[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 vdso_data_store 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;
	VMA_ITERATOR(vmi, mm, 0);

	mmap_read_lock(mm);

	for_each_vma(vmi, vma) {
		if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA64].dm))
			zap_vma_pages(vma);
#ifdef CONFIG_COMPAT_VDSO
		if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA32].dm))
			zap_vma_pages(vma);
#endif
	}

	mmap_read_unlock(mm);
	return 0;
}
#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 (system_supports_bti_kernel())
		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((void *)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	*/
d0fba048	72	static union vdso_data_store vdso_data_store __page_aligned_data;
28b1a824	73	struct vdso_data *vdso_data = vdso_data_store.data;
9031fefd	74
871402e0 DS	75	static int vdso_mremap(const struct vm_special_mapping *sm,
871402e0 DS	76	struct vm_area_struct *new_vma)
c7aa2d71	77	{
c7aa2d71 VF	78	current->mm->context.vdso = (void *)new_vma->vm_start;
	79
	80	return 0;
	81	}
	82
a7dcf58a	83	static int __init __vdso_init(enum vdso_abi abi)
c7aa2d71 VF	84	{
	85	int i;
	86	struct page **vdso_pagelist;
	87	unsigned long pfn;
	88
d3418f38	89	if (memcmp(vdso_info[abi].vdso_code_start, "\177ELF", 4)) {
c7aa2d71 VF	90	pr_err("vDSO is not a valid ELF object!\n");
	91	return -EINVAL;
	92	}
	93
d3418f38 MR	94	vdso_info[abi].vdso_pages = (
	95	vdso_info[abi].vdso_code_end -
	96	vdso_info[abi].vdso_code_start) >>
c7aa2d71 VF	97	PAGE_SHIFT;
c7aa2d71 VF	98
d53b5c01	99	vdso_pagelist = kcalloc(vdso_info[abi].vdso_pages,
c7aa2d71 VF	100	sizeof(struct page *),
	101	GFP_KERNEL);
	102	if (vdso_pagelist == NULL)
	103	return -ENOMEM;
	104
c7aa2d71	105	/* Grab the vDSO code pages. */
d3418f38	106	pfn = sym_to_pfn(vdso_info[abi].vdso_code_start);
c7aa2d71	107
d3418f38	108	for (i = 0; i < vdso_info[abi].vdso_pages; i++)
d53b5c01	109	vdso_pagelist[i] = pfn_to_page(pfn + i);
c7aa2d71	110
d53b5c01	111	vdso_info[abi].cm->pages = vdso_pagelist;
c7aa2d71 VF	112
	113	return 0;
	114	}
	115
1b6867d2	116	#ifdef CONFIG_TIME_NS
3503d56c AV	117	struct vdso_data arch_get_vdso_data(void vvar_page)
	118	{
	119	return (struct vdso_data *)(vvar_page);
	120	}
	121
1b6867d2 AV	122	/*
	123	* The vvar mapping contains data for a specific time namespace, so when a task
	124	* changes namespace we must unmap its vvar data for the old namespace.
	125	* Subsequent faults will map in data for the new namespace.
	126	*
	127	* For more details see timens_setup_vdso_data().
	128	*/
	129	int vdso_join_timens(struct task_struct task, struct time_namespace ns)
	130	{
	131	struct mm_struct *mm = task->mm;
	132	struct vm_area_struct *vma;
de2b84d2	133	VMA_ITERATOR(vmi, mm, 0);
1b6867d2 AV	134
	135	mmap_read_lock(mm);
	136
de2b84d2	137	for_each_vma(vmi, vma) {
1b6867d2	138	if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA64].dm))
e9adcfec	139	zap_vma_pages(vma);
1b6867d2 AV	140	#ifdef CONFIG_COMPAT_VDSO
1b6867d2 AV	141	if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA32].dm))
e9adcfec	142	zap_vma_pages(vma);
1b6867d2 AV	143	#endif
	144	}
	145
	146	mmap_read_unlock(mm);
	147	return 0;
	148	}
	149	#endif
	150
d53b5c01 AV	151	static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
	152	struct vm_area_struct vma, struct vm_fault vmf)
	153	{
ee3cda8e AV	154	struct page *timens_page = find_timens_vvar_page(vma);
	155	unsigned long pfn;
	156
	157	switch (vmf->pgoff) {
	158	case VVAR_DATA_PAGE_OFFSET:
	159	if (timens_page)
	160	pfn = page_to_pfn(timens_page);
	161	else
	162	pfn = sym_to_pfn(vdso_data);
	163	break;
	164	#ifdef CONFIG_TIME_NS
	165	case VVAR_TIMENS_PAGE_OFFSET:
	166	/*
	167	* If a task belongs to a time namespace then a namespace
	168	* specific VVAR is mapped with the VVAR_DATA_PAGE_OFFSET and
	169	* the real VVAR page is mapped with the VVAR_TIMENS_PAGE_OFFSET
	170	* offset.
	171	* See also the comment near timens_setup_vdso_data().
	172	*/
	173	if (!timens_page)
	174	return VM_FAULT_SIGBUS;
	175	pfn = sym_to_pfn(vdso_data);
	176	break;
	177	#endif /* CONFIG_TIME_NS */
	178	default:
	179	return VM_FAULT_SIGBUS;
	180	}
	181
	182	return vmf_insert_pfn(vma, vmf->address, pfn);
d53b5c01 AV	183	}
d53b5c01 AV	184
d3418f38	185	static int __setup_additional_pages(enum vdso_abi abi,
c7aa2d71 VF	186	struct mm_struct *mm,
	187	struct linux_binprm *bprm,
	188	int uses_interp)
	189	{
	190	unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
bf740a90	191	unsigned long gp_flags = 0;
c7aa2d71 VF	192	void *ret;
c7aa2d71 VF	193
3503d56c AV	194	BUILD_BUG_ON(VVAR_NR_PAGES != __VVAR_PAGES);
3503d56c AV	195
d3418f38	196	vdso_text_len = vdso_info[abi].vdso_pages << PAGE_SHIFT;
c7aa2d71	197	/* Be sure to map the data page */
3503d56c	198	vdso_mapping_len = vdso_text_len + VVAR_NR_PAGES * PAGE_SIZE;
c7aa2d71 VF	199
	200	vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0);
	201	if (IS_ERR_VALUE(vdso_base)) {
	202	ret = ERR_PTR(vdso_base);
	203	goto up_fail;
	204	}
	205
3503d56c	206	ret = _install_special_mapping(mm, vdso_base, VVAR_NR_PAGES * PAGE_SIZE,
d53b5c01	207	VM_READ\|VM_MAYREAD\|VM_PFNMAP,
d3418f38	208	vdso_info[abi].dm);
c7aa2d71 VF	209	if (IS_ERR(ret))
	210	goto up_fail;
	211
bbbb6577	212	if (system_supports_bti_kernel())
bf740a90 MB	213	gp_flags = VM_ARM64_BTI;
bf740a90 MB	214
3503d56c	215	vdso_base += VVAR_NR_PAGES * PAGE_SIZE;
c7aa2d71 VF	216	mm->context.vdso = (void *)vdso_base;
c7aa2d71 VF	217	ret = _install_special_mapping(mm, vdso_base, vdso_text_len,
bf740a90	218	VM_READ\|VM_EXEC\|gp_flags\|
c7aa2d71	219	VM_MAYREAD\|VM_MAYWRITE\|VM_MAYEXEC,
d3418f38	220	vdso_info[abi].cm);
c7aa2d71 VF	221	if (IS_ERR(ret))
	222	goto up_fail;
	223
	224	return 0;
	225
	226	up_fail:
	227	mm->context.vdso = NULL;
	228	return PTR_ERR(ret);
	229	}
	230
9031fefd WD	231	#ifdef CONFIG_COMPAT
	232	/*
	233	* Create and map the vectors page for AArch32 tasks.
	234	*/
1d09094a MR	235	enum aarch32_map {
1d09094a MR	236	AA32_MAP_VECTORS, /* kuser helpers */
0cbc2659	237	AA32_MAP_SIGPAGE,
1d09094a MR	238	AA32_MAP_VVAR,
1d09094a MR	239	AA32_MAP_VDSO,
1d09094a	240	};
74fc72e7 MR	241
74fc72e7 MR	242	static struct page *aarch32_vectors_page __ro_after_init;
74fc72e7	243	static struct page *aarch32_sig_page __ro_after_init;
74fc72e7	244
7adbf10e WD	245	static int aarch32_sigpage_mremap(const struct vm_special_mapping *sm,
	246	struct vm_area_struct *new_vma)
	247	{
	248	current->mm->context.sigpage = (void *)new_vma->vm_start;
	249
	250	return 0;
	251	}
	252
1d09094a MR	253	static struct vm_special_mapping aarch32_vdso_maps[] = {
1d09094a MR	254	[AA32_MAP_VECTORS] = {
0d747f65	255	.name = "[vectors]", /* ABI */
74fc72e7	256	.pages = &aarch32_vectors_page,
0d747f65	257	},
0cbc2659 WD	258	[AA32_MAP_SIGPAGE] = {
	259	.name = "[sigpage]", /* ABI */
	260	.pages = &aarch32_sig_page,
7adbf10e	261	.mremap = aarch32_sigpage_mremap,
0cbc2659	262	},
1d09094a	263	[AA32_MAP_VVAR] = {
7c1deeeb	264	.name = "[vvar]",
d53b5c01	265	.fault = vvar_fault,
7c1deeeb	266	},
1d09094a	267	[AA32_MAP_VDSO] = {
7c1deeeb	268	.name = "[vdso]",
871402e0	269	.mremap = vdso_mremap,
7c1deeeb	270	},
0d747f65	271	};
9031fefd	272
1255a734	273	static int aarch32_alloc_kuser_vdso_page(void)
9031fefd WD	274	{
	275	extern char __kuser_helper_start[], __kuser_helper_end[];
	276	int kuser_sz = __kuser_helper_end - __kuser_helper_start;
1255a734	277	unsigned long vdso_page;
9031fefd	278
af1b3cf2 VF	279	if (!IS_ENABLED(CONFIG_KUSER_HELPERS))
	280	return 0;
	281
7cd6ca1d	282	vdso_page = get_zeroed_page(GFP_KERNEL);
1255a734	283	if (!vdso_page)
0d747f65	284	return -ENOMEM;
9031fefd	285
1255a734	286	memcpy((void *)(vdso_page + 0x1000 - kuser_sz), __kuser_helper_start,
0d747f65	287	kuser_sz);
b0abde80	288	aarch32_vectors_page = virt_to_page((void *)vdso_page);
1255a734 VF	289	return 0;
	290	}
	291
6e554abd	292	#define COMPAT_SIGPAGE_POISON_WORD 0xe7fddef1
a39060b0	293	static int aarch32_alloc_sigpage(void)
1255a734 VF	294	{
	295	extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];
	296	int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start;
6e554abd WD	297	__le32 poison = cpu_to_le32(COMPAT_SIGPAGE_POISON_WORD);
6e554abd WD	298	void *sigpage;
9031fefd	299
6e554abd	300	sigpage = (void *)__get_free_page(GFP_KERNEL);
1255a734 VF	301	if (!sigpage)
1255a734 VF	302	return -ENOMEM;
0d747f65	303
6e554abd WD	304	memset32(sigpage, (__force u32)poison, PAGE_SIZE / sizeof(poison));
6e554abd WD	305	memcpy(sigpage, __aarch32_sigret_code_start, sigret_sz);
74fc72e7	306	aarch32_sig_page = virt_to_page(sigpage);
a39060b0 WD	307	return 0;
a39060b0 WD	308	}
9031fefd	309
a7dcf58a	310	static int __init __aarch32_alloc_vdso_pages(void)
a39060b0	311	{
0cbc2659 WD	312
	313	if (!IS_ENABLED(CONFIG_COMPAT_VDSO))
	314	return 0;
	315
a39060b0 WD	316	vdso_info[VDSO_ABI_AA32].dm = &aarch32_vdso_maps[AA32_MAP_VVAR];
a39060b0 WD	317	vdso_info[VDSO_ABI_AA32].cm = &aarch32_vdso_maps[AA32_MAP_VDSO];
9031fefd	318
a39060b0	319	return __vdso_init(VDSO_ABI_AA32);
9031fefd	320	}
7c1deeeb VF	321
	322	static int __init aarch32_alloc_vdso_pages(void)
	323	{
a39060b0 WD	324	int ret;
a39060b0 WD	325
a39060b0 WD	326	ret = __aarch32_alloc_vdso_pages();
	327	if (ret)
	328	return ret;
a39060b0 WD	329
	330	ret = aarch32_alloc_sigpage();
	331	if (ret)
	332	return ret;
	333
	334	return aarch32_alloc_kuser_vdso_page();
7c1deeeb	335	}
0d747f65	336	arch_initcall(aarch32_alloc_vdso_pages);
9031fefd	337
0d747f65	338	static int aarch32_kuser_helpers_setup(struct mm_struct *mm)
9031fefd	339	{
0d747f65	340	void *ret;
2fea7f6c	341
af1b3cf2 VF	342	if (!IS_ENABLED(CONFIG_KUSER_HELPERS))
	343	return 0;
	344
0d747f65 VF	345	/*
	346	* Avoid VM_MAYWRITE for compatibility with arch/arm/, where it's
	347	* not safe to CoW the page containing the CPU exception vectors.
	348	*/
	349	ret = _install_special_mapping(mm, AARCH32_VECTORS_BASE, PAGE_SIZE,
	350	VM_READ \| VM_EXEC \|
	351	VM_MAYREAD \| VM_MAYEXEC,
1d09094a	352	&aarch32_vdso_maps[AA32_MAP_VECTORS]);
0d747f65 VF	353
	354	return PTR_ERR_OR_ZERO(ret);
	355	}
	356
	357	static int aarch32_sigreturn_setup(struct mm_struct *mm)
	358	{
	359	unsigned long addr;
2fea7f6c	360	void *ret;
9031fefd	361
0d747f65 VF	362	addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
	363	if (IS_ERR_VALUE(addr)) {
	364	ret = ERR_PTR(addr);
	365	goto out;
	366	}
9031fefd	367
0d747f65 VF	368	/*
	369	* VM_MAYWRITE is required to allow gdb to Copy-on-Write and
	370	* set breakpoints.
	371	*/
2fea7f6c	372	ret = _install_special_mapping(mm, addr, PAGE_SIZE,
0d747f65 VF	373	VM_READ \| VM_EXEC \| VM_MAYREAD \|
0d747f65 VF	374	VM_MAYWRITE \| VM_MAYEXEC,
1d09094a	375	&aarch32_vdso_maps[AA32_MAP_SIGPAGE]);
0d747f65 VF	376	if (IS_ERR(ret))
0d747f65 VF	377	goto out;
9031fefd	378
a39060b0	379	mm->context.sigpage = (void *)addr;
9031fefd	380
0d747f65	381	out:
2fea7f6c	382	return PTR_ERR_OR_ZERO(ret);
9031fefd	383	}
0d747f65 VF	384
	385	int aarch32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
	386	{
	387	struct mm_struct *mm = current->mm;
	388	int ret;
	389
d8ed45c5	390	if (mmap_write_lock_killable(mm))
0d747f65 VF	391	return -EINTR;
	392
	393	ret = aarch32_kuser_helpers_setup(mm);
	394	if (ret)
	395	goto out;
	396
0cbc2659	397	if (IS_ENABLED(CONFIG_COMPAT_VDSO)) {
2a30aca8	398	ret = __setup_additional_pages(VDSO_ABI_AA32, mm, bprm,
0cbc2659 WD	399	uses_interp);
	400	if (ret)
	401	goto out;
	402	}
0d747f65	403
a39060b0	404	ret = aarch32_sigreturn_setup(mm);
0d747f65	405	out:
d8ed45c5	406	mmap_write_unlock(mm);
0d747f65 VF	407	return ret;
0d747f65 VF	408	}
9031fefd WD	409	#endif /* CONFIG_COMPAT */
9031fefd WD	410
1d09094a MR	411	enum aarch64_map {
	412	AA64_MAP_VVAR,
	413	AA64_MAP_VDSO,
	414	};
	415
	416	static struct vm_special_mapping aarch64_vdso_maps[] __ro_after_init = {
	417	[AA64_MAP_VVAR] = {
5a9e3e15	418	.name = "[vvar]",
d53b5c01	419	.fault = vvar_fault,
5a9e3e15	420	},
1d09094a	421	[AA64_MAP_VDSO] = {
5a9e3e15	422	.name = "[vdso]",
73958695	423	.mremap = vdso_mremap,
5a9e3e15 JZ	424	},
5a9e3e15 JZ	425	};
2fea7f6c	426
9031fefd WD	427	static int __init vdso_init(void)
9031fefd WD	428	{
1d09094a MR	429	vdso_info[VDSO_ABI_AA64].dm = &aarch64_vdso_maps[AA64_MAP_VVAR];
1d09094a MR	430	vdso_info[VDSO_ABI_AA64].cm = &aarch64_vdso_maps[AA64_MAP_VDSO];
601255ae	431
d3418f38	432	return __vdso_init(VDSO_ABI_AA64);
9031fefd WD	433	}
	434	arch_initcall(vdso_init);
	435
2a30aca8	436	int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
9031fefd WD	437	{
9031fefd WD	438	struct mm_struct *mm = current->mm;
c7aa2d71	439	int ret;
9031fefd	440
d8ed45c5	441	if (mmap_write_lock_killable(mm))
69048176	442	return -EINTR;
9031fefd	443
2a30aca8	444	ret = __setup_additional_pages(VDSO_ABI_AA64, mm, bprm, uses_interp);
d8ed45c5	445	mmap_write_unlock(mm);
9031fefd	446
c7aa2d71	447	return ret;
9031fefd	448	}