[deliverable/linux.git] / arch / s390 / lib / uaccess_pt.c

/*
 *  arch/s390/lib/uaccess_pt.c
 *
 *  User access functions based on page table walks for enhanced
 *  system layout without hardware support.
 *
 *    Copyright IBM Corp. 2006
 *    Author(s): Gerald Schaefer (gerald.schaefer@de.ibm.com)
 */

#include <linux/errno.h>
#include <linux/hardirq.h>
#include <linux/mm.h>
#include <asm/uaccess.h>
#include <asm/futex.h>
#include "uaccess.h"

static inline pte_t *follow_table(struct mm_struct *mm, unsigned long addr)
{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;

	pgd = pgd_offset(mm, addr);
	if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
		return (pte_t *) 0x3a;

	pud = pud_offset(pgd, addr);
	if (pud_none(*pud) || unlikely(pud_bad(*pud)))
		return (pte_t *) 0x3b;

	pmd = pmd_offset(pud, addr);
	if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
		return (pte_t *) 0x10;

	return pte_offset_map(pmd, addr);
}

static __always_inline size_t __user_copy_pt(unsigned long uaddr, void *kptr,
					     size_t n, int write_user)
{
	struct mm_struct *mm = current->mm;
	unsigned long offset, pfn, done, size;
	pte_t *pte;
	void *from, *to;

	done = 0;
retry:
	spin_lock(&mm->page_table_lock);
	do {
		pte = follow_table(mm, uaddr);
		if ((unsigned long) pte < 0x1000)
			goto fault;
		if (!pte_present(*pte)) {
			pte = (pte_t *) 0x11;
			goto fault;
		} else if (write_user && !pte_write(*pte)) {
			pte = (pte_t *) 0x04;
			goto fault;
		}

		pfn = pte_pfn(*pte);
		offset = uaddr & (PAGE_SIZE - 1);
		size = min(n - done, PAGE_SIZE - offset);
		if (write_user) {
			to = (void *)((pfn << PAGE_SHIFT) + offset);
			from = kptr + done;
		} else {
			from = (void *)((pfn << PAGE_SHIFT) + offset);
			to = kptr + done;
		}
		memcpy(to, from, size);
		done += size;
		uaddr += size;
	} while (done < n);
	spin_unlock(&mm->page_table_lock);
	return n - done;
fault:
	spin_unlock(&mm->page_table_lock);
	if (__handle_fault(uaddr, (unsigned long) pte, write_user))
		return n - done;
	goto retry;
}

/*
 * Do DAT for user address by page table walk, return kernel address.
 * This function needs to be called with current->mm->page_table_lock held.
 */
static __always_inline unsigned long __dat_user_addr(unsigned long uaddr)
{
	struct mm_struct *mm = current->mm;
	unsigned long pfn;
	pte_t *pte;
	int rc;

retry:
	pte = follow_table(mm, uaddr);
	if ((unsigned long) pte < 0x1000)
		goto fault;
	if (!pte_present(*pte)) {
		pte = (pte_t *) 0x11;
		goto fault;
	}

	pfn = pte_pfn(*pte);
	return (pfn << PAGE_SHIFT) + (uaddr & (PAGE_SIZE - 1));
fault:
	spin_unlock(&mm->page_table_lock);
	rc = __handle_fault(uaddr, (unsigned long) pte, 0);
	spin_lock(&mm->page_table_lock);
	if (!rc)
		goto retry;
	return 0;
}

size_t copy_from_user_pt(size_t n, const void __user *from, void *to)
{
	size_t rc;

	if (segment_eq(get_fs(), KERNEL_DS)) {
		memcpy(to, (void __kernel __force *) from, n);
		return 0;
	}
	rc = __user_copy_pt((unsigned long) from, to, n, 0);
	if (unlikely(rc))
		memset(to + n - rc, 0, rc);
	return rc;
}

size_t copy_to_user_pt(size_t n, void __user *to, const void *from)
{
	if (segment_eq(get_fs(), KERNEL_DS)) {
		memcpy((void __kernel __force *) to, from, n);
		return 0;
	}
	return __user_copy_pt((unsigned long) to, (void *) from, n, 1);
}

static size_t clear_user_pt(size_t n, void __user *to)
{
	long done, size, ret;

	if (segment_eq(get_fs(), KERNEL_DS)) {
		memset((void __kernel __force *) to, 0, n);
		return 0;
	}
	done = 0;
	do {
		if (n - done > PAGE_SIZE)
			size = PAGE_SIZE;
		else
			size = n - done;
		ret = __user_copy_pt((unsigned long) to + done,
				      &empty_zero_page, size, 1);
		done += size;
		if (ret)
			return ret + n - done;
	} while (done < n);
	return 0;
}

static size_t strnlen_user_pt(size_t count, const char __user *src)
{
	char *addr;
	unsigned long uaddr = (unsigned long) src;
	struct mm_struct *mm = current->mm;
	unsigned long offset, pfn, done, len;
	pte_t *pte;
	size_t len_str;

	if (segment_eq(get_fs(), KERNEL_DS))
		return strnlen((const char __kernel __force *) src, count) + 1;
	done = 0;
retry:
	spin_lock(&mm->page_table_lock);
	do {
		pte = follow_table(mm, uaddr);
		if ((unsigned long) pte < 0x1000)
			goto fault;
		if (!pte_present(*pte)) {
			pte = (pte_t *) 0x11;
			goto fault;
		}

		pfn = pte_pfn(*pte);
		offset = uaddr & (PAGE_SIZE-1);
		addr = (char *)(pfn << PAGE_SHIFT) + offset;
		len = min(count - done, PAGE_SIZE - offset);
		len_str = strnlen(addr, len);
		done += len_str;
		uaddr += len_str;
	} while ((len_str == len) && (done < count));
	spin_unlock(&mm->page_table_lock);
	return done + 1;
fault:
	spin_unlock(&mm->page_table_lock);
	if (__handle_fault(uaddr, (unsigned long) pte, 0))
		return 0;
	goto retry;
}

static size_t strncpy_from_user_pt(size_t count, const char __user *src,
				   char *dst)
{
	size_t n = strnlen_user_pt(count, src);

	if (!n)
		return -EFAULT;
	if (n > count)
		n = count;
	if (segment_eq(get_fs(), KERNEL_DS)) {
		memcpy(dst, (const char __kernel __force *) src, n);
		if (dst[n-1] == '\0')
			return n-1;
		else
			return n;
	}
	if (__user_copy_pt((unsigned long) src, dst, n, 0))
		return -EFAULT;
	if (dst[n-1] == '\0')
		return n-1;
	else
		return n;
}

static size_t copy_in_user_pt(size_t n, void __user *to,
			      const void __user *from)
{
	struct mm_struct *mm = current->mm;
	unsigned long offset_from, offset_to, offset_max, pfn_from, pfn_to,
		      uaddr, done, size, error_code;
	unsigned long uaddr_from = (unsigned long) from;
	unsigned long uaddr_to = (unsigned long) to;
	pte_t *pte_from, *pte_to;
	int write_user;

	if (segment_eq(get_fs(), KERNEL_DS)) {
		memcpy((void __force *) to, (void __force *) from, n);
		return 0;
	}
	done = 0;
retry:
	spin_lock(&mm->page_table_lock);
	do {
		write_user = 0;
		uaddr = uaddr_from;
		pte_from = follow_table(mm, uaddr_from);
		error_code = (unsigned long) pte_from;
		if (error_code < 0x1000)
			goto fault;
		if (!pte_present(*pte_from)) {
			error_code = 0x11;
			goto fault;
		}

		write_user = 1;
		uaddr = uaddr_to;
		pte_to = follow_table(mm, uaddr_to);
		error_code = (unsigned long) pte_to;
		if (error_code < 0x1000)
			goto fault;
		if (!pte_present(*pte_to)) {
			error_code = 0x11;
			goto fault;
		} else if (!pte_write(*pte_to)) {
			error_code = 0x04;
			goto fault;
		}

		pfn_from = pte_pfn(*pte_from);
		pfn_to = pte_pfn(*pte_to);
		offset_from = uaddr_from & (PAGE_SIZE-1);
		offset_to = uaddr_from & (PAGE_SIZE-1);
		offset_max = max(offset_from, offset_to);
		size = min(n - done, PAGE_SIZE - offset_max);

		memcpy((void *)(pfn_to << PAGE_SHIFT) + offset_to,
		       (void *)(pfn_from << PAGE_SHIFT) + offset_from, size);
		done += size;
		uaddr_from += size;
		uaddr_to += size;
	} while (done < n);
	spin_unlock(&mm->page_table_lock);
	return n - done;
fault:
	spin_unlock(&mm->page_table_lock);
	if (__handle_fault(uaddr, error_code, write_user))
		return n - done;
	goto retry;
}

#define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg)	\
	asm volatile("0: l   %1,0(%6)\n"				\
		     "1: " insn						\
		     "2: cs  %1,%2,0(%6)\n"				\
		     "3: jl  1b\n"					\
		     "   lhi %0,0\n"					\
		     "4:\n"						\
		     EX_TABLE(0b,4b) EX_TABLE(2b,4b) EX_TABLE(3b,4b)	\
		     : "=d" (ret), "=&d" (oldval), "=&d" (newval),	\
		       "=m" (*uaddr)					\
		     : "0" (-EFAULT), "d" (oparg), "a" (uaddr),		\
		       "m" (*uaddr) : "cc" );

static int __futex_atomic_op_pt(int op, int __user *uaddr, int oparg, int *old)
{
	int oldval = 0, newval, ret;

	switch (op) {
	case FUTEX_OP_SET:
		__futex_atomic_op("lr %2,%5\n",
				  ret, oldval, newval, uaddr, oparg);
		break;
	case FUTEX_OP_ADD:
		__futex_atomic_op("lr %2,%1\nar %2,%5\n",
				  ret, oldval, newval, uaddr, oparg);
		break;
	case FUTEX_OP_OR:
		__futex_atomic_op("lr %2,%1\nor %2,%5\n",
				  ret, oldval, newval, uaddr, oparg);
		break;
	case FUTEX_OP_ANDN:
		__futex_atomic_op("lr %2,%1\nnr %2,%5\n",
				  ret, oldval, newval, uaddr, oparg);
		break;
	case FUTEX_OP_XOR:
		__futex_atomic_op("lr %2,%1\nxr %2,%5\n",
				  ret, oldval, newval, uaddr, oparg);
		break;
	default:
		ret = -ENOSYS;
	}
	if (ret == 0)
		*old = oldval;
	return ret;
}

int futex_atomic_op_pt(int op, int __user *uaddr, int oparg, int *old)
{
	int ret;

	if (segment_eq(get_fs(), KERNEL_DS))
		return __futex_atomic_op_pt(op, uaddr, oparg, old);
	spin_lock(&current->mm->page_table_lock);
	uaddr = (int __user *) __dat_user_addr((unsigned long) uaddr);
	if (!uaddr) {
		spin_unlock(&current->mm->page_table_lock);
		return -EFAULT;
	}
	get_page(virt_to_page(uaddr));
	spin_unlock(&current->mm->page_table_lock);
	ret = __futex_atomic_op_pt(op, uaddr, oparg, old);
	put_page(virt_to_page(uaddr));
	return ret;
}

static int __futex_atomic_cmpxchg_pt(int *uval, int __user *uaddr,
				     int oldval, int newval)
{
	int ret;

	asm volatile("0: cs   %1,%4,0(%5)\n"
		     "1: la   %0,0\n"
		     "2:\n"
		     EX_TABLE(0b,2b) EX_TABLE(1b,2b)
		     : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
		     : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
		     : "cc", "memory" );
	*uval = oldval;
	return ret;
}

int futex_atomic_cmpxchg_pt(int *uval, int __user *uaddr,
			    int oldval, int newval)
{
	int ret;

	if (segment_eq(get_fs(), KERNEL_DS))
		return __futex_atomic_cmpxchg_pt(uval, uaddr, oldval, newval);
	spin_lock(&current->mm->page_table_lock);
	uaddr = (int __user *) __dat_user_addr((unsigned long) uaddr);
	if (!uaddr) {
		spin_unlock(&current->mm->page_table_lock);
		return -EFAULT;
	}
	get_page(virt_to_page(uaddr));
	spin_unlock(&current->mm->page_table_lock);
	ret = __futex_atomic_cmpxchg_pt(uval, uaddr, oldval, newval);
	put_page(virt_to_page(uaddr));
	return ret;
}

struct uaccess_ops uaccess_pt = {
	.copy_from_user		= copy_from_user_pt,
	.copy_from_user_small	= copy_from_user_pt,
	.copy_to_user		= copy_to_user_pt,
	.copy_to_user_small	= copy_to_user_pt,
	.copy_in_user		= copy_in_user_pt,
	.clear_user		= clear_user_pt,
	.strnlen_user		= strnlen_user_pt,
	.strncpy_from_user	= strncpy_from_user_pt,
	.futex_atomic_op	= futex_atomic_op_pt,
	.futex_atomic_cmpxchg	= futex_atomic_cmpxchg_pt,
};
Commit	Line	Data
59f35d53 GS	1	/*
	2	* arch/s390/lib/uaccess_pt.c
	3	*
c1821c2e GS	4	* User access functions based on page table walks for enhanced
c1821c2e GS	5	* system layout without hardware support.
59f35d53 GS	6	*
	7	* Copyright IBM Corp. 2006
	8	* Author(s): Gerald Schaefer (gerald.schaefer@de.ibm.com)
	9	*/
	10
	11	#include <linux/errno.h>
d8ad075e	12	#include <linux/hardirq.h>
59f35d53	13	#include <linux/mm.h>
22155914	14	#include <asm/uaccess.h>
59f35d53	15	#include <asm/futex.h>
2b67fc46	16	#include "uaccess.h"
59f35d53	17
e4aa402e MS	18	static inline pte_t follow_table(struct mm_struct mm, unsigned long addr)
	19	{
	20	pgd_t *pgd;
190a1d72	21	pud_t *pud;
e4aa402e MS	22	pmd_t *pmd;
	23
	24	pgd = pgd_offset(mm, addr);
	25	if (pgd_none(pgd) \|\| unlikely(pgd_bad(pgd)))
6c1e3e79	26	return (pte_t *) 0x3a;
e4aa402e	27
190a1d72 MS	28	pud = pud_offset(pgd, addr);
190a1d72 MS	29	if (pud_none(pud) \|\| unlikely(pud_bad(pud)))
6c1e3e79	30	return (pte_t *) 0x3b;
190a1d72 MS	31
190a1d72 MS	32	pmd = pmd_offset(pud, addr);
e4aa402e	33	if (pmd_none(pmd) \|\| unlikely(pmd_bad(pmd)))
6c1e3e79	34	return (pte_t *) 0x10;
e4aa402e MS	35
	36	return pte_offset_map(pmd, addr);
	37	}
	38
6c1e3e79 GS	39	static __always_inline size_t __user_copy_pt(unsigned long uaddr, void *kptr,
6c1e3e79 GS	40	size_t n, int write_user)
59f35d53 GS	41	{
	42	struct mm_struct *mm = current->mm;
	43	unsigned long offset, pfn, done, size;
59f35d53 GS	44	pte_t *pte;
	45	void from, to;
	46
	47	done = 0;
	48	retry:
	49	spin_lock(&mm->page_table_lock);
	50	do {
e4aa402e	51	pte = follow_table(mm, uaddr);
6c1e3e79 GS	52	if ((unsigned long) pte < 0x1000)
	53	goto fault;
	54	if (!pte_present(*pte)) {
	55	pte = (pte_t *) 0x11;
59f35d53	56	goto fault;
6c1e3e79 GS	57	} else if (write_user && !pte_write(*pte)) {
	58	pte = (pte_t *) 0x04;
	59	goto fault;
	60	}
59f35d53 GS	61
59f35d53 GS	62	pfn = pte_pfn(*pte);
59f35d53 GS	63	offset = uaddr & (PAGE_SIZE - 1);
	64	size = min(n - done, PAGE_SIZE - offset);
	65	if (write_user) {
	66	to = (void *)((pfn << PAGE_SHIFT) + offset);
	67	from = kptr + done;
	68	} else {
	69	from = (void *)((pfn << PAGE_SHIFT) + offset);
	70	to = kptr + done;
	71	}
	72	memcpy(to, from, size);
	73	done += size;
	74	uaddr += size;
	75	} while (done < n);
59f35d53 GS	76	spin_unlock(&mm->page_table_lock);
	77	return n - done;
	78	fault:
	79	spin_unlock(&mm->page_table_lock);
6c1e3e79	80	if (__handle_fault(uaddr, (unsigned long) pte, write_user))
59f35d53 GS	81	return n - done;
	82	goto retry;
	83	}
	84
c1821c2e GS	85	/*
	86	* Do DAT for user address by page table walk, return kernel address.
	87	* This function needs to be called with current->mm->page_table_lock held.
	88	*/
6c1e3e79	89	static __always_inline unsigned long __dat_user_addr(unsigned long uaddr)
c1821c2e GS	90	{
c1821c2e GS	91	struct mm_struct *mm = current->mm;
6c1e3e79	92	unsigned long pfn;
c1821c2e GS	93	pte_t *pte;
	94	int rc;
	95
c1821c2e	96	retry:
e4aa402e	97	pte = follow_table(mm, uaddr);
6c1e3e79 GS	98	if ((unsigned long) pte < 0x1000)
	99	goto fault;
	100	if (!pte_present(*pte)) {
	101	pte = (pte_t *) 0x11;
c1821c2e	102	goto fault;
6c1e3e79	103	}
c1821c2e GS	104
c1821c2e GS	105	pfn = pte_pfn(*pte);
6c1e3e79	106	return (pfn << PAGE_SHIFT) + (uaddr & (PAGE_SIZE - 1));
c1821c2e GS	107	fault:
c1821c2e GS	108	spin_unlock(&mm->page_table_lock);
6c1e3e79	109	rc = __handle_fault(uaddr, (unsigned long) pte, 0);
c1821c2e	110	spin_lock(&mm->page_table_lock);
6c1e3e79 GS	111	if (!rc)
	112	goto retry;
	113	return 0;
c1821c2e GS	114	}
c1821c2e GS	115
59f35d53 GS	116	size_t copy_from_user_pt(size_t n, const void __user from, void to)
	117	{
	118	size_t rc;
	119
	120	if (segment_eq(get_fs(), KERNEL_DS)) {
	121	memcpy(to, (void __kernel __force *) from, n);
	122	return 0;
	123	}
	124	rc = __user_copy_pt((unsigned long) from, to, n, 0);
	125	if (unlikely(rc))
	126	memset(to + n - rc, 0, rc);
	127	return rc;
	128	}
	129
	130	size_t copy_to_user_pt(size_t n, void __user to, const void from)
	131	{
	132	if (segment_eq(get_fs(), KERNEL_DS)) {
	133	memcpy((void __kernel __force *) to, from, n);
	134	return 0;
	135	}
	136	return __user_copy_pt((unsigned long) to, (void *) from, n, 1);
	137	}
c1821c2e GS	138
	139	static size_t clear_user_pt(size_t n, void __user *to)
	140	{
	141	long done, size, ret;
	142
	143	if (segment_eq(get_fs(), KERNEL_DS)) {
	144	memset((void __kernel __force *) to, 0, n);
	145	return 0;
	146	}
	147	done = 0;
	148	do {
	149	if (n - done > PAGE_SIZE)
	150	size = PAGE_SIZE;
	151	else
	152	size = n - done;
	153	ret = __user_copy_pt((unsigned long) to + done,
	154	&empty_zero_page, size, 1);
	155	done += size;
	156	if (ret)
	157	return ret + n - done;
	158	} while (done < n);
	159	return 0;
	160	}
	161
	162	static size_t strnlen_user_pt(size_t count, const char __user *src)
	163	{
	164	char *addr;
	165	unsigned long uaddr = (unsigned long) src;
	166	struct mm_struct *mm = current->mm;
	167	unsigned long offset, pfn, done, len;
c1821c2e GS	168	pte_t *pte;
	169	size_t len_str;
	170
	171	if (segment_eq(get_fs(), KERNEL_DS))
	172	return strnlen((const char __kernel __force *) src, count) + 1;
	173	done = 0;
	174	retry:
	175	spin_lock(&mm->page_table_lock);
	176	do {
e4aa402e	177	pte = follow_table(mm, uaddr);
6c1e3e79	178	if ((unsigned long) pte < 0x1000)
c1821c2e	179	goto fault;
6c1e3e79 GS	180	if (!pte_present(*pte)) {
	181	pte = (pte_t *) 0x11;
	182	goto fault;
	183	}
c1821c2e GS	184
c1821c2e GS	185	pfn = pte_pfn(*pte);
c1821c2e GS	186	offset = uaddr & (PAGE_SIZE-1);
	187	addr = (char *)(pfn << PAGE_SHIFT) + offset;
	188	len = min(count - done, PAGE_SIZE - offset);
	189	len_str = strnlen(addr, len);
	190	done += len_str;
	191	uaddr += len_str;
	192	} while ((len_str == len) && (done < count));
c1821c2e GS	193	spin_unlock(&mm->page_table_lock);
	194	return done + 1;
	195	fault:
	196	spin_unlock(&mm->page_table_lock);
6c1e3e79	197	if (__handle_fault(uaddr, (unsigned long) pte, 0))
c1821c2e	198	return 0;
c1821c2e GS	199	goto retry;
	200	}
	201
	202	static size_t strncpy_from_user_pt(size_t count, const char __user *src,
	203	char *dst)
	204	{
	205	size_t n = strnlen_user_pt(count, src);
	206
	207	if (!n)
	208	return -EFAULT;
	209	if (n > count)
	210	n = count;
	211	if (segment_eq(get_fs(), KERNEL_DS)) {
	212	memcpy(dst, (const char __kernel __force *) src, n);
	213	if (dst[n-1] == '\0')
	214	return n-1;
	215	else
	216	return n;
	217	}
	218	if (__user_copy_pt((unsigned long) src, dst, n, 0))
	219	return -EFAULT;
	220	if (dst[n-1] == '\0')
	221	return n-1;
	222	else
	223	return n;
	224	}
	225
	226	static size_t copy_in_user_pt(size_t n, void __user *to,
	227	const void __user *from)
	228	{
	229	struct mm_struct *mm = current->mm;
	230	unsigned long offset_from, offset_to, offset_max, pfn_from, pfn_to,
6c1e3e79	231	uaddr, done, size, error_code;
c1821c2e GS	232	unsigned long uaddr_from = (unsigned long) from;
c1821c2e GS	233	unsigned long uaddr_to = (unsigned long) to;
c1821c2e GS	234	pte_t pte_from, pte_to;
	235	int write_user;
	236
3f12ebce HC	237	if (segment_eq(get_fs(), KERNEL_DS)) {
	238	memcpy((void __force ) to, (void __force ) from, n);
	239	return 0;
	240	}
c1821c2e GS	241	done = 0;
	242	retry:
	243	spin_lock(&mm->page_table_lock);
	244	do {
6c1e3e79 GS	245	write_user = 0;
6c1e3e79 GS	246	uaddr = uaddr_from;
e4aa402e	247	pte_from = follow_table(mm, uaddr_from);
6c1e3e79 GS	248	error_code = (unsigned long) pte_from;
	249	if (error_code < 0x1000)
	250	goto fault;
	251	if (!pte_present(*pte_from)) {
	252	error_code = 0x11;
c1821c2e GS	253	goto fault;
c1821c2e GS	254	}
e4aa402e	255
6c1e3e79 GS	256	write_user = 1;
6c1e3e79 GS	257	uaddr = uaddr_to;
e4aa402e	258	pte_to = follow_table(mm, uaddr_to);
6c1e3e79 GS	259	error_code = (unsigned long) pte_to;
	260	if (error_code < 0x1000)
	261	goto fault;
	262	if (!pte_present(*pte_to)) {
	263	error_code = 0x11;
	264	goto fault;
	265	} else if (!pte_write(*pte_to)) {
	266	error_code = 0x04;
c1821c2e GS	267	goto fault;
	268	}
	269
	270	pfn_from = pte_pfn(*pte_from);
c1821c2e	271	pfn_to = pte_pfn(*pte_to);
c1821c2e GS	272	offset_from = uaddr_from & (PAGE_SIZE-1);
	273	offset_to = uaddr_from & (PAGE_SIZE-1);
	274	offset_max = max(offset_from, offset_to);
	275	size = min(n - done, PAGE_SIZE - offset_max);
	276
	277	memcpy((void *)(pfn_to << PAGE_SHIFT) + offset_to,
	278	(void *)(pfn_from << PAGE_SHIFT) + offset_from, size);
	279	done += size;
	280	uaddr_from += size;
	281	uaddr_to += size;
	282	} while (done < n);
c1821c2e GS	283	spin_unlock(&mm->page_table_lock);
	284	return n - done;
	285	fault:
	286	spin_unlock(&mm->page_table_lock);
6c1e3e79	287	if (__handle_fault(uaddr, error_code, write_user))
c1821c2e GS	288	return n - done;
	289	goto retry;
	290	}
	291
	292	#define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg) \
	293	asm volatile("0: l %1,0(%6)\n" \
	294	"1: " insn \
	295	"2: cs %1,%2,0(%6)\n" \
	296	"3: jl 1b\n" \
	297	" lhi %0,0\n" \
	298	"4:\n" \
	299	EX_TABLE(0b,4b) EX_TABLE(2b,4b) EX_TABLE(3b,4b) \
	300	: "=d" (ret), "=&d" (oldval), "=&d" (newval), \
	301	"=m" (*uaddr) \
	302	: "0" (-EFAULT), "d" (oparg), "a" (uaddr), \
	303	"m" (*uaddr) : "cc" );
	304
3f12ebce	305	static int __futex_atomic_op_pt(int op, int __user uaddr, int oparg, int old)
c1821c2e GS	306	{
	307	int oldval = 0, newval, ret;
	308
c1821c2e GS	309	switch (op) {
	310	case FUTEX_OP_SET:
	311	__futex_atomic_op("lr %2,%5\n",
	312	ret, oldval, newval, uaddr, oparg);
	313	break;
	314	case FUTEX_OP_ADD:
	315	__futex_atomic_op("lr %2,%1\nar %2,%5\n",
	316	ret, oldval, newval, uaddr, oparg);
	317	break;
	318	case FUTEX_OP_OR:
	319	__futex_atomic_op("lr %2,%1\nor %2,%5\n",
	320	ret, oldval, newval, uaddr, oparg);
	321	break;
	322	case FUTEX_OP_ANDN:
	323	__futex_atomic_op("lr %2,%1\nnr %2,%5\n",
	324	ret, oldval, newval, uaddr, oparg);
	325	break;
	326	case FUTEX_OP_XOR:
	327	__futex_atomic_op("lr %2,%1\nxr %2,%5\n",
	328	ret, oldval, newval, uaddr, oparg);
	329	break;
	330	default:
	331	ret = -ENOSYS;
	332	}
3f12ebce HC	333	if (ret == 0)
3f12ebce HC	334	*old = oldval;
c1821c2e GS	335	return ret;
	336	}
	337
3f12ebce	338	int futex_atomic_op_pt(int op, int __user uaddr, int oparg, int old)
c1821c2e GS	339	{
	340	int ret;
	341
3f12ebce HC	342	if (segment_eq(get_fs(), KERNEL_DS))
3f12ebce HC	343	return __futex_atomic_op_pt(op, uaddr, oparg, old);
c1821c2e GS	344	spin_lock(&current->mm->page_table_lock);
	345	uaddr = (int __user *) __dat_user_addr((unsigned long) uaddr);
	346	if (!uaddr) {
	347	spin_unlock(&current->mm->page_table_lock);
	348	return -EFAULT;
	349	}
	350	get_page(virt_to_page(uaddr));
	351	spin_unlock(&current->mm->page_table_lock);
3f12ebce HC	352	ret = __futex_atomic_op_pt(op, uaddr, oparg, old);
	353	put_page(virt_to_page(uaddr));
	354	return ret;
	355	}
	356
37a9d912 ML	357	static int __futex_atomic_cmpxchg_pt(int uval, int __user uaddr,
37a9d912 ML	358	int oldval, int newval)
3f12ebce HC	359	{
	360	int ret;
	361
	362	asm volatile("0: cs %1,%4,0(%5)\n"
37a9d912	363	"1: la %0,0\n"
3f12ebce HC	364	"2:\n"
3f12ebce HC	365	EX_TABLE(0b,2b) EX_TABLE(1b,2b)
c1821c2e GS	366	: "=d" (ret), "+d" (oldval), "=m" (*uaddr)
	367	: "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
	368	: "cc", "memory" );
37a9d912	369	*uval = oldval;
3f12ebce HC	370	return ret;
	371	}
	372
37a9d912 ML	373	int futex_atomic_cmpxchg_pt(int uval, int __user uaddr,
37a9d912 ML	374	int oldval, int newval)
3f12ebce HC	375	{
	376	int ret;
	377
	378	if (segment_eq(get_fs(), KERNEL_DS))
37a9d912	379	return __futex_atomic_cmpxchg_pt(uval, uaddr, oldval, newval);
3f12ebce HC	380	spin_lock(&current->mm->page_table_lock);
	381	uaddr = (int __user *) __dat_user_addr((unsigned long) uaddr);
	382	if (!uaddr) {
	383	spin_unlock(&current->mm->page_table_lock);
	384	return -EFAULT;
	385	}
	386	get_page(virt_to_page(uaddr));
	387	spin_unlock(&current->mm->page_table_lock);
37a9d912	388	ret = __futex_atomic_cmpxchg_pt(uval, uaddr, oldval, newval);
c1821c2e GS	389	put_page(virt_to_page(uaddr));
	390	return ret;
	391	}
	392
	393	struct uaccess_ops uaccess_pt = {
	394	.copy_from_user = copy_from_user_pt,
	395	.copy_from_user_small = copy_from_user_pt,
	396	.copy_to_user = copy_to_user_pt,
	397	.copy_to_user_small = copy_to_user_pt,
	398	.copy_in_user = copy_in_user_pt,
	399	.clear_user = clear_user_pt,
	400	.strnlen_user = strnlen_user_pt,
	401	.strncpy_from_user = strncpy_from_user_pt,
	402	.futex_atomic_op = futex_atomic_op_pt,
	403	.futex_atomic_cmpxchg = futex_atomic_cmpxchg_pt,
	404	};