[thirdparty/kernel/linux.git] / arch / x86 / entry / vdso / vma.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2007 Andi Kleen, SUSE Labs.
 *
 * This contains most of the x86 vDSO kernel-side code.
 */
#include <linux/mm.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/random.h>
#include <linux/elf.h>
#include <linux/cpu.h>
#include <linux/ptrace.h>
#include <linux/time_namespace.h>

#include <asm/pvclock.h>
#include <asm/vgtod.h>
#include <asm/proto.h>
#include <asm/vdso.h>
#include <asm/vvar.h>
#include <asm/tlb.h>
#include <asm/page.h>
#include <asm/desc.h>
#include <asm/cpufeature.h>
#include <clocksource/hyperv_timer.h>

#undef _ASM_X86_VVAR_H
#define EMIT_VVAR(name, offset)	\
	const size_t name ## _offset = offset;
#include <asm/vvar.h>

struct vdso_data *arch_get_vdso_data(void *vvar_page)
{
	return (struct vdso_data *)(vvar_page + _vdso_data_offset);
}
#undef EMIT_VVAR

unsigned int vclocks_used __read_mostly;

#if defined(CONFIG_X86_64)
unsigned int __read_mostly vdso64_enabled = 1;
#endif

int __init init_vdso_image(const struct vdso_image *image)
{
	BUILD_BUG_ON(VDSO_CLOCKMODE_MAX >= 32);
	BUG_ON(image->size % PAGE_SIZE != 0);

	apply_alternatives((struct alt_instr *)(image->data + image->alt),
			   (struct alt_instr *)(image->data + image->alt +
						image->alt_len));

	return 0;
}

static const struct vm_special_mapping vvar_mapping;
struct linux_binprm;

static vm_fault_t vdso_fault(const struct vm_special_mapping *sm,
		      struct vm_area_struct *vma, struct vm_fault *vmf)
{
	const struct vdso_image *image = vma->vm_mm->context.vdso_image;

	if (!image || (vmf->pgoff << PAGE_SHIFT) >= image->size)
		return VM_FAULT_SIGBUS;

	vmf->page = virt_to_page(image->data + (vmf->pgoff << PAGE_SHIFT));
	get_page(vmf->page);
	return 0;
}

static void vdso_fix_landing(const struct vdso_image *image,
		struct vm_area_struct *new_vma)
{
#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
	if (in_ia32_syscall() && image == &vdso_image_32) {
		struct pt_regs *regs = current_pt_regs();
		unsigned long vdso_land = image->sym_int80_landing_pad;
		unsigned long old_land_addr = vdso_land +
			(unsigned long)current->mm->context.vdso;

		/* Fixing userspace landing - look at do_fast_syscall_32 */
		if (regs->ip == old_land_addr)
			regs->ip = new_vma->vm_start + vdso_land;
	}
#endif
}

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

	vdso_fix_landing(image, new_vma);
	current->mm->context.vdso = (void __user *)new_vma->vm_start;

	return 0;
}

#ifdef CONFIG_TIME_NS
/*
 * The vvar page layout depends on whether a task belongs to the root or
 * non-root time namespace. Whenever a task changes its namespace, the VVAR
 * page tables are cleared and then they will re-faulted with a
 * corresponding layout.
 * See also the comment near timens_setup_vdso_data() for details.
 */
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, &vvar_mapping))
			zap_vma_pages(vma);
	}
	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)
{
	const struct vdso_image *image = vma->vm_mm->context.vdso_image;
	unsigned long pfn;
	long sym_offset;

	if (!image)
		return VM_FAULT_SIGBUS;

	sym_offset = (long)(vmf->pgoff << PAGE_SHIFT) +
		image->sym_vvar_start;

	/*
	 * Sanity check: a symbol offset of zero means that the page
	 * does not exist for this vdso image, not that the page is at
	 * offset zero relative to the text mapping.  This should be
	 * impossible here, because sym_offset should only be zero for
	 * the page past the end of the vvar mapping.
	 */
	if (sym_offset == 0)
		return VM_FAULT_SIGBUS;

	if (sym_offset == image->sym_vvar_page) {
		struct page *timens_page = find_timens_vvar_page(vma);

		pfn = __pa_symbol(&__vvar_page) >> PAGE_SHIFT;

		/*
		 * If a task belongs to a time namespace then a namespace
		 * specific VVAR is mapped with the sym_vvar_page offset and
		 * the real VVAR page is mapped with the sym_timens_page
		 * offset.
		 * See also the comment near timens_setup_vdso_data().
		 */
		if (timens_page) {
			unsigned long addr;
			vm_fault_t err;

			/*
			 * Optimization: inside time namespace pre-fault
			 * VVAR page too. As on timens page there are only
			 * offsets for clocks on VVAR, it'll be faulted
			 * shortly by VDSO code.
			 */
			addr = vmf->address + (image->sym_timens_page - sym_offset);
			err = vmf_insert_pfn(vma, addr, pfn);
			if (unlikely(err & VM_FAULT_ERROR))
				return err;

			pfn = page_to_pfn(timens_page);
		}

		return vmf_insert_pfn(vma, vmf->address, pfn);
	} else if (sym_offset == image->sym_pvclock_page) {
		struct pvclock_vsyscall_time_info *pvti =
			pvclock_get_pvti_cpu0_va();
		if (pvti && vclock_was_used(VDSO_CLOCKMODE_PVCLOCK)) {
			return vmf_insert_pfn_prot(vma, vmf->address,
					__pa(pvti) >> PAGE_SHIFT,
					pgprot_decrypted(vma->vm_page_prot));
		}
	} else if (sym_offset == image->sym_hvclock_page) {
		pfn = hv_get_tsc_pfn();

		if (pfn && vclock_was_used(VDSO_CLOCKMODE_HVCLOCK))
			return vmf_insert_pfn(vma, vmf->address, pfn);
	} else if (sym_offset == image->sym_timens_page) {
		struct page *timens_page = find_timens_vvar_page(vma);

		if (!timens_page)
			return VM_FAULT_SIGBUS;

		pfn = __pa_symbol(&__vvar_page) >> PAGE_SHIFT;
		return vmf_insert_pfn(vma, vmf->address, pfn);
	}

	return VM_FAULT_SIGBUS;
}

static const struct vm_special_mapping vdso_mapping = {
	.name = "[vdso]",
	.fault = vdso_fault,
	.mremap = vdso_mremap,
};
static const struct vm_special_mapping vvar_mapping = {
	.name = "[vvar]",
	.fault = vvar_fault,
};

/*
 * Add vdso and vvar mappings to current process.
 * @image          - blob to map
 * @addr           - request a specific address (zero to map at free addr)
 */
static int map_vdso(const struct vdso_image *image, unsigned long addr)
{
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	unsigned long text_start;
	int ret = 0;

	if (mmap_write_lock_killable(mm))
		return -EINTR;

	addr = get_unmapped_area(NULL, addr,
				 image->size - image->sym_vvar_start, 0, 0);
	if (IS_ERR_VALUE(addr)) {
		ret = addr;
		goto up_fail;
	}

	text_start = addr - image->sym_vvar_start;

	/*
	 * MAYWRITE to allow gdb to COW and set breakpoints
	 */
	vma = _install_special_mapping(mm,
				       text_start,
				       image->size,
				       VM_READ|VM_EXEC|
				       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
				       &vdso_mapping);

	if (IS_ERR(vma)) {
		ret = PTR_ERR(vma);
		goto up_fail;
	}

	vma = _install_special_mapping(mm,
				       addr,
				       -image->sym_vvar_start,
				       VM_READ|VM_MAYREAD|VM_IO|VM_DONTDUMP|
				       VM_PFNMAP,
				       &vvar_mapping);

	if (IS_ERR(vma)) {
		ret = PTR_ERR(vma);
		do_munmap(mm, text_start, image->size, NULL);
	} else {
		current->mm->context.vdso = (void __user *)text_start;
		current->mm->context.vdso_image = image;
	}

up_fail:
	mmap_write_unlock(mm);
	return ret;
}

int map_vdso_once(const struct vdso_image *image, unsigned long addr)
{
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	VMA_ITERATOR(vmi, mm, 0);

	mmap_write_lock(mm);
	/*
	 * Check if we have already mapped vdso blob - fail to prevent
	 * abusing from userspace install_special_mapping, which may
	 * not do accounting and rlimit right.
	 * We could search vma near context.vdso, but it's a slowpath,
	 * so let's explicitly check all VMAs to be completely sure.
	 */
	for_each_vma(vmi, vma) {
		if (vma_is_special_mapping(vma, &vdso_mapping) ||
				vma_is_special_mapping(vma, &vvar_mapping)) {
			mmap_write_unlock(mm);
			return -EEXIST;
		}
	}
	mmap_write_unlock(mm);

	return map_vdso(image, addr);
}

#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
static int load_vdso32(void)
{
	if (vdso32_enabled != 1)  /* Other values all mean "disabled" */
		return 0;

	return map_vdso(&vdso_image_32, 0);
}
#endif

#ifdef CONFIG_X86_64
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
	if (!vdso64_enabled)
		return 0;

	return map_vdso(&vdso_image_64, 0);
}

#ifdef CONFIG_COMPAT
int compat_arch_setup_additional_pages(struct linux_binprm *bprm,
				       int uses_interp, bool x32)
{
#ifdef CONFIG_X86_X32_ABI
	if (x32) {
		if (!vdso64_enabled)
			return 0;
		return map_vdso(&vdso_image_x32, 0);
	}
#endif
#ifdef CONFIG_IA32_EMULATION
	return load_vdso32();
#else
	return 0;
#endif
}
#endif
#else
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
	return load_vdso32();
}
#endif

bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
{
#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
	const struct vdso_image *image = current->mm->context.vdso_image;
	unsigned long vdso = (unsigned long) current->mm->context.vdso;

	if (in_ia32_syscall() && image == &vdso_image_32) {
		if (regs->ip == vdso + image->sym_vdso32_sigreturn_landing_pad ||
		    regs->ip == vdso + image->sym_vdso32_rt_sigreturn_landing_pad)
			return true;
	}
#endif
	return false;
}

#ifdef CONFIG_X86_64
static __init int vdso_setup(char *s)
{
	vdso64_enabled = simple_strtoul(s, NULL, 0);
	return 1;
}
__setup("vdso=", vdso_setup);
#endif /* CONFIG_X86_64 */
Commit	Line	Data
003ba957	1	// SPDX-License-Identifier: GPL-2.0-only
2aae950b	2	/*
2aae950b	3	* Copyright 2007 Andi Kleen, SUSE Labs.
1c0c1b93 AL	4	*
1c0c1b93 AL	5	* This contains most of the x86 vDSO kernel-side code.
2aae950b AK	6	*/
2aae950b AK	7	#include <linux/mm.h>
4e950f6f	8	#include <linux/err.h>
2aae950b	9	#include <linux/sched.h>
68db0cf1	10	#include <linux/sched/task_stack.h>
5a0e3ad6	11	#include <linux/slab.h>
2aae950b AK	12	#include <linux/init.h>
2aae950b AK	13	#include <linux/random.h>
3fa89ca7	14	#include <linux/elf.h>
d4f829dd	15	#include <linux/cpu.h>
b059a453	16	#include <linux/ptrace.h>
af34ebeb DS	17	#include <linux/time_namespace.h>
af34ebeb DS	18
cc1e24fd	19	#include <asm/pvclock.h>
2aae950b AK	20	#include <asm/vgtod.h>
2aae950b AK	21	#include <asm/proto.h>
7f3646aa	22	#include <asm/vdso.h>
1c0c1b93	23	#include <asm/vvar.h>
af34ebeb	24	#include <asm/tlb.h>
aafade24	25	#include <asm/page.h>
d4f829dd	26	#include <asm/desc.h>
cd4d09ec	27	#include <asm/cpufeature.h>
dd2cb348	28	#include <clocksource/hyperv_timer.h>
2aae950b	29
64b302ab DS	30	#undef _ASM_X86_VVAR_H
	31	#define EMIT_VVAR(name, offset) \
	32	const size_t name ## _offset = offset;
	33	#include <asm/vvar.h>
	34
	35	struct vdso_data arch_get_vdso_data(void vvar_page)
	36	{
	37	return (struct vdso_data *)(vvar_page + _vdso_data_offset);
	38	}
	39	#undef EMIT_VVAR
	40
eec399dd TG	41	unsigned int vclocks_used __read_mostly;
eec399dd TG	42
b4b541a6	43	#if defined(CONFIG_X86_64)
3d7ee969	44	unsigned int __read_mostly vdso64_enabled = 1;
b4b541a6	45	#endif
1a21d4e0	46
4c382d72	47	int __init init_vdso_image(const struct vdso_image *image)
1a21d4e0	48	{
4c382d72	49	BUILD_BUG_ON(VDSO_CLOCKMODE_MAX >= 32);
6f121e54	50	BUG_ON(image->size % PAGE_SIZE != 0);
1a21d4e0	51
6f121e54 AL	52	apply_alternatives((struct alt_instr *)(image->data + image->alt),
	53	(struct alt_instr *)(image->data + image->alt +
	54	image->alt_len));
4c382d72 BG	55
4c382d72 BG	56	return 0;
1a21d4e0	57	}
1b3f2a72	58
70ddf651	59	static const struct vm_special_mapping vvar_mapping;
2aae950b AK	60	struct linux_binprm;
2aae950b AK	61
b13fd1dc	62	static vm_fault_t vdso_fault(const struct vm_special_mapping *sm,
05ef76b2 AL	63	struct vm_area_struct vma, struct vm_fault vmf)
	64	{
	65	const struct vdso_image *image = vma->vm_mm->context.vdso_image;
	66
	67	if (!image \|\| (vmf->pgoff << PAGE_SHIFT) >= image->size)
	68	return VM_FAULT_SIGBUS;
	69
	70	vmf->page = virt_to_page(image->data + (vmf->pgoff << PAGE_SHIFT));
	71	get_page(vmf->page);
	72	return 0;
	73	}
	74
b059a453 DS	75	static void vdso_fix_landing(const struct vdso_image *image,
	76	struct vm_area_struct *new_vma)
	77	{
	78	#if defined CONFIG_X86_32 \|\| defined CONFIG_IA32_EMULATION
	79	if (in_ia32_syscall() && image == &vdso_image_32) {
	80	struct pt_regs *regs = current_pt_regs();
	81	unsigned long vdso_land = image->sym_int80_landing_pad;
	82	unsigned long old_land_addr = vdso_land +
	83	(unsigned long)current->mm->context.vdso;
	84
	85	/* Fixing userspace landing - look at do_fast_syscall_32 */
	86	if (regs->ip == old_land_addr)
	87	regs->ip = new_vma->vm_start + vdso_land;
	88	}
	89	#endif
	90	}
	91
	92	static int vdso_mremap(const struct vm_special_mapping *sm,
	93	struct vm_area_struct *new_vma)
	94	{
b059a453 DS	95	const struct vdso_image *image = current->mm->context.vdso_image;
b059a453 DS	96
b059a453 DS	97	vdso_fix_landing(image, new_vma);
	98	current->mm->context.vdso = (void __user *)new_vma->vm_start;
	99
	100	return 0;
	101	}
05ef76b2	102
af34ebeb	103	#ifdef CONFIG_TIME_NS
70ddf651 DS	104	/*
	105	* The vvar page layout depends on whether a task belongs to the root or
	106	* non-root time namespace. Whenever a task changes its namespace, the VVAR
	107	* page tables are cleared and then they will re-faulted with a
	108	* corresponding layout.
	109	* See also the comment near timens_setup_vdso_data() for details.
	110	*/
	111	int vdso_join_timens(struct task_struct task, struct time_namespace ns)
	112	{
	113	struct mm_struct *mm = task->mm;
	114	struct vm_area_struct *vma;
a3884621	115	VMA_ITERATOR(vmi, mm, 0);
70ddf651	116
42815808	117	mmap_read_lock(mm);
a3884621	118	for_each_vma(vmi, vma) {
70ddf651	119	if (vma_is_special_mapping(vma, &vvar_mapping))
e9adcfec	120	zap_vma_pages(vma);
70ddf651	121	}
42815808	122	mmap_read_unlock(mm);
a3884621	123
70ddf651 DS	124	return 0;
70ddf651 DS	125	}
af34ebeb DS	126	#endif
af34ebeb DS	127
b13fd1dc	128	static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
a48a7042 AL	129	struct vm_area_struct vma, struct vm_fault vmf)
	130	{
	131	const struct vdso_image *image = vma->vm_mm->context.vdso_image;
af34ebeb	132	unsigned long pfn;
a48a7042	133	long sym_offset;
a48a7042 AL	134
	135	if (!image)
	136	return VM_FAULT_SIGBUS;
	137
	138	sym_offset = (long)(vmf->pgoff << PAGE_SHIFT) +
	139	image->sym_vvar_start;
	140
	141	/*
	142	* Sanity check: a symbol offset of zero means that the page
	143	* does not exist for this vdso image, not that the page is at
	144	* offset zero relative to the text mapping. This should be
	145	* impossible here, because sym_offset should only be zero for
	146	* the page past the end of the vvar mapping.
	147	*/
	148	if (sym_offset == 0)
	149	return VM_FAULT_SIGBUS;
	150
	151	if (sym_offset == image->sym_vvar_page) {
af34ebeb DS	152	struct page *timens_page = find_timens_vvar_page(vma);
	153
	154	pfn = __pa_symbol(&__vvar_page) >> PAGE_SHIFT;
	155
	156	/*
	157	* If a task belongs to a time namespace then a namespace
	158	* specific VVAR is mapped with the sym_vvar_page offset and
	159	* the real VVAR page is mapped with the sym_timens_page
	160	* offset.
	161	* See also the comment near timens_setup_vdso_data().
	162	*/
e6b28ec6 DS	163	if (timens_page) {
	164	unsigned long addr;
	165	vm_fault_t err;
	166
	167	/*
	168	* Optimization: inside time namespace pre-fault
	169	* VVAR page too. As on timens page there are only
	170	* offsets for clocks on VVAR, it'll be faulted
	171	* shortly by VDSO code.
	172	*/
	173	addr = vmf->address + (image->sym_timens_page - sym_offset);
	174	err = vmf_insert_pfn(vma, addr, pfn);
	175	if (unlikely(err & VM_FAULT_ERROR))
	176	return err;
	177
af34ebeb	178	pfn = page_to_pfn(timens_page);
e6b28ec6	179	}
af34ebeb DS	180
af34ebeb DS	181	return vmf_insert_pfn(vma, vmf->address, pfn);
a48a7042 AL	182	} else if (sym_offset == image->sym_pvclock_page) {
a48a7042 AL	183	struct pvclock_vsyscall_time_info *pvti =
9f08890a	184	pvclock_get_pvti_cpu0_va();
b95a8a27	185	if (pvti && vclock_was_used(VDSO_CLOCKMODE_PVCLOCK)) {
b13fd1dc MW	186	return vmf_insert_pfn_prot(vma, vmf->address,
	187	__pa(pvti) >> PAGE_SHIFT,
	188	pgprot_decrypted(vma->vm_page_prot));
a48a7042	189	}
90b20432	190	} else if (sym_offset == image->sym_hvclock_page) {
364adc45	191	pfn = hv_get_tsc_pfn();
90b20432	192
364adc45 SK	193	if (pfn && vclock_was_used(VDSO_CLOCKMODE_HVCLOCK))
364adc45 SK	194	return vmf_insert_pfn(vma, vmf->address, pfn);
af34ebeb DS	195	} else if (sym_offset == image->sym_timens_page) {
	196	struct page *timens_page = find_timens_vvar_page(vma);
	197
	198	if (!timens_page)
	199	return VM_FAULT_SIGBUS;
	200
	201	pfn = __pa_symbol(&__vvar_page) >> PAGE_SHIFT;
	202	return vmf_insert_pfn(vma, vmf->address, pfn);
a48a7042 AL	203	}
a48a7042 AL	204
a48a7042 AL	205	return VM_FAULT_SIGBUS;
	206	}
	207
2eefd878 DS	208	static const struct vm_special_mapping vdso_mapping = {
	209	.name = "[vdso]",
	210	.fault = vdso_fault,
	211	.mremap = vdso_mremap,
	212	};
	213	static const struct vm_special_mapping vvar_mapping = {
	214	.name = "[vvar]",
	215	.fault = vvar_fault,
	216	};
	217
576ebfef DS	218	/*
	219	* Add vdso and vvar mappings to current process.
	220	* @image - blob to map
	221	* @addr - request a specific address (zero to map at free addr)
	222	*/
	223	static int map_vdso(const struct vdso_image *image, unsigned long addr)
2aae950b AK	224	{
2aae950b AK	225	struct mm_struct *mm = current->mm;
18d0a6fd	226	struct vm_area_struct *vma;
576ebfef	227	unsigned long text_start;
18d0a6fd	228	int ret = 0;
b059a453	229
d8ed45c5	230	if (mmap_write_lock_killable(mm))
69048176	231	return -EINTR;
18d0a6fd	232
e6577a7c AL	233	addr = get_unmapped_area(NULL, addr,
e6577a7c AL	234	image->size - image->sym_vvar_start, 0, 0);
2aae950b AK	235	if (IS_ERR_VALUE(addr)) {
	236	ret = addr;
	237	goto up_fail;
	238	}
	239
e6577a7c	240	text_start = addr - image->sym_vvar_start;
f7b6eb3f	241
18d0a6fd AL	242	/*
	243	* MAYWRITE to allow gdb to COW and set breakpoints
	244	*/
a62c34bd	245	vma = _install_special_mapping(mm,
e6577a7c	246	text_start,
a62c34bd AL	247	image->size,
	248	VM_READ\|VM_EXEC\|
	249	VM_MAYREAD\|VM_MAYWRITE\|VM_MAYEXEC,
b059a453	250	&vdso_mapping);
18d0a6fd	251
a62c34bd AL	252	if (IS_ERR(vma)) {
a62c34bd AL	253	ret = PTR_ERR(vma);
18d0a6fd	254	goto up_fail;
a62c34bd	255	}
18d0a6fd AL	256
18d0a6fd AL	257	vma = _install_special_mapping(mm,
e6577a7c AL	258	addr,
e6577a7c AL	259	-image->sym_vvar_start,
a48a7042 AL	260	VM_READ\|VM_MAYREAD\|VM_IO\|VM_DONTDUMP\|
a48a7042 AL	261	VM_PFNMAP,
a62c34bd	262	&vvar_mapping);
18d0a6fd AL	263
	264	if (IS_ERR(vma)) {
	265	ret = PTR_ERR(vma);
897ab3e0	266	do_munmap(mm, text_start, image->size, NULL);
67dece7d DS	267	} else {
	268	current->mm->context.vdso = (void __user *)text_start;
	269	current->mm->context.vdso_image = image;
f7b6eb3f	270	}
2aae950b	271
2aae950b	272	up_fail:
d8ed45c5	273	mmap_write_unlock(mm);
2aae950b AK	274	return ret;
	275	}
	276
2eefd878 DS	277	int map_vdso_once(const struct vdso_image *image, unsigned long addr)
	278	{
	279	struct mm_struct *mm = current->mm;
	280	struct vm_area_struct *vma;
a3884621	281	VMA_ITERATOR(vmi, mm, 0);
2eefd878	282
d8ed45c5	283	mmap_write_lock(mm);
2eefd878 DS	284	/*
2eefd878 DS	285	* Check if we have already mapped vdso blob - fail to prevent
163b0991	286	* abusing from userspace install_special_mapping, which may
2eefd878 DS	287	* not do accounting and rlimit right.
2eefd878 DS	288	* We could search vma near context.vdso, but it's a slowpath,
a97673a1	289	* so let's explicitly check all VMAs to be completely sure.
2eefd878	290	*/
a3884621	291	for_each_vma(vmi, vma) {
2eefd878 DS	292	if (vma_is_special_mapping(vma, &vdso_mapping) \|\|
2eefd878 DS	293	vma_is_special_mapping(vma, &vvar_mapping)) {
d8ed45c5	294	mmap_write_unlock(mm);
2eefd878 DS	295	return -EEXIST;
	296	}
	297	}
d8ed45c5	298	mmap_write_unlock(mm);
2eefd878 DS	299
	300	return map_vdso(image, addr);
	301	}
	302
ab8b82ee	303	#if defined(CONFIG_X86_32) \|\| defined(CONFIG_IA32_EMULATION)
18d0a6fd AL	304	static int load_vdso32(void)
18d0a6fd AL	305	{
18d0a6fd AL	306	if (vdso32_enabled != 1) /* Other values all mean "disabled" */
	307	return 0;
	308
576ebfef	309	return map_vdso(&vdso_image_32, 0);
18d0a6fd AL	310	}
	311	#endif
	312
	313	#ifdef CONFIG_X86_64
1a21d4e0 L	314	int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
1a21d4e0 L	315	{
18d0a6fd AL	316	if (!vdso64_enabled)
	317	return 0;
	318
3c6539b4	319	return map_vdso(&vdso_image_64, 0);
1a21d4e0 L	320	}
1a21d4e0 L	321
18d0a6fd AL	322	#ifdef CONFIG_COMPAT
18d0a6fd AL	323	int compat_arch_setup_additional_pages(struct linux_binprm *bprm,
3316ec8c	324	int uses_interp, bool x32)
18d0a6fd	325	{
1a21d4e0	326	#ifdef CONFIG_X86_X32_ABI
3316ec8c	327	if (x32) {
18d0a6fd AL	328	if (!vdso64_enabled)
18d0a6fd AL	329	return 0;
3c6539b4	330	return map_vdso(&vdso_image_x32, 0);
18d0a6fd AL	331	}
18d0a6fd AL	332	#endif
ab8b82ee	333	#ifdef CONFIG_IA32_EMULATION
18d0a6fd	334	return load_vdso32();
ab8b82ee BG	335	#else
	336	return 0;
	337	#endif
18d0a6fd AL	338	}
	339	#endif
	340	#else
	341	int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
1a21d4e0	342	{
18d0a6fd	343	return load_vdso32();
1a21d4e0 L	344	}
	345	#endif
	346
c5c87812 GKB	347	bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
	348	{
	349	#if defined(CONFIG_X86_32) \|\| defined(CONFIG_IA32_EMULATION)
	350	const struct vdso_image *image = current->mm->context.vdso_image;
	351	unsigned long vdso = (unsigned long) current->mm->context.vdso;
	352
	353	if (in_ia32_syscall() && image == &vdso_image_32) {
	354	if (regs->ip == vdso + image->sym_vdso32_sigreturn_landing_pad \|\|
	355	regs->ip == vdso + image->sym_vdso32_rt_sigreturn_landing_pad)
	356	return true;
	357	}
	358	#endif
	359	return false;
	360	}
	361
18d0a6fd	362	#ifdef CONFIG_X86_64
2aae950b AK	363	static __init int vdso_setup(char *s)
2aae950b AK	364	{
3d7ee969	365	vdso64_enabled = simple_strtoul(s, NULL, 0);
12441ccd	366	return 1;
2aae950b AK	367	}
2aae950b AK	368	__setup("vdso=", vdso_setup);
1c0c1b93	369	#endif /* CONFIG_X86_64 */