[mirror_ubuntu-zesty-kernel.git] / arch / s390 / lib / uaccess.c

/*
 *  Standard user space access functions based on mvcp/mvcs and doing
 *  interesting things in the secondary space mode.
 *
 *    Copyright IBM Corp. 2006,2014
 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
 *		 Gerald Schaefer (gerald.schaefer@de.ibm.com)
 */

#include <linux/jump_label.h>
#include <linux/uaccess.h>
#include <linux/export.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <asm/mmu_context.h>
#include <asm/facility.h>

#ifndef CONFIG_64BIT
#define AHI	"ahi"
#define ALR	"alr"
#define CLR	"clr"
#define LHI	"lhi"
#define SLR	"slr"
#else
#define AHI	"aghi"
#define ALR	"algr"
#define CLR	"clgr"
#define LHI	"lghi"
#define SLR	"slgr"
#endif

static struct static_key have_mvcos = STATIC_KEY_INIT_FALSE;

static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr,
						 unsigned long size)
{
	register unsigned long reg0 asm("0") = 0x81UL;
	unsigned long tmp1, tmp2;

	tmp1 = -4096UL;
	asm volatile(
		"0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
		"9: jz    7f\n"
		"1:"ALR"  %0,%3\n"
		"  "SLR"  %1,%3\n"
		"  "SLR"  %2,%3\n"
		"   j     0b\n"
		"2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
		"   nr    %4,%3\n"	/* %4 = (ptr + 4095) & -4096 */
		"  "SLR"  %4,%1\n"
		"  "CLR"  %0,%4\n"	/* copy crosses next page boundary? */
		"   jnh   4f\n"
		"3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
		"10:"SLR"  %0,%4\n"
		"  "ALR"  %2,%4\n"
		"4:"LHI"  %4,-1\n"
		"  "ALR"  %4,%0\n"	/* copy remaining size, subtract 1 */
		"   bras  %3,6f\n"	/* memset loop */
		"   xc    0(1,%2),0(%2)\n"
		"5: xc    0(256,%2),0(%2)\n"
		"   la    %2,256(%2)\n"
		"6:"AHI"  %4,-256\n"
		"   jnm   5b\n"
		"   ex    %4,0(%3)\n"
		"   j     8f\n"
		"7:"SLR"  %0,%0\n"
		"8:\n"
		EX_TABLE(0b,2b) EX_TABLE(3b,4b) EX_TABLE(9b,2b) EX_TABLE(10b,4b)
		: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
		: "d" (reg0) : "cc", "memory");
	return size;
}

static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
						unsigned long size)
{
	unsigned long tmp1, tmp2;

	load_kernel_asce();
	tmp1 = -256UL;
	asm volatile(
		"   sacf  0\n"
		"0: mvcp  0(%0,%2),0(%1),%3\n"
		"10:jz    8f\n"
		"1:"ALR"  %0,%3\n"
		"   la    %1,256(%1)\n"
		"   la    %2,256(%2)\n"
		"2: mvcp  0(%0,%2),0(%1),%3\n"
		"11:jnz   1b\n"
		"   j     8f\n"
		"3: la    %4,255(%1)\n"	/* %4 = ptr + 255 */
		"  "LHI"  %3,-4096\n"
		"   nr    %4,%3\n"	/* %4 = (ptr + 255) & -4096 */
		"  "SLR"  %4,%1\n"
		"  "CLR"  %0,%4\n"	/* copy crosses next page boundary? */
		"   jnh   5f\n"
		"4: mvcp  0(%4,%2),0(%1),%3\n"
		"12:"SLR"  %0,%4\n"
		"  "ALR"  %2,%4\n"
		"5:"LHI"  %4,-1\n"
		"  "ALR"  %4,%0\n"	/* copy remaining size, subtract 1 */
		"   bras  %3,7f\n"	/* memset loop */
		"   xc    0(1,%2),0(%2)\n"
		"6: xc    0(256,%2),0(%2)\n"
		"   la    %2,256(%2)\n"
		"7:"AHI"  %4,-256\n"
		"   jnm   6b\n"
		"   ex    %4,0(%3)\n"
		"   j     9f\n"
		"8:"SLR"  %0,%0\n"
		"9: sacf  768\n"
		EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,5b)
		EX_TABLE(10b,3b) EX_TABLE(11b,3b) EX_TABLE(12b,5b)
		: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
		: : "cc", "memory");
	return size;
}

unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
{
	if (static_key_false(&have_mvcos))
		return copy_from_user_mvcos(to, from, n);
	return copy_from_user_mvcp(to, from, n);
}
EXPORT_SYMBOL(__copy_from_user);

static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
					       unsigned long size)
{
	register unsigned long reg0 asm("0") = 0x810000UL;
	unsigned long tmp1, tmp2;

	tmp1 = -4096UL;
	asm volatile(
		"0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
		"6: jz    4f\n"
		"1:"ALR"  %0,%3\n"
		"  "SLR"  %1,%3\n"
		"  "SLR"  %2,%3\n"
		"   j     0b\n"
		"2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
		"   nr    %4,%3\n"	/* %4 = (ptr + 4095) & -4096 */
		"  "SLR"  %4,%1\n"
		"  "CLR"  %0,%4\n"	/* copy crosses next page boundary? */
		"   jnh   5f\n"
		"3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
		"7:"SLR"  %0,%4\n"
		"   j     5f\n"
		"4:"SLR"  %0,%0\n"
		"5:\n"
		EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
		: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
		: "d" (reg0) : "cc", "memory");
	return size;
}

static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
					      unsigned long size)
{
	unsigned long tmp1, tmp2;

	load_kernel_asce();
	tmp1 = -256UL;
	asm volatile(
		"   sacf  0\n"
		"0: mvcs  0(%0,%1),0(%2),%3\n"
		"7: jz    5f\n"
		"1:"ALR"  %0,%3\n"
		"   la    %1,256(%1)\n"
		"   la    %2,256(%2)\n"
		"2: mvcs  0(%0,%1),0(%2),%3\n"
		"8: jnz   1b\n"
		"   j     5f\n"
		"3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
		"  "LHI"  %3,-4096\n"
		"   nr    %4,%3\n"	/* %4 = (ptr + 255) & -4096 */
		"  "SLR"  %4,%1\n"
		"  "CLR"  %0,%4\n"	/* copy crosses next page boundary? */
		"   jnh   6f\n"
		"4: mvcs  0(%4,%1),0(%2),%3\n"
		"9:"SLR"  %0,%4\n"
		"   j     6f\n"
		"5:"SLR"  %0,%0\n"
		"6: sacf  768\n"
		EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
		EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
		: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
		: : "cc", "memory");
	return size;
}

unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
{
	if (static_key_false(&have_mvcos))
		return copy_to_user_mvcos(to, from, n);
	return copy_to_user_mvcs(to, from, n);
}
EXPORT_SYMBOL(__copy_to_user);

static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from,
					       unsigned long size)
{
	register unsigned long reg0 asm("0") = 0x810081UL;
	unsigned long tmp1, tmp2;

	tmp1 = -4096UL;
	/* FIXME: copy with reduced length. */
	asm volatile(
		"0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
		"   jz	  2f\n"
		"1:"ALR"  %0,%3\n"
		"  "SLR"  %1,%3\n"
		"  "SLR"  %2,%3\n"
		"   j	  0b\n"
		"2:"SLR"  %0,%0\n"
		"3: \n"
		EX_TABLE(0b,3b)
		: "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
		: "d" (reg0) : "cc", "memory");
	return size;
}

static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from,
					     unsigned long size)
{
	unsigned long tmp1;

	load_kernel_asce();
	asm volatile(
		"   sacf  256\n"
		"  "AHI"  %0,-1\n"
		"   jo	  5f\n"
		"   bras  %3,3f\n"
		"0:"AHI"  %0,257\n"
		"1: mvc	  0(1,%1),0(%2)\n"
		"   la	  %1,1(%1)\n"
		"   la	  %2,1(%2)\n"
		"  "AHI"  %0,-1\n"
		"   jnz	  1b\n"
		"   j	  5f\n"
		"2: mvc	  0(256,%1),0(%2)\n"
		"   la	  %1,256(%1)\n"
		"   la	  %2,256(%2)\n"
		"3:"AHI"  %0,-256\n"
		"   jnm	  2b\n"
		"4: ex	  %0,1b-0b(%3)\n"
		"5: "SLR"  %0,%0\n"
		"6: sacf  768\n"
		EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
		: "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
		: : "cc", "memory");
	return size;
}

unsigned long __copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
	if (static_key_false(&have_mvcos))
		return copy_in_user_mvcos(to, from, n);
	return copy_in_user_mvc(to, from, n);
}
EXPORT_SYMBOL(__copy_in_user);

static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size)
{
	register unsigned long reg0 asm("0") = 0x810000UL;
	unsigned long tmp1, tmp2;

	tmp1 = -4096UL;
	asm volatile(
		"0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
		"   jz	  4f\n"
		"1:"ALR"  %0,%2\n"
		"  "SLR"  %1,%2\n"
		"   j	  0b\n"
		"2: la	  %3,4095(%1)\n"/* %4 = to + 4095 */
		"   nr	  %3,%2\n"	/* %4 = (to + 4095) & -4096 */
		"  "SLR"  %3,%1\n"
		"  "CLR"  %0,%3\n"	/* copy crosses next page boundary? */
		"   jnh	  5f\n"
		"3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
		"  "SLR"  %0,%3\n"
		"   j	  5f\n"
		"4:"SLR"  %0,%0\n"
		"5:\n"
		EX_TABLE(0b,2b) EX_TABLE(3b,5b)
		: "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
		: "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
	return size;
}

static inline unsigned long clear_user_xc(void __user *to, unsigned long size)
{
	unsigned long tmp1, tmp2;

	load_kernel_asce();
	asm volatile(
		"   sacf  256\n"
		"  "AHI"  %0,-1\n"
		"   jo    5f\n"
		"   bras  %3,3f\n"
		"   xc    0(1,%1),0(%1)\n"
		"0:"AHI"  %0,257\n"
		"   la    %2,255(%1)\n" /* %2 = ptr + 255 */
		"   srl   %2,12\n"
		"   sll   %2,12\n"	/* %2 = (ptr + 255) & -4096 */
		"  "SLR"  %2,%1\n"
		"  "CLR"  %0,%2\n"	/* clear crosses next page boundary? */
		"   jnh   5f\n"
		"  "AHI"  %2,-1\n"
		"1: ex    %2,0(%3)\n"
		"  "AHI"  %2,1\n"
		"  "SLR"  %0,%2\n"
		"   j     5f\n"
		"2: xc    0(256,%1),0(%1)\n"
		"   la    %1,256(%1)\n"
		"3:"AHI"  %0,-256\n"
		"   jnm   2b\n"
		"4: ex    %0,0(%3)\n"
		"5: "SLR"  %0,%0\n"
		"6: sacf  768\n"
		EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
		: "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
		: : "cc", "memory");
	return size;
}

unsigned long __clear_user(void __user *to, unsigned long size)
{
	if (static_key_false(&have_mvcos))
			return clear_user_mvcos(to, size);
	return clear_user_xc(to, size);
}
EXPORT_SYMBOL(__clear_user);

static inline unsigned long strnlen_user_srst(const char __user *src,
					      unsigned long size)
{
	register unsigned long reg0 asm("0") = 0;
	unsigned long tmp1, tmp2;

	asm volatile(
		"   la    %2,0(%1)\n"
		"   la    %3,0(%0,%1)\n"
		"  "SLR"  %0,%0\n"
		"   sacf  256\n"
		"0: srst  %3,%2\n"
		"   jo    0b\n"
		"   la    %0,1(%3)\n"	/* strnlen_user results includes \0 */
		"  "SLR"  %0,%1\n"
		"1: sacf  768\n"
		EX_TABLE(0b,1b)
		: "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
		: "d" (reg0) : "cc", "memory");
	return size;
}

unsigned long __strnlen_user(const char __user *src, unsigned long size)
{
	if (unlikely(!size))
		return 0;
	load_kernel_asce();
	return strnlen_user_srst(src, size);
}
EXPORT_SYMBOL(__strnlen_user);

long __strncpy_from_user(char *dst, const char __user *src, long size)
{
	size_t done, len, offset, len_str;

	if (unlikely(size <= 0))
		return 0;
	done = 0;
	do {
		offset = (size_t)src & ~PAGE_MASK;
		len = min(size - done, PAGE_SIZE - offset);
		if (copy_from_user(dst, src, len))
			return -EFAULT;
		len_str = strnlen(dst, len);
		done += len_str;
		src += len_str;
		dst += len_str;
	} while ((len_str == len) && (done < size));
	return done;
}
EXPORT_SYMBOL(__strncpy_from_user);

/*
 * The "old" uaccess variant without mvcos can be enforced with the
 * uaccess_primary kernel parameter. This is mainly for debugging purposes.
 */
static int uaccess_primary __initdata;

static int __init parse_uaccess_pt(char *__unused)
{
	uaccess_primary = 1;
	return 0;
}
early_param("uaccess_primary", parse_uaccess_pt);

static int __init uaccess_init(void)
{
	if (IS_ENABLED(CONFIG_64BIT) && !uaccess_primary && test_facility(27))
		static_key_slow_inc(&have_mvcos);
	return 0;
}
early_initcall(uaccess_init);
Commit	Line	Data
457f2180 HC	1	/*
	2	* Standard user space access functions based on mvcp/mvcs and doing
	3	* interesting things in the secondary space mode.
	4	*
	5	* Copyright IBM Corp. 2006,2014
	6	* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
	7	* Gerald Schaefer (gerald.schaefer@de.ibm.com)
	8	*/
	9
	10	#include <linux/jump_label.h>
	11	#include <linux/uaccess.h>
	12	#include <linux/export.h>
	13	#include <linux/errno.h>
	14	#include <linux/mm.h>
	15	#include <asm/mmu_context.h>
	16	#include <asm/facility.h>
	17
	18	#ifndef CONFIG_64BIT
	19	#define AHI "ahi"
	20	#define ALR "alr"
	21	#define CLR "clr"
	22	#define LHI "lhi"
	23	#define SLR "slr"
	24	#else
	25	#define AHI "aghi"
	26	#define ALR "algr"
	27	#define CLR "clgr"
	28	#define LHI "lghi"
	29	#define SLR "slgr"
	30	#endif
	31
	32	static struct static_key have_mvcos = STATIC_KEY_INIT_FALSE;
	33
	34	static inline unsigned long copy_from_user_mvcos(void x, const void __user ptr,
	35	unsigned long size)
	36	{
	37	register unsigned long reg0 asm("0") = 0x81UL;
	38	unsigned long tmp1, tmp2;
	39
	40	tmp1 = -4096UL;
	41	asm volatile(
	42	"0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
	43	"9: jz 7f\n"
	44	"1:"ALR" %0,%3\n"
	45	" "SLR" %1,%3\n"
	46	" "SLR" %2,%3\n"
	47	" j 0b\n"
	48	"2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
	49	" nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
	50	" "SLR" %4,%1\n"
	51	" "CLR" %0,%4\n" /* copy crosses next page boundary? */
	52	" jnh 4f\n"
	53	"3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
	54	"10:"SLR" %0,%4\n"
	55	" "ALR" %2,%4\n"
	56	"4:"LHI" %4,-1\n"
	57	" "ALR" %4,%0\n" /* copy remaining size, subtract 1 */
	58	" bras %3,6f\n" /* memset loop */
	59	" xc 0(1,%2),0(%2)\n"
	60	"5: xc 0(256,%2),0(%2)\n"
	61	" la %2,256(%2)\n"
	62	"6:"AHI" %4,-256\n"
	63	" jnm 5b\n"
	64	" ex %4,0(%3)\n"
65	" j 8f\n"
66	"7:"SLR" %0,%0\n"
67	"8:\n"
68	EX_TABLE(0b,2b) EX_TABLE(3b,4b) EX_TABLE(9b,2b) EX_TABLE(10b,4b)
69	: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
70	: "d" (reg0) : "cc", "memory");
71	return size;
72	}
73
74	static inline unsigned long copy_from_user_mvcp(void x, const void __user ptr,
75	unsigned long size)
76	{
77	unsigned long tmp1, tmp2;
78
beef560b	79	load_kernel_asce();
457f2180 HC	80	tmp1 = -256UL;
	81	asm volatile(
	82	" sacf 0\n"
	83	"0: mvcp 0(%0,%2),0(%1),%3\n"
	84	"10:jz 8f\n"
	85	"1:"ALR" %0,%3\n"
	86	" la %1,256(%1)\n"
	87	" la %2,256(%2)\n"
	88	"2: mvcp 0(%0,%2),0(%1),%3\n"
	89	"11:jnz 1b\n"
	90	" j 8f\n"
	91	"3: la %4,255(%1)\n" /* %4 = ptr + 255 */
	92	" "LHI" %3,-4096\n"
	93	" nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
	94	" "SLR" %4,%1\n"
	95	" "CLR" %0,%4\n" /* copy crosses next page boundary? */
	96	" jnh 5f\n"
	97	"4: mvcp 0(%4,%2),0(%1),%3\n"
	98	"12:"SLR" %0,%4\n"
	99	" "ALR" %2,%4\n"
	100	"5:"LHI" %4,-1\n"
	101	" "ALR" %4,%0\n" /* copy remaining size, subtract 1 */
	102	" bras %3,7f\n" /* memset loop */
	103	" xc 0(1,%2),0(%2)\n"
	104	"6: xc 0(256,%2),0(%2)\n"
	105	" la %2,256(%2)\n"
	106	"7:"AHI" %4,-256\n"
	107	" jnm 6b\n"
	108	" ex %4,0(%3)\n"
	109	" j 9f\n"
	110	"8:"SLR" %0,%0\n"
	111	"9: sacf 768\n"
	112	EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,5b)
	113	EX_TABLE(10b,3b) EX_TABLE(11b,3b) EX_TABLE(12b,5b)
	114	: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
	115	: : "cc", "memory");
	116	return size;
	117	}
	118
	119	unsigned long __copy_from_user(void to, const void __user from, unsigned long n)
	120	{
	121	if (static_key_false(&have_mvcos))
	122	return copy_from_user_mvcos(to, from, n);
	123	return copy_from_user_mvcp(to, from, n);
	124	}
	125	EXPORT_SYMBOL(__copy_from_user);
	126
	127	static inline unsigned long copy_to_user_mvcos(void __user ptr, const void x,
	128	unsigned long size)
	129	{
	130	register unsigned long reg0 asm("0") = 0x810000UL;
	131	unsigned long tmp1, tmp2;
	132
	133	tmp1 = -4096UL;
	134	asm volatile(
	135	"0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
	136	"6: jz 4f\n"
	137	"1:"ALR" %0,%3\n"
	138	" "SLR" %1,%3\n"
	139	" "SLR" %2,%3\n"
	140	" j 0b\n"
	141	"2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
	142	" nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
	143	" "SLR" %4,%1\n"
144	" "CLR" %0,%4\n" /* copy crosses next page boundary? */
145	" jnh 5f\n"
146	"3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
147	"7:"SLR" %0,%4\n"
148	" j 5f\n"
149	"4:"SLR" %0,%0\n"
150	"5:\n"
151	EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
152	: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
153	: "d" (reg0) : "cc", "memory");
154	return size;
155	}
156
157	static inline unsigned long copy_to_user_mvcs(void __user ptr, const void x,
158	unsigned long size)
159	{
160	unsigned long tmp1, tmp2;
161
beef560b	162	load_kernel_asce();
457f2180 HC	163	tmp1 = -256UL;
	164	asm volatile(
	165	" sacf 0\n"
	166	"0: mvcs 0(%0,%1),0(%2),%3\n"
	167	"7: jz 5f\n"
	168	"1:"ALR" %0,%3\n"
	169	" la %1,256(%1)\n"
	170	" la %2,256(%2)\n"
	171	"2: mvcs 0(%0,%1),0(%2),%3\n"
	172	"8: jnz 1b\n"
	173	" j 5f\n"
	174	"3: la %4,255(%1)\n" /* %4 = ptr + 255 */
	175	" "LHI" %3,-4096\n"
	176	" nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
	177	" "SLR" %4,%1\n"
	178	" "CLR" %0,%4\n" /* copy crosses next page boundary? */
	179	" jnh 6f\n"
	180	"4: mvcs 0(%4,%1),0(%2),%3\n"
	181	"9:"SLR" %0,%4\n"
	182	" j 6f\n"
	183	"5:"SLR" %0,%0\n"
	184	"6: sacf 768\n"
	185	EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
	186	EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
	187	: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
	188	: : "cc", "memory");
	189	return size;
	190	}
	191
	192	unsigned long __copy_to_user(void __user to, const void from, unsigned long n)
	193	{
	194	if (static_key_false(&have_mvcos))
	195	return copy_to_user_mvcos(to, from, n);
	196	return copy_to_user_mvcs(to, from, n);
	197	}
	198	EXPORT_SYMBOL(__copy_to_user);
	199
	200	static inline unsigned long copy_in_user_mvcos(void __user to, const void __user from,
	201	unsigned long size)
	202	{
	203	register unsigned long reg0 asm("0") = 0x810081UL;
	204	unsigned long tmp1, tmp2;
	205
	206	tmp1 = -4096UL;
	207	/* FIXME: copy with reduced length. */
	208	asm volatile(
	209	"0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
	210	" jz 2f\n"
	211	"1:"ALR" %0,%3\n"
	212	" "SLR" %1,%3\n"
	213	" "SLR" %2,%3\n"
	214	" j 0b\n"
	215	"2:"SLR" %0,%0\n"
	216	"3: \n"
	217	EX_TABLE(0b,3b)
	218	: "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
	219	: "d" (reg0) : "cc", "memory");
	220	return size;
	221	}
	222
	223	static inline unsigned long copy_in_user_mvc(void __user to, const void __user from,
	224	unsigned long size)
	225	{
	226	unsigned long tmp1;
227
beef560b	228	load_kernel_asce();
457f2180 HC	229	asm volatile(
	230	" sacf 256\n"
	231	" "AHI" %0,-1\n"
	232	" jo 5f\n"
	233	" bras %3,3f\n"
	234	"0:"AHI" %0,257\n"
	235	"1: mvc 0(1,%1),0(%2)\n"
	236	" la %1,1(%1)\n"
	237	" la %2,1(%2)\n"
	238	" "AHI" %0,-1\n"
	239	" jnz 1b\n"
	240	" j 5f\n"
	241	"2: mvc 0(256,%1),0(%2)\n"
	242	" la %1,256(%1)\n"
	243	" la %2,256(%2)\n"
	244	"3:"AHI" %0,-256\n"
	245	" jnm 2b\n"
	246	"4: ex %0,1b-0b(%3)\n"
	247	"5: "SLR" %0,%0\n"
	248	"6: sacf 768\n"
	249	EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
	250	: "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
	251	: : "cc", "memory");
	252	return size;
	253	}
	254
	255	unsigned long __copy_in_user(void __user to, const void __user from, unsigned long n)
	256	{
	257	if (static_key_false(&have_mvcos))
	258	return copy_in_user_mvcos(to, from, n);
	259	return copy_in_user_mvc(to, from, n);
	260	}
	261	EXPORT_SYMBOL(__copy_in_user);
	262
	263	static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size)
	264	{
	265	register unsigned long reg0 asm("0") = 0x810000UL;
	266	unsigned long tmp1, tmp2;
	267
	268	tmp1 = -4096UL;
	269	asm volatile(
	270	"0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
	271	" jz 4f\n"
	272	"1:"ALR" %0,%2\n"
	273	" "SLR" %1,%2\n"
	274	" j 0b\n"
	275	"2: la %3,4095(%1)\n"/* %4 = to + 4095 */
	276	" nr %3,%2\n" /* %4 = (to + 4095) & -4096 */
	277	" "SLR" %3,%1\n"
	278	" "CLR" %0,%3\n" /* copy crosses next page boundary? */
	279	" jnh 5f\n"
	280	"3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
	281	" "SLR" %0,%3\n"
	282	" j 5f\n"
	283	"4:"SLR" %0,%0\n"
	284	"5:\n"
	285	EX_TABLE(0b,2b) EX_TABLE(3b,5b)
	286	: "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
	287	: "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
	288	return size;
	289	}
	290
	291	static inline unsigned long clear_user_xc(void __user *to, unsigned long size)
	292	{
293	unsigned long tmp1, tmp2;
294
beef560b	295	load_kernel_asce();
457f2180 HC	296	asm volatile(
	297	" sacf 256\n"
	298	" "AHI" %0,-1\n"
	299	" jo 5f\n"
	300	" bras %3,3f\n"
	301	" xc 0(1,%1),0(%1)\n"
	302	"0:"AHI" %0,257\n"
	303	" la %2,255(%1)\n" /* %2 = ptr + 255 */
	304	" srl %2,12\n"
	305	" sll %2,12\n" /* %2 = (ptr + 255) & -4096 */
	306	" "SLR" %2,%1\n"
	307	" "CLR" %0,%2\n" /* clear crosses next page boundary? */
	308	" jnh 5f\n"
	309	" "AHI" %2,-1\n"
	310	"1: ex %2,0(%3)\n"
	311	" "AHI" %2,1\n"
	312	" "SLR" %0,%2\n"
	313	" j 5f\n"
	314	"2: xc 0(256,%1),0(%1)\n"
	315	" la %1,256(%1)\n"
	316	"3:"AHI" %0,-256\n"
	317	" jnm 2b\n"
	318	"4: ex %0,0(%3)\n"
	319	"5: "SLR" %0,%0\n"
	320	"6: sacf 768\n"
	321	EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
	322	: "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
	323	: : "cc", "memory");
	324	return size;
	325	}
	326
	327	unsigned long __clear_user(void __user *to, unsigned long size)
	328	{
	329	if (static_key_false(&have_mvcos))
	330	return clear_user_mvcos(to, size);
	331	return clear_user_xc(to, size);
	332	}
	333	EXPORT_SYMBOL(__clear_user);
	334
	335	static inline unsigned long strnlen_user_srst(const char __user *src,
	336	unsigned long size)
	337	{
	338	register unsigned long reg0 asm("0") = 0;
	339	unsigned long tmp1, tmp2;
	340
457f2180 HC	341	asm volatile(
	342	" la %2,0(%1)\n"
	343	" la %3,0(%0,%1)\n"
	344	" "SLR" %0,%0\n"
	345	" sacf 256\n"
	346	"0: srst %3,%2\n"
	347	" jo 0b\n"
	348	" la %0,1(%3)\n" /* strnlen_user results includes \0 */
	349	" "SLR" %0,%1\n"
	350	"1: sacf 768\n"
	351	EX_TABLE(0b,1b)
	352	: "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
	353	: "d" (reg0) : "cc", "memory");
	354	return size;
	355	}
	356
	357	unsigned long __strnlen_user(const char __user *src, unsigned long size)
	358	{
fa255f51 HC	359	if (unlikely(!size))
fa255f51 HC	360	return 0;
beef560b	361	load_kernel_asce();
457f2180 HC	362	return strnlen_user_srst(src, size);
	363	}
	364	EXPORT_SYMBOL(__strnlen_user);
	365
	366	long __strncpy_from_user(char dst, const char __user src, long size)
	367	{
	368	size_t done, len, offset, len_str;
	369
	370	if (unlikely(size <= 0))
	371	return 0;
	372	done = 0;
	373	do {
	374	offset = (size_t)src & ~PAGE_MASK;
	375	len = min(size - done, PAGE_SIZE - offset);
	376	if (copy_from_user(dst, src, len))
	377	return -EFAULT;
	378	len_str = strnlen(dst, len);
	379	done += len_str;
	380	src += len_str;
	381	dst += len_str;
	382	} while ((len_str == len) && (done < size));
	383	return done;
	384	}
	385	EXPORT_SYMBOL(__strncpy_from_user);
	386
	387	/*
	388	* The "old" uaccess variant without mvcos can be enforced with the
	389	* uaccess_primary kernel parameter. This is mainly for debugging purposes.
	390	*/
	391	static int uaccess_primary __initdata;
	392
	393	static int __init parse_uaccess_pt(char *__unused)
	394	{
	395	uaccess_primary = 1;
	396	return 0;
	397	}
	398	early_param("uaccess_primary", parse_uaccess_pt);
	399
	400	static int __init uaccess_init(void)
	401	{
	402	if (IS_ENABLED(CONFIG_64BIT) && !uaccess_primary && test_facility(27))
	403	static_key_slow_inc(&have_mvcos);
	404	return 0;
	405	}
	406	early_initcall(uaccess_init);