/*
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* 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, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#ifndef _ASM_TILE_UACCESS_H
#define _ASM_TILE_UACCESS_H
/*
* User space memory access functions
*/
#include <linux/sched.h>
#include <linux/mm.h>
#include <asm-generic/uaccess-unaligned.h>
#include <asm/processor.h>
#include <asm/page.h>
#define VERIFY_READ 0
#define VERIFY_WRITE 1
/*
* 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 MAKE_MM_SEG(a) ((mm_segment_t) { (a) })
#define KERNEL_DS MAKE_MM_SEG(-1UL)
#define USER_DS MAKE_MM_SEG(PAGE_OFFSET)
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
#define set_fs(x) (current_thread_info()->addr_limit = (x))
#define segment_eq(a, b) ((a).seg == (b).seg)
#ifndef __tilegx__
/*
* We could allow mapping all 16 MB at 0xfc000000, but we set up a
* special hack in arch_setup_additional_pages() to auto-create a mapping
* for the first 16 KB, and it would seem strange to have different
* user-accessible semantics for memory at 0xfc000000 and above 0xfc004000.
*/
static inline int is_arch_mappable_range(unsigned long addr,
unsigned long size)
{
return (addr >= MEM_USER_INTRPT &&
addr < (MEM_USER_INTRPT + INTRPT_SIZE) &&
size <= (MEM_USER_INTRPT + INTRPT_SIZE) - addr);
}
#define is_arch_mappable_range is_arch_mappable_range
#else
#define is_arch_mappable_range(addr, size) 0
#endif
/*
* Test whether a block of memory is a valid user space address.
* Returns 0 if the range is valid, nonzero otherwise.
*/
int __range_ok(unsigned long addr, unsigned long size);
/**
* 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(__range_ok((unsigned long)(addr), (size)) == 0); \
})
/*
* 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);
/*
* We return the __get_user_N function results in a structure,
* thus in r0 and r1. If "err" is zero, "val" is the result
* of the read; otherwise, "err" is -EFAULT.
*
* We rarely need 8-byte values on a 32-bit architecture, but
* we size the structure to accommodate. In practice, for the
* the smaller reads, we can zero the high word for free, and
* the caller will ignore it by virtue of casting anyway.
*/
struct __get_user {
unsigned long long val;
int err;
};
/*
* FIXME: we should express these as inline extended assembler, since
* they're fundamentally just a variable dereference and some
* supporting exception_table gunk. Note that (a la i386) we can
* extend the copy_to_user and copy_from_user routines to call into
* such extended assembler routines, though we will have to use a
* different return code in that case (1, 2, or 4, rather than -EFAULT).
*/
extern struct __get_user __get_user_1(const void __user *);
extern struct __get_user __get_user_2(const void __user *);
extern struct __get_user __get_user_4(const void __user *);
extern struct __get_user __get_user_8(const void __user *);
extern int __put_user_1(long, void __user *);
extern int __put_user_2(long, void __user *);
extern int __put_user_4(long, void __user *);
extern int __put_user_8(long long, void __user *);
/* Unimplemented routines to cause linker failures */
extern struct __get_user __get_user_bad(void);
extern int __put_user_bad(void);
/*
* Careful: we have to cast the result to the type of the pointer
* for sign reasons.
*/
/**
* __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.
*
* Returns zero on success, or -EFAULT on error.
* On error, the variable @x is set to zero.
*
* Caller must check the pointer with access_ok() before calling this
* function.
*/
#define __get_user(x, ptr) \
({ struct __get_user __ret; \
__typeof__(*(ptr)) const __user *__gu_addr = (ptr); \
__chk_user_ptr(__gu_addr); \
switch (sizeof(*(__gu_addr))) { \
case 1: \
__ret = __get_user_1(__gu_addr); \
break; \
case 2: \
__ret = __get_user_2(__gu_addr); \
break; \
case 4: \
__ret = __get_user_4(__gu_addr); \
break; \
case 8: \
__ret = __get_user_8(__gu_addr); \
break; \
default: \
__ret = __get_user_bad(); \
break; \
} \
(x) = (__typeof__(*__gu_addr)) (__typeof__(*__gu_addr - *__gu_addr)) \
__ret.val; \
__ret.err; \
})
/**
* __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.
*
* Implementation note: The "case 8" logic of casting to the type of
* the result of subtracting the value from itself is basically a way
* of keeping all integer types the same, but casting any pointers to
* ptrdiff_t, i.e. also an integer type. This way there are no
* questionable casts seen by the compiler on an ILP32 platform.
*/
#define __put_user(x, ptr) \
({ \
int __pu_err = 0; \
__typeof__(*(ptr)) __user *__pu_addr = (ptr); \
typeof(*__pu_addr) __pu_val = (x); \
__chk_user_ptr(__pu_addr); \
switch (sizeof(__pu_val)) { \
case 1: \
__pu_err = __put_user_1((long)__pu_val, __pu_addr); \
break; \
case 2: \
__pu_err = __put_user_2((long)__pu_val, __pu_addr); \
break; \
case 4: \
__pu_err = __put_user_4((long)__pu_val, __pu_addr); \
break; \
case 8: \
__pu_err = \
__put_user_8((__typeof__(__pu_val - __pu_val))__pu_val,\
__pu_addr); \
break; \
default: \
__pu_err = __put_user_bad(); \
break; \
} \
__pu_err; \
})
/*
* The versions of get_user and put_user without initial underscores
* check the address of their arguments to make sure they are not
* in kernel space.
*/
#define put_user(x, ptr) \
({ \
__typeof__(*(ptr)) __user *__Pu_addr = (ptr); \
access_ok(VERIFY_WRITE, (__Pu_addr), sizeof(*(__Pu_addr))) ? \
__put_user((x), (__Pu_addr)) : \
-EFAULT; \
})
#define get_user(x, ptr) \
({ \
__typeof__(*(ptr)) const __user *__Gu_addr = (ptr); \
access_ok(VERIFY_READ, (__Gu_addr), sizeof(*(__Gu_addr))) ? \
__get_user((x), (__Gu_addr)) : \
((x) = 0, -EFAULT); \
})
/**
* __copy_to_user() - copy data into user space, with less checking.
* @to: Destination address, in user space.
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
*
* Copy data from kernel space to user space. Caller must check
* the specified block with access_ok() before calling this function.
*
* Returns number of bytes that could not be copied.
* On success, this will be zero.
*
* An alternate version - __copy_to_user_inatomic() - is designed
* to be called from atomic context, typically bracketed by calls
* to pagefault_disable() and pagefault_enable().
*/
extern unsigned long __must_check __copy_to_user_inatomic(
void __user *to, const void *from, unsigned long n);
static inline unsigned long __must_check
__copy_to_user(void __user *to, const void *from, unsigned long n)
{
might_fault();
return __copy_to_user_inatomic(to, from, 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;
}
/**
* __copy_from_user() - copy data from user space, with less checking.
* @to: Destination address, in kernel space.
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
*
* Copy data from user space to kernel space. Caller must check
* the specified block with access_ok() before calling this function.
*
* Returns number of bytes that could not be copied.
* On success, this will be zero.
*
* If some data could not be copied, this function will pad the copied
* data to the requested size using zero bytes.
*
* An alternate version - __copy_from_user_inatomic() - is designed
* to be called from atomic context, typically bracketed by calls
* to pagefault_disable() and pagefault_enable(). This version
* does *NOT* pad with zeros.
*/
extern unsigned long __must_check __copy_from_user_inatomic(
void *to, const void __user *from, unsigned long n);
extern unsigned long __must_check __copy_from_user_zeroing(
void *to, const void __user *from, unsigned long n);
static inline unsigned long __must_check
__copy_from_user(void *to, const void __user *from, unsigned long n)
{
might_fault();
return __copy_from_user_zeroing(to, from, 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
memset(to, 0, n);
return n;
}
#ifdef CONFIG_DEBUG_COPY_FROM_USER
extern void copy_from_user_overflow(void)
__compiletime_warning("copy_from_user() size is not provably correct");
static inline unsigned long __must_check copy_from_user(void *to,
const void __user *from,
unsigned long n)
{
int sz = __compiletime_object_size(to);
if (likely(sz == -1 || sz >= n))
n = _copy_from_user(to, from, n);
else
copy_from_user_overflow();
return n;
}
#else
#define copy_from_user _copy_from_user
#endif
#ifdef __tilegx__
/**
* __copy_in_user() - copy data within user space, with less checking.
* @to: Destination address, in user space.
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
*
* Copy data from user space to user space. Caller must check
* the specified blocks with access_ok() before calling this function.
*
* Returns number of bytes that could not be copied.
* On success, this will be zero.
*/
extern unsigned long __copy_in_user_inatomic(
void __user *to, const void __user *from, unsigned long n);
static inline unsigned long __must_check
__copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
might_sleep();
return __copy_in_user_inatomic(to, from, n);
}
static inline unsigned long __must_check
copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
if (access_ok(VERIFY_WRITE, to, n) && access_ok(VERIFY_READ, from, n))
n = __copy_in_user(to, from, n);
return n;
}
#endif
/**
* strlen_user: - Get the size of a string in user space.
* @str: The string to measure.
*
* Context: User context only. This function may sleep.
*
* Get the size of a NUL-terminated string in user space.
*
* Returns the size of the string INCLUDING the terminating NUL.
* On exception, returns 0.
*
* If there is a limit on the length of a valid string, you may wish to
* consider using strnlen_user() instead.
*/
extern long strnlen_user_asm(const char __user *str, long n);
static inline long __must_check strnlen_user(const char __user *str, long n)
{
might_fault();
return strnlen_user_asm(str, n);
}
#define strlen_user(str) strnlen_user(str, LONG_MAX)
/**
* strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
* @dst: Destination address, in kernel space. This buffer must be at
* least @count bytes long.
* @src: Source address, in user space.
* @count: Maximum number of bytes to copy, including the trailing NUL.
*
* Copies a NUL-terminated string from userspace to kernel space.
* Caller must check the specified block with access_ok() before calling
* this function.
*
* On success, returns the length of the string (not including the trailing
* NUL).
*
* If access to userspace fails, returns -EFAULT (some data may have been
* copied).
*
* If @count is smaller than the length of the string, copies @count bytes
* and returns @count.
*/
extern long strncpy_from_user_asm(char *dst, const char __user *src, long);
static inline long __must_check __strncpy_from_user(
char *dst, const char __user *src, long count)
{
might_fault();
return strncpy_from_user_asm(dst, src, count);
}
static inline long __must_check strncpy_from_user(
char *dst, const char __user *src, long count)
{
if (access_ok(VERIFY_READ, src, 1))
return __strncpy_from_user(dst, src, count);
return -EFAULT;
}
/**
* clear_user: - Zero a block of memory in user space.
* @mem: Destination address, in user space.
* @len: Number of bytes to zero.
*
* Zero a block of memory in user space.
*
* Returns number of bytes that could not be cleared.
* On success, this will be zero.
*/
extern unsigned long clear_user_asm(void __user *mem, unsigned long len);
static inline unsigned long __must_check __clear_user(
void __user *mem, unsigned long len)
{
might_fault();
return clear_user_asm(mem, len);
}
static inline unsigned long __must_check clear_user(
void __user *mem, unsigned long len)
{
if (access_ok(VERIFY_WRITE, mem, len))
return __clear_user(mem, len);
return len;
}
/**
* flush_user: - Flush a block of memory in user space from cache.
* @mem: Destination address, in user space.
* @len: Number of bytes to flush.
*
* Returns number of bytes that could not be flushed.
* On success, this will be zero.
*/
extern unsigned long flush_user_asm(void __user *mem, unsigned long len);
static inline unsigned long __must_check __flush_user(
void __user *mem, unsigned long len)
{
int retval;
might_fault();
retval = flush_user_asm(mem, len);
mb_incoherent();
return retval;
}
static inline unsigned long __must_check flush_user(
void __user *mem, unsigned long len)
{
if (access_ok(VERIFY_WRITE, mem, len))
return __flush_user(mem, len);
return len;
}
/**
* inv_user: - Invalidate a block of memory in user space from cache.
* @mem: Destination address, in user space.
* @len: Number of bytes to invalidate.
*
* Returns number of bytes that could not be invalidated.
* On success, this will be zero.
*
* Note that on Tile64, the "inv" operation is in fact a
* "flush and invalidate", so cache write-backs will occur prior
* to the cache being marked invalid.
*/
extern unsigned long inv_user_asm(void __user *mem, unsigned long len);
static inline unsigned long __must_check __inv_user(
void __user *mem, unsigned long len)
{
int retval;
might_fault();
retval = inv_user_asm(mem, len);
mb_incoherent();
return retval;
}
static inline unsigned long __must_check inv_user(
void __user *mem, unsigned long len)
{
if (access_ok(VERIFY_WRITE, mem, len))
return __inv_user(mem, len);
return len;
}
/**
* finv_user: - Flush-inval a block of memory in user space from cache.
* @mem: Destination address, in user space.
* @len: Number of bytes to invalidate.
*
* Returns number of bytes that could not be flush-invalidated.
* On success, this will be zero.
*/
extern unsigned long finv_user_asm(void __user *mem, unsigned long len);
static inline unsigned long __must_check __finv_user(
void __user *mem, unsigned long len)
{
int retval;
might_fault();
retval = finv_user_asm(mem, len);
mb_incoherent();
return retval;
}
static inline unsigned long __must_check finv_user(
void __user *mem, unsigned long len)
{
if (access_ok(VERIFY_WRITE, mem, len))
return __finv_user(mem, len);
return len;
}
#endif /* _ASM_TILE_UACCESS_H */
