[mirror_ubuntu-artful-kernel.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/signal.h>
#include <linux/sched/mm.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();
	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;

	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 &&
		    (!vma || addr + len <= vm_start_gap(vma)))
			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;
	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();
	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;
	}

	/* 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 &&
				(!vma || addr + len <= vm_start_gap(vma)))
			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;
	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;
}

unsigned long arch_mmap_rnd(void)
{
	unsigned long rnd;

	rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1);

	return rnd << PAGE_SHIFT;
}

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

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

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

/*
 * 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>
3f07c014	8	#include <linux/sched/signal.h>
01042607	9	#include <linux/sched/mm.h>
09d9bae0	10	#include <linux/io.h>
df5419a9	11	#include <linux/personality.h>
cc92c28b	12	#include <linux/random.h>
41dfaa93	13	#include <asm/cachetype.h>
1da177e4 LT	14
	15	#define COLOUR_ALIGN(addr,pgoff) \
	16	((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \
	17	(((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))
	18
7dbaa466 RH	19	/* gap between mmap and stack */
	20	#define MIN_GAP (12810241024UL)
	21	#define MAX_GAP ((TASK_SIZE)/6*5)
	22
	23	static int mmap_is_legacy(void)
	24	{
	25	if (current->personality & ADDR_COMPAT_LAYOUT)
	26	return 1;
	27
	28	if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
	29	return 1;
	30
	31	return sysctl_legacy_va_layout;
	32	}
	33
	34	static unsigned long mmap_base(unsigned long rnd)
	35	{
	36	unsigned long gap = rlimit(RLIMIT_STACK);
	37
	38	if (gap < MIN_GAP)
	39	gap = MIN_GAP;
	40	else if (gap > MAX_GAP)
	41	gap = MAX_GAP;
	42
	43	return PAGE_ALIGN(TASK_SIZE - gap - rnd);
	44	}
	45
1da177e4 LT	46	/*
	47	* We need to ensure that shared mappings are correctly aligned to
	48	* avoid aliasing issues with VIPT caches. We need to ensure that
	49	* a specific page of an object is always mapped at a multiple of
	50	* SHMLBA bytes.
	51	*
	52	* We unconditionally provide this function for all cases, however
	53	* in the VIVT case, we optimise out the alignment rules.
	54	*/
	55	unsigned long
	56	arch_get_unmapped_area(struct file *filp, unsigned long addr,
	57	unsigned long len, unsigned long pgoff, unsigned long flags)
	58	{
	59	struct mm_struct *mm = current->mm;
	60	struct vm_area_struct *vma;
41dfaa93 RH	61	int do_align = 0;
41dfaa93 RH	62	int aliasing = cache_is_vipt_aliasing();
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
	85	if (addr) {
	86	if (do_align)
	87	addr = COLOUR_ALIGN(addr, pgoff);
	88	else
	89	addr = PAGE_ALIGN(addr);
	90
	91	vma = find_vma(mm, addr);
	92	if (TASK_SIZE - len >= addr &&
1be7107f	93	(!vma \|\| addr + len <= vm_start_gap(vma)))
1da177e4 LT	94	return addr;
1da177e4 LT	95	}
1da177e4	96
394ef640 ML	97	info.flags = 0;
	98	info.length = len;
	99	info.low_limit = mm->mmap_base;
	100	info.high_limit = TASK_SIZE;
	101	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
	102	info.align_offset = pgoff << PAGE_SHIFT;
	103	return vm_unmapped_area(&info);
1da177e4 LT	104	}
1da177e4 LT	105
7dbaa466 RH	106	unsigned long
	107	arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
	108	const unsigned long len, const unsigned long pgoff,
	109	const unsigned long flags)
	110	{
	111	struct vm_area_struct *vma;
	112	struct mm_struct *mm = current->mm;
	113	unsigned long addr = addr0;
	114	int do_align = 0;
	115	int aliasing = cache_is_vipt_aliasing();
394ef640	116	struct vm_unmapped_area_info info;
7dbaa466 RH	117
	118	/*
	119	* We only need to do colour alignment if either the I or D
	120	* caches alias.
	121	*/
	122	if (aliasing)
	123	do_align = filp \|\| (flags & MAP_SHARED);
	124
	125	/* requested length too big for entire address space */
	126	if (len > TASK_SIZE)
	127	return -ENOMEM;
	128
	129	if (flags & MAP_FIXED) {
	130	if (aliasing && flags & MAP_SHARED &&
	131	(addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
	132	return -EINVAL;
	133	return addr;
	134	}
	135
	136	/* requesting a specific address */
	137	if (addr) {
	138	if (do_align)
	139	addr = COLOUR_ALIGN(addr, pgoff);
	140	else
	141	addr = PAGE_ALIGN(addr);
	142	vma = find_vma(mm, addr);
	143	if (TASK_SIZE - len >= addr &&
1be7107f	144	(!vma \|\| addr + len <= vm_start_gap(vma)))
7dbaa466 RH	145	return addr;
	146	}
	147
394ef640 ML	148	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
394ef640 ML	149	info.length = len;
d8aa712c	150	info.low_limit = FIRST_USER_ADDRESS;
394ef640 ML	151	info.high_limit = mm->mmap_base;
	152	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
	153	info.align_offset = pgoff << PAGE_SHIFT;
	154	addr = vm_unmapped_area(&info);
7dbaa466	155
7dbaa466 RH	156	/*
	157	* A failed mmap() very likely causes application failure,
	158	* so fall back to the bottom-up function here. This scenario
	159	* can happen with large stack limits and large mmap()
	160	* allocations.
	161	*/
394ef640 ML	162	if (addr & ~PAGE_MASK) {
	163	VM_BUG_ON(addr != -ENOMEM);
	164	info.flags = 0;
	165	info.low_limit = mm->mmap_base;
	166	info.high_limit = TASK_SIZE;
	167	addr = vm_unmapped_area(&info);
	168	}
7dbaa466 RH	169
	170	return addr;
	171	}
	172
2b68f6ca	173	unsigned long arch_mmap_rnd(void)
fbbc400f KC	174	{
	175	unsigned long rnd;
	176
5ef11c35	177	rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1);
fbbc400f KC	178
	179	return rnd << PAGE_SHIFT;
	180	}
	181
7dbaa466 RH	182	void arch_pick_mmap_layout(struct mm_struct *mm)
	183	{
	184	unsigned long random_factor = 0UL;
	185
fbbc400f	186	if (current->flags & PF_RANDOMIZE)
2b68f6ca	187	random_factor = arch_mmap_rnd();
7dbaa466 RH	188
	189	if (mmap_is_legacy()) {
	190	mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
	191	mm->get_unmapped_area = arch_get_unmapped_area;
7dbaa466 RH	192	} else {
	193	mm->mmap_base = mmap_base(random_factor);
	194	mm->get_unmapped_area = arch_get_unmapped_area_topdown;
7dbaa466 RH	195	}
7dbaa466 RH	196	}
51635ad2 LB	197
	198	/*
	199	* You really shouldn't be using read() or write() on /dev/mem. This
	200	* might go away in the future.
	201	*/
7e6735c3	202	int valid_phys_addr_range(phys_addr_t addr, size_t size)
51635ad2	203	{
9ae3ae0b AR	204	if (addr < PHYS_OFFSET)
9ae3ae0b AR	205	return 0;
6806bfe1	206	if (addr + size > __pa(high_memory - 1) + 1)
51635ad2 LB	207	return 0;
	208
	209	return 1;
	210	}
	211
	212	/*
3159f372	213	* Do not allow /dev/mem mappings beyond the supported physical range.
51635ad2 LB	214	*/
	215	int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
	216	{
3159f372	217	return (pfn + (size >> PAGE_SHIFT)) <= (1 + (PHYS_MASK >> PAGE_SHIFT));
51635ad2	218	}
087aaffc NP	219
	220	#ifdef CONFIG_STRICT_DEVMEM
	221
	222	#include <linux/ioport.h>
	223
	224	/*
	225	* devmem_is_allowed() checks to see if /dev/mem access to a certain
	226	* address is valid. The argument is a physical page number.
	227	* We mimic x86 here by disallowing access to system RAM as well as
	228	* device-exclusive MMIO regions. This effectively disable read()/write()
	229	* on /dev/mem.
	230	*/
	231	int devmem_is_allowed(unsigned long pfn)
	232	{
	233	if (iomem_is_exclusive(pfn << PAGE_SHIFT))
	234	return 0;
	235	if (!page_is_ram(pfn))
	236	return 1;
	237	return 0;
	238	}
	239
	240	#endif