[linux.git] / arch / riscv / include / asm / uaccess.h

/*
 * Copyright (C) 2012 Regents of the University of California
 *
 *   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, version 2.
 *
 *   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.
 *
 * This file was copied from include/asm-generic/uaccess.h
 */

#ifndef _ASM_RISCV_UACCESS_H
#define _ASM_RISCV_UACCESS_H

/*
 * User space memory access functions
 */
#include <linux/errno.h>
#include <linux/compiler.h>
#include <linux/thread_info.h>
#include <asm/byteorder.h>
#include <asm/asm.h>

#define __enable_user_access()							\
	__asm__ __volatile__ ("csrs sstatus, %0" : : "r" (SR_SUM) : "memory")
#define __disable_user_access()							\
	__asm__ __volatile__ ("csrc sstatus, %0" : : "r" (SR_SUM) : "memory")

/*
 * The fs value determines whether argument validity checking should be
 * performed or not.  If get_fs() == USER_DS, checking is performed, with
 * get_fs() == KERNEL_DS, checking is bypassed.
 *
 * For historical reasons, these macros are grossly misnamed.
 */

#define KERNEL_DS	(~0UL)
#define USER_DS		(TASK_SIZE)

#define get_ds()	(KERNEL_DS)
#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))

#define user_addr_max()	(get_fs())


#define VERIFY_READ	0
#define VERIFY_WRITE	1

/**
 * access_ok: - Checks if a user space pointer is valid
 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
 *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
 *        to write to a block, it is always safe to read from it.
 * @addr: User space pointer to start of block to check
 * @size: Size of block to check
 *
 * Context: User context only.  This function may sleep.
 *
 * Checks if a pointer to a block of memory in user space is valid.
 *
 * Returns true (nonzero) if the memory block may be valid, false (zero)
 * if it is definitely invalid.
 *
 * Note that, depending on architecture, this function probably just
 * checks that the pointer is in the user space range - after calling
 * this function, memory access functions may still return -EFAULT.
 */
#define access_ok(type, addr, size) ({					\
	__chk_user_ptr(addr);						\
	likely(__access_ok((unsigned long __force)(addr), (size)));	\
})

/*
 * Ensure that the range [addr, addr+size) is within the process's
 * address space
 */
static inline int __access_ok(unsigned long addr, unsigned long size)
{
	const mm_segment_t fs = get_fs();

	return (size <= fs) && (addr <= (fs - size));
}

/*
 * 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 *state);

#if defined(__LITTLE_ENDIAN)
#define __MSW	1
#define __LSW	0
#elif defined(__BIG_ENDIAN)
#define __MSW	0
#define	__LSW	1
#else
#error "Unknown endianness"
#endif

/*
 * 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.
 */

#define __get_user_asm(insn, x, ptr, err)			\
do {								\
	uintptr_t __tmp;					\
	__typeof__(x) __x;					\
	__enable_user_access();					\
	__asm__ __volatile__ (					\
		"1:\n"						\
		"	" insn " %1, %3\n"			\
		"2:\n"						\
		"	.section .fixup,\"ax\"\n"		\
		"	.balign 4\n"				\
		"3:\n"						\
		"	li %0, %4\n"				\
		"	li %1, 0\n"				\
		"	jump 2b, %2\n"				\
		"	.previous\n"				\
		"	.section __ex_table,\"a\"\n"		\
		"	.balign " RISCV_SZPTR "\n"			\
		"	" RISCV_PTR " 1b, 3b\n"			\
		"	.previous"				\
		: "+r" (err), "=&r" (__x), "=r" (__tmp)		\
		: "m" (*(ptr)), "i" (-EFAULT));			\
	__disable_user_access();				\
	(x) = __x;						\
} while (0)

#ifdef CONFIG_64BIT
#define __get_user_8(x, ptr, err) \
	__get_user_asm("ld", x, ptr, err)
#else /* !CONFIG_64BIT */
#define __get_user_8(x, ptr, err)				\
do {								\
	u32 __user *__ptr = (u32 __user *)(ptr);		\
	u32 __lo, __hi;						\
	uintptr_t __tmp;					\
	__enable_user_access();					\
	__asm__ __volatile__ (					\
		"1:\n"						\
		"	lw %1, %4\n"				\
		"2:\n"						\
		"	lw %2, %5\n"				\
		"3:\n"						\
		"	.section .fixup,\"ax\"\n"		\
		"	.balign 4\n"				\
		"4:\n"						\
		"	li %0, %6\n"				\
		"	li %1, 0\n"				\
		"	li %2, 0\n"				\
		"	jump 3b, %3\n"				\
		"	.previous\n"				\
		"	.section __ex_table,\"a\"\n"		\
		"	.balign " RISCV_SZPTR "\n"			\
		"	" RISCV_PTR " 1b, 4b\n"			\
		"	" RISCV_PTR " 2b, 4b\n"			\
		"	.previous"				\
		: "+r" (err), "=&r" (__lo), "=r" (__hi),	\
			"=r" (__tmp)				\
		: "m" (__ptr[__LSW]), "m" (__ptr[__MSW]),	\
			"i" (-EFAULT));				\
	__disable_user_access();				\
	(x) = (__typeof__(x))((__typeof__((x)-(x)))(		\
		(((u64)__hi << 32) | __lo)));			\
} while (0)
#endif /* CONFIG_64BIT */


/**
 * __get_user: - Get a simple variable from user space, with less checking.
 * @x:   Variable to store result.
 * @ptr: Source address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple variable from user space to kernel
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and the result of
 * dereferencing @ptr must be assignable to @x without a cast.
 *
 * Caller must check the pointer with access_ok() before calling this
 * function.
 *
 * Returns zero on success, or -EFAULT on error.
 * On error, the variable @x is set to zero.
 */
#define __get_user(x, ptr)					\
({								\
	register long __gu_err = 0;				\
	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);	\
	__chk_user_ptr(__gu_ptr);				\
	switch (sizeof(*__gu_ptr)) {				\
	case 1:							\
		__get_user_asm("lb", (x), __gu_ptr, __gu_err);	\
		break;						\
	case 2:							\
		__get_user_asm("lh", (x), __gu_ptr, __gu_err);	\
		break;						\
	case 4:							\
		__get_user_asm("lw", (x), __gu_ptr, __gu_err);	\
		break;						\
	case 8:							\
		__get_user_8((x), __gu_ptr, __gu_err);	\
		break;						\
	default:						\
		BUILD_BUG();					\
	}							\
	__gu_err;						\
})

/**
 * get_user: - Get a simple variable from user space.
 * @x:   Variable to store result.
 * @ptr: Source address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple variable from user space to kernel
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and the result of
 * dereferencing @ptr must be assignable to @x without a cast.
 *
 * Returns zero on success, or -EFAULT on error.
 * On error, the variable @x is set to zero.
 */
#define get_user(x, ptr)					\
({								\
	const __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(insn, x, ptr, err)			\
do {								\
	uintptr_t __tmp;					\
	__typeof__(*(ptr)) __x = x;				\
	__enable_user_access();					\
	__asm__ __volatile__ (					\
		"1:\n"						\
		"	" insn " %z3, %2\n"			\
		"2:\n"						\
		"	.section .fixup,\"ax\"\n"		\
		"	.balign 4\n"				\
		"3:\n"						\
		"	li %0, %4\n"				\
		"	jump 2b, %1\n"				\
		"	.previous\n"				\
		"	.section __ex_table,\"a\"\n"		\
		"	.balign " RISCV_SZPTR "\n"			\
		"	" RISCV_PTR " 1b, 3b\n"			\
		"	.previous"				\
		: "+r" (err), "=r" (__tmp), "=m" (*(ptr))	\
		: "rJ" (__x), "i" (-EFAULT));			\
	__disable_user_access();				\
} while (0)

#ifdef CONFIG_64BIT
#define __put_user_8(x, ptr, err) \
	__put_user_asm("sd", x, ptr, err)
#else /* !CONFIG_64BIT */
#define __put_user_8(x, ptr, err)				\
do {								\
	u32 __user *__ptr = (u32 __user *)(ptr);		\
	u64 __x = (__typeof__((x)-(x)))(x);			\
	uintptr_t __tmp;					\
	__enable_user_access();					\
	__asm__ __volatile__ (					\
		"1:\n"						\
		"	sw %z4, %2\n"				\
		"2:\n"						\
		"	sw %z5, %3\n"				\
		"3:\n"						\
		"	.section .fixup,\"ax\"\n"		\
		"	.balign 4\n"				\
		"4:\n"						\
		"	li %0, %6\n"				\
		"	jump 2b, %1\n"				\
		"	.previous\n"				\
		"	.section __ex_table,\"a\"\n"		\
		"	.balign " RISCV_SZPTR "\n"			\
		"	" RISCV_PTR " 1b, 4b\n"			\
		"	" RISCV_PTR " 2b, 4b\n"			\
		"	.previous"				\
		: "+r" (err), "=r" (__tmp),			\
			"=m" (__ptr[__LSW]),			\
			"=m" (__ptr[__MSW])			\
		: "rJ" (__x), "rJ" (__x >> 32), "i" (-EFAULT));	\
	__disable_user_access();				\
} while (0)
#endif /* CONFIG_64BIT */


/**
 * __put_user: - Write a simple value into user space, with less checking.
 * @x:   Value to copy to user space.
 * @ptr: Destination address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple value from kernel space to user
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 * to the result of dereferencing @ptr.
 *
 * Caller must check the pointer with access_ok() before calling this
 * function.
 *
 * Returns zero on success, or -EFAULT on error.
 */
#define __put_user(x, ptr)					\
({								\
	register long __pu_err = 0;				\
	__typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
	__chk_user_ptr(__gu_ptr);				\
	switch (sizeof(*__gu_ptr)) {				\
	case 1:							\
		__put_user_asm("sb", (x), __gu_ptr, __pu_err);	\
		break;						\
	case 2:							\
		__put_user_asm("sh", (x), __gu_ptr, __pu_err);	\
		break;						\
	case 4:							\
		__put_user_asm("sw", (x), __gu_ptr, __pu_err);	\
		break;						\
	case 8:							\
		__put_user_8((x), __gu_ptr, __pu_err);	\
		break;						\
	default:						\
		BUILD_BUG();					\
	}							\
	__pu_err;						\
})

/**
 * put_user: - Write a simple value into user space.
 * @x:   Value to copy to user space.
 * @ptr: Destination address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple value from kernel space to user
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 * to the result of dereferencing @ptr.
 *
 * Returns zero on success, or -EFAULT on error.
 */
#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 __asm_copy_to_user(void __user *to,
	const void *from, unsigned long n);
extern unsigned long __must_check __asm_copy_from_user(void *to,
	const void __user *from, unsigned long n);

static inline unsigned long
raw_copy_from_user(void *to, const void __user *from, unsigned long n)
{
	return __asm_copy_from_user(to, from, n);
}

static inline unsigned long
raw_copy_to_user(void __user *to, const void *from, unsigned long n)
{
	return __asm_copy_to_user(to, from, n);
}

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

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

extern
unsigned long __must_check __clear_user(void __user *addr, unsigned long n);

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

/*
 * Atomic compare-and-exchange, but with a fixup for userspace faults.  Faults
 * will set "err" to -EFAULT, while successful accesses return the previous
 * value.
 */
#define __cmpxchg_user(ptr, old, new, err, size, lrb, scb)	\
({								\
	__typeof__(ptr) __ptr = (ptr);				\
	__typeof__(*(ptr)) __old = (old);			\
	__typeof__(*(ptr)) __new = (new);			\
	__typeof__(*(ptr)) __ret;				\
	__typeof__(err) __err = 0;				\
	register unsigned int __rc;				\
	__enable_user_access();					\
	switch (size) {						\
	case 4:							\
		__asm__ __volatile__ (				\
		"0:\n"						\
		"	lr.w" #scb " %[ret], %[ptr]\n"		\
		"	bne          %[ret], %z[old], 1f\n"	\
		"	sc.w" #lrb " %[rc], %z[new], %[ptr]\n"	\
		"	bnez         %[rc], 0b\n"		\
		"1:\n"						\
		".section .fixup,\"ax\"\n"			\
		".balign 4\n"					\
		"2:\n"						\
		"	li %[err], %[efault]\n"			\
		"	jump 1b, %[rc]\n"			\
		".previous\n"					\
		".section __ex_table,\"a\"\n"			\
		".balign " RISCV_SZPTR "\n"			\
		"	" RISCV_PTR " 1b, 2b\n"			\
		".previous\n"					\
			: [ret] "=&r" (__ret),			\
			  [rc]  "=&r" (__rc),			\
			  [ptr] "+A" (*__ptr),			\
			  [err] "=&r" (__err)			\
			: [old] "rJ" (__old),			\
			  [new] "rJ" (__new),			\
			  [efault] "i" (-EFAULT));		\
		break;						\
	case 8:							\
		__asm__ __volatile__ (				\
		"0:\n"						\
		"	lr.d" #scb " %[ret], %[ptr]\n"		\
		"	bne          %[ret], %z[old], 1f\n"	\
		"	sc.d" #lrb " %[rc], %z[new], %[ptr]\n"	\
		"	bnez         %[rc], 0b\n"		\
		"1:\n"						\
		".section .fixup,\"ax\"\n"			\
		".balign 4\n"					\
		"2:\n"						\
		"	li %[err], %[efault]\n"			\
		"	jump 1b, %[rc]\n"			\
		".previous\n"					\
		".section __ex_table,\"a\"\n"			\
		".balign " RISCV_SZPTR "\n"			\
		"	" RISCV_PTR " 1b, 2b\n"			\
		".previous\n"					\
			: [ret] "=&r" (__ret),			\
			  [rc]  "=&r" (__rc),			\
			  [ptr] "+A" (*__ptr),			\
			  [err] "=&r" (__err)			\
			: [old] "rJ" (__old),			\
			  [new] "rJ" (__new),			\
			  [efault] "i" (-EFAULT));		\
		break;						\
	default:						\
		BUILD_BUG();					\
	}							\
	__disable_user_access();				\
	(err) = __err;						\
	__ret;							\
})

#endif /* _ASM_RISCV_UACCESS_H */
Commit	Line	Data
5d8544e2 PD	1	/*
	2	* Copyright (C) 2012 Regents of the University of California
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License
	6	* as published by the Free Software Foundation, version 2.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	11	* GNU General Public License for more details.
	12	*
	13	* This file was copied from include/asm-generic/uaccess.h
	14	*/
	15
	16	#ifndef _ASM_RISCV_UACCESS_H
	17	#define _ASM_RISCV_UACCESS_H
	18
	19	/*
	20	* User space memory access functions
	21	*/
	22	#include <linux/errno.h>
	23	#include <linux/compiler.h>
	24	#include <linux/thread_info.h>
	25	#include <asm/byteorder.h>
	26	#include <asm/asm.h>
	27
	28	#define __enable_user_access() \
	29	__asm__ __volatile__ ("csrs sstatus, %0" : : "r" (SR_SUM) : "memory")
	30	#define __disable_user_access() \
	31	__asm__ __volatile__ ("csrc sstatus, %0" : : "r" (SR_SUM) : "memory")
	32
	33	/*
	34	* The fs value determines whether argument validity checking should be
	35	* performed or not. If get_fs() == USER_DS, checking is performed, with
	36	* get_fs() == KERNEL_DS, checking is bypassed.
	37	*
	38	* For historical reasons, these macros are grossly misnamed.
	39	*/
	40
	41	#define KERNEL_DS (~0UL)
	42	#define USER_DS (TASK_SIZE)
	43
	44	#define get_ds() (KERNEL_DS)
	45	#define get_fs() (current_thread_info()->addr_limit)
	46
	47	static inline void set_fs(mm_segment_t fs)
	48	{
	49	current_thread_info()->addr_limit = fs;
	50	}
	51
	52	#define segment_eq(a, b) ((a) == (b))
	53
	54	#define user_addr_max() (get_fs())
	55
	56
	57	#define VERIFY_READ 0
	58	#define VERIFY_WRITE 1
	59
	60	/**
	61	* access_ok: - Checks if a user space pointer is valid
	62	* @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
	63	* %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
	64	* to write to a block, it is always safe to read from it.
65	* @addr: User space pointer to start of block to check
66	* @size: Size of block to check
67	*
68	* Context: User context only. This function may sleep.
69	*
70	* Checks if a pointer to a block of memory in user space is valid.
71	*
72	* Returns true (nonzero) if the memory block may be valid, false (zero)
73	* if it is definitely invalid.
74	*
75	* Note that, depending on architecture, this function probably just
76	* checks that the pointer is in the user space range - after calling
77	* this function, memory access functions may still return -EFAULT.
78	*/
79	#define access_ok(type, addr, size) ({ \
80	__chk_user_ptr(addr); \
81	likely(__access_ok((unsigned long __force)(addr), (size))); \
82	})
83
84	/*
85	* Ensure that the range [addr, addr+size) is within the process's
86	* address space
87	*/
88	static inline int __access_ok(unsigned long addr, unsigned long size)
89	{
90	const mm_segment_t fs = get_fs();
91
92	return (size <= fs) && (addr <= (fs - size));
93	}
94
95	/*
96	* The exception table consists of pairs of addresses: the first is the
97	* address of an instruction that is allowed to fault, and the second is
98	* the address at which the program should continue. No registers are
99	* modified, so it is entirely up to the continuation code to figure out
100	* what to do.
101	*
102	* All the routines below use bits of fixup code that are out of line
103	* with the main instruction path. This means when everything is well,
104	* we don't even have to jump over them. Further, they do not intrude
105	* on our cache or tlb entries.
106	*/
107
108	struct exception_table_entry {
109	unsigned long insn, fixup;
110	};
111
112	extern int fixup_exception(struct pt_regs *state);
113
114	#if defined(__LITTLE_ENDIAN)
115	#define __MSW 1
116	#define __LSW 0
117	#elif defined(__BIG_ENDIAN)
118	#define __MSW 0
119	#define __LSW 1
120	#else
121	#error "Unknown endianness"
122	#endif
123
124	/*
125	* The "__xxx" versions of the user access functions do not verify the address
126	* space - it must have been done previously with a separate "access_ok()"
127	* call.
128	*/
129
5d8544e2 PD	130	#define __get_user_asm(insn, x, ptr, err) \
	131	do { \
	132	uintptr_t __tmp; \
	133	__typeof__(x) __x; \
	134	__enable_user_access(); \
	135	__asm__ __volatile__ ( \
	136	"1:\n" \
	137	" " insn " %1, %3\n" \
	138	"2:\n" \
	139	" .section .fixup,\"ax\"\n" \
	140	" .balign 4\n" \
	141	"3:\n" \
	142	" li %0, %4\n" \
	143	" li %1, 0\n" \
	144	" jump 2b, %2\n" \
	145	" .previous\n" \
	146	" .section __ex_table,\"a\"\n" \
	147	" .balign " RISCV_SZPTR "\n" \
	148	" " RISCV_PTR " 1b, 3b\n" \
	149	" .previous" \
	150	: "+r" (err), "=&r" (__x), "=r" (__tmp) \
	151	: "m" (*(ptr)), "i" (-EFAULT)); \
	152	__disable_user_access(); \
	153	(x) = __x; \
	154	} while (0)
5d8544e2 PD	155
	156	#ifdef CONFIG_64BIT
	157	#define __get_user_8(x, ptr, err) \
	158	__get_user_asm("ld", x, ptr, err)
	159	#else /* !CONFIG_64BIT */
5d8544e2 PD	160	#define __get_user_8(x, ptr, err) \
	161	do { \
	162	u32 __user __ptr = (u32 __user )(ptr); \
	163	u32 __lo, __hi; \
	164	uintptr_t __tmp; \
	165	__enable_user_access(); \
	166	__asm__ __volatile__ ( \
	167	"1:\n" \
	168	" lw %1, %4\n" \
	169	"2:\n" \
	170	" lw %2, %5\n" \
	171	"3:\n" \
	172	" .section .fixup,\"ax\"\n" \
	173	" .balign 4\n" \
	174	"4:\n" \
	175	" li %0, %6\n" \
	176	" li %1, 0\n" \
	177	" li %2, 0\n" \
	178	" jump 3b, %3\n" \
	179	" .previous\n" \
	180	" .section __ex_table,\"a\"\n" \
	181	" .balign " RISCV_SZPTR "\n" \
	182	" " RISCV_PTR " 1b, 4b\n" \
	183	" " RISCV_PTR " 2b, 4b\n" \
	184	" .previous" \
	185	: "+r" (err), "=&r" (__lo), "=r" (__hi), \
	186	"=r" (__tmp) \
	187	: "m" (__ptr[__LSW]), "m" (__ptr[__MSW]), \
	188	"i" (-EFAULT)); \
	189	__disable_user_access(); \
	190	(x) = (__typeof__(x))((__typeof__((x)-(x)))( \
	191	(((u64)__hi << 32) \| __lo))); \
	192	} while (0)
5d8544e2 PD	193	#endif /* CONFIG_64BIT */
	194
	195
	196	/**
	197	* __get_user: - Get a simple variable from user space, with less checking.
	198	* @x: Variable to store result.
	199	* @ptr: Source address, in user space.
	200	*
	201	* Context: User context only. This function may sleep.
	202	*
	203	* This macro copies a single simple variable from user space to kernel
	204	* space. It supports simple types like char and int, but not larger
	205	* data types like structures or arrays.
	206	*
	207	* @ptr must have pointer-to-simple-variable type, and the result of
	208	* dereferencing @ptr must be assignable to @x without a cast.
	209	*
	210	* Caller must check the pointer with access_ok() before calling this
	211	* function.
	212	*
	213	* Returns zero on success, or -EFAULT on error.
	214	* On error, the variable @x is set to zero.
	215	*/
	216	#define __get_user(x, ptr) \
	217	({ \
	218	register long __gu_err = 0; \
	219	const __typeof__((ptr)) __user __gu_ptr = (ptr); \
	220	__chk_user_ptr(__gu_ptr); \
	221	switch (sizeof(*__gu_ptr)) { \
	222	case 1: \
	223	__get_user_asm("lb", (x), __gu_ptr, __gu_err); \
	224	break; \
	225	case 2: \
	226	__get_user_asm("lh", (x), __gu_ptr, __gu_err); \
	227	break; \
	228	case 4: \
	229	__get_user_asm("lw", (x), __gu_ptr, __gu_err); \
	230	break; \
	231	case 8: \
	232	__get_user_8((x), __gu_ptr, __gu_err); \
	233	break; \
	234	default: \
	235	BUILD_BUG(); \
	236	} \
	237	__gu_err; \
	238	})
	239
	240	/**
	241	* get_user: - Get a simple variable from user space.
	242	* @x: Variable to store result.
	243	* @ptr: Source address, in user space.
	244	*
	245	* Context: User context only. This function may sleep.
	246	*
	247	* This macro copies a single simple variable from user space to kernel
	248	* space. It supports simple types like char and int, but not larger
	249	* data types like structures or arrays.
	250	*
	251	* @ptr must have pointer-to-simple-variable type, and the result of
	252	* dereferencing @ptr must be assignable to @x without a cast.
	253	*
	254	* Returns zero on success, or -EFAULT on error.
	255	* On error, the variable @x is set to zero.
	256	*/
257	#define get_user(x, ptr) \
258	({ \
259	const __typeof__((ptr)) __user __p = (ptr); \
260	might_fault(); \
261	access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \
262	__get_user((x), __p) : \
263	((x) = 0, -EFAULT); \
264	})
265
5d8544e2 PD	266	#define __put_user_asm(insn, x, ptr, err) \
	267	do { \
	268	uintptr_t __tmp; \
	269	__typeof__(*(ptr)) __x = x; \
	270	__enable_user_access(); \
	271	__asm__ __volatile__ ( \
	272	"1:\n" \
	273	" " insn " %z3, %2\n" \
	274	"2:\n" \
	275	" .section .fixup,\"ax\"\n" \
	276	" .balign 4\n" \
	277	"3:\n" \
	278	" li %0, %4\n" \
	279	" jump 2b, %1\n" \
	280	" .previous\n" \
	281	" .section __ex_table,\"a\"\n" \
	282	" .balign " RISCV_SZPTR "\n" \
	283	" " RISCV_PTR " 1b, 3b\n" \
	284	" .previous" \
	285	: "+r" (err), "=r" (__tmp), "=m" (*(ptr)) \
	286	: "rJ" (__x), "i" (-EFAULT)); \
	287	__disable_user_access(); \
	288	} while (0)
5d8544e2 PD	289
	290	#ifdef CONFIG_64BIT
	291	#define __put_user_8(x, ptr, err) \
	292	__put_user_asm("sd", x, ptr, err)
	293	#else /* !CONFIG_64BIT */
5d8544e2 PD	294	#define __put_user_8(x, ptr, err) \
	295	do { \
	296	u32 __user __ptr = (u32 __user )(ptr); \
	297	u64 __x = (__typeof__((x)-(x)))(x); \
	298	uintptr_t __tmp; \
	299	__enable_user_access(); \
	300	__asm__ __volatile__ ( \
	301	"1:\n" \
	302	" sw %z4, %2\n" \
	303	"2:\n" \
	304	" sw %z5, %3\n" \
	305	"3:\n" \
	306	" .section .fixup,\"ax\"\n" \
	307	" .balign 4\n" \
	308	"4:\n" \
	309	" li %0, %6\n" \
	310	" jump 2b, %1\n" \
	311	" .previous\n" \
	312	" .section __ex_table,\"a\"\n" \
	313	" .balign " RISCV_SZPTR "\n" \
	314	" " RISCV_PTR " 1b, 4b\n" \
	315	" " RISCV_PTR " 2b, 4b\n" \
	316	" .previous" \
	317	: "+r" (err), "=r" (__tmp), \
	318	"=m" (__ptr[__LSW]), \
	319	"=m" (__ptr[__MSW]) \
	320	: "rJ" (__x), "rJ" (__x >> 32), "i" (-EFAULT)); \
	321	__disable_user_access(); \
	322	} while (0)
5d8544e2 PD	323	#endif /* CONFIG_64BIT */
	324
	325
	326	/**
	327	* __put_user: - Write a simple value into user space, with less checking.
	328	* @x: Value to copy to user space.
	329	* @ptr: Destination address, in user space.
	330	*
	331	* Context: User context only. This function may sleep.
	332	*
	333	* This macro copies a single simple value from kernel space to user
	334	* space. It supports simple types like char and int, but not larger
	335	* data types like structures or arrays.
	336	*
	337	* @ptr must have pointer-to-simple-variable type, and @x must be assignable
	338	* to the result of dereferencing @ptr.
	339	*
	340	* Caller must check the pointer with access_ok() before calling this
	341	* function.
	342	*
	343	* Returns zero on success, or -EFAULT on error.
	344	*/
	345	#define __put_user(x, ptr) \
	346	({ \
	347	register long __pu_err = 0; \
	348	__typeof__((ptr)) __user __gu_ptr = (ptr); \
	349	__chk_user_ptr(__gu_ptr); \
	350	switch (sizeof(*__gu_ptr)) { \
	351	case 1: \
	352	__put_user_asm("sb", (x), __gu_ptr, __pu_err); \
	353	break; \
	354	case 2: \
	355	__put_user_asm("sh", (x), __gu_ptr, __pu_err); \
	356	break; \
	357	case 4: \
	358	__put_user_asm("sw", (x), __gu_ptr, __pu_err); \
	359	break; \
	360	case 8: \
	361	__put_user_8((x), __gu_ptr, __pu_err); \
	362	break; \
	363	default: \
	364	BUILD_BUG(); \
	365	} \
	366	__pu_err; \
	367	})
	368
	369	/**
	370	* put_user: - Write a simple value into user space.
	371	* @x: Value to copy to user space.
	372	* @ptr: Destination address, in user space.
	373	*
	374	* Context: User context only. This function may sleep.
	375	*
	376	* This macro copies a single simple value from kernel space to user
	377	* space. It supports simple types like char and int, but not larger
	378	* data types like structures or arrays.
	379	*
	380	* @ptr must have pointer-to-simple-variable type, and @x must be assignable
	381	* to the result of dereferencing @ptr.
	382	*
	383	* Returns zero on success, or -EFAULT on error.
	384	*/
	385	#define put_user(x, ptr) \
	386	({ \
387	__typeof__((ptr)) __user __p = (ptr); \
388	might_fault(); \
389	access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ? \
390	__put_user((x), __p) : \
391	-EFAULT; \
392	})
393
394
86406d51 LVO	395	extern unsigned long __must_check __asm_copy_to_user(void __user *to,
	396	const void *from, unsigned long n);
	397	extern unsigned long __must_check __asm_copy_from_user(void *to,
5d8544e2 PD	398	const void __user *from, unsigned long n);
	399
	400	static inline unsigned long
	401	raw_copy_from_user(void to, const void __user from, unsigned long n)
	402	{
21f70d4a	403	return __asm_copy_from_user(to, from, n);
5d8544e2 PD	404	}
	405
	406	static inline unsigned long
	407	raw_copy_to_user(void __user to, const void from, unsigned long n)
	408	{
21f70d4a	409	return __asm_copy_to_user(to, from, n);
5d8544e2 PD	410	}
	411
	412	extern long strncpy_from_user(char dest, const char __user src, long count);
	413
	414	extern long __must_check strlen_user(const char __user *str);
	415	extern long __must_check strnlen_user(const char __user *str, long n);
	416
	417	extern
	418	unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
	419
	420	static inline
	421	unsigned long __must_check clear_user(void __user *to, unsigned long n)
	422	{
	423	might_fault();
	424	return access_ok(VERIFY_WRITE, to, n) ?
	425	__clear_user(to, n) : n;
	426	}
	427
	428	/*
	429	* Atomic compare-and-exchange, but with a fixup for userspace faults. Faults
	430	* will set "err" to -EFAULT, while successful accesses return the previous
	431	* value.
	432	*/
5d8544e2 PD	433	#define __cmpxchg_user(ptr, old, new, err, size, lrb, scb) \
	434	({ \
	435	__typeof__(ptr) __ptr = (ptr); \
	436	__typeof__(*(ptr)) __old = (old); \
	437	__typeof__(*(ptr)) __new = (new); \
	438	__typeof__(*(ptr)) __ret; \
	439	__typeof__(err) __err = 0; \
	440	register unsigned int __rc; \
	441	__enable_user_access(); \
	442	switch (size) { \
	443	case 4: \
	444	__asm__ __volatile__ ( \
	445	"0:\n" \
	446	" lr.w" #scb " %[ret], %[ptr]\n" \
	447	" bne %[ret], %z[old], 1f\n" \
	448	" sc.w" #lrb " %[rc], %z[new], %[ptr]\n" \
	449	" bnez %[rc], 0b\n" \
	450	"1:\n" \
	451	".section .fixup,\"ax\"\n" \
	452	".balign 4\n" \
	453	"2:\n" \
	454	" li %[err], %[efault]\n" \
	455	" jump 1b, %[rc]\n" \
	456	".previous\n" \
	457	".section __ex_table,\"a\"\n" \
	458	".balign " RISCV_SZPTR "\n" \
	459	" " RISCV_PTR " 1b, 2b\n" \
	460	".previous\n" \
	461	: [ret] "=&r" (__ret), \
	462	[rc] "=&r" (__rc), \
	463	[ptr] "+A" (*__ptr), \
	464	[err] "=&r" (__err) \
	465	: [old] "rJ" (__old), \
	466	[new] "rJ" (__new), \
	467	[efault] "i" (-EFAULT)); \
	468	break; \
	469	case 8: \
	470	__asm__ __volatile__ ( \
	471	"0:\n" \
	472	" lr.d" #scb " %[ret], %[ptr]\n" \
	473	" bne %[ret], %z[old], 1f\n" \
	474	" sc.d" #lrb " %[rc], %z[new], %[ptr]\n" \
	475	" bnez %[rc], 0b\n" \
	476	"1:\n" \
	477	".section .fixup,\"ax\"\n" \
	478	".balign 4\n" \
	479	"2:\n" \
	480	" li %[err], %[efault]\n" \
	481	" jump 1b, %[rc]\n" \
	482	".previous\n" \
	483	".section __ex_table,\"a\"\n" \
	484	".balign " RISCV_SZPTR "\n" \
	485	" " RISCV_PTR " 1b, 2b\n" \
	486	".previous\n" \
	487	: [ret] "=&r" (__ret), \
	488	[rc] "=&r" (__rc), \
	489	[ptr] "+A" (*__ptr), \
	490	[err] "=&r" (__err) \
	491	: [old] "rJ" (__old), \
	492	[new] "rJ" (__new), \
	493	[efault] "i" (-EFAULT)); \
	494	break; \
	495	default: \
	496	BUILD_BUG(); \
497	} \
498	__disable_user_access(); \
499	(err) = __err; \
500	__ret; \
501	})
5d8544e2 PD	502
5d8544e2 PD	503	#endif /* _ASM_RISCV_UACCESS_H */