[thirdparty/kernel/linux.git] / arch / arm / mm / mmap.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  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
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/arch/arm/mm/mmap.c
	4	*/
1da177e4 LT	5	#include <linux/fs.h>
	6	#include <linux/mm.h>
	7	#include <linux/mman.h>
	8	#include <linux/shm.h>
3f07c014	9	#include <linux/sched/signal.h>
01042607	10	#include <linux/sched/mm.h>
09d9bae0	11	#include <linux/io.h>
df5419a9	12	#include <linux/personality.h>
cc92c28b	13	#include <linux/random.h>
41dfaa93	14	#include <asm/cachetype.h>
1da177e4 LT	15
	16	#define COLOUR_ALIGN(addr,pgoff) \
	17	((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \
	18	(((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))
	19
7dbaa466 RH	20	/* gap between mmap and stack */
	21	#define MIN_GAP (12810241024UL)
	22	#define MAX_GAP ((TASK_SIZE)/6*5)
	23
	24	static int mmap_is_legacy(void)
	25	{
	26	if (current->personality & ADDR_COMPAT_LAYOUT)
	27	return 1;
	28
	29	if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
	30	return 1;
	31
	32	return sysctl_legacy_va_layout;
	33	}
	34
	35	static unsigned long mmap_base(unsigned long rnd)
	36	{
	37	unsigned long gap = rlimit(RLIMIT_STACK);
	38
	39	if (gap < MIN_GAP)
	40	gap = MIN_GAP;
	41	else if (gap > MAX_GAP)
	42	gap = MAX_GAP;
	43
	44	return PAGE_ALIGN(TASK_SIZE - gap - rnd);
	45	}
	46
1da177e4 LT	47	/*
	48	* We need to ensure that shared mappings are correctly aligned to
	49	* avoid aliasing issues with VIPT caches. We need to ensure that
	50	* a specific page of an object is always mapped at a multiple of
	51	* SHMLBA bytes.
	52	*
	53	* We unconditionally provide this function for all cases, however
	54	* in the VIVT case, we optimise out the alignment rules.
	55	*/
	56	unsigned long
	57	arch_get_unmapped_area(struct file *filp, unsigned long addr,
	58	unsigned long len, unsigned long pgoff, unsigned long flags)
	59	{
	60	struct mm_struct *mm = current->mm;
	61	struct vm_area_struct *vma;
41dfaa93 RH	62	int do_align = 0;
41dfaa93 RH	63	int aliasing = cache_is_vipt_aliasing();
394ef640	64	struct vm_unmapped_area_info info;
1da177e4 LT	65
	66	/*
	67	* We only need to do colour alignment if either the I or D
41dfaa93	68	* caches alias.
1da177e4	69	*/
41dfaa93 RH	70	if (aliasing)
41dfaa93 RH	71	do_align = filp \|\| (flags & MAP_SHARED);
1da177e4 LT	72
1da177e4 LT	73	/*
acec0ac0	74	* We enforce the MAP_FIXED case.
1da177e4 LT	75	*/
1da177e4 LT	76	if (flags & MAP_FIXED) {
e77414e0 AV	77	if (aliasing && flags & MAP_SHARED &&
e77414e0 AV	78	(addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
1da177e4 LT	79	return -EINVAL;
	80	return addr;
	81	}
	82
	83	if (len > TASK_SIZE)
	84	return -ENOMEM;
	85
	86	if (addr) {
	87	if (do_align)
	88	addr = COLOUR_ALIGN(addr, pgoff);
	89	else
	90	addr = PAGE_ALIGN(addr);
	91
	92	vma = find_vma(mm, addr);
	93	if (TASK_SIZE - len >= addr &&
1be7107f	94	(!vma \|\| addr + len <= vm_start_gap(vma)))
1da177e4 LT	95	return addr;
1da177e4 LT	96	}
1da177e4	97
394ef640 ML	98	info.flags = 0;
	99	info.length = len;
	100	info.low_limit = mm->mmap_base;
	101	info.high_limit = TASK_SIZE;
	102	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
	103	info.align_offset = pgoff << PAGE_SHIFT;
	104	return vm_unmapped_area(&info);
1da177e4 LT	105	}
1da177e4 LT	106
7dbaa466 RH	107	unsigned long
	108	arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
	109	const unsigned long len, const unsigned long pgoff,
	110	const unsigned long flags)
	111	{
	112	struct vm_area_struct *vma;
	113	struct mm_struct *mm = current->mm;
	114	unsigned long addr = addr0;
	115	int do_align = 0;
	116	int aliasing = cache_is_vipt_aliasing();
394ef640	117	struct vm_unmapped_area_info info;
7dbaa466 RH	118
	119	/*
	120	* We only need to do colour alignment if either the I or D
	121	* caches alias.
	122	*/
	123	if (aliasing)
	124	do_align = filp \|\| (flags & MAP_SHARED);
	125
	126	/* requested length too big for entire address space */
	127	if (len > TASK_SIZE)
	128	return -ENOMEM;
	129
	130	if (flags & MAP_FIXED) {
	131	if (aliasing && flags & MAP_SHARED &&
	132	(addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
	133	return -EINVAL;
	134	return addr;
	135	}
	136
	137	/* requesting a specific address */
	138	if (addr) {
	139	if (do_align)
	140	addr = COLOUR_ALIGN(addr, pgoff);
	141	else
	142	addr = PAGE_ALIGN(addr);
	143	vma = find_vma(mm, addr);
	144	if (TASK_SIZE - len >= addr &&
1be7107f	145	(!vma \|\| addr + len <= vm_start_gap(vma)))
7dbaa466 RH	146	return addr;
	147	}
	148
394ef640 ML	149	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
394ef640 ML	150	info.length = len;
d8aa712c	151	info.low_limit = FIRST_USER_ADDRESS;
394ef640 ML	152	info.high_limit = mm->mmap_base;
	153	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
	154	info.align_offset = pgoff << PAGE_SHIFT;
	155	addr = vm_unmapped_area(&info);
7dbaa466	156
7dbaa466 RH	157	/*
	158	* A failed mmap() very likely causes application failure,
	159	* so fall back to the bottom-up function here. This scenario
	160	* can happen with large stack limits and large mmap()
	161	* allocations.
	162	*/
394ef640 ML	163	if (addr & ~PAGE_MASK) {
	164	VM_BUG_ON(addr != -ENOMEM);
	165	info.flags = 0;
	166	info.low_limit = mm->mmap_base;
	167	info.high_limit = TASK_SIZE;
	168	addr = vm_unmapped_area(&info);
	169	}
7dbaa466 RH	170
	171	return addr;
	172	}
	173
2b68f6ca	174	unsigned long arch_mmap_rnd(void)
fbbc400f KC	175	{
	176	unsigned long rnd;
	177
5ef11c35	178	rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1);
fbbc400f KC	179
	180	return rnd << PAGE_SHIFT;
	181	}
	182
7dbaa466 RH	183	void arch_pick_mmap_layout(struct mm_struct *mm)
	184	{
	185	unsigned long random_factor = 0UL;
	186
fbbc400f	187	if (current->flags & PF_RANDOMIZE)
2b68f6ca	188	random_factor = arch_mmap_rnd();
7dbaa466 RH	189
	190	if (mmap_is_legacy()) {
	191	mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
	192	mm->get_unmapped_area = arch_get_unmapped_area;
7dbaa466 RH	193	} else {
	194	mm->mmap_base = mmap_base(random_factor);
	195	mm->get_unmapped_area = arch_get_unmapped_area_topdown;
7dbaa466 RH	196	}
7dbaa466 RH	197	}
51635ad2 LB	198
	199	/*
	200	* You really shouldn't be using read() or write() on /dev/mem. This
	201	* might go away in the future.
	202	*/
7e6735c3	203	int valid_phys_addr_range(phys_addr_t addr, size_t size)
51635ad2	204	{
9ae3ae0b AR	205	if (addr < PHYS_OFFSET)
9ae3ae0b AR	206	return 0;
6806bfe1	207	if (addr + size > __pa(high_memory - 1) + 1)
51635ad2 LB	208	return 0;
	209
	210	return 1;
	211	}
	212
	213	/*
3159f372	214	* Do not allow /dev/mem mappings beyond the supported physical range.
51635ad2 LB	215	*/
	216	int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
	217	{
3159f372	218	return (pfn + (size >> PAGE_SHIFT)) <= (1 + (PHYS_MASK >> PAGE_SHIFT));
51635ad2	219	}
087aaffc NP	220
	221	#ifdef CONFIG_STRICT_DEVMEM
	222
	223	#include <linux/ioport.h>
	224
	225	/*
	226	* devmem_is_allowed() checks to see if /dev/mem access to a certain
	227	* address is valid. The argument is a physical page number.
	228	* We mimic x86 here by disallowing access to system RAM as well as
	229	* device-exclusive MMIO regions. This effectively disable read()/write()
	230	* on /dev/mem.
	231	*/
	232	int devmem_is_allowed(unsigned long pfn)
	233	{
	234	if (iomem_is_exclusive(pfn << PAGE_SHIFT))
	235	return 0;
	236	if (!page_is_ram(pfn))
	237	return 1;
	238	return 0;
	239	}
	240
	241	#endif