[mirror_ubuntu-zesty-kernel.git] / mm / process_vm_access.c

/*
 * linux/mm/process_vm_access.c
 *
 * Copyright (C) 2010-2011 Christopher Yeoh <cyeoh@au1.ibm.com>, IBM Corp.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/mm.h>
#include <linux/uio.h>
#include <linux/sched.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
 * @start_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) {
			if (copy > iov_iter_count(iter))
				copy = iov_iter_count(iter);
			copied = iov_iter_copy_from_user(page, iter,
					offset, copy);
			iov_iter_advance(iter, copied);
			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 *);

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

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

		/* Get the pages we're interested in */
		down_read(&mm->mmap_sem);
		pages = get_user_pages(task, mm, pa, pages,
				      vm_write, 0, process_pages, NULL);
		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 */
	rcu_read_lock();
	task = find_task_by_vpid(pid);
	if (task)
		get_task_struct(task);
	rcu_read_unlock();
	if (!task) {
		rc = -ESRCH;
		goto free_proc_pages;
	}

	mm = mm_access(task, PTRACE_MODE_ATTACH);
	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;

	if (flags != 0)
		return -EINVAL;

	/* Check iovecs */
	if (vm_write)
		rc = rw_copy_check_uvector(WRITE, lvec, liovcnt, UIO_FASTIOV,
					   iovstack_l, &iov_l);
	else
		rc = rw_copy_check_uvector(READ, lvec, liovcnt, UIO_FASTIOV,
					   iovstack_l, &iov_l);
	if (rc <= 0)
		goto free_iovecs;

	iov_iter_init(&iter, iov_l, liovcnt, rc, 0);

	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);
	if (iov_l != iovstack_l)
		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;

	if (flags != 0)
		return -EINVAL;

	if (vm_write)
		rc = compat_rw_copy_check_uvector(WRITE, lvec, liovcnt,
						  UIO_FASTIOV, iovstack_l,
						  &iov_l);
	else
		rc = compat_rw_copy_check_uvector(READ, lvec, liovcnt,
						  UIO_FASTIOV, iovstack_l,
						  &iov_l);
	if (rc <= 0)
		goto free_iovecs;
	iov_iter_init(&iter, iov_l, liovcnt, rc, 0);
	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);
	if (iov_l != iovstack_l)
		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
fcf63409 CY	1	/*
	2	* linux/mm/process_vm_access.c
	3	*
	4	* Copyright (C) 2010-2011 Christopher Yeoh <cyeoh@au1.ibm.com>, IBM Corp.
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11
	12	#include <linux/mm.h>
	13	#include <linux/uio.h>
	14	#include <linux/sched.h>
	15	#include <linux/highmem.h>
	16	#include <linux/ptrace.h>
	17	#include <linux/slab.h>
	18	#include <linux/syscalls.h>
	19
	20	#ifdef CONFIG_COMPAT
	21	#include <linux/compat.h>
	22	#endif
	23
	24	/**
	25	* process_vm_rw_pages - read/write pages from task specified
4bafbec7	26	* @pages: array of pointers to pages we want to copy
fcf63409 CY	27	* @start_offset: offset in page to start copying from/to
fcf63409 CY	28	* @len: number of bytes to copy
4bafbec7	29	* @iter: where to copy to/from locally
fcf63409	30	* @vm_write: 0 means copy from, 1 means copy to
fcf63409 CY	31	* Returns 0 on success, error code otherwise
fcf63409 CY	32	*/
70eca12d AV	33	static int process_vm_rw_pages(struct page **pages,
70eca12d AV	34	unsigned offset,
e21345f9	35	size_t len,
9f78bdfa	36	struct iov_iter *iter,
9acc1a0f	37	int vm_write)
fcf63409	38	{
fcf63409	39	/* Do the copy for each page */
9acc1a0f	40	while (len && iov_iter_count(iter)) {
70eca12d	41	struct page page = pages++;
e21345f9	42	size_t copy = PAGE_SIZE - offset;
70eca12d	43	size_t copied;
240f3905	44
e21345f9 AV	45	if (copy > len)
	46	copy = len;
	47
240f3905	48	if (vm_write) {
70eca12d AV	49	if (copy > iov_iter_count(iter))
	50	copy = iov_iter_count(iter);
	51	copied = iov_iter_copy_from_user(page, iter,
	52	offset, copy);
	53	iov_iter_advance(iter, copied);
240f3905	54	set_page_dirty_lock(page);
fcf63409	55	} else {
70eca12d	56	copied = copy_page_to_iter(page, offset, copy, iter);
fcf63409	57	}
70eca12d AV	58	len -= copied;
	59	if (copied < copy && iov_iter_count(iter))
	60	return -EFAULT;
	61	offset = 0;
fcf63409	62	}
70eca12d	63	return 0;
fcf63409 CY	64	}
	65
	66	/* Maximum number of pages kmalloc'd to hold struct page's during copy */
	67	#define PVM_MAX_KMALLOC_PAGES (PAGE_SIZE * 2)
	68
	69	/**
	70	* process_vm_rw_single_vec - read/write pages from task specified
	71	* @addr: start memory address of target process
	72	* @len: size of area to copy to/from
4bafbec7	73	* @iter: where to copy to/from locally
fcf63409 CY	74	* @process_pages: struct pages area that can store at least
	75	* nr_pages_to_copy struct page pointers
	76	* @mm: mm for task
	77	* @task: task to read/write from
	78	* @vm_write: 0 means copy from, 1 means copy to
fcf63409 CY	79	* Returns 0 on success or on failure error code
	80	*/
	81	static int process_vm_rw_single_vec(unsigned long addr,
	82	unsigned long len,
9f78bdfa	83	struct iov_iter *iter,
fcf63409 CY	84	struct page **process_pages,
	85	struct mm_struct *mm,
	86	struct task_struct *task,
9acc1a0f	87	int vm_write)
fcf63409 CY	88	{
	89	unsigned long pa = addr & PAGE_MASK;
	90	unsigned long start_offset = addr - pa;
	91	unsigned long nr_pages;
fcf63409	92	ssize_t rc = 0;
fcf63409 CY	93	unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
	94	/ sizeof(struct pages *);
	95
fcf63409 CY	96	/* Work out address and page range required */
	97	if (len == 0)
	98	return 0;
	99	nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1;
	100
4bafbec7 AV	101	while (!rc && nr_pages && iov_iter_count(iter)) {
	102	int pages = min(nr_pages, max_pages_per_loop);
	103	size_t bytes;
fcf63409	104
70eca12d AV	105	/* Get the pages we're interested in */
70eca12d AV	106	down_read(&mm->mmap_sem);
4bafbec7 AV	107	pages = get_user_pages(task, mm, pa, pages,
4bafbec7 AV	108	vm_write, 0, process_pages, NULL);
70eca12d	109	up_read(&mm->mmap_sem);
fcf63409	110
4bafbec7	111	if (pages <= 0)
70eca12d AV	112	return -EFAULT;
70eca12d AV	113
4bafbec7 AV	114	bytes = pages * PAGE_SIZE - start_offset;
	115	if (bytes > len)
	116	bytes = len;
e21345f9	117
70eca12d	118	rc = process_vm_rw_pages(process_pages,
4bafbec7	119	start_offset, bytes, iter,
9acc1a0f	120	vm_write);
4bafbec7	121	len -= bytes;
fcf63409	122	start_offset = 0;
4bafbec7 AV	123	nr_pages -= pages;
	124	pa += pages * PAGE_SIZE;
	125	while (pages)
	126	put_page(process_pages[--pages]);
fcf63409 CY	127	}
	128
	129	return rc;
	130	}
	131
	132	/* Maximum number of entries for process pages array
	133	which lives on stack */
	134	#define PVM_MAX_PP_ARRAY_COUNT 16
	135
	136	/**
	137	* process_vm_rw_core - core of reading/writing pages from task specified
	138	* @pid: PID of process to read/write from/to
4bafbec7	139	* @iter: where to copy to/from locally
fcf63409 CY	140	* @rvec: iovec array specifying where to copy to/from in the other process
	141	* @riovcnt: size of rvec array
	142	* @flags: currently unused
	143	* @vm_write: 0 if reading from other process, 1 if writing to other process
	144	* Returns the number of bytes read/written or error code. May
	145	* return less bytes than expected if an error occurs during the copying
	146	* process.
	147	*/
9f78bdfa	148	static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,
fcf63409 CY	149	const struct iovec *rvec,
	150	unsigned long riovcnt,
	151	unsigned long flags, int vm_write)
	152	{
	153	struct task_struct *task;
	154	struct page *pp_stack[PVM_MAX_PP_ARRAY_COUNT];
	155	struct page **process_pages = pp_stack;
	156	struct mm_struct *mm;
	157	unsigned long i;
	158	ssize_t rc = 0;
fcf63409 CY	159	unsigned long nr_pages = 0;
fcf63409 CY	160	unsigned long nr_pages_iov;
fcf63409	161	ssize_t iov_len;
9acc1a0f	162	size_t total_len = iov_iter_count(iter);
fcf63409 CY	163
	164	/*
	165	* Work out how many pages of struct pages we're going to need
	166	* when eventually calling get_user_pages
	167	*/
	168	for (i = 0; i < riovcnt; i++) {
	169	iov_len = rvec[i].iov_len;
	170	if (iov_len > 0) {
	171	nr_pages_iov = ((unsigned long)rvec[i].iov_base
	172	+ iov_len)
	173	/ PAGE_SIZE - (unsigned long)rvec[i].iov_base
	174	/ PAGE_SIZE + 1;
	175	nr_pages = max(nr_pages, nr_pages_iov);
	176	}
	177	}
	178
	179	if (nr_pages == 0)
	180	return 0;
	181
	182	if (nr_pages > PVM_MAX_PP_ARRAY_COUNT) {
	183	/* For reliability don't try to kmalloc more than
	184	2 pages worth */
	185	process_pages = kmalloc(min_t(size_t, PVM_MAX_KMALLOC_PAGES,
	186	sizeof(struct pages )nr_pages),
	187	GFP_KERNEL);
	188
	189	if (!process_pages)
	190	return -ENOMEM;
	191	}
	192
	193	/* Get process information */
	194	rcu_read_lock();
	195	task = find_task_by_vpid(pid);
	196	if (task)
	197	get_task_struct(task);
	198	rcu_read_unlock();
	199	if (!task) {
	200	rc = -ESRCH;
	201	goto free_proc_pages;
	202	}
	203
8cdb878d CY	204	mm = mm_access(task, PTRACE_MODE_ATTACH);
	205	if (!mm \|\| IS_ERR(mm)) {
	206	rc = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH;
	207	/*
	208	* Explicitly map EACCES to EPERM as EPERM is a more a
	209	* appropriate error code for process_vw_readv/writev
	210	*/
	211	if (rc == -EACCES)
	212	rc = -EPERM;
fcf63409 CY	213	goto put_task_struct;
	214	}
	215
9acc1a0f	216	for (i = 0; i < riovcnt && iov_iter_count(iter) && !rc; i++)
fcf63409 CY	217	rc = process_vm_rw_single_vec(
fcf63409 CY	218	(unsigned long)rvec[i].iov_base, rvec[i].iov_len,
9acc1a0f AV	219	iter, process_pages, mm, task, vm_write);
	220
	221	/* copied = space before - space after */
	222	total_len -= iov_iter_count(iter);
	223
	224	/* If we have managed to copy any data at all then
	225	we return the number of bytes copied. Otherwise
	226	we return the error code */
	227	if (total_len)
	228	rc = total_len;
fcf63409	229
fcf63409 CY	230	mmput(mm);
	231
	232	put_task_struct:
	233	put_task_struct(task);
	234
	235	free_proc_pages:
	236	if (process_pages != pp_stack)
	237	kfree(process_pages);
	238	return rc;
	239	}
	240
	241	/**
	242	* process_vm_rw - check iovecs before calling core routine
	243	* @pid: PID of process to read/write from/to
	244	* @lvec: iovec array specifying where to copy to/from locally
	245	* @liovcnt: size of lvec array
	246	* @rvec: iovec array specifying where to copy to/from in the other process
	247	* @riovcnt: size of rvec array
	248	* @flags: currently unused
	249	* @vm_write: 0 if reading from other process, 1 if writing to other process
	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 CY	266	ssize_t rc;
	267
	268	if (flags != 0)
	269	return -EINVAL;
	270
	271	/* Check iovecs */
	272	if (vm_write)
	273	rc = rw_copy_check_uvector(WRITE, lvec, liovcnt, UIO_FASTIOV,
ac34ebb3	274	iovstack_l, &iov_l);
fcf63409 CY	275	else
fcf63409 CY	276	rc = rw_copy_check_uvector(READ, lvec, liovcnt, UIO_FASTIOV,
ac34ebb3	277	iovstack_l, &iov_l);
fcf63409 CY	278	if (rc <= 0)
	279	goto free_iovecs;
	280
9f78bdfa AV	281	iov_iter_init(&iter, iov_l, liovcnt, rc, 0);
9f78bdfa AV	282
ac34ebb3 CY	283	rc = rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV,
ac34ebb3 CY	284	iovstack_r, &iov_r);
fcf63409 CY	285	if (rc <= 0)
	286	goto free_iovecs;
	287
9f78bdfa	288	rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);
fcf63409 CY	289
	290	free_iovecs:
	291	if (iov_r != iovstack_r)
	292	kfree(iov_r);
	293	if (iov_l != iovstack_l)
	294	kfree(iov_l);
	295
	296	return rc;
	297	}
	298
	299	SYSCALL_DEFINE6(process_vm_readv, pid_t, pid, const struct iovec __user *, lvec,
	300	unsigned long, liovcnt, const struct iovec __user *, rvec,
	301	unsigned long, riovcnt, unsigned long, flags)
	302	{
	303	return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 0);
	304	}
	305
	306	SYSCALL_DEFINE6(process_vm_writev, pid_t, pid,
	307	const struct iovec __user *, lvec,
	308	unsigned long, liovcnt, const struct iovec __user *, rvec,
	309	unsigned long, riovcnt, unsigned long, flags)
	310	{
	311	return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 1);
	312	}
	313
	314	#ifdef CONFIG_COMPAT
	315
2eb2e141	316	static ssize_t
fcf63409 CY	317	compat_process_vm_rw(compat_pid_t pid,
	318	const struct compat_iovec __user *lvec,
	319	unsigned long liovcnt,
	320	const struct compat_iovec __user *rvec,
	321	unsigned long riovcnt,
	322	unsigned long flags, int vm_write)
	323	{
	324	struct iovec iovstack_l[UIO_FASTIOV];
	325	struct iovec iovstack_r[UIO_FASTIOV];
	326	struct iovec *iov_l = iovstack_l;
	327	struct iovec *iov_r = iovstack_r;
9f78bdfa	328	struct iov_iter iter;
fcf63409 CY	329	ssize_t rc = -EFAULT;
	330
	331	if (flags != 0)
	332	return -EINVAL;
	333
fcf63409 CY	334	if (vm_write)
	335	rc = compat_rw_copy_check_uvector(WRITE, lvec, liovcnt,
	336	UIO_FASTIOV, iovstack_l,
ac34ebb3	337	&iov_l);
fcf63409 CY	338	else
	339	rc = compat_rw_copy_check_uvector(READ, lvec, liovcnt,
	340	UIO_FASTIOV, iovstack_l,
ac34ebb3	341	&iov_l);
fcf63409 CY	342	if (rc <= 0)
fcf63409 CY	343	goto free_iovecs;
9f78bdfa	344	iov_iter_init(&iter, iov_l, liovcnt, rc, 0);
ac34ebb3	345	rc = compat_rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt,
fcf63409	346	UIO_FASTIOV, iovstack_r,
ac34ebb3	347	&iov_r);
fcf63409 CY	348	if (rc <= 0)
	349	goto free_iovecs;
	350
9f78bdfa	351	rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);
fcf63409 CY	352
	353	free_iovecs:
	354	if (iov_r != iovstack_r)
	355	kfree(iov_r);
	356	if (iov_l != iovstack_l)
	357	kfree(iov_l);
fcf63409 CY	358	return rc;
	359	}
	360
2f2728f6 HC	361	COMPAT_SYSCALL_DEFINE6(process_vm_readv, 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, 0);
	370	}
	371
2f2728f6 HC	372	COMPAT_SYSCALL_DEFINE6(process_vm_writev, compat_pid_t, pid,
	373	const struct compat_iovec __user *, lvec,
	374	compat_ulong_t, liovcnt,
	375	const struct compat_iovec __user *, rvec,
	376	compat_ulong_t, riovcnt,
	377	compat_ulong_t, flags)
fcf63409 CY	378	{
	379	return compat_process_vm_rw(pid, lvec, liovcnt, rvec,
	380	riovcnt, flags, 1);
	381	}
	382
	383	#endif