[linux-2.6-block.git] / arch / arm64 / kernel / vdso.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * VDSO implementations.
 *
 * Copyright (C) 2012 ARM Limited
 *
 * Author: Will Deacon <will.deacon@arm.com>
 */

#include <linux/cache.h>
#include <linux/clocksource.h>
#include <linux/elf.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/slab.h>
#include <linux/time_namespace.h>
#include <linux/timekeeper_internal.h>
#include <linux/vmalloc.h>
#include <vdso/datapage.h>
#include <vdso/helpers.h>
#include <vdso/vsyscall.h>

#include <asm/cacheflush.h>
#include <asm/signal32.h>
#include <asm/vdso.h>

enum vdso_abi {
	VDSO_ABI_AA64,
	VDSO_ABI_AA32,
};

enum vvar_pages {
	VVAR_DATA_PAGE_OFFSET,
	VVAR_TIMENS_PAGE_OFFSET,
	VVAR_NR_PAGES,
};

struct vdso_abi_info {
	const char *name;
	const char *vdso_code_start;
	const char *vdso_code_end;
	unsigned long vdso_pages;
	/* Data Mapping */
	struct vm_special_mapping *dm;
	/* Code Mapping */
	struct vm_special_mapping *cm;
};

static struct vdso_abi_info vdso_info[] __ro_after_init = {
	[VDSO_ABI_AA64] = {
		.name = "vdso",
		.vdso_code_start = vdso_start,
		.vdso_code_end = vdso_end,
	},
#ifdef CONFIG_COMPAT_VDSO
	[VDSO_ABI_AA32] = {
		.name = "vdso32",
		.vdso_code_start = vdso32_start,
		.vdso_code_end = vdso32_end,
	},
#endif /* CONFIG_COMPAT_VDSO */
};

/*
 * The vDSO data page.
 */
static union {
	struct vdso_data	data[CS_BASES];
	u8			page[PAGE_SIZE];
} vdso_data_store __page_aligned_data;
struct vdso_data *vdso_data = vdso_data_store.data;

static int vdso_mremap(const struct vm_special_mapping *sm,
		struct vm_area_struct *new_vma)
{
	current->mm->context.vdso = (void *)new_vma->vm_start;

	return 0;
}

static int __init __vdso_init(enum vdso_abi abi)
{
	int i;
	struct page **vdso_pagelist;
	unsigned long pfn;

	if (memcmp(vdso_info[abi].vdso_code_start, "\177ELF", 4)) {
		pr_err("vDSO is not a valid ELF object!\n");
		return -EINVAL;
	}

	vdso_info[abi].vdso_pages = (
			vdso_info[abi].vdso_code_end -
			vdso_info[abi].vdso_code_start) >>
			PAGE_SHIFT;

	vdso_pagelist = kcalloc(vdso_info[abi].vdso_pages,
				sizeof(struct page *),
				GFP_KERNEL);
	if (vdso_pagelist == NULL)
		return -ENOMEM;

	/* Grab the vDSO code pages. */
	pfn = sym_to_pfn(vdso_info[abi].vdso_code_start);

	for (i = 0; i < vdso_info[abi].vdso_pages; i++)
		vdso_pagelist[i] = pfn_to_page(pfn + i);

	vdso_info[abi].cm->pages = vdso_pagelist;

	return 0;
}

#ifdef CONFIG_TIME_NS
struct vdso_data *arch_get_vdso_data(void *vvar_page)
{
	return (struct vdso_data *)(vvar_page);
}

/*
 * The vvar mapping contains data for a specific time namespace, so when a task
 * changes namespace we must unmap its vvar data for the old namespace.
 * Subsequent faults will map in data for the new namespace.
 *
 * For more details see timens_setup_vdso_data().
 */
int vdso_join_timens(struct task_struct *task, struct time_namespace *ns)
{
	struct mm_struct *mm = task->mm;
	struct vm_area_struct *vma;

	mmap_read_lock(mm);

	for (vma = mm->mmap; vma; vma = vma->vm_next) {
		unsigned long size = vma->vm_end - vma->vm_start;

		if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA64].dm))
			zap_page_range(vma, vma->vm_start, size);
#ifdef CONFIG_COMPAT_VDSO
		if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA32].dm))
			zap_page_range(vma, vma->vm_start, size);
#endif
	}

	mmap_read_unlock(mm);
	return 0;
}

static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
{
	if (likely(vma->vm_mm == current->mm))
		return current->nsproxy->time_ns->vvar_page;

	/*
	 * VM_PFNMAP | VM_IO protect .fault() handler from being called
	 * through interfaces like /proc/$pid/mem or
	 * process_vm_{readv,writev}() as long as there's no .access()
	 * in special_mapping_vmops.
	 * For more details check_vma_flags() and __access_remote_vm()
	 */
	WARN(1, "vvar_page accessed remotely");

	return NULL;
}
#else
static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
{
	return NULL;
}
#endif

static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
			     struct vm_area_struct *vma, struct vm_fault *vmf)
{
	struct page *timens_page = find_timens_vvar_page(vma);
	unsigned long pfn;

	switch (vmf->pgoff) {
	case VVAR_DATA_PAGE_OFFSET:
		if (timens_page)
			pfn = page_to_pfn(timens_page);
		else
			pfn = sym_to_pfn(vdso_data);
		break;
#ifdef CONFIG_TIME_NS
	case VVAR_TIMENS_PAGE_OFFSET:
		/*
		 * If a task belongs to a time namespace then a namespace
		 * specific VVAR is mapped with the VVAR_DATA_PAGE_OFFSET and
		 * the real VVAR page is mapped with the VVAR_TIMENS_PAGE_OFFSET
		 * offset.
		 * See also the comment near timens_setup_vdso_data().
		 */
		if (!timens_page)
			return VM_FAULT_SIGBUS;
		pfn = sym_to_pfn(vdso_data);
		break;
#endif /* CONFIG_TIME_NS */
	default:
		return VM_FAULT_SIGBUS;
	}

	return vmf_insert_pfn(vma, vmf->address, pfn);
}

static int __setup_additional_pages(enum vdso_abi abi,
				    struct mm_struct *mm,
				    struct linux_binprm *bprm,
				    int uses_interp)
{
	unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
	unsigned long gp_flags = 0;
	void *ret;

	BUILD_BUG_ON(VVAR_NR_PAGES != __VVAR_PAGES);

	vdso_text_len = vdso_info[abi].vdso_pages << PAGE_SHIFT;
	/* Be sure to map the data page */
	vdso_mapping_len = vdso_text_len + VVAR_NR_PAGES * PAGE_SIZE;

	vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0);
	if (IS_ERR_VALUE(vdso_base)) {
		ret = ERR_PTR(vdso_base);
		goto up_fail;
	}

	ret = _install_special_mapping(mm, vdso_base, VVAR_NR_PAGES * PAGE_SIZE,
				       VM_READ|VM_MAYREAD|VM_PFNMAP,
				       vdso_info[abi].dm);
	if (IS_ERR(ret))
		goto up_fail;

	if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL) && system_supports_bti())
		gp_flags = VM_ARM64_BTI;

	vdso_base += VVAR_NR_PAGES * PAGE_SIZE;
	mm->context.vdso = (void *)vdso_base;
	ret = _install_special_mapping(mm, vdso_base, vdso_text_len,
				       VM_READ|VM_EXEC|gp_flags|
				       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
				       vdso_info[abi].cm);
	if (IS_ERR(ret))
		goto up_fail;

	return 0;

up_fail:
	mm->context.vdso = NULL;
	return PTR_ERR(ret);
}

#ifdef CONFIG_COMPAT
/*
 * Create and map the vectors page for AArch32 tasks.
 */
enum aarch32_map {
	AA32_MAP_VECTORS, /* kuser helpers */
	AA32_MAP_SIGPAGE,
	AA32_MAP_VVAR,
	AA32_MAP_VDSO,
};

static struct page *aarch32_vectors_page __ro_after_init;
static struct page *aarch32_sig_page __ro_after_init;

static int aarch32_sigpage_mremap(const struct vm_special_mapping *sm,
				  struct vm_area_struct *new_vma)
{
	current->mm->context.sigpage = (void *)new_vma->vm_start;

	return 0;
}

static struct vm_special_mapping aarch32_vdso_maps[] = {
	[AA32_MAP_VECTORS] = {
		.name	= "[vectors]", /* ABI */
		.pages	= &aarch32_vectors_page,
	},
	[AA32_MAP_SIGPAGE] = {
		.name	= "[sigpage]", /* ABI */
		.pages	= &aarch32_sig_page,
		.mremap	= aarch32_sigpage_mremap,
	},
	[AA32_MAP_VVAR] = {
		.name = "[vvar]",
		.fault = vvar_fault,
	},
	[AA32_MAP_VDSO] = {
		.name = "[vdso]",
		.mremap = vdso_mremap,
	},
};

static int aarch32_alloc_kuser_vdso_page(void)
{
	extern char __kuser_helper_start[], __kuser_helper_end[];
	int kuser_sz = __kuser_helper_end - __kuser_helper_start;
	unsigned long vdso_page;

	if (!IS_ENABLED(CONFIG_KUSER_HELPERS))
		return 0;

	vdso_page = get_zeroed_page(GFP_KERNEL);
	if (!vdso_page)
		return -ENOMEM;

	memcpy((void *)(vdso_page + 0x1000 - kuser_sz), __kuser_helper_start,
	       kuser_sz);
	aarch32_vectors_page = virt_to_page(vdso_page);
	return 0;
}

#define COMPAT_SIGPAGE_POISON_WORD	0xe7fddef1
static int aarch32_alloc_sigpage(void)
{
	extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];
	int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start;
	__le32 poison = cpu_to_le32(COMPAT_SIGPAGE_POISON_WORD);
	void *sigpage;

	sigpage = (void *)__get_free_page(GFP_KERNEL);
	if (!sigpage)
		return -ENOMEM;

	memset32(sigpage, (__force u32)poison, PAGE_SIZE / sizeof(poison));
	memcpy(sigpage, __aarch32_sigret_code_start, sigret_sz);
	aarch32_sig_page = virt_to_page(sigpage);
	return 0;
}

static int __init __aarch32_alloc_vdso_pages(void)
{

	if (!IS_ENABLED(CONFIG_COMPAT_VDSO))
		return 0;

	vdso_info[VDSO_ABI_AA32].dm = &aarch32_vdso_maps[AA32_MAP_VVAR];
	vdso_info[VDSO_ABI_AA32].cm = &aarch32_vdso_maps[AA32_MAP_VDSO];

	return __vdso_init(VDSO_ABI_AA32);
}

static int __init aarch32_alloc_vdso_pages(void)
{
	int ret;

	ret = __aarch32_alloc_vdso_pages();
	if (ret)
		return ret;

	ret = aarch32_alloc_sigpage();
	if (ret)
		return ret;

	return aarch32_alloc_kuser_vdso_page();
}
arch_initcall(aarch32_alloc_vdso_pages);

static int aarch32_kuser_helpers_setup(struct mm_struct *mm)
{
	void *ret;

	if (!IS_ENABLED(CONFIG_KUSER_HELPERS))
		return 0;

	/*
	 * Avoid VM_MAYWRITE for compatibility with arch/arm/, where it's
	 * not safe to CoW the page containing the CPU exception vectors.
	 */
	ret = _install_special_mapping(mm, AARCH32_VECTORS_BASE, PAGE_SIZE,
				       VM_READ | VM_EXEC |
				       VM_MAYREAD | VM_MAYEXEC,
				       &aarch32_vdso_maps[AA32_MAP_VECTORS]);

	return PTR_ERR_OR_ZERO(ret);
}

static int aarch32_sigreturn_setup(struct mm_struct *mm)
{
	unsigned long addr;
	void *ret;

	addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
	if (IS_ERR_VALUE(addr)) {
		ret = ERR_PTR(addr);
		goto out;
	}

	/*
	 * VM_MAYWRITE is required to allow gdb to Copy-on-Write and
	 * set breakpoints.
	 */
	ret = _install_special_mapping(mm, addr, PAGE_SIZE,
				       VM_READ | VM_EXEC | VM_MAYREAD |
				       VM_MAYWRITE | VM_MAYEXEC,
				       &aarch32_vdso_maps[AA32_MAP_SIGPAGE]);
	if (IS_ERR(ret))
		goto out;

	mm->context.sigpage = (void *)addr;

out:
	return PTR_ERR_OR_ZERO(ret);
}

int aarch32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
	struct mm_struct *mm = current->mm;
	int ret;

	if (mmap_write_lock_killable(mm))
		return -EINTR;

	ret = aarch32_kuser_helpers_setup(mm);
	if (ret)
		goto out;

	if (IS_ENABLED(CONFIG_COMPAT_VDSO)) {
		ret = __setup_additional_pages(VDSO_ABI_AA32, mm, bprm,
					       uses_interp);
		if (ret)
			goto out;
	}

	ret = aarch32_sigreturn_setup(mm);
out:
	mmap_write_unlock(mm);
	return ret;
}
#endif /* CONFIG_COMPAT */

enum aarch64_map {
	AA64_MAP_VVAR,
	AA64_MAP_VDSO,
};

static struct vm_special_mapping aarch64_vdso_maps[] __ro_after_init = {
	[AA64_MAP_VVAR] = {
		.name	= "[vvar]",
		.fault = vvar_fault,
	},
	[AA64_MAP_VDSO] = {
		.name	= "[vdso]",
		.mremap = vdso_mremap,
	},
};

static int __init vdso_init(void)
{
	vdso_info[VDSO_ABI_AA64].dm = &aarch64_vdso_maps[AA64_MAP_VVAR];
	vdso_info[VDSO_ABI_AA64].cm = &aarch64_vdso_maps[AA64_MAP_VDSO];

	return __vdso_init(VDSO_ABI_AA64);
}
arch_initcall(vdso_init);

int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
	struct mm_struct *mm = current->mm;
	int ret;

	if (mmap_write_lock_killable(mm))
		return -EINTR;

	ret = __setup_additional_pages(VDSO_ABI_AA64, mm, bprm, uses_interp);
	mmap_write_unlock(mm);

	return ret;
}
Commit	Line	Data
caab277b	1	// SPDX-License-Identifier: GPL-2.0-only
9031fefd	2	/*
0d747f65	3	* VDSO implementations.
9031fefd WD	4	*
	5	* Copyright (C) 2012 ARM Limited
	6	*
9031fefd WD	7	* Author: Will Deacon <will.deacon@arm.com>
	8	*/
	9
5a9e3e15	10	#include <linux/cache.h>
9031fefd WD	11	#include <linux/clocksource.h>
	12	#include <linux/elf.h>
	13	#include <linux/err.h>
	14	#include <linux/errno.h>
	15	#include <linux/gfp.h>
5a9e3e15	16	#include <linux/kernel.h>
9031fefd WD	17	#include <linux/mm.h>
	18	#include <linux/sched.h>
	19	#include <linux/signal.h>
	20	#include <linux/slab.h>
ee3cda8e	21	#include <linux/time_namespace.h>
c60b0c28	22	#include <linux/timekeeper_internal.h>
9031fefd	23	#include <linux/vmalloc.h>
28b1a824 VF	24	#include <vdso/datapage.h>
	25	#include <vdso/helpers.h>
	26	#include <vdso/vsyscall.h>
9031fefd WD	27
	28	#include <asm/cacheflush.h>
	29	#include <asm/signal32.h>
	30	#include <asm/vdso.h>
9031fefd	31
d3418f38 MR	32	enum vdso_abi {
d3418f38 MR	33	VDSO_ABI_AA64,
d3418f38	34	VDSO_ABI_AA32,
c7aa2d71	35	};
c7aa2d71	36
3503d56c AV	37	enum vvar_pages {
	38	VVAR_DATA_PAGE_OFFSET,
	39	VVAR_TIMENS_PAGE_OFFSET,
	40	VVAR_NR_PAGES,
	41	};
	42
d3418f38	43	struct vdso_abi_info {
c7aa2d71 VF	44	const char *name;
	45	const char *vdso_code_start;
	46	const char *vdso_code_end;
	47	unsigned long vdso_pages;
	48	/* Data Mapping */
	49	struct vm_special_mapping *dm;
	50	/* Code Mapping */
	51	struct vm_special_mapping *cm;
	52	};
	53
d3418f38 MR	54	static struct vdso_abi_info vdso_info[] __ro_after_init = {
d3418f38 MR	55	[VDSO_ABI_AA64] = {
c7aa2d71 VF	56	.name = "vdso",
	57	.vdso_code_start = vdso_start,
	58	.vdso_code_end = vdso_end,
	59	},
7c1deeeb	60	#ifdef CONFIG_COMPAT_VDSO
d3418f38	61	[VDSO_ABI_AA32] = {
7c1deeeb VF	62	.name = "vdso32",
	63	.vdso_code_start = vdso32_start,
	64	.vdso_code_end = vdso32_end,
	65	},
	66	#endif /* CONFIG_COMPAT_VDSO */
c7aa2d71	67	};
9031fefd WD	68
	69	/*
	70	* The vDSO data page.
	71	*/
	72	static union {
28b1a824	73	struct vdso_data data[CS_BASES];
9031fefd WD	74	u8 page[PAGE_SIZE];
9031fefd WD	75	} vdso_data_store __page_aligned_data;
28b1a824	76	struct vdso_data *vdso_data = vdso_data_store.data;
9031fefd	77
871402e0 DS	78	static int vdso_mremap(const struct vm_special_mapping *sm,
871402e0 DS	79	struct vm_area_struct *new_vma)
c7aa2d71	80	{
c7aa2d71 VF	81	current->mm->context.vdso = (void *)new_vma->vm_start;
	82
	83	return 0;
	84	}
	85
a7dcf58a	86	static int __init __vdso_init(enum vdso_abi abi)
c7aa2d71 VF	87	{
	88	int i;
	89	struct page **vdso_pagelist;
	90	unsigned long pfn;
	91
d3418f38	92	if (memcmp(vdso_info[abi].vdso_code_start, "\177ELF", 4)) {
c7aa2d71 VF	93	pr_err("vDSO is not a valid ELF object!\n");
	94	return -EINVAL;
	95	}
	96
d3418f38 MR	97	vdso_info[abi].vdso_pages = (
	98	vdso_info[abi].vdso_code_end -
	99	vdso_info[abi].vdso_code_start) >>
c7aa2d71 VF	100	PAGE_SHIFT;
c7aa2d71 VF	101
d53b5c01	102	vdso_pagelist = kcalloc(vdso_info[abi].vdso_pages,
c7aa2d71 VF	103	sizeof(struct page *),
	104	GFP_KERNEL);
	105	if (vdso_pagelist == NULL)
	106	return -ENOMEM;
	107
c7aa2d71	108	/* Grab the vDSO code pages. */
d3418f38	109	pfn = sym_to_pfn(vdso_info[abi].vdso_code_start);
c7aa2d71	110
d3418f38	111	for (i = 0; i < vdso_info[abi].vdso_pages; i++)
d53b5c01	112	vdso_pagelist[i] = pfn_to_page(pfn + i);
c7aa2d71	113
d53b5c01	114	vdso_info[abi].cm->pages = vdso_pagelist;
c7aa2d71 VF	115
	116	return 0;
	117	}
	118
1b6867d2	119	#ifdef CONFIG_TIME_NS
3503d56c AV	120	struct vdso_data arch_get_vdso_data(void vvar_page)
	121	{
	122	return (struct vdso_data *)(vvar_page);
	123	}
	124
1b6867d2 AV	125	/*
	126	* The vvar mapping contains data for a specific time namespace, so when a task
	127	* changes namespace we must unmap its vvar data for the old namespace.
	128	* Subsequent faults will map in data for the new namespace.
	129	*
	130	* For more details see timens_setup_vdso_data().
	131	*/
	132	int vdso_join_timens(struct task_struct task, struct time_namespace ns)
	133	{
	134	struct mm_struct *mm = task->mm;
	135	struct vm_area_struct *vma;
	136
	137	mmap_read_lock(mm);
	138
	139	for (vma = mm->mmap; vma; vma = vma->vm_next) {
	140	unsigned long size = vma->vm_end - vma->vm_start;
	141
	142	if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA64].dm))
	143	zap_page_range(vma, vma->vm_start, size);
	144	#ifdef CONFIG_COMPAT_VDSO
	145	if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA32].dm))
	146	zap_page_range(vma, vma->vm_start, size);
	147	#endif
	148	}
	149
	150	mmap_read_unlock(mm);
	151	return 0;
	152	}
ee3cda8e AV	153
	154	static struct page find_timens_vvar_page(struct vm_area_struct vma)
	155	{
	156	if (likely(vma->vm_mm == current->mm))
	157	return current->nsproxy->time_ns->vvar_page;
	158
	159	/*
	160	* VM_PFNMAP \| VM_IO protect .fault() handler from being called
	161	* through interfaces like /proc/$pid/mem or
	162	* process_vm_{readv,writev}() as long as there's no .access()
	163	* in special_mapping_vmops.
	164	* For more details check_vma_flags() and __access_remote_vm()
	165	*/
	166	WARN(1, "vvar_page accessed remotely");
	167
	168	return NULL;
	169	}
	170	#else
	171	static struct page find_timens_vvar_page(struct vm_area_struct vma)
	172	{
	173	return NULL;
	174	}
1b6867d2 AV	175	#endif
1b6867d2 AV	176
d53b5c01 AV	177	static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
	178	struct vm_area_struct vma, struct vm_fault vmf)
	179	{
ee3cda8e AV	180	struct page *timens_page = find_timens_vvar_page(vma);
	181	unsigned long pfn;
	182
	183	switch (vmf->pgoff) {
	184	case VVAR_DATA_PAGE_OFFSET:
	185	if (timens_page)
	186	pfn = page_to_pfn(timens_page);
	187	else
	188	pfn = sym_to_pfn(vdso_data);
	189	break;
	190	#ifdef CONFIG_TIME_NS
	191	case VVAR_TIMENS_PAGE_OFFSET:
	192	/*
	193	* If a task belongs to a time namespace then a namespace
	194	* specific VVAR is mapped with the VVAR_DATA_PAGE_OFFSET and
	195	* the real VVAR page is mapped with the VVAR_TIMENS_PAGE_OFFSET
	196	* offset.
	197	* See also the comment near timens_setup_vdso_data().
	198	*/
	199	if (!timens_page)
	200	return VM_FAULT_SIGBUS;
	201	pfn = sym_to_pfn(vdso_data);
	202	break;
	203	#endif /* CONFIG_TIME_NS */
	204	default:
	205	return VM_FAULT_SIGBUS;
	206	}
	207
	208	return vmf_insert_pfn(vma, vmf->address, pfn);
d53b5c01 AV	209	}
d53b5c01 AV	210
d3418f38	211	static int __setup_additional_pages(enum vdso_abi abi,
c7aa2d71 VF	212	struct mm_struct *mm,
	213	struct linux_binprm *bprm,
	214	int uses_interp)
	215	{
	216	unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
bf740a90	217	unsigned long gp_flags = 0;
c7aa2d71 VF	218	void *ret;
c7aa2d71 VF	219
3503d56c AV	220	BUILD_BUG_ON(VVAR_NR_PAGES != __VVAR_PAGES);
3503d56c AV	221
d3418f38	222	vdso_text_len = vdso_info[abi].vdso_pages << PAGE_SHIFT;
c7aa2d71	223	/* Be sure to map the data page */
3503d56c	224	vdso_mapping_len = vdso_text_len + VVAR_NR_PAGES * PAGE_SIZE;
c7aa2d71 VF	225
	226	vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0);
	227	if (IS_ERR_VALUE(vdso_base)) {
	228	ret = ERR_PTR(vdso_base);
	229	goto up_fail;
	230	}
	231
3503d56c	232	ret = _install_special_mapping(mm, vdso_base, VVAR_NR_PAGES * PAGE_SIZE,
d53b5c01	233	VM_READ\|VM_MAYREAD\|VM_PFNMAP,
d3418f38	234	vdso_info[abi].dm);
c7aa2d71 VF	235	if (IS_ERR(ret))
	236	goto up_fail;
	237
bf740a90 MB	238	if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL) && system_supports_bti())
	239	gp_flags = VM_ARM64_BTI;
	240
3503d56c	241	vdso_base += VVAR_NR_PAGES * PAGE_SIZE;
c7aa2d71 VF	242	mm->context.vdso = (void *)vdso_base;
c7aa2d71 VF	243	ret = _install_special_mapping(mm, vdso_base, vdso_text_len,
bf740a90	244	VM_READ\|VM_EXEC\|gp_flags\|
c7aa2d71	245	VM_MAYREAD\|VM_MAYWRITE\|VM_MAYEXEC,
d3418f38	246	vdso_info[abi].cm);
c7aa2d71 VF	247	if (IS_ERR(ret))
	248	goto up_fail;
	249
	250	return 0;
	251
	252	up_fail:
	253	mm->context.vdso = NULL;
	254	return PTR_ERR(ret);
	255	}
	256
9031fefd WD	257	#ifdef CONFIG_COMPAT
	258	/*
	259	* Create and map the vectors page for AArch32 tasks.
	260	*/
1d09094a MR	261	enum aarch32_map {
1d09094a MR	262	AA32_MAP_VECTORS, /* kuser helpers */
0cbc2659	263	AA32_MAP_SIGPAGE,
1d09094a MR	264	AA32_MAP_VVAR,
1d09094a MR	265	AA32_MAP_VDSO,
1d09094a	266	};
74fc72e7 MR	267
74fc72e7 MR	268	static struct page *aarch32_vectors_page __ro_after_init;
74fc72e7	269	static struct page *aarch32_sig_page __ro_after_init;
74fc72e7	270
7adbf10e WD	271	static int aarch32_sigpage_mremap(const struct vm_special_mapping *sm,
	272	struct vm_area_struct *new_vma)
	273	{
	274	current->mm->context.sigpage = (void *)new_vma->vm_start;
	275
	276	return 0;
	277	}
	278
1d09094a MR	279	static struct vm_special_mapping aarch32_vdso_maps[] = {
1d09094a MR	280	[AA32_MAP_VECTORS] = {
0d747f65	281	.name = "[vectors]", /* ABI */
74fc72e7	282	.pages = &aarch32_vectors_page,
0d747f65	283	},
0cbc2659 WD	284	[AA32_MAP_SIGPAGE] = {
	285	.name = "[sigpage]", /* ABI */
	286	.pages = &aarch32_sig_page,
7adbf10e	287	.mremap = aarch32_sigpage_mremap,
0cbc2659	288	},
1d09094a	289	[AA32_MAP_VVAR] = {
7c1deeeb	290	.name = "[vvar]",
d53b5c01	291	.fault = vvar_fault,
7c1deeeb	292	},
1d09094a	293	[AA32_MAP_VDSO] = {
7c1deeeb	294	.name = "[vdso]",
871402e0	295	.mremap = vdso_mremap,
7c1deeeb	296	},
0d747f65	297	};
9031fefd	298
1255a734	299	static int aarch32_alloc_kuser_vdso_page(void)
9031fefd WD	300	{
	301	extern char __kuser_helper_start[], __kuser_helper_end[];
	302	int kuser_sz = __kuser_helper_end - __kuser_helper_start;
1255a734	303	unsigned long vdso_page;
9031fefd	304
af1b3cf2 VF	305	if (!IS_ENABLED(CONFIG_KUSER_HELPERS))
	306	return 0;
	307
7cd6ca1d	308	vdso_page = get_zeroed_page(GFP_KERNEL);
1255a734	309	if (!vdso_page)
0d747f65	310	return -ENOMEM;
9031fefd	311
1255a734	312	memcpy((void *)(vdso_page + 0x1000 - kuser_sz), __kuser_helper_start,
0d747f65	313	kuser_sz);
74fc72e7	314	aarch32_vectors_page = virt_to_page(vdso_page);
1255a734 VF	315	return 0;
	316	}
	317
6e554abd	318	#define COMPAT_SIGPAGE_POISON_WORD 0xe7fddef1
a39060b0	319	static int aarch32_alloc_sigpage(void)
1255a734 VF	320	{
	321	extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];
	322	int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start;
6e554abd WD	323	__le32 poison = cpu_to_le32(COMPAT_SIGPAGE_POISON_WORD);
6e554abd WD	324	void *sigpage;
9031fefd	325
6e554abd	326	sigpage = (void *)__get_free_page(GFP_KERNEL);
1255a734 VF	327	if (!sigpage)
1255a734 VF	328	return -ENOMEM;
0d747f65	329
6e554abd WD	330	memset32(sigpage, (__force u32)poison, PAGE_SIZE / sizeof(poison));
6e554abd WD	331	memcpy(sigpage, __aarch32_sigret_code_start, sigret_sz);
74fc72e7	332	aarch32_sig_page = virt_to_page(sigpage);
a39060b0 WD	333	return 0;
a39060b0 WD	334	}
9031fefd	335
a7dcf58a	336	static int __init __aarch32_alloc_vdso_pages(void)
a39060b0	337	{
0cbc2659 WD	338
	339	if (!IS_ENABLED(CONFIG_COMPAT_VDSO))
	340	return 0;
	341
a39060b0 WD	342	vdso_info[VDSO_ABI_AA32].dm = &aarch32_vdso_maps[AA32_MAP_VVAR];
a39060b0 WD	343	vdso_info[VDSO_ABI_AA32].cm = &aarch32_vdso_maps[AA32_MAP_VDSO];
9031fefd	344
a39060b0	345	return __vdso_init(VDSO_ABI_AA32);
9031fefd	346	}
7c1deeeb VF	347
	348	static int __init aarch32_alloc_vdso_pages(void)
	349	{
a39060b0 WD	350	int ret;
a39060b0 WD	351
a39060b0 WD	352	ret = __aarch32_alloc_vdso_pages();
	353	if (ret)
	354	return ret;
a39060b0 WD	355
	356	ret = aarch32_alloc_sigpage();
	357	if (ret)
	358	return ret;
	359
	360	return aarch32_alloc_kuser_vdso_page();
7c1deeeb	361	}
0d747f65	362	arch_initcall(aarch32_alloc_vdso_pages);
9031fefd	363
0d747f65	364	static int aarch32_kuser_helpers_setup(struct mm_struct *mm)
9031fefd	365	{
0d747f65	366	void *ret;
2fea7f6c	367
af1b3cf2 VF	368	if (!IS_ENABLED(CONFIG_KUSER_HELPERS))
	369	return 0;
	370
0d747f65 VF	371	/*
	372	* Avoid VM_MAYWRITE for compatibility with arch/arm/, where it's
	373	* not safe to CoW the page containing the CPU exception vectors.
	374	*/
	375	ret = _install_special_mapping(mm, AARCH32_VECTORS_BASE, PAGE_SIZE,
	376	VM_READ \| VM_EXEC \|
	377	VM_MAYREAD \| VM_MAYEXEC,
1d09094a	378	&aarch32_vdso_maps[AA32_MAP_VECTORS]);
0d747f65 VF	379
	380	return PTR_ERR_OR_ZERO(ret);
	381	}
	382
	383	static int aarch32_sigreturn_setup(struct mm_struct *mm)
	384	{
	385	unsigned long addr;
2fea7f6c	386	void *ret;
9031fefd	387
0d747f65 VF	388	addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
	389	if (IS_ERR_VALUE(addr)) {
	390	ret = ERR_PTR(addr);
	391	goto out;
	392	}
9031fefd	393
0d747f65 VF	394	/*
	395	* VM_MAYWRITE is required to allow gdb to Copy-on-Write and
	396	* set breakpoints.
	397	*/
2fea7f6c	398	ret = _install_special_mapping(mm, addr, PAGE_SIZE,
0d747f65 VF	399	VM_READ \| VM_EXEC \| VM_MAYREAD \|
0d747f65 VF	400	VM_MAYWRITE \| VM_MAYEXEC,
1d09094a	401	&aarch32_vdso_maps[AA32_MAP_SIGPAGE]);
0d747f65 VF	402	if (IS_ERR(ret))
0d747f65 VF	403	goto out;
9031fefd	404
a39060b0	405	mm->context.sigpage = (void *)addr;
9031fefd	406
0d747f65	407	out:
2fea7f6c	408	return PTR_ERR_OR_ZERO(ret);
9031fefd	409	}
0d747f65 VF	410
	411	int aarch32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
	412	{
	413	struct mm_struct *mm = current->mm;
	414	int ret;
	415
d8ed45c5	416	if (mmap_write_lock_killable(mm))
0d747f65 VF	417	return -EINTR;
	418
	419	ret = aarch32_kuser_helpers_setup(mm);
	420	if (ret)
	421	goto out;
	422
0cbc2659	423	if (IS_ENABLED(CONFIG_COMPAT_VDSO)) {
2a30aca8	424	ret = __setup_additional_pages(VDSO_ABI_AA32, mm, bprm,
0cbc2659 WD	425	uses_interp);
	426	if (ret)
	427	goto out;
	428	}
0d747f65	429
a39060b0	430	ret = aarch32_sigreturn_setup(mm);
0d747f65	431	out:
d8ed45c5	432	mmap_write_unlock(mm);
0d747f65 VF	433	return ret;
0d747f65 VF	434	}
9031fefd WD	435	#endif /* CONFIG_COMPAT */
9031fefd WD	436
1d09094a MR	437	enum aarch64_map {
	438	AA64_MAP_VVAR,
	439	AA64_MAP_VDSO,
	440	};
	441
	442	static struct vm_special_mapping aarch64_vdso_maps[] __ro_after_init = {
	443	[AA64_MAP_VVAR] = {
5a9e3e15	444	.name = "[vvar]",
d53b5c01	445	.fault = vvar_fault,
5a9e3e15	446	},
1d09094a	447	[AA64_MAP_VDSO] = {
5a9e3e15	448	.name = "[vdso]",
73958695	449	.mremap = vdso_mremap,
5a9e3e15 JZ	450	},
5a9e3e15 JZ	451	};
2fea7f6c	452
9031fefd WD	453	static int __init vdso_init(void)
9031fefd WD	454	{
1d09094a MR	455	vdso_info[VDSO_ABI_AA64].dm = &aarch64_vdso_maps[AA64_MAP_VVAR];
1d09094a MR	456	vdso_info[VDSO_ABI_AA64].cm = &aarch64_vdso_maps[AA64_MAP_VDSO];
601255ae	457
d3418f38	458	return __vdso_init(VDSO_ABI_AA64);
9031fefd WD	459	}
	460	arch_initcall(vdso_init);
	461
2a30aca8	462	int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
9031fefd WD	463	{
9031fefd WD	464	struct mm_struct *mm = current->mm;
c7aa2d71	465	int ret;
9031fefd	466
d8ed45c5	467	if (mmap_write_lock_killable(mm))
69048176	468	return -EINTR;
9031fefd	469
2a30aca8	470	ret = __setup_additional_pages(VDSO_ABI_AA64, mm, bprm, uses_interp);
d8ed45c5	471	mmap_write_unlock(mm);
9031fefd	472
c7aa2d71	473	return ret;
9031fefd	474	}