[linux-2.6-block.git] / mm / process_vm_access.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * linux/mm/process_vm_access.c
 *
 * Copyright (C) 2010-2011 Christopher Yeoh <cyeoh@au1.ibm.com>, IBM Corp.
 */

#include <linux/mm.h>
#include <linux/uio.h>
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/highmem.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/syscalls.h>

#ifdef CONFIG_COMPAT
#include <linux/compat.h>
#endif

/**
 * process_vm_rw_pages - read/write pages from task specified
 * @pages: array of pointers to pages we want to copy
 * @offset: offset in page to start copying from/to
 * @len: number of bytes to copy
 * @iter: where to copy to/from locally
 * @vm_write: 0 means copy from, 1 means copy to
 * Returns 0 on success, error code otherwise
 */
static int process_vm_rw_pages(struct page **pages,
			       unsigned offset,
			       size_t len,
			       struct iov_iter *iter,
			       int vm_write)
{
	/* Do the copy for each page */
	while (len && iov_iter_count(iter)) {
		struct page *page = *pages++;
		size_t copy = PAGE_SIZE - offset;
		size_t copied;

		if (copy > len)
			copy = len;

		if (vm_write) {
			copied = copy_page_from_iter(page, offset, copy, iter);
			set_page_dirty_lock(page);
		} else {
			copied = copy_page_to_iter(page, offset, copy, iter);
		}
		len -= copied;
		if (copied < copy && iov_iter_count(iter))
			return -EFAULT;
		offset = 0;
	}
	return 0;
}

/* Maximum number of pages kmalloc'd to hold struct page's during copy */
#define PVM_MAX_KMALLOC_PAGES (PAGE_SIZE * 2)

/**
 * process_vm_rw_single_vec - read/write pages from task specified
 * @addr: start memory address of target process
 * @len: size of area to copy to/from
 * @iter: where to copy to/from locally
 * @process_pages: struct pages area that can store at least
 *  nr_pages_to_copy struct page pointers
 * @mm: mm for task
 * @task: task to read/write from
 * @vm_write: 0 means copy from, 1 means copy to
 * Returns 0 on success or on failure error code
 */
static int process_vm_rw_single_vec(unsigned long addr,
				    unsigned long len,
				    struct iov_iter *iter,
				    struct page **process_pages,
				    struct mm_struct *mm,
				    struct task_struct *task,
				    int vm_write)
{
	unsigned long pa = addr & PAGE_MASK;
	unsigned long start_offset = addr - pa;
	unsigned long nr_pages;
	ssize_t rc = 0;
	unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
		/ sizeof(struct pages *);
	unsigned int flags = 0;

	/* Work out address and page range required */
	if (len == 0)
		return 0;
	nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1;

	if (vm_write)
		flags |= FOLL_WRITE;

	while (!rc && nr_pages && iov_iter_count(iter)) {
		int pages = min(nr_pages, max_pages_per_loop);
		int locked = 1;
		size_t bytes;

		/*
		 * Get the pages we're interested in.  We must
		 * access remotely because task/mm might not
		 * current/current->mm
		 */
		down_read(&mm->mmap_sem);
		pages = get_user_pages_remote(task, mm, pa, pages, flags,
					      process_pages, NULL, &locked);
		if (locked)
			up_read(&mm->mmap_sem);
		if (pages <= 0)
			return -EFAULT;

		bytes = pages * PAGE_SIZE - start_offset;
		if (bytes > len)
			bytes = len;

		rc = process_vm_rw_pages(process_pages,
					 start_offset, bytes, iter,
					 vm_write);
		len -= bytes;
		start_offset = 0;
		nr_pages -= pages;
		pa += pages * PAGE_SIZE;
		while (pages)
			put_page(process_pages[--pages]);
	}

	return rc;
}

/* Maximum number of entries for process pages array
   which lives on stack */
#define PVM_MAX_PP_ARRAY_COUNT 16

/**
 * process_vm_rw_core - core of reading/writing pages from task specified
 * @pid: PID of process to read/write from/to
 * @iter: where to copy to/from locally
 * @rvec: iovec array specifying where to copy to/from in the other process
 * @riovcnt: size of rvec array
 * @flags: currently unused
 * @vm_write: 0 if reading from other process, 1 if writing to other process
 *
 * Returns the number of bytes read/written or error code. May
 *  return less bytes than expected if an error occurs during the copying
 *  process.
 */
static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,
				  const struct iovec *rvec,
				  unsigned long riovcnt,
				  unsigned long flags, int vm_write)
{
	struct task_struct *task;
	struct page *pp_stack[PVM_MAX_PP_ARRAY_COUNT];
	struct page **process_pages = pp_stack;
	struct mm_struct *mm;
	unsigned long i;
	ssize_t rc = 0;
	unsigned long nr_pages = 0;
	unsigned long nr_pages_iov;
	ssize_t iov_len;
	size_t total_len = iov_iter_count(iter);

	/*
	 * Work out how many pages of struct pages we're going to need
	 * when eventually calling get_user_pages
	 */
	for (i = 0; i < riovcnt; i++) {
		iov_len = rvec[i].iov_len;
		if (iov_len > 0) {
			nr_pages_iov = ((unsigned long)rvec[i].iov_base
					+ iov_len)
				/ PAGE_SIZE - (unsigned long)rvec[i].iov_base
				/ PAGE_SIZE + 1;
			nr_pages = max(nr_pages, nr_pages_iov);
		}
	}

	if (nr_pages == 0)
		return 0;

	if (nr_pages > PVM_MAX_PP_ARRAY_COUNT) {
		/* For reliability don't try to kmalloc more than
		   2 pages worth */
		process_pages = kmalloc(min_t(size_t, PVM_MAX_KMALLOC_PAGES,
					      sizeof(struct pages *)*nr_pages),
					GFP_KERNEL);

		if (!process_pages)
			return -ENOMEM;
	}

	/* Get process information */
	task = find_get_task_by_vpid(pid);
	if (!task) {
		rc = -ESRCH;
		goto free_proc_pages;
	}

	mm = mm_access(task, PTRACE_MODE_ATTACH_REALCREDS);
	if (!mm || IS_ERR(mm)) {
		rc = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH;
		/*
		 * Explicitly map EACCES to EPERM as EPERM is a more a
		 * appropriate error code for process_vw_readv/writev
		 */
		if (rc == -EACCES)
			rc = -EPERM;
		goto put_task_struct;
	}

	for (i = 0; i < riovcnt && iov_iter_count(iter) && !rc; i++)
		rc = process_vm_rw_single_vec(
			(unsigned long)rvec[i].iov_base, rvec[i].iov_len,
			iter, process_pages, mm, task, vm_write);

	/* copied = space before - space after */
	total_len -= iov_iter_count(iter);

	/* If we have managed to copy any data at all then
	   we return the number of bytes copied. Otherwise
	   we return the error code */
	if (total_len)
		rc = total_len;

	mmput(mm);

put_task_struct:
	put_task_struct(task);

free_proc_pages:
	if (process_pages != pp_stack)
		kfree(process_pages);
	return rc;
}

/**
 * process_vm_rw - check iovecs before calling core routine
 * @pid: PID of process to read/write from/to
 * @lvec: iovec array specifying where to copy to/from locally
 * @liovcnt: size of lvec array
 * @rvec: iovec array specifying where to copy to/from in the other process
 * @riovcnt: size of rvec array
 * @flags: currently unused
 * @vm_write: 0 if reading from other process, 1 if writing to other process
 *
 * Returns the number of bytes read/written or error code. May
 *  return less bytes than expected if an error occurs during the copying
 *  process.
 */
static ssize_t process_vm_rw(pid_t pid,
			     const struct iovec __user *lvec,
			     unsigned long liovcnt,
			     const struct iovec __user *rvec,
			     unsigned long riovcnt,
			     unsigned long flags, int vm_write)
{
	struct iovec iovstack_l[UIO_FASTIOV];
	struct iovec iovstack_r[UIO_FASTIOV];
	struct iovec *iov_l = iovstack_l;
	struct iovec *iov_r = iovstack_r;
	struct iov_iter iter;
	ssize_t rc;
	int dir = vm_write ? WRITE : READ;

	if (flags != 0)
		return -EINVAL;

	/* Check iovecs */
	rc = import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter);
	if (rc < 0)
		return rc;
	if (!iov_iter_count(&iter))
		goto free_iovecs;

	rc = rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV,
				   iovstack_r, &iov_r);
	if (rc <= 0)
		goto free_iovecs;

	rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);

free_iovecs:
	if (iov_r != iovstack_r)
		kfree(iov_r);
	kfree(iov_l);

	return rc;
}

SYSCALL_DEFINE6(process_vm_readv, pid_t, pid, const struct iovec __user *, lvec,
		unsigned long, liovcnt, const struct iovec __user *, rvec,
		unsigned long, riovcnt,	unsigned long, flags)
{
	return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 0);
}

SYSCALL_DEFINE6(process_vm_writev, pid_t, pid,
		const struct iovec __user *, lvec,
		unsigned long, liovcnt, const struct iovec __user *, rvec,
		unsigned long, riovcnt,	unsigned long, flags)
{
	return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 1);
}

#ifdef CONFIG_COMPAT

static ssize_t
compat_process_vm_rw(compat_pid_t pid,
		     const struct compat_iovec __user *lvec,
		     unsigned long liovcnt,
		     const struct compat_iovec __user *rvec,
		     unsigned long riovcnt,
		     unsigned long flags, int vm_write)
{
	struct iovec iovstack_l[UIO_FASTIOV];
	struct iovec iovstack_r[UIO_FASTIOV];
	struct iovec *iov_l = iovstack_l;
	struct iovec *iov_r = iovstack_r;
	struct iov_iter iter;
	ssize_t rc = -EFAULT;
	int dir = vm_write ? WRITE : READ;

	if (flags != 0)
		return -EINVAL;

	rc = compat_import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter);
	if (rc < 0)
		return rc;
	if (!iov_iter_count(&iter))
		goto free_iovecs;
	rc = compat_rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt,
					  UIO_FASTIOV, iovstack_r,
					  &iov_r);
	if (rc <= 0)
		goto free_iovecs;

	rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);

free_iovecs:
	if (iov_r != iovstack_r)
		kfree(iov_r);
	kfree(iov_l);
	return rc;
}

COMPAT_SYSCALL_DEFINE6(process_vm_readv, compat_pid_t, pid,
		       const struct compat_iovec __user *, lvec,
		       compat_ulong_t, liovcnt,
		       const struct compat_iovec __user *, rvec,
		       compat_ulong_t, riovcnt,
		       compat_ulong_t, flags)
{
	return compat_process_vm_rw(pid, lvec, liovcnt, rvec,
				    riovcnt, flags, 0);
}

COMPAT_SYSCALL_DEFINE6(process_vm_writev, compat_pid_t, pid,
		       const struct compat_iovec __user *, lvec,
		       compat_ulong_t, liovcnt,
		       const struct compat_iovec __user *, rvec,
		       compat_ulong_t, riovcnt,
		       compat_ulong_t, flags)
{
	return compat_process_vm_rw(pid, lvec, liovcnt, rvec,
				    riovcnt, flags, 1);
}

#endif
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
fcf63409 CY	2	/*
	3	* linux/mm/process_vm_access.c
	4	*
	5	* Copyright (C) 2010-2011 Christopher Yeoh <cyeoh@au1.ibm.com>, IBM Corp.
fcf63409 CY	6	*/
	7
	8	#include <linux/mm.h>
	9	#include <linux/uio.h>
	10	#include <linux/sched.h>
6e84f315	11	#include <linux/sched/mm.h>
fcf63409 CY	12	#include <linux/highmem.h>
	13	#include <linux/ptrace.h>
	14	#include <linux/slab.h>
	15	#include <linux/syscalls.h>
	16
	17	#ifdef CONFIG_COMPAT
	18	#include <linux/compat.h>
	19	#endif
	20
	21	/**
	22	* process_vm_rw_pages - read/write pages from task specified
4bafbec7	23	* @pages: array of pointers to pages we want to copy
f144c390	24	* @offset: offset in page to start copying from/to
fcf63409	25	* @len: number of bytes to copy
4bafbec7	26	* @iter: where to copy to/from locally
fcf63409	27	* @vm_write: 0 means copy from, 1 means copy to
fcf63409 CY	28	* Returns 0 on success, error code otherwise
fcf63409 CY	29	*/
70eca12d AV	30	static int process_vm_rw_pages(struct page **pages,
70eca12d AV	31	unsigned offset,
e21345f9	32	size_t len,
9f78bdfa	33	struct iov_iter *iter,
9acc1a0f	34	int vm_write)
fcf63409	35	{
fcf63409	36	/* Do the copy for each page */
9acc1a0f	37	while (len && iov_iter_count(iter)) {
70eca12d	38	struct page page = pages++;
e21345f9	39	size_t copy = PAGE_SIZE - offset;
70eca12d	40	size_t copied;
240f3905	41
e21345f9 AV	42	if (copy > len)
	43	copy = len;
	44
240f3905	45	if (vm_write) {
e7c24607	46	copied = copy_page_from_iter(page, offset, copy, iter);
240f3905	47	set_page_dirty_lock(page);
fcf63409	48	} else {
70eca12d	49	copied = copy_page_to_iter(page, offset, copy, iter);
fcf63409	50	}
70eca12d AV	51	len -= copied;
	52	if (copied < copy && iov_iter_count(iter))
	53	return -EFAULT;
	54	offset = 0;
fcf63409	55	}
70eca12d	56	return 0;
fcf63409 CY	57	}
	58
	59	/* Maximum number of pages kmalloc'd to hold struct page's during copy */
	60	#define PVM_MAX_KMALLOC_PAGES (PAGE_SIZE * 2)
	61
	62	/**
	63	* process_vm_rw_single_vec - read/write pages from task specified
	64	* @addr: start memory address of target process
	65	* @len: size of area to copy to/from
4bafbec7	66	* @iter: where to copy to/from locally
fcf63409 CY	67	* @process_pages: struct pages area that can store at least
	68	* nr_pages_to_copy struct page pointers
	69	* @mm: mm for task
	70	* @task: task to read/write from
	71	* @vm_write: 0 means copy from, 1 means copy to
fcf63409 CY	72	* Returns 0 on success or on failure error code
	73	*/
	74	static int process_vm_rw_single_vec(unsigned long addr,
	75	unsigned long len,
9f78bdfa	76	struct iov_iter *iter,
fcf63409 CY	77	struct page **process_pages,
	78	struct mm_struct *mm,
	79	struct task_struct *task,
9acc1a0f	80	int vm_write)
fcf63409 CY	81	{
	82	unsigned long pa = addr & PAGE_MASK;
	83	unsigned long start_offset = addr - pa;
	84	unsigned long nr_pages;
fcf63409	85	ssize_t rc = 0;
fcf63409 CY	86	unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
fcf63409 CY	87	/ sizeof(struct pages *);
8b7457ef	88	unsigned int flags = 0;
fcf63409	89
fcf63409 CY	90	/* Work out address and page range required */
	91	if (len == 0)
	92	return 0;
	93	nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1;
	94
d4944b0e LS	95	if (vm_write)
	96	flags \|= FOLL_WRITE;
	97
4bafbec7 AV	98	while (!rc && nr_pages && iov_iter_count(iter)) {
4bafbec7 AV	99	int pages = min(nr_pages, max_pages_per_loop);
8b7457ef	100	int locked = 1;
4bafbec7	101	size_t bytes;
fcf63409	102
1e987790 DH	103	/*
1e987790 DH	104	* Get the pages we're interested in. We must
8b7457ef	105	* access remotely because task/mm might not
1e987790 DH	106	* current/current->mm
1e987790 DH	107	*/
8b7457ef LS	108	down_read(&mm->mmap_sem);
	109	pages = get_user_pages_remote(task, mm, pa, pages, flags,
	110	process_pages, NULL, &locked);
	111	if (locked)
	112	up_read(&mm->mmap_sem);
4bafbec7	113	if (pages <= 0)
70eca12d AV	114	return -EFAULT;
70eca12d AV	115
4bafbec7 AV	116	bytes = pages * PAGE_SIZE - start_offset;
	117	if (bytes > len)
	118	bytes = len;
e21345f9	119
70eca12d	120	rc = process_vm_rw_pages(process_pages,
4bafbec7	121	start_offset, bytes, iter,
9acc1a0f	122	vm_write);
4bafbec7	123	len -= bytes;
fcf63409	124	start_offset = 0;
4bafbec7 AV	125	nr_pages -= pages;
	126	pa += pages * PAGE_SIZE;
	127	while (pages)
	128	put_page(process_pages[--pages]);
fcf63409 CY	129	}
	130
	131	return rc;
	132	}
	133
	134	/* Maximum number of entries for process pages array
	135	which lives on stack */
	136	#define PVM_MAX_PP_ARRAY_COUNT 16
	137
	138	/**
	139	* process_vm_rw_core - core of reading/writing pages from task specified
	140	* @pid: PID of process to read/write from/to
4bafbec7	141	* @iter: where to copy to/from locally
fcf63409 CY	142	* @rvec: iovec array specifying where to copy to/from in the other process
	143	* @riovcnt: size of rvec array
	144	* @flags: currently unused
	145	* @vm_write: 0 if reading from other process, 1 if writing to other process
a5d09bed	146	*
fcf63409 CY	147	* Returns the number of bytes read/written or error code. May
	148	* return less bytes than expected if an error occurs during the copying
	149	* process.
	150	*/
9f78bdfa	151	static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,
fcf63409 CY	152	const struct iovec *rvec,
	153	unsigned long riovcnt,
	154	unsigned long flags, int vm_write)
	155	{
	156	struct task_struct *task;
	157	struct page *pp_stack[PVM_MAX_PP_ARRAY_COUNT];
	158	struct page **process_pages = pp_stack;
	159	struct mm_struct *mm;
	160	unsigned long i;
	161	ssize_t rc = 0;
fcf63409 CY	162	unsigned long nr_pages = 0;
fcf63409 CY	163	unsigned long nr_pages_iov;
fcf63409	164	ssize_t iov_len;
9acc1a0f	165	size_t total_len = iov_iter_count(iter);
fcf63409 CY	166
	167	/*
	168	* Work out how many pages of struct pages we're going to need
	169	* when eventually calling get_user_pages
	170	*/
	171	for (i = 0; i < riovcnt; i++) {
	172	iov_len = rvec[i].iov_len;
	173	if (iov_len > 0) {
	174	nr_pages_iov = ((unsigned long)rvec[i].iov_base
	175	+ iov_len)
	176	/ PAGE_SIZE - (unsigned long)rvec[i].iov_base
	177	/ PAGE_SIZE + 1;
	178	nr_pages = max(nr_pages, nr_pages_iov);
	179	}
	180	}
	181
	182	if (nr_pages == 0)
	183	return 0;
	184
	185	if (nr_pages > PVM_MAX_PP_ARRAY_COUNT) {
	186	/* For reliability don't try to kmalloc more than
	187	2 pages worth */
	188	process_pages = kmalloc(min_t(size_t, PVM_MAX_KMALLOC_PAGES,
	189	sizeof(struct pages )nr_pages),
	190	GFP_KERNEL);
	191
	192	if (!process_pages)
	193	return -ENOMEM;
	194	}
	195
	196	/* Get process information */
2ee08260	197	task = find_get_task_by_vpid(pid);
fcf63409 CY	198	if (!task) {
	199	rc = -ESRCH;
	200	goto free_proc_pages;
	201	}
	202
caaee623	203	mm = mm_access(task, PTRACE_MODE_ATTACH_REALCREDS);
8cdb878d CY	204	if (!mm \|\| IS_ERR(mm)) {
	205	rc = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH;
	206	/*
	207	* Explicitly map EACCES to EPERM as EPERM is a more a
	208	* appropriate error code for process_vw_readv/writev
	209	*/
	210	if (rc == -EACCES)
	211	rc = -EPERM;
fcf63409 CY	212	goto put_task_struct;
	213	}
	214
9acc1a0f	215	for (i = 0; i < riovcnt && iov_iter_count(iter) && !rc; i++)
fcf63409 CY	216	rc = process_vm_rw_single_vec(
fcf63409 CY	217	(unsigned long)rvec[i].iov_base, rvec[i].iov_len,
9acc1a0f AV	218	iter, process_pages, mm, task, vm_write);
	219
	220	/* copied = space before - space after */
	221	total_len -= iov_iter_count(iter);
	222
	223	/* If we have managed to copy any data at all then
	224	we return the number of bytes copied. Otherwise
	225	we return the error code */
	226	if (total_len)
	227	rc = total_len;
fcf63409	228
fcf63409 CY	229	mmput(mm);
	230
	231	put_task_struct:
	232	put_task_struct(task);
	233
	234	free_proc_pages:
	235	if (process_pages != pp_stack)
	236	kfree(process_pages);
	237	return rc;
	238	}
	239
	240	/**
	241	* process_vm_rw - check iovecs before calling core routine
	242	* @pid: PID of process to read/write from/to
	243	* @lvec: iovec array specifying where to copy to/from locally
	244	* @liovcnt: size of lvec array
	245	* @rvec: iovec array specifying where to copy to/from in the other process
	246	* @riovcnt: size of rvec array
	247	* @flags: currently unused
	248	* @vm_write: 0 if reading from other process, 1 if writing to other process
a5d09bed	249	*
fcf63409 CY	250	* Returns the number of bytes read/written or error code. May
	251	* return less bytes than expected if an error occurs during the copying
	252	* process.
	253	*/
	254	static ssize_t process_vm_rw(pid_t pid,
	255	const struct iovec __user *lvec,
	256	unsigned long liovcnt,
	257	const struct iovec __user *rvec,
	258	unsigned long riovcnt,
	259	unsigned long flags, int vm_write)
	260	{
	261	struct iovec iovstack_l[UIO_FASTIOV];
	262	struct iovec iovstack_r[UIO_FASTIOV];
	263	struct iovec *iov_l = iovstack_l;
	264	struct iovec *iov_r = iovstack_r;
9f78bdfa	265	struct iov_iter iter;
fcf63409	266	ssize_t rc;
17d17e72	267	int dir = vm_write ? WRITE : READ;
fcf63409 CY	268
	269	if (flags != 0)
	270	return -EINVAL;
	271
	272	/* Check iovecs */
17d17e72 AV	273	rc = import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter);
	274	if (rc < 0)
	275	return rc;
	276	if (!iov_iter_count(&iter))
fcf63409 CY	277	goto free_iovecs;
fcf63409 CY	278
ac34ebb3 CY	279	rc = rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV,
ac34ebb3 CY	280	iovstack_r, &iov_r);
fcf63409 CY	281	if (rc <= 0)
	282	goto free_iovecs;
	283
9f78bdfa	284	rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);
fcf63409 CY	285
	286	free_iovecs:
	287	if (iov_r != iovstack_r)
	288	kfree(iov_r);
17d17e72	289	kfree(iov_l);
fcf63409 CY	290
	291	return rc;
	292	}
	293
	294	SYSCALL_DEFINE6(process_vm_readv, pid_t, pid, const struct iovec __user *, lvec,
	295	unsigned long, liovcnt, const struct iovec __user *, rvec,
	296	unsigned long, riovcnt, unsigned long, flags)
	297	{
	298	return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 0);
	299	}
	300
	301	SYSCALL_DEFINE6(process_vm_writev, pid_t, pid,
	302	const struct iovec __user *, lvec,
	303	unsigned long, liovcnt, const struct iovec __user *, rvec,
	304	unsigned long, riovcnt, unsigned long, flags)
	305	{
	306	return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 1);
	307	}
	308
	309	#ifdef CONFIG_COMPAT
	310
2eb2e141	311	static ssize_t
fcf63409 CY	312	compat_process_vm_rw(compat_pid_t pid,
	313	const struct compat_iovec __user *lvec,
	314	unsigned long liovcnt,
	315	const struct compat_iovec __user *rvec,
	316	unsigned long riovcnt,
	317	unsigned long flags, int vm_write)
	318	{
	319	struct iovec iovstack_l[UIO_FASTIOV];
	320	struct iovec iovstack_r[UIO_FASTIOV];
	321	struct iovec *iov_l = iovstack_l;
	322	struct iovec *iov_r = iovstack_r;
9f78bdfa	323	struct iov_iter iter;
fcf63409	324	ssize_t rc = -EFAULT;
17d17e72	325	int dir = vm_write ? WRITE : READ;
fcf63409 CY	326
	327	if (flags != 0)
	328	return -EINVAL;
	329
17d17e72 AV	330	rc = compat_import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter);
	331	if (rc < 0)
	332	return rc;
	333	if (!iov_iter_count(&iter))
fcf63409	334	goto free_iovecs;
ac34ebb3	335	rc = compat_rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt,
fcf63409	336	UIO_FASTIOV, iovstack_r,
ac34ebb3	337	&iov_r);
fcf63409 CY	338	if (rc <= 0)
	339	goto free_iovecs;
	340
9f78bdfa	341	rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);
fcf63409 CY	342
	343	free_iovecs:
	344	if (iov_r != iovstack_r)
	345	kfree(iov_r);
17d17e72	346	kfree(iov_l);
fcf63409 CY	347	return rc;
	348	}
	349
2f2728f6 HC	350	COMPAT_SYSCALL_DEFINE6(process_vm_readv, compat_pid_t, pid,
	351	const struct compat_iovec __user *, lvec,
	352	compat_ulong_t, liovcnt,
	353	const struct compat_iovec __user *, rvec,
	354	compat_ulong_t, riovcnt,
	355	compat_ulong_t, flags)
fcf63409 CY	356	{
	357	return compat_process_vm_rw(pid, lvec, liovcnt, rvec,
	358	riovcnt, flags, 0);
	359	}
	360
2f2728f6 HC	361	COMPAT_SYSCALL_DEFINE6(process_vm_writev, compat_pid_t, pid,
	362	const struct compat_iovec __user *, lvec,
	363	compat_ulong_t, liovcnt,
	364	const struct compat_iovec __user *, rvec,
	365	compat_ulong_t, riovcnt,
	366	compat_ulong_t, flags)
fcf63409 CY	367	{
	368	return compat_process_vm_rw(pid, lvec, liovcnt, rvec,
	369	riovcnt, flags, 1);
	370	}
	371
	372	#endif