALIGN(addr, pgoff);
		else
			addr = PAGE_ALIGN(addr);
		vma = find_vma(mm, addr);
		if (TASK_SIZE - len >= addr && check_heap_stack_gap(vma, addr, len, offset))
			return addr;
	}

	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
	info.length = len;
	info.low_limit = FIRST_USER_ADDRESS;
	info.high_limit = mm->mmap_base;
	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
	info.align_offset = pgoff << PAGE_SHIFT;
	info.threadstack_offset = offset;
	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 = mm->mmap_base;
		info.high_limit = TASK_SIZE;
		addr = vm_unmapped_area(&info);
	}

	return addr;
}

void arch_pick_mmap_layout(struct mm_struct *mm)
{
	unsigned long random_factor = 0UL;

#ifdef CONFIG_PAX_RANDMMAP
	if (!(mm->pax_flags & MF_PAX_RANDMMAP))
#endif

	/* 8 bits of randomness in 20 address space bits */
	if ((current->flags & PF_RANDOMIZE) &&
	    !(current->personality & ADDR_NO_RANDOMIZE))
		random_factor = (get_random_int() % (1 << 8)) << PAGE_SHIFT;

	if (mmap_is_legacy()) {
		mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;

#ifdef CONFIG_PAX_RANDMMAP
		if (mm->pax_flags & MF_PAX_RANDMMAP)
			mm->mmap_base += mm->delta_mmap;
#endif

		mm->get_unmapped_area = arch_get_unmapped_area;
	} else {
		mm->mmap_base = mmap_base(random_factor);

#ifdef CONFIG_PAX_RANDMMAP
		if (mm->pax_flags & MF_PAX_RANDMMAP)
			mm->mmap_base -= mm->delta_mmap + mm->delta_stack;
#endif

		mm->get_unmapped_area = arch_get_unmapped_area_topdown;
	}
}

/*
 * You really shouldn't be using read() or write() on /dev/mem.  This
 * might go away in the future.
 */
int valid_phys_addr_range(phys_addr_t addr, size_t size)
{
	if (addr < PHYS_OFFSET)
		return 0;
	if (addr + size > __pa(high_memory - 1) + 1)
		return 0;

	return 1;
}

/*
 * Do not allow /dev/mem mappings beyond the supported physical range.
 */
int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
{
	return (pfn + (size >> PAGE_SHIFT)) <= (1 + (PHYS_MASK >> PAGE_SHIFT));
}

#ifdef CONFIG_STRICT_DEVMEM

#include <linux/ioport.h>

/*
 * devmem_is_allowed() checks to see if /dev/mem access to a certain
 * address is valid. The argument is a physical page number.
 * We mimic x86 here by disallowing access to system RAM as well as
 * device-exclusive MMIO regions. This effectively disable read()/write()
 * on /dev/mem.
 */
int devmem_is_allowed(unsigned long pfn)
{
	if (iomem_is_exclusive(pfn << PAGE_SHIFT))
		return 0;
	if (!page_is_ram(pfn))
		return 1;
	return 0;
}

#endif
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/arm/mm/mmap.c
	3	*/
1da177e4 LT	4	#include <linux/fs.h>
	5	#include <linux/mm.h>
	6	#include <linux/mman.h>
	7	#include <linux/shm.h>
e8edc6e0	8	#include <linux/sched.h>
09d9bae0	9	#include <linux/io.h>
df5419a9	10	#include <linux/personality.h>
cc92c28b	11	#include <linux/random.h>
41dfaa93	12	#include <asm/cachetype.h>
1da177e4 LT	13
	14	#define COLOUR_ALIGN(addr,pgoff) \
	15	((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \
	16	(((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))
	17
7dbaa466 RH	18	/* gap between mmap and stack */
	19	#define MIN_GAP (12810241024UL)
	20	#define MAX_GAP ((TASK_SIZE)/6*5)
	21
	22	static int mmap_is_legacy(void)
	23	{
	24	if (current->personality & ADDR_COMPAT_LAYOUT)
	25	return 1;
	26
	27	if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
	28	return 1;
	29
	30	return sysctl_legacy_va_layout;
	31	}
	32
	33	static unsigned long mmap_base(unsigned long rnd)
	34	{
	35	unsigned long gap = rlimit(RLIMIT_STACK);
	36
	37	if (gap < MIN_GAP)
	38	gap = MIN_GAP;
	39	else if (gap > MAX_GAP)
	40	gap = MAX_GAP;
	41
	42	return PAGE_ALIGN(TASK_SIZE - gap - rnd);
	43	}
	44
1da177e4 LT	45	/*
	46	* We need to ensure that shared mappings are correctly aligned to
	47	* avoid aliasing issues with VIPT caches. We need to ensure that
	48	* a specific page of an object is always mapped at a multiple of
	49	* SHMLBA bytes.
	50	*
	51	* We unconditionally provide this function for all cases, however
	52	* in the VIVT case, we optimise out the alignment rules.
	53	*/
	54	unsigned long
	55	arch_get_unmapped_area(struct file *filp, unsigned long addr,
	56	unsigned long len, unsigned long pgoff, unsigned long flags)
	57	{
	58	struct mm_struct *mm = current->mm;
	59	struct vm_area_struct *vma;
41dfaa93 RH	60	int do_align = 0;
41dfaa93 RH	61	int aliasing = cache_is_vipt_aliasing();
63d9c273	62	unsigned long offset = gr_rand_threadstack_offset(mm, filp, flags);
394ef640	63	struct vm_unmapped_area_info info;
1da177e4 LT	64
	65	/*
	66	* We only need to do colour alignment if either the I or D
41dfaa93	67	* caches alias.
1da177e4	68	*/
41dfaa93 RH	69	if (aliasing)
41dfaa93 RH	70	do_align = filp \|\| (flags & MAP_SHARED);
1da177e4 LT	71
1da177e4 LT	72	/*
acec0ac0	73	* We enforce the MAP_FIXED case.
1da177e4 LT	74	*/
1da177e4 LT	75	if (flags & MAP_FIXED) {
e77414e0 AV	76	if (aliasing && flags & MAP_SHARED &&
e77414e0 AV	77	(addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
1da177e4 LT	78	return -EINVAL;
	79	return addr;
	80	}
	81
	82	if (len > TASK_SIZE)
	83	return -ENOMEM;
	84
63d9c273 MT	85	#ifdef CONFIG_PAX_RANDMMAP
	86	if (!(mm->pax_flags & MF_PAX_RANDMMAP))
	87	#endif
	88
1da177e4 LT	89	if (addr) {
	90	if (do_align)
	91	addr = COLOUR_ALIGN(addr, pgoff);
	92	else
	93	addr = PAGE_ALIGN(addr);
	94
	95	vma = find_vma(mm, addr);
63d9c273	96	if (TASK_SIZE - len >= addr && check_heap_stack_gap(vma, addr, len, offset))
1da177e4 LT	97	return addr;
1da177e4 LT	98	}
1da177e4	99
394ef640 ML	100	info.flags = 0;
	101	info.length = len;
	102	info.low_limit = mm->mmap_base;
	103	info.high_limit = TASK_SIZE;
	104	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
	105	info.align_offset = pgoff << PAGE_SHIFT;
63d9c273	106	info.threadstack_offset = offset;
394ef640	107	return vm_unmapped_area(&info);
1da177e4 LT	108	}
1da177e4 LT	109
7dbaa466 RH	110	unsigned long
	111	arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
	112	const unsigned long len, const unsigned long pgoff,
	113	const unsigned long flags)
	114	{
	115	struct vm_area_struct *vma;
	116	struct mm_struct *mm = current->mm;
	117	unsigned long addr = addr0;
	118	int do_align = 0;
	119	int aliasing = cache_is_vipt_aliasing();
63d9c273	120	unsigned long offset = gr_rand_threadstack_offset(mm, filp, flags);
394ef640	121	struct vm_unmapped_area_info info;
7dbaa466 RH	122
	123	/*
	124	* We only need to do colour alignment if either the I or D
	125	* caches alias.
	126	*/
	127	if (aliasing)
	128	do_align = filp \|\| (flags & MAP_SHARED);
	129
	130	/* requested length too big for entire address space */
	131	if (len > TASK_SIZE)
	132	return -ENOMEM;
	133
	134	if (flags & MAP_FIXED) {
	135	if (aliasing && flags & MAP_SHARED &&
	136	(addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
	137	return -EINVAL;
	138	return addr;
	139	}
	140
63d9c273 MT	141	#ifdef CONFIG_PAX_RANDMMAP
	142	if (!(mm->pax_flags & MF_PAX_RANDMMAP))
	143	#endif
	144
7dbaa466 RH	145	/* requesting a specific address */
	146	if (addr) {
	147	if (do_align)
	148	addr = COLOUR_ALIGN(addr, pgoff);
	149	else
	150	addr = PAGE_ALIGN(addr);
	151	vma = find_vma(mm, addr);
63d9c273	152	if (TASK_SIZE - len >= addr && check_heap_stack_gap(vma, addr, len, offset))
7dbaa466 RH	153	return addr;
	154	}
	155
394ef640 ML	156	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
394ef640 ML	157	info.length = len;
d8aa712c	158	info.low_limit = FIRST_USER_ADDRESS;
394ef640 ML	159	info.high_limit = mm->mmap_base;
	160	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
	161	info.align_offset = pgoff << PAGE_SHIFT;
63d9c273	162	info.threadstack_offset = offset;
394ef640	163	addr = vm_unmapped_area(&info);
7dbaa466	164
7dbaa466 RH	165	/*
	166	* A failed mmap() very likely causes application failure,
	167	* so fall back to the bottom-up function here. This scenario
	168	* can happen with large stack limits and large mmap()
	169	* allocations.
	170	*/
394ef640 ML	171	if (addr & ~PAGE_MASK) {
	172	VM_BUG_ON(addr != -ENOMEM);
	173	info.flags = 0;
	174	info.low_limit = mm->mmap_base;
	175	info.high_limit = TASK_SIZE;
	176	addr = vm_unmapped_area(&info);
	177	}
7dbaa466 RH	178
	179	return addr;
	180	}
	181
	182	void arch_pick_mmap_layout(struct mm_struct *mm)
	183	{
	184	unsigned long random_factor = 0UL;
	185
63d9c273 MT	186	#ifdef CONFIG_PAX_RANDMMAP
	187	if (!(mm->pax_flags & MF_PAX_RANDMMAP))
	188	#endif
	189
7dbaa466 RH	190	/* 8 bits of randomness in 20 address space bits */
	191	if ((current->flags & PF_RANDOMIZE) &&
	192	!(current->personality & ADDR_NO_RANDOMIZE))
	193	random_factor = (get_random_int() % (1 << 8)) << PAGE_SHIFT;
	194
	195	if (mmap_is_legacy()) {
	196	mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
63d9c273 MT	197
	198	#ifdef CONFIG_PAX_RANDMMAP
	199	if (mm->pax_flags & MF_PAX_RANDMMAP)
	200	mm->mmap_base += mm->delta_mmap;
	201	#endif
	202
7dbaa466	203	mm->get_unmapped_area = arch_get_unmapped_area;
7dbaa466 RH	204	} else {
7dbaa466 RH	205	mm->mmap_base = mmap_base(random_factor);
63d9c273 MT	206
	207	#ifdef CONFIG_PAX_RANDMMAP
	208	if (mm->pax_flags & MF_PAX_RANDMMAP)
	209	mm->mmap_base -= mm->delta_mmap + mm->delta_stack;
	210	#endif
	211
7dbaa466	212	mm->get_unmapped_area = arch_get_unmapped_area_topdown;
7dbaa466 RH	213	}
7dbaa466 RH	214	}
51635ad2 LB	215
	216	/*
	217	* You really shouldn't be using read() or write() on /dev/mem. This
	218	* might go away in the future.
	219	*/
7e6735c3	220	int valid_phys_addr_range(phys_addr_t addr, size_t size)
51635ad2	221	{
9ae3ae0b AR	222	if (addr < PHYS_OFFSET)
9ae3ae0b AR	223	return 0;
6806bfe1	224	if (addr + size > __pa(high_memory - 1) + 1)
51635ad2 LB	225	return 0;
	226
	227	return 1;
	228	}
	229
	230	/*
3159f372	231	* Do not allow /dev/mem mappings beyond the supported physical range.
51635ad2 LB	232	*/
	233	int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
	234	{
3159f372	235	return (pfn + (size >> PAGE_SHIFT)) <= (1 + (PHYS_MASK >> PAGE_SHIFT));
51635ad2	236	}
087aaffc NP	237
	238	#ifdef CONFIG_STRICT_DEVMEM
	239
	240	#include <linux/ioport.h>
	241
	242	/*
	243	* devmem_is_allowed() checks to see if /dev/mem access to a certain
	244	* address is valid. The argument is a physical page number.
	245	* We mimic x86 here by disallowing access to system RAM as well as
	246	* device-exclusive MMIO regions. This effectively disable read()/write()
	247	* on /dev/mem.
	248	*/
	249	int devmem_is_allowed(unsigned long pfn)
	250	{
	251	if (iomem_is_exclusive(pfn << PAGE_SHIFT))
	252	return 0;
	253	if (!page_is_ram(pfn))
	254	return 1;
	255	return 0;
	256	}
	257
	258	#endif