[GitHub/mt8127/android_kernel_alcatel_ttab.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>

static inline unsigned long COLOUR_ALIGN_DOWN(unsigned long addr,
					      unsigned long pgoff)
{
	unsigned long base = addr & ~(SHMLBA-1);
	unsigned long off = (pgoff << PAGE_SHIFT) & (SHMLBA-1);

	if (base + off <= addr)
		return base + off;

	return base - off;
}

#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;
	unsigned long start_addr;
	int do_align = 0;
	int aliasing = cache_is_vipt_aliasing();

	/*
	 * 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 <= vma->vm_start))
			return addr;
	}
	if (len > mm->cached_hole_size) {
	        start_addr = addr = mm->free_area_cache;
	} else {
	        start_addr = addr = mm->mmap_base;
	        mm->cached_hole_size = 0;
	}

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

	for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
		/* At this point:  (!vma || addr < vma->vm_end). */
		if (TASK_SIZE - len < addr) {
			/*
			 * Start a new search - just in case we missed
			 * some holes.
			 */
			if (start_addr != TASK_UNMAPPED_BASE) {
				start_addr = addr = TASK_UNMAPPED_BASE;
				mm->cached_hole_size = 0;
				goto full_search;
			}
			return -ENOMEM;
		}
		if (!vma || addr + len <= vma->vm_start) {
			/*
			 * Remember the place where we stopped the search:
			 */
			mm->free_area_cache = addr + len;
			return addr;
		}
		if (addr + mm->cached_hole_size < vma->vm_start)
		        mm->cached_hole_size = vma->vm_start - addr;
		addr = vma->vm_end;
		if (do_align)
			addr = COLOUR_ALIGN(addr, pgoff);
	}
}

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();

	/*
	 * 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 <= vma->vm_start))
			return addr;
	}

	/* check if free_area_cache is useful for us */
	if (len <= mm->cached_hole_size) {
		mm->cached_hole_size = 0;
		mm->free_area_cache = mm->mmap_base;
	}

	/* either no address requested or can't fit in requested address hole */
	addr = mm->free_area_cache;
	if (do_align) {
		unsigned long base = COLOUR_ALIGN_DOWN(addr - len, pgoff);
		addr = base + len;
	}

	/* make sure it can fit in the remaining address space */
	if (addr > len) {
		vma = find_vma(mm, addr-len);
		if (!vma || addr <= vma->vm_start)
			/* remember the address as a hint for next time */
			return (mm->free_area_cache = addr-len);
	}

	if (mm->mmap_base < len)
		goto bottomup;

	addr = mm->mmap_base - len;
	if (do_align)
		addr = COLOUR_ALIGN_DOWN(addr, pgoff);

	do {
		/*
		 * Lookup failure means no vma is above this address,
		 * else if new region fits below vma->vm_start,
		 * return with success:
		 */
		vma = find_vma(mm, addr);
		if (!vma || addr+len <= vma->vm_start)
			/* remember the address as a hint for next time */
			return (mm->free_area_cache = addr);

		/* remember the largest hole we saw so far */
		if (addr + mm->cached_hole_size < vma->vm_start)
			mm->cached_hole_size = vma->vm_start - addr;

		/* try just below the current vma->vm_start */
		addr = vma->vm_start - len;
		if (do_align)
			addr = COLOUR_ALIGN_DOWN(addr, pgoff);
	} while (len < vma->vm_start);

bottomup:
	/*
	 * 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.
	 */
	mm->cached_hole_size = ~0UL;
	mm->free_area_cache = TASK_UNMAPPED_BASE;
	addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
	/*
	 * Restore the topdown base:
	 */
	mm->free_area_cache = mm->mmap_base;
	mm->cached_hole_size = ~0UL;

	return addr;
}

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

	/* 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;
		mm->get_unmapped_area = arch_get_unmapped_area;
		mm->unmap_area = arch_unmap_area;
	} else {
		mm->mmap_base = mmap_base(random_factor);
		mm->get_unmapped_area = arch_get_unmapped_area_topdown;
		mm->unmap_area = arch_unmap_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(unsigned long addr, size_t size)
{
	if (addr < PHYS_OFFSET)
		return 0;
	if (addr + size > __pa(high_memory - 1) + 1)
		return 0;

	return 1;
}

/*
 * We don't use supersection mappings for mmap() on /dev/mem, which
 * means that we can't map the memory area above the 4G barrier into
 * userspace.
 */
int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
{
	return !(pfn + (size >> PAGE_SHIFT) > 0x00100000);
}

#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	13
7dbaa466 RH	14	static inline unsigned long COLOUR_ALIGN_DOWN(unsigned long addr,
	15	unsigned long pgoff)
	16	{
	17	unsigned long base = addr & ~(SHMLBA-1);
	18	unsigned long off = (pgoff << PAGE_SHIFT) & (SHMLBA-1);
	19
	20	if (base + off <= addr)
	21	return base + off;
	22
	23	return base - off;
	24	}
	25
1da177e4 LT	26	#define COLOUR_ALIGN(addr,pgoff) \
	27	((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \
	28	(((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))
	29
7dbaa466 RH	30	/* gap between mmap and stack */
	31	#define MIN_GAP (12810241024UL)
	32	#define MAX_GAP ((TASK_SIZE)/6*5)
	33
	34	static int mmap_is_legacy(void)
	35	{
	36	if (current->personality & ADDR_COMPAT_LAYOUT)
	37	return 1;
	38
	39	if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
	40	return 1;
	41
	42	return sysctl_legacy_va_layout;
	43	}
	44
	45	static unsigned long mmap_base(unsigned long rnd)
	46	{
	47	unsigned long gap = rlimit(RLIMIT_STACK);
	48
	49	if (gap < MIN_GAP)
	50	gap = MIN_GAP;
	51	else if (gap > MAX_GAP)
	52	gap = MAX_GAP;
	53
	54	return PAGE_ALIGN(TASK_SIZE - gap - rnd);
	55	}
	56
1da177e4 LT	57	/*
	58	* We need to ensure that shared mappings are correctly aligned to
	59	* avoid aliasing issues with VIPT caches. We need to ensure that
	60	* a specific page of an object is always mapped at a multiple of
	61	* SHMLBA bytes.
	62	*
	63	* We unconditionally provide this function for all cases, however
	64	* in the VIVT case, we optimise out the alignment rules.
	65	*/
	66	unsigned long
	67	arch_get_unmapped_area(struct file *filp, unsigned long addr,
	68	unsigned long len, unsigned long pgoff, unsigned long flags)
	69	{
	70	struct mm_struct *mm = current->mm;
	71	struct vm_area_struct *vma;
	72	unsigned long start_addr;
41dfaa93 RH	73	int do_align = 0;
41dfaa93 RH	74	int aliasing = cache_is_vipt_aliasing();
1da177e4 LT	75
	76	/*
	77	* We only need to do colour alignment if either the I or D
41dfaa93	78	* caches alias.
1da177e4	79	*/
41dfaa93 RH	80	if (aliasing)
41dfaa93 RH	81	do_align = filp \|\| (flags & MAP_SHARED);
1da177e4 LT	82
1da177e4 LT	83	/*
acec0ac0	84	* We enforce the MAP_FIXED case.
1da177e4 LT	85	*/
1da177e4 LT	86	if (flags & MAP_FIXED) {
e77414e0 AV	87	if (aliasing && flags & MAP_SHARED &&
e77414e0 AV	88	(addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
1da177e4 LT	89	return -EINVAL;
	90	return addr;
	91	}
	92
	93	if (len > TASK_SIZE)
	94	return -ENOMEM;
	95
	96	if (addr) {
	97	if (do_align)
	98	addr = COLOUR_ALIGN(addr, pgoff);
	99	else
	100	addr = PAGE_ALIGN(addr);
	101
	102	vma = find_vma(mm, addr);
	103	if (TASK_SIZE - len >= addr &&
	104	(!vma \|\| addr + len <= vma->vm_start))
	105	return addr;
	106	}
1363c3cd WW	107	if (len > mm->cached_hole_size) {
	108	start_addr = addr = mm->free_area_cache;
	109	} else {
7dbaa466	110	start_addr = addr = mm->mmap_base;
1363c3cd WW	111	mm->cached_hole_size = 0;
1363c3cd WW	112	}
1da177e4 LT	113
	114	full_search:
	115	if (do_align)
	116	addr = COLOUR_ALIGN(addr, pgoff);
	117	else
	118	addr = PAGE_ALIGN(addr);
	119
	120	for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
	121	/* At this point: (!vma \|\| addr < vma->vm_end). */
	122	if (TASK_SIZE - len < addr) {
	123	/*
	124	* Start a new search - just in case we missed
	125	* some holes.
	126	*/
	127	if (start_addr != TASK_UNMAPPED_BASE) {
	128	start_addr = addr = TASK_UNMAPPED_BASE;
1363c3cd	129	mm->cached_hole_size = 0;
1da177e4 LT	130	goto full_search;
	131	}
	132	return -ENOMEM;
	133	}
	134	if (!vma \|\| addr + len <= vma->vm_start) {
	135	/*
	136	* Remember the place where we stopped the search:
	137	*/
	138	mm->free_area_cache = addr + len;
	139	return addr;
	140	}
1363c3cd WW	141	if (addr + mm->cached_hole_size < vma->vm_start)
1363c3cd WW	142	mm->cached_hole_size = vma->vm_start - addr;
1da177e4 LT	143	addr = vma->vm_end;
	144	if (do_align)
	145	addr = COLOUR_ALIGN(addr, pgoff);
	146	}
	147	}
	148
7dbaa466 RH	149	unsigned long
	150	arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
	151	const unsigned long len, const unsigned long pgoff,
	152	const unsigned long flags)
	153	{
	154	struct vm_area_struct *vma;
	155	struct mm_struct *mm = current->mm;
	156	unsigned long addr = addr0;
	157	int do_align = 0;
	158	int aliasing = cache_is_vipt_aliasing();
	159
	160	/*
	161	* We only need to do colour alignment if either the I or D
	162	* caches alias.
	163	*/
	164	if (aliasing)
	165	do_align = filp \|\| (flags & MAP_SHARED);
	166
	167	/* requested length too big for entire address space */
	168	if (len > TASK_SIZE)
	169	return -ENOMEM;
	170
	171	if (flags & MAP_FIXED) {
	172	if (aliasing && flags & MAP_SHARED &&
	173	(addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
	174	return -EINVAL;
	175	return addr;
	176	}
	177
	178	/* requesting a specific address */
	179	if (addr) {
	180	if (do_align)
	181	addr = COLOUR_ALIGN(addr, pgoff);
	182	else
	183	addr = PAGE_ALIGN(addr);
	184	vma = find_vma(mm, addr);
	185	if (TASK_SIZE - len >= addr &&
	186	(!vma \|\| addr + len <= vma->vm_start))
	187	return addr;
	188	}
	189
	190	/* check if free_area_cache is useful for us */
	191	if (len <= mm->cached_hole_size) {
	192	mm->cached_hole_size = 0;
	193	mm->free_area_cache = mm->mmap_base;
	194	}
	195
	196	/* either no address requested or can't fit in requested address hole */
	197	addr = mm->free_area_cache;
	198	if (do_align) {
	199	unsigned long base = COLOUR_ALIGN_DOWN(addr - len, pgoff);
	200	addr = base + len;
	201	}
	202
	203	/* make sure it can fit in the remaining address space */
	204	if (addr > len) {
	205	vma = find_vma(mm, addr-len);
	206	if (!vma \|\| addr <= vma->vm_start)
	207	/* remember the address as a hint for next time */
	208	return (mm->free_area_cache = addr-len);
	209	}
	210
	211	if (mm->mmap_base < len)
	212	goto bottomup;
213
214	addr = mm->mmap_base - len;
215	if (do_align)
216	addr = COLOUR_ALIGN_DOWN(addr, pgoff);
217
218	do {
219	/*
220	* Lookup failure means no vma is above this address,
221	* else if new region fits below vma->vm_start,
222	* return with success:
223	*/
224	vma = find_vma(mm, addr);
225	if (!vma \|\| addr+len <= vma->vm_start)
226	/* remember the address as a hint for next time */
227	return (mm->free_area_cache = addr);
228
229	/* remember the largest hole we saw so far */
230	if (addr + mm->cached_hole_size < vma->vm_start)
231	mm->cached_hole_size = vma->vm_start - addr;
232
233	/* try just below the current vma->vm_start */
234	addr = vma->vm_start - len;
235	if (do_align)
236	addr = COLOUR_ALIGN_DOWN(addr, pgoff);
237	} while (len < vma->vm_start);
238
239	bottomup:
240	/*
241	* A failed mmap() very likely causes application failure,
242	* so fall back to the bottom-up function here. This scenario
243	* can happen with large stack limits and large mmap()
244	* allocations.
245	*/
246	mm->cached_hole_size = ~0UL;
247	mm->free_area_cache = TASK_UNMAPPED_BASE;
248	addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
249	/*
250	* Restore the topdown base:
251	*/
252	mm->free_area_cache = mm->mmap_base;
253	mm->cached_hole_size = ~0UL;
254
255	return addr;
256	}
257
258	void arch_pick_mmap_layout(struct mm_struct *mm)
259	{
260	unsigned long random_factor = 0UL;
261
262	/* 8 bits of randomness in 20 address space bits */
263	if ((current->flags & PF_RANDOMIZE) &&
264	!(current->personality & ADDR_NO_RANDOMIZE))
265	random_factor = (get_random_int() % (1 << 8)) << PAGE_SHIFT;
266
267	if (mmap_is_legacy()) {
268	mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
269	mm->get_unmapped_area = arch_get_unmapped_area;
270	mm->unmap_area = arch_unmap_area;
271	} else {
272	mm->mmap_base = mmap_base(random_factor);
273	mm->get_unmapped_area = arch_get_unmapped_area_topdown;
274	mm->unmap_area = arch_unmap_area_topdown;
275	}
276	}
51635ad2 LB	277
	278	/*
	279	* You really shouldn't be using read() or write() on /dev/mem. This
	280	* might go away in the future.
	281	*/
	282	int valid_phys_addr_range(unsigned long addr, size_t size)
	283	{
9ae3ae0b AR	284	if (addr < PHYS_OFFSET)
9ae3ae0b AR	285	return 0;
6806bfe1	286	if (addr + size > __pa(high_memory - 1) + 1)
51635ad2 LB	287	return 0;
	288
	289	return 1;
	290	}
	291
	292	/*
	293	* We don't use supersection mappings for mmap() on /dev/mem, which
	294	* means that we can't map the memory area above the 4G barrier into
	295	* userspace.
	296	*/
	297	int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
	298	{
	299	return !(pfn + (size >> PAGE_SHIFT) > 0x00100000);
	300	}
087aaffc NP	301
	302	#ifdef CONFIG_STRICT_DEVMEM
	303
	304	#include <linux/ioport.h>
	305
	306	/*
	307	* devmem_is_allowed() checks to see if /dev/mem access to a certain
	308	* address is valid. The argument is a physical page number.
	309	* We mimic x86 here by disallowing access to system RAM as well as
	310	* device-exclusive MMIO regions. This effectively disable read()/write()
	311	* on /dev/mem.
	312	*/
	313	int devmem_is_allowed(unsigned long pfn)
	314	{
	315	if (iomem_is_exclusive(pfn << PAGE_SHIFT))
	316	return 0;
	317	if (!page_is_ram(pfn))
	318	return 1;
	319	return 0;
	320	}
	321
	322	#endif