[mirror_ubuntu-artful-kernel.git] / arch / arm64 / include / asm / uaccess.h

/*
 * Based on arch/arm/include/asm/uaccess.h
 *
 * Copyright (C) 2012 ARM Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef __ASM_UACCESS_H
#define __ASM_UACCESS_H

/*
 * User space memory access functions
 */
#include <linux/string.h>
#include <linux/thread_info.h>

#include <asm/alternative.h>
#include <asm/cpufeature.h>
#include <asm/ptrace.h>
#include <asm/sysreg.h>
#include <asm/errno.h>
#include <asm/memory.h>
#include <asm/compiler.h>

#define VERIFY_READ 0
#define VERIFY_WRITE 1

/*
 * The exception table consists of pairs of addresses: the first is the
 * address of an instruction that is allowed to fault, and the second is
 * the address at which the program should continue.  No registers are
 * modified, so it is entirely up to the continuation code to figure out
 * what to do.
 *
 * All the routines below use bits of fixup code that are out of line
 * with the main instruction path.  This means when everything is well,
 * we don't even have to jump over them.  Further, they do not intrude
 * on our cache or tlb entries.
 */

struct exception_table_entry
{
	unsigned long insn, fixup;
};

extern int fixup_exception(struct pt_regs *regs);

#define KERNEL_DS	(-1UL)
#define get_ds()	(KERNEL_DS)

#define USER_DS		TASK_SIZE_64
#define get_fs()	(current_thread_info()->addr_limit)

static inline void set_fs(mm_segment_t fs)
{
	current_thread_info()->addr_limit = fs;
}

#define segment_eq(a, b)	((a) == (b))

/*
 * Return 1 if addr < current->addr_limit, 0 otherwise.
 */
#define __addr_ok(addr)							\
({									\
	unsigned long flag;						\
	asm("cmp %1, %0; cset %0, lo"					\
		: "=&r" (flag)						\
		: "r" (addr), "0" (current_thread_info()->addr_limit)	\
		: "cc");						\
	flag;								\
})

/*
 * Test whether a block of memory is a valid user space address.
 * Returns 1 if the range is valid, 0 otherwise.
 *
 * This is equivalent to the following test:
 * (u65)addr + (u65)size <= current->addr_limit
 *
 * This needs 65-bit arithmetic.
 */
#define __range_ok(addr, size)						\
({									\
	unsigned long flag, roksum;					\
	__chk_user_ptr(addr);						\
	asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, ls"		\
		: "=&r" (flag), "=&r" (roksum)				\
		: "1" (addr), "Ir" (size),				\
		  "r" (current_thread_info()->addr_limit)		\
		: "cc");						\
	flag;								\
})

#define access_ok(type, addr, size)	__range_ok(addr, size)
#define user_addr_max			get_fs

/*
 * The "__xxx" versions of the user access functions do not verify the address
 * space - it must have been done previously with a separate "access_ok()"
 * call.
 *
 * The "__xxx_error" versions set the third argument to -EFAULT if an error
 * occurs, and leave it unchanged on success.
 */
#define __get_user_asm(instr, reg, x, addr, err)			\
	asm volatile(							\
	"1:	" instr "	" reg "1, [%2]\n"			\
	"2:\n"								\
	"	.section .fixup, \"ax\"\n"				\
	"	.align	2\n"						\
	"3:	mov	%w0, %3\n"					\
	"	mov	%1, #0\n"					\
	"	b	2b\n"						\
	"	.previous\n"						\
	"	.section __ex_table,\"a\"\n"				\
	"	.align	3\n"						\
	"	.quad	1b, 3b\n"					\
	"	.previous"						\
	: "+r" (err), "=&r" (x)						\
	: "r" (addr), "i" (-EFAULT))

#define __get_user_err(x, ptr, err)					\
do {									\
	unsigned long __gu_val;						\
	__chk_user_ptr(ptr);						\
	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN,	\
			CONFIG_ARM64_PAN));				\
	switch (sizeof(*(ptr))) {					\
	case 1:								\
		__get_user_asm("ldrb", "%w", __gu_val, (ptr), (err));	\
		break;							\
	case 2:								\
		__get_user_asm("ldrh", "%w", __gu_val, (ptr), (err));	\
		break;							\
	case 4:								\
		__get_user_asm("ldr", "%w", __gu_val, (ptr), (err));	\
		break;							\
	case 8:								\
		__get_user_asm("ldr", "%",  __gu_val, (ptr), (err));	\
		break;							\
	default:							\
		BUILD_BUG();						\
	}								\
	(x) = (__force __typeof__(*(ptr)))__gu_val;			\
	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN,	\
			CONFIG_ARM64_PAN));				\
} while (0)

#define __get_user(x, ptr)						\
({									\
	int __gu_err = 0;						\
	__get_user_err((x), (ptr), __gu_err);				\
	__gu_err;							\
})

#define __get_user_error(x, ptr, err)					\
({									\
	__get_user_err((x), (ptr), (err));				\
	(void)0;							\
})

#define __get_user_unaligned __get_user

#define get_user(x, ptr)						\
({									\
	__typeof__(*(ptr)) __user *__p = (ptr);				\
	might_fault();							\
	access_ok(VERIFY_READ, __p, sizeof(*__p)) ?			\
		__get_user((x), __p) :					\
		((x) = 0, -EFAULT);					\
})

#define __put_user_asm(instr, reg, x, addr, err)			\
	asm volatile(							\
	"1:	" instr "	" reg "1, [%2]\n"			\
	"2:\n"								\
	"	.section .fixup,\"ax\"\n"				\
	"	.align	2\n"						\
	"3:	mov	%w0, %3\n"					\
	"	b	2b\n"						\
	"	.previous\n"						\
	"	.section __ex_table,\"a\"\n"				\
	"	.align	3\n"						\
	"	.quad	1b, 3b\n"					\
	"	.previous"						\
	: "+r" (err)							\
	: "r" (x), "r" (addr), "i" (-EFAULT))

#define __put_user_err(x, ptr, err)					\
do {									\
	__typeof__(*(ptr)) __pu_val = (x);				\
	__chk_user_ptr(ptr);						\
	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN,	\
			CONFIG_ARM64_PAN));				\
	switch (sizeof(*(ptr))) {					\
	case 1:								\
		__put_user_asm("strb", "%w", __pu_val, (ptr), (err));	\
		break;							\
	case 2:								\
		__put_user_asm("strh", "%w", __pu_val, (ptr), (err));	\
		break;							\
	case 4:								\
		__put_user_asm("str",  "%w", __pu_val, (ptr), (err));	\
		break;							\
	case 8:								\
		__put_user_asm("str",  "%", __pu_val, (ptr), (err));	\
		break;							\
	default:							\
		BUILD_BUG();						\
	}								\
	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN,	\
			CONFIG_ARM64_PAN));				\
} while (0)

#define __put_user(x, ptr)						\
({									\
	int __pu_err = 0;						\
	__put_user_err((x), (ptr), __pu_err);				\
	__pu_err;							\
})

#define __put_user_error(x, ptr, err)					\
({									\
	__put_user_err((x), (ptr), (err));				\
	(void)0;							\
})

#define __put_user_unaligned __put_user

#define put_user(x, ptr)						\
({									\
	__typeof__(*(ptr)) __user *__p = (ptr);				\
	might_fault();							\
	access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ?			\
		__put_user((x), __p) :					\
		-EFAULT;						\
})

extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n);
extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);

static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
{
	if (access_ok(VERIFY_READ, from, n))
		n = __copy_from_user(to, from, n);
	else /* security hole - plug it */
		memset(to, 0, n);
	return n;
}

static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
{
	if (access_ok(VERIFY_WRITE, to, n))
		n = __copy_to_user(to, from, n);
	return n;
}

static inline unsigned long __must_check copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
	if (access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n))
		n = __copy_in_user(to, from, n);
	return n;
}

#define __copy_to_user_inatomic __copy_to_user
#define __copy_from_user_inatomic __copy_from_user

static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
{
	if (access_ok(VERIFY_WRITE, to, n))
		n = __clear_user(to, n);
	return n;
}

extern long strncpy_from_user(char *dest, const char __user *src, long count);

extern __must_check long strlen_user(const char __user *str);
extern __must_check long strnlen_user(const char __user *str, long n);

#endif /* __ASM_UACCESS_H */
Commit	Line	Data
0aea86a2 CM	1	/*
	2	* Based on arch/arm/include/asm/uaccess.h
	3	*
	4	* Copyright (C) 2012 ARM Ltd.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	17	*/
	18	#ifndef __ASM_UACCESS_H
	19	#define __ASM_UACCESS_H
	20
	21	/*
	22	* User space memory access functions
	23	*/
	24	#include <linux/string.h>
	25	#include <linux/thread_info.h>
	26
338d4f49 JM	27	#include <asm/alternative.h>
338d4f49 JM	28	#include <asm/cpufeature.h>
0aea86a2	29	#include <asm/ptrace.h>
338d4f49	30	#include <asm/sysreg.h>
0aea86a2 CM	31	#include <asm/errno.h>
	32	#include <asm/memory.h>
	33	#include <asm/compiler.h>
	34
	35	#define VERIFY_READ 0
	36	#define VERIFY_WRITE 1
	37
	38	/*
	39	* The exception table consists of pairs of addresses: the first is the
	40	* address of an instruction that is allowed to fault, and the second is
	41	* the address at which the program should continue. No registers are
	42	* modified, so it is entirely up to the continuation code to figure out
	43	* what to do.
	44	*
	45	* All the routines below use bits of fixup code that are out of line
	46	* with the main instruction path. This means when everything is well,
	47	* we don't even have to jump over them. Further, they do not intrude
	48	* on our cache or tlb entries.
	49	*/
	50
	51	struct exception_table_entry
	52	{
	53	unsigned long insn, fixup;
	54	};
	55
	56	extern int fixup_exception(struct pt_regs *regs);
	57
	58	#define KERNEL_DS (-1UL)
	59	#define get_ds() (KERNEL_DS)
	60
	61	#define USER_DS TASK_SIZE_64
	62	#define get_fs() (current_thread_info()->addr_limit)
	63
	64	static inline void set_fs(mm_segment_t fs)
	65	{
	66	current_thread_info()->addr_limit = fs;
	67	}
	68
967f0e5d	69	#define segment_eq(a, b) ((a) == (b))
0aea86a2 CM	70
	71	/*
	72	* Return 1 if addr < current->addr_limit, 0 otherwise.
	73	*/
	74	#define __addr_ok(addr) \
	75	({ \
	76	unsigned long flag; \
	77	asm("cmp %1, %0; cset %0, lo" \
	78	: "=&r" (flag) \
	79	: "r" (addr), "0" (current_thread_info()->addr_limit) \
	80	: "cc"); \
	81	flag; \
	82	})
	83
	84	/*
	85	* Test whether a block of memory is a valid user space address.
	86	* Returns 1 if the range is valid, 0 otherwise.
	87	*
	88	* This is equivalent to the following test:
31b1e940	89	* (u65)addr + (u65)size <= current->addr_limit
0aea86a2 CM	90	*
	91	* This needs 65-bit arithmetic.
	92	*/
	93	#define __range_ok(addr, size) \
	94	({ \
	95	unsigned long flag, roksum; \
	96	__chk_user_ptr(addr); \
31b1e940	97	asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, ls" \
0aea86a2 CM	98	: "=&r" (flag), "=&r" (roksum) \
	99	: "1" (addr), "Ir" (size), \
	100	"r" (current_thread_info()->addr_limit) \
	101	: "cc"); \
	102	flag; \
	103	})
	104
	105	#define access_ok(type, addr, size) __range_ok(addr, size)
12a0ef7b	106	#define user_addr_max get_fs
0aea86a2 CM	107
	108	/*
	109	* The "__xxx" versions of the user access functions do not verify the address
	110	* space - it must have been done previously with a separate "access_ok()"
	111	* call.
	112	*
	113	* The "__xxx_error" versions set the third argument to -EFAULT if an error
	114	* occurs, and leave it unchanged on success.
	115	*/
	116	#define __get_user_asm(instr, reg, x, addr, err) \
	117	asm volatile( \
	118	"1: " instr " " reg "1, [%2]\n" \
	119	"2:\n" \
	120	" .section .fixup, \"ax\"\n" \
	121	" .align 2\n" \
	122	"3: mov %w0, %3\n" \
	123	" mov %1, #0\n" \
	124	" b 2b\n" \
	125	" .previous\n" \
	126	" .section __ex_table,\"a\"\n" \
	127	" .align 3\n" \
	128	" .quad 1b, 3b\n" \
	129	" .previous" \
	130	: "+r" (err), "=&r" (x) \
	131	: "r" (addr), "i" (-EFAULT))
	132
	133	#define __get_user_err(x, ptr, err) \
	134	do { \
	135	unsigned long __gu_val; \
	136	__chk_user_ptr(ptr); \
338d4f49 JM	137	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, \
338d4f49 JM	138	CONFIG_ARM64_PAN)); \
0aea86a2 CM	139	switch (sizeof(*(ptr))) { \
	140	case 1: \
	141	__get_user_asm("ldrb", "%w", __gu_val, (ptr), (err)); \
	142	break; \
	143	case 2: \
	144	__get_user_asm("ldrh", "%w", __gu_val, (ptr), (err)); \
	145	break; \
	146	case 4: \
	147	__get_user_asm("ldr", "%w", __gu_val, (ptr), (err)); \
	148	break; \
	149	case 8: \
	150	__get_user_asm("ldr", "%", __gu_val, (ptr), (err)); \
	151	break; \
	152	default: \
	153	BUILD_BUG(); \
	154	} \
58fff517	155	(x) = (__force __typeof__(*(ptr)))__gu_val; \
338d4f49 JM	156	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, \
338d4f49 JM	157	CONFIG_ARM64_PAN)); \
0aea86a2 CM	158	} while (0)
	159
	160	#define __get_user(x, ptr) \
	161	({ \
	162	int __gu_err = 0; \
	163	__get_user_err((x), (ptr), __gu_err); \
	164	__gu_err; \
	165	})
	166
	167	#define __get_user_error(x, ptr, err) \
	168	({ \
	169	__get_user_err((x), (ptr), (err)); \
	170	(void)0; \
	171	})
	172
	173	#define __get_user_unaligned __get_user
	174
	175	#define get_user(x, ptr) \
	176	({ \
1f65c13e	177	__typeof__((ptr)) __user __p = (ptr); \
56d2ef78	178	might_fault(); \
1f65c13e AT	179	access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \
1f65c13e AT	180	__get_user((x), __p) : \
0aea86a2 CM	181	((x) = 0, -EFAULT); \
	182	})
	183
	184	#define __put_user_asm(instr, reg, x, addr, err) \
	185	asm volatile( \
	186	"1: " instr " " reg "1, [%2]\n" \
	187	"2:\n" \
	188	" .section .fixup,\"ax\"\n" \
	189	" .align 2\n" \
	190	"3: mov %w0, %3\n" \
	191	" b 2b\n" \
	192	" .previous\n" \
	193	" .section __ex_table,\"a\"\n" \
	194	" .align 3\n" \
	195	" .quad 1b, 3b\n" \
	196	" .previous" \
	197	: "+r" (err) \
	198	: "r" (x), "r" (addr), "i" (-EFAULT))
	199
	200	#define __put_user_err(x, ptr, err) \
	201	do { \
	202	__typeof__(*(ptr)) __pu_val = (x); \
	203	__chk_user_ptr(ptr); \
338d4f49 JM	204	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, \
338d4f49 JM	205	CONFIG_ARM64_PAN)); \
0aea86a2 CM	206	switch (sizeof(*(ptr))) { \
	207	case 1: \
	208	__put_user_asm("strb", "%w", __pu_val, (ptr), (err)); \
	209	break; \
	210	case 2: \
	211	__put_user_asm("strh", "%w", __pu_val, (ptr), (err)); \
	212	break; \
	213	case 4: \
	214	__put_user_asm("str", "%w", __pu_val, (ptr), (err)); \
	215	break; \
	216	case 8: \
	217	__put_user_asm("str", "%", __pu_val, (ptr), (err)); \
	218	break; \
	219	default: \
	220	BUILD_BUG(); \
	221	} \
338d4f49 JM	222	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, \
338d4f49 JM	223	CONFIG_ARM64_PAN)); \
0aea86a2 CM	224	} while (0)
	225
	226	#define __put_user(x, ptr) \
	227	({ \
	228	int __pu_err = 0; \
	229	__put_user_err((x), (ptr), __pu_err); \
	230	__pu_err; \
	231	})
	232
	233	#define __put_user_error(x, ptr, err) \
	234	({ \
	235	__put_user_err((x), (ptr), (err)); \
	236	(void)0; \
	237	})
	238
	239	#define __put_user_unaligned __put_user
	240
	241	#define put_user(x, ptr) \
	242	({ \
1f65c13e	243	__typeof__((ptr)) __user __p = (ptr); \
56d2ef78	244	might_fault(); \
1f65c13e AT	245	access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ? \
1f65c13e AT	246	__put_user((x), __p) : \
0aea86a2 CM	247	-EFAULT; \
	248	})
	249
	250	extern unsigned long __must_check __copy_from_user(void to, const void __user from, unsigned long n);
	251	extern unsigned long __must_check __copy_to_user(void __user to, const void from, unsigned long n);
	252	extern unsigned long __must_check __copy_in_user(void __user to, const void __user from, unsigned long n);
	253	extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
	254
0aea86a2 CM	255	static inline unsigned long __must_check copy_from_user(void to, const void __user from, unsigned long n)
	256	{
	257	if (access_ok(VERIFY_READ, from, n))
	258	n = __copy_from_user(to, from, n);
	259	else /* security hole - plug it */
	260	memset(to, 0, n);
	261	return n;
	262	}
	263
	264	static inline unsigned long __must_check copy_to_user(void __user to, const void from, unsigned long n)
	265	{
	266	if (access_ok(VERIFY_WRITE, to, n))
	267	n = __copy_to_user(to, from, n);
	268	return n;
	269	}
	270
	271	static inline unsigned long __must_check copy_in_user(void __user to, const void __user from, unsigned long n)
	272	{
	273	if (access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n))
	274	n = __copy_in_user(to, from, n);
	275	return n;
	276	}
	277
	278	#define __copy_to_user_inatomic __copy_to_user
	279	#define __copy_from_user_inatomic __copy_from_user
	280
	281	static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
	282	{
	283	if (access_ok(VERIFY_WRITE, to, n))
	284	n = __clear_user(to, n);
	285	return n;
	286	}
	287
12a0ef7b	288	extern long strncpy_from_user(char dest, const char __user src, long count);
0aea86a2	289
12a0ef7b WD	290	extern __must_check long strlen_user(const char __user *str);
12a0ef7b WD	291	extern __must_check long strnlen_user(const char __user *str, long n);
0aea86a2 CM	292
0aea86a2 CM	293	#endif /* __ASM_UACCESS_H */