[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>

#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;
}

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(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();
394ef640	62	struct vm_unmapped_area_info info;
1da177e4 LT	63
	64	/*
	65	* We only need to do colour alignment if either the I or D
41dfaa93	66	* caches alias.
1da177e4	67	*/
41dfaa93 RH	68	if (aliasing)
41dfaa93 RH	69	do_align = filp \|\| (flags & MAP_SHARED);
1da177e4 LT	70
1da177e4 LT	71	/*
acec0ac0	72	* We enforce the MAP_FIXED case.
1da177e4 LT	73	*/
1da177e4 LT	74	if (flags & MAP_FIXED) {
e77414e0 AV	75	if (aliasing && flags & MAP_SHARED &&
e77414e0 AV	76	(addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
1da177e4 LT	77	return -EINVAL;
	78	return addr;
	79	}
	80
	81	if (len > TASK_SIZE)
	82	return -ENOMEM;
	83
	84	if (addr) {
	85	if (do_align)
	86	addr = COLOUR_ALIGN(addr, pgoff);
	87	else
	88	addr = PAGE_ALIGN(addr);
	89
	90	vma = find_vma(mm, addr);
	91	if (TASK_SIZE - len >= addr &&
1ad9a25d	92	(!vma \|\| addr + len <= vm_start_gap(vma)))
1da177e4 LT	93	return addr;
1da177e4 LT	94	}
1da177e4	95
394ef640 ML	96	info.flags = 0;
	97	info.length = len;
	98	info.low_limit = mm->mmap_base;
	99	info.high_limit = TASK_SIZE;
	100	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
	101	info.align_offset = pgoff << PAGE_SHIFT;
	102	return vm_unmapped_area(&info);
1da177e4 LT	103	}
1da177e4 LT	104
7dbaa466 RH	105	unsigned long
	106	arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
	107	const unsigned long len, const unsigned long pgoff,
	108	const unsigned long flags)
	109	{
	110	struct vm_area_struct *vma;
	111	struct mm_struct *mm = current->mm;
	112	unsigned long addr = addr0;
	113	int do_align = 0;
	114	int aliasing = cache_is_vipt_aliasing();
394ef640	115	struct vm_unmapped_area_info info;
7dbaa466 RH	116
	117	/*
	118	* We only need to do colour alignment if either the I or D
	119	* caches alias.
	120	*/
	121	if (aliasing)
	122	do_align = filp \|\| (flags & MAP_SHARED);
	123
	124	/* requested length too big for entire address space */
	125	if (len > TASK_SIZE)
	126	return -ENOMEM;
	127
	128	if (flags & MAP_FIXED) {
	129	if (aliasing && flags & MAP_SHARED &&
	130	(addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
	131	return -EINVAL;
	132	return addr;
	133	}
	134
	135	/* requesting a specific address */
	136	if (addr) {
	137	if (do_align)
	138	addr = COLOUR_ALIGN(addr, pgoff);
	139	else
	140	addr = PAGE_ALIGN(addr);
	141	vma = find_vma(mm, addr);
	142	if (TASK_SIZE - len >= addr &&
1ad9a25d	143	(!vma \|\| addr + len <= vm_start_gap(vma)))
7dbaa466 RH	144	return addr;
	145	}
	146
394ef640 ML	147	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
394ef640 ML	148	info.length = len;
d47787bd	149	info.low_limit = FIRST_USER_ADDRESS;
394ef640 ML	150	info.high_limit = mm->mmap_base;
	151	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
	152	info.align_offset = pgoff << PAGE_SHIFT;
	153	addr = vm_unmapped_area(&info);
7dbaa466	154
7dbaa466 RH	155	/*
	156	* A failed mmap() very likely causes application failure,
	157	* so fall back to the bottom-up function here. This scenario
	158	* can happen with large stack limits and large mmap()
	159	* allocations.
	160	*/
394ef640 ML	161	if (addr & ~PAGE_MASK) {
	162	VM_BUG_ON(addr != -ENOMEM);
	163	info.flags = 0;
	164	info.low_limit = mm->mmap_base;
	165	info.high_limit = TASK_SIZE;
	166	addr = vm_unmapped_area(&info);
	167	}
7dbaa466 RH	168
	169	return addr;
	170	}
	171
	172	void arch_pick_mmap_layout(struct mm_struct *mm)
	173	{
	174	unsigned long random_factor = 0UL;
	175
	176	/* 8 bits of randomness in 20 address space bits */
	177	if ((current->flags & PF_RANDOMIZE) &&
	178	!(current->personality & ADDR_NO_RANDOMIZE))
	179	random_factor = (get_random_int() % (1 << 8)) << PAGE_SHIFT;
	180
	181	if (mmap_is_legacy()) {
	182	mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
	183	mm->get_unmapped_area = arch_get_unmapped_area;
	184	mm->unmap_area = arch_unmap_area;
	185	} else {
	186	mm->mmap_base = mmap_base(random_factor);
	187	mm->get_unmapped_area = arch_get_unmapped_area_topdown;
	188	mm->unmap_area = arch_unmap_area_topdown;
	189	}
	190	}
51635ad2 LB	191
	192	/*
	193	* You really shouldn't be using read() or write() on /dev/mem. This
	194	* might go away in the future.
	195	*/
7e6735c3	196	int valid_phys_addr_range(phys_addr_t addr, size_t size)
51635ad2	197	{
9ae3ae0b AR	198	if (addr < PHYS_OFFSET)
9ae3ae0b AR	199	return 0;
6806bfe1	200	if (addr + size > __pa(high_memory - 1) + 1)
51635ad2 LB	201	return 0;
	202
	203	return 1;
	204	}
	205
	206	/*
b6b461e9	207	* Do not allow /dev/mem mappings beyond the supported physical range.
51635ad2 LB	208	*/
	209	int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
	210	{
b6b461e9	211	return (pfn + (size >> PAGE_SHIFT)) <= (1 + (PHYS_MASK >> PAGE_SHIFT));
51635ad2	212	}
087aaffc NP	213
	214	#ifdef CONFIG_STRICT_DEVMEM
	215
	216	#include <linux/ioport.h>
	217
	218	/*
	219	* devmem_is_allowed() checks to see if /dev/mem access to a certain
	220	* address is valid. The argument is a physical page number.
	221	* We mimic x86 here by disallowing access to system RAM as well as
	222	* device-exclusive MMIO regions. This effectively disable read()/write()
	223	* on /dev/mem.
	224	*/
	225	int devmem_is_allowed(unsigned long pfn)
	226	{
	227	if (iomem_is_exclusive(pfn << PAGE_SHIFT))
	228	return 0;
	229	if (!page_is_ram(pfn))
	230	return 1;
	231	return 0;
	232	}
	233
	234	#endif