[GitHub/LineageOS/android_kernel_motorola_exynos9610.git] / arch / mips / mm / mmap.c

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2011 Wind River Systems,
 *   written by Ralf Baechle <ralf@linux-mips.org>
 */
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/export.h>
#include <linux/personality.h>
#include <linux/random.h>
#include <linux/sched/signal.h>
#include <linux/sched/mm.h>

unsigned long shm_align_mask = PAGE_SIZE - 1;	/* Sane caches */
EXPORT_SYMBOL(shm_align_mask);

/* 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);
}

#define COLOUR_ALIGN(addr, pgoff)				\
	((((addr) + shm_align_mask) & ~shm_align_mask) +	\
	 (((pgoff) << PAGE_SHIFT) & shm_align_mask))

enum mmap_allocation_direction {UP, DOWN};

static unsigned long arch_get_unmapped_area_common(struct file *filp,
	unsigned long addr0, unsigned long len, unsigned long pgoff,
	unsigned long flags, enum mmap_allocation_direction dir)
{
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	unsigned long addr = addr0;
	int do_color_align;
	struct vm_unmapped_area_info info;

	if (unlikely(len > TASK_SIZE))
		return -ENOMEM;

	if (flags & MAP_FIXED) {
		/* Even MAP_FIXED mappings must reside within TASK_SIZE */
		if (TASK_SIZE - len < addr)
			return -EINVAL;

		/*
		 * We do not accept a shared mapping if it would violate
		 * cache aliasing constraints.
		 */
		if ((flags & MAP_SHARED) &&
		    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
			return -EINVAL;
		return addr;
	}

	do_color_align = 0;
	if (filp || (flags & MAP_SHARED))
		do_color_align = 1;

	/* requesting a specific address */
	if (addr) {
		if (do_color_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.length = len;
	info.align_mask = do_color_align ? (PAGE_MASK & shm_align_mask) : 0;
	info.align_offset = pgoff << PAGE_SHIFT;

	if (dir == DOWN) {
		info.flags = VM_UNMAPPED_AREA_TOPDOWN;
		info.low_limit = PAGE_SIZE;
		info.high_limit = mm->mmap_base;
		addr = vm_unmapped_area(&info);

		if (!(addr & ~PAGE_MASK))
			return addr;

		/*
		 * 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.
		 */
	}

	info.flags = 0;
	info.low_limit = mm->mmap_base;
	info.high_limit = TASK_SIZE;
	return vm_unmapped_area(&info);
}

unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
	unsigned long len, unsigned long pgoff, unsigned long flags)
{
	return arch_get_unmapped_area_common(filp,
			addr0, len, pgoff, flags, UP);
}

/*
 * There is no need to export this but sched.h declares the function as
 * extern so making it static here results in an error.
 */
unsigned long arch_get_unmapped_area_topdown(struct file *filp,
	unsigned long addr0, unsigned long len, unsigned long pgoff,
	unsigned long flags)
{
	return arch_get_unmapped_area_common(filp,
			addr0, len, pgoff, flags, DOWN);
}

unsigned long arch_mmap_rnd(void)
{
	unsigned long rnd;

#ifdef CONFIG_COMPAT
	if (TASK_IS_32BIT_ADDR)
		rnd = get_random_long() & ((1UL << mmap_rnd_compat_bits) - 1);
	else
#endif /* CONFIG_COMPAT */
		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;
	}
}

static inline unsigned long brk_rnd(void)
{
	unsigned long rnd = get_random_long();

	rnd = rnd << PAGE_SHIFT;
	/* 8MB for 32bit, 256MB for 64bit */
	if (TASK_IS_32BIT_ADDR)
		rnd = rnd & 0x7ffffful;
	else
		rnd = rnd & 0xffffffful;

	return rnd;
}

unsigned long arch_randomize_brk(struct mm_struct *mm)
{
	unsigned long base = mm->brk;
	unsigned long ret;

	ret = PAGE_ALIGN(base + brk_rnd());

	if (ret < mm->brk)
		return mm->brk;

	return ret;
}

int __virt_addr_valid(const volatile void *kaddr)
{
	return pfn_valid(PFN_DOWN(virt_to_phys(kaddr)));
}
EXPORT_SYMBOL_GPL(__virt_addr_valid);
Commit	Line	Data
6f6c3c33 RB	1	/*
	2	* This file is subject to the terms and conditions of the GNU General Public
	3	* License. See the file "COPYING" in the main directory of this archive
	4	* for more details.
	5	*
	6	* Copyright (C) 2011 Wind River Systems,
	7	* written by Ralf Baechle <ralf@linux-mips.org>
	8	*/
16650107	9	#include <linux/compiler.h>
6f6c3c33 RB	10	#include <linux/errno.h>
	11	#include <linux/mm.h>
	12	#include <linux/mman.h>
d9ba5778	13	#include <linux/export.h>
d0be89f6	14	#include <linux/personality.h>
6f6c3c33	15	#include <linux/random.h>
3f07c014	16	#include <linux/sched/signal.h>
01042607	17	#include <linux/sched/mm.h>
6f6c3c33 RB	18
6f6c3c33 RB	19	unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */
6f6c3c33 RB	20	EXPORT_SYMBOL(shm_align_mask);
6f6c3c33 RB	21
d0be89f6 JP	22	/* gap between mmap and stack */
d0be89f6 JP	23	#define MIN_GAP (12810241024UL)
16650107	24	#define MAX_GAP ((TASK_SIZE)/6*5)
d0be89f6 JP	25
	26	static int mmap_is_legacy(void)
	27	{
	28	if (current->personality & ADDR_COMPAT_LAYOUT)
	29	return 1;
	30
	31	if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
	32	return 1;
	33
	34	return sysctl_legacy_va_layout;
	35	}
	36
	37	static unsigned long mmap_base(unsigned long rnd)
	38	{
	39	unsigned long gap = rlimit(RLIMIT_STACK);
	40
	41	if (gap < MIN_GAP)
	42	gap = MIN_GAP;
	43	else if (gap > MAX_GAP)
	44	gap = MAX_GAP;
	45
	46	return PAGE_ALIGN(TASK_SIZE - gap - rnd);
	47	}
	48
16650107	49	#define COLOUR_ALIGN(addr, pgoff) \
6f6c3c33 RB	50	((((addr) + shm_align_mask) & ~shm_align_mask) + \
	51	(((pgoff) << PAGE_SHIFT) & shm_align_mask))
	52
d0be89f6 JP	53	enum mmap_allocation_direction {UP, DOWN};
d0be89f6 JP	54
16650107	55	static unsigned long arch_get_unmapped_area_common(struct file *filp,
d0be89f6 JP	56	unsigned long addr0, unsigned long len, unsigned long pgoff,
d0be89f6 JP	57	unsigned long flags, enum mmap_allocation_direction dir)
6f6c3c33	58	{
d0be89f6 JP	59	struct mm_struct *mm = current->mm;
	60	struct vm_area_struct *vma;
	61	unsigned long addr = addr0;
6f6c3c33	62	int do_color_align;
b6661861	63	struct vm_unmapped_area_info info;
6f6c3c33	64
d0be89f6	65	if (unlikely(len > TASK_SIZE))
6f6c3c33 RB	66	return -ENOMEM;
	67
	68	if (flags & MAP_FIXED) {
d0be89f6	69	/* Even MAP_FIXED mappings must reside within TASK_SIZE */
6f6c3c33 RB	70	if (TASK_SIZE - len < addr)
	71	return -EINVAL;
	72
	73	/*
	74	* We do not accept a shared mapping if it would violate
	75	* cache aliasing constraints.
	76	*/
	77	if ((flags & MAP_SHARED) &&
	78	((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
	79	return -EINVAL;
	80	return addr;
	81	}
	82
	83	do_color_align = 0;
	84	if (filp \|\| (flags & MAP_SHARED))
	85	do_color_align = 1;
d0be89f6 JP	86
d0be89f6 JP	87	/* requesting a specific address */
6f6c3c33 RB	88	if (addr) {
	89	if (do_color_align)
	90	addr = COLOUR_ALIGN(addr, pgoff);
	91	else
	92	addr = PAGE_ALIGN(addr);
d0be89f6 JP	93
d0be89f6 JP	94	vma = find_vma(mm, addr);
6f6c3c33	95	if (TASK_SIZE - len >= addr &&
1be7107f	96	(!vma \|\| addr + len <= vm_start_gap(vma)))
6f6c3c33 RB	97	return addr;
6f6c3c33 RB	98	}
6f6c3c33	99
b6661861 ML	100	info.length = len;
	101	info.align_mask = do_color_align ? (PAGE_MASK & shm_align_mask) : 0;
	102	info.align_offset = pgoff << PAGE_SHIFT;
d0be89f6	103
b6661861 ML	104	if (dir == DOWN) {
	105	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
	106	info.low_limit = PAGE_SIZE;
	107	info.high_limit = mm->mmap_base;
	108	addr = vm_unmapped_area(&info);
	109
	110	if (!(addr & ~PAGE_MASK))
	111	return addr;
d0be89f6	112
d0be89f6 JP	113	/*
	114	* A failed mmap() very likely causes application failure,
	115	* so fall back to the bottom-up function here. This scenario
	116	* can happen with large stack limits and large mmap()
	117	* allocations.
	118	*/
6f6c3c33	119	}
b6661861 ML	120
	121	info.flags = 0;
	122	info.low_limit = mm->mmap_base;
	123	info.high_limit = TASK_SIZE;
	124	return vm_unmapped_area(&info);
6f6c3c33 RB	125	}
6f6c3c33 RB	126
d0be89f6 JP	127	unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
	128	unsigned long len, unsigned long pgoff, unsigned long flags)
	129	{
16650107	130	return arch_get_unmapped_area_common(filp,
d0be89f6 JP	131	addr0, len, pgoff, flags, UP);
	132	}
	133
	134	/*
	135	* There is no need to export this but sched.h declares the function as
	136	* extern so making it static here results in an error.
	137	*/
	138	unsigned long arch_get_unmapped_area_topdown(struct file *filp,
	139	unsigned long addr0, unsigned long len, unsigned long pgoff,
	140	unsigned long flags)
	141	{
16650107	142	return arch_get_unmapped_area_common(filp,
d0be89f6 JP	143	addr0, len, pgoff, flags, DOWN);
	144	}
	145
2b68f6ca	146	unsigned long arch_mmap_rnd(void)
1f0569df KC	147	{
	148	unsigned long rnd;
	149
109c32ff	150	#ifdef CONFIG_COMPAT
1f0569df	151	if (TASK_IS_32BIT_ADDR)
109c32ff	152	rnd = get_random_long() & ((1UL << mmap_rnd_compat_bits) - 1);
1f0569df	153	else
109c32ff MR	154	#endif /* CONFIG_COMPAT */
109c32ff MR	155	rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1);
1f0569df	156
109c32ff	157	return rnd << PAGE_SHIFT;
1f0569df KC	158	}
1f0569df KC	159
6f6c3c33 RB	160	void arch_pick_mmap_layout(struct mm_struct *mm)
	161	{
	162	unsigned long random_factor = 0UL;
	163
1f0569df	164	if (current->flags & PF_RANDOMIZE)
2b68f6ca	165	random_factor = arch_mmap_rnd();
6f6c3c33	166
d0be89f6 JP	167	if (mmap_is_legacy()) {
	168	mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
	169	mm->get_unmapped_area = arch_get_unmapped_area;
d0be89f6 JP	170	} else {
	171	mm->mmap_base = mmap_base(random_factor);
	172	mm->get_unmapped_area = arch_get_unmapped_area_topdown;
d0be89f6	173	}
6f6c3c33 RB	174	}
	175
	176	static inline unsigned long brk_rnd(void)
	177	{
5ef11c35	178	unsigned long rnd = get_random_long();
6f6c3c33 RB	179
	180	rnd = rnd << PAGE_SHIFT;
	181	/* 8MB for 32bit, 256MB for 64bit */
	182	if (TASK_IS_32BIT_ADDR)
	183	rnd = rnd & 0x7ffffful;
	184	else
	185	rnd = rnd & 0xffffffful;
	186
	187	return rnd;
	188	}
	189
	190	unsigned long arch_randomize_brk(struct mm_struct *mm)
	191	{
	192	unsigned long base = mm->brk;
	193	unsigned long ret;
	194
	195	ret = PAGE_ALIGN(base + brk_rnd());
	196
	197	if (ret < mm->brk)
	198	return mm->brk;
	199
	200	return ret;
	201	}
196897a2 SR	202
	203	int __virt_addr_valid(const volatile void *kaddr)
	204	{
	205	return pfn_valid(PFN_DOWN(virt_to_phys(kaddr)));
	206	}
	207	EXPORT_SYMBOL_GPL(__virt_addr_valid);