/*
* 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 3b, %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 __copy_user(void __user *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 __copy_user(to, from, n);
}
static inline unsigned long
raw_copy_to_user(void __user *to, const void *from, unsigned long n)
{
return __copy_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 */