leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
Files
12700c17fc286149324f92d6d380bc48e43f253d
linux/arch/nios2/include/asm/uaccess.h
Arnd Bergmann 12700c17fc uaccess: generalize access_ok() 
There are many different ways that access_ok() is defined across
architectures, but in the end, they all just compare against the
user_addr_max() value or they accept anything.

Provide one definition that works for most architectures, checking
against TASK_SIZE_MAX for user processes or skipping the check inside
of uaccess_kernel() sections.

For architectures without CONFIG_SET_FS(), this should be the fastest
check, as it comes down to a single comparison of a pointer against a
compile-time constant, while the architecture specific versions tend to
do something more complex for historic reasons or get something wrong.

Type checking for __user annotations is handled inconsistently across
architectures, but this is easily simplified as well by using an inline
function that takes a 'const void __user *' argument. A handful of
callers need an extra __user annotation for this.

Some architectures had trick to use 33-bit or 65-bit arithmetic on the
addresses to calculate the overflow, however this simpler version uses
fewer registers, which means it can produce better object code in the
end despite needing a second (statically predicted) branch.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64, asm-generic]
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Stafford Horne <shorne@gmail.com>
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2022-02-25 09:36:05 +01:00

202 lines
5.1 KiB
C
Raw Blame History

/*
* User space memory access functions for Nios II
*
* Copyright (C) 2010-2011, Tobias Klauser <tklauser@distanz.ch>
* Copyright (C) 2009, Wind River Systems Inc
* Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#ifndef _ASM_NIOS2_UACCESS_H
#define _ASM_NIOS2_UACCESS_H
#include <linux/string.h>
#include <asm/page.h>
#include <asm/extable.h>
/*
* Segment stuff
*/
#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
#define USER_DS MAKE_MM_SEG(0x80000000UL)
#define KERNEL_DS MAKE_MM_SEG(0)
#define get_fs() (current_thread_info()->addr_limit)
#define set_fs(seg) (current_thread_info()->addr_limit = (seg))
#include <asm-generic/access_ok.h>
# define __EX_TABLE_SECTION ".section __ex_table,\"a\"\n"
/*
* Zero Userspace
*/
static inline unsigned long __must_check __clear_user(void __user *to,
unsigned long n)
{
__asm__ __volatile__ (
"1: stb zero, 0(%1)\n"
" addi %0, %0, -1\n"
" addi %1, %1, 1\n"
" bne %0, zero, 1b\n"
"2:\n"
__EX_TABLE_SECTION
".word 1b, 2b\n"
".previous\n"
: "=r" (n), "=r" (to)
: "0" (n), "1" (to)
);
return n;
}
static inline unsigned long __must_check clear_user(void __user *to,
unsigned long n)
{
if (!access_ok(to, n))
return n;
return __clear_user(to, n);
}
extern unsigned long
raw_copy_from_user(void *to, const void __user *from, unsigned long n);
extern unsigned long
raw_copy_to_user(void __user *to, const void *from, unsigned long n);
#define INLINE_COPY_FROM_USER
#define INLINE_COPY_TO_USER
extern long strncpy_from_user(char *__to, const char __user *__from,
long __len);
extern __must_check long strnlen_user(const char __user *s, long n);
/* Optimized macros */
#define __get_user_asm(val, insn, addr, err) \
{ \
unsigned long __gu_val; \
__asm__ __volatile__( \
" movi %0, %3\n" \
"1: " insn " %1, 0(%2)\n" \
" movi %0, 0\n" \
"2:\n" \
" .section __ex_table,\"a\"\n" \
" .word 1b, 2b\n" \
" .previous" \
: "=&r" (err), "=r" (__gu_val) \
: "r" (addr), "i" (-EFAULT)); \
val = (__force __typeof__(*(addr)))__gu_val; \
}
extern void __get_user_unknown(void);
#define __get_user_8(val, ptr, err) do { \
u64 __val = 0; \
err = 0; \
if (raw_copy_from_user(&(__val), ptr, sizeof(val))) { \
err = -EFAULT; \
} else { \
val = (typeof(val))(typeof((val) - (val)))__val; \
} \
} while (0)
#define __get_user_common(val, size, ptr, err) \
do { \
switch (size) { \
case 1: \
__get_user_asm(val, "ldbu", ptr, err); \
break; \
case 2: \
__get_user_asm(val, "ldhu", ptr, err); \
break; \
case 4: \
__get_user_asm(val, "ldw", ptr, err); \
break; \
case 8: \
__get_user_8(val, ptr, err); \
break; \
default: \
__get_user_unknown(); \
break; \
} \
} while (0)
#define __get_user(x, ptr) \
({ \
long __gu_err = -EFAULT; \
const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
__get_user_common(x, sizeof(*(ptr)), __gu_ptr, __gu_err); \
__gu_err; \
})
#define get_user(x, ptr) \
({ \
long __gu_err = -EFAULT; \
const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
if (access_ok( __gu_ptr, sizeof(*__gu_ptr))) \
__get_user_common(x, sizeof(*__gu_ptr), \
__gu_ptr, __gu_err); \
__gu_err; \
})
#define __put_user_asm(val, insn, ptr, err) \
{ \
__asm__ __volatile__( \
" movi %0, %3\n" \
"1: " insn " %1, 0(%2)\n" \
" movi %0, 0\n" \
"2:\n" \
" .section __ex_table,\"a\"\n" \
" .word 1b, 2b\n" \
" .previous\n" \
: "=&r" (err) \
: "r" (val), "r" (ptr), "i" (-EFAULT)); \
}
#define __put_user_common(__pu_val, __pu_ptr) \
({ \
long __pu_err = -EFAULT; \
switch (sizeof(*__pu_ptr)) { \
case 1: \
__put_user_asm(__pu_val, "stb", __pu_ptr, __pu_err); \
break; \
case 2: \
__put_user_asm(__pu_val, "sth", __pu_ptr, __pu_err); \
break; \
case 4: \
__put_user_asm(__pu_val, "stw", __pu_ptr, __pu_err); \
break; \
default: \
/* XXX: This looks wrong... */ \
__pu_err = 0; \
if (__copy_to_user(__pu_ptr, &(__pu_val), \
sizeof(*__pu_ptr))) \
__pu_err = -EFAULT; \
break; \
} \
__pu_err; \
})
#define __put_user(x, ptr) \
({ \
__auto_type __pu_ptr = (ptr); \
typeof(*__pu_ptr) __pu_val = (typeof(*__pu_ptr))(x); \
__put_user_common(__pu_val, __pu_ptr); \
})
#define put_user(x, ptr) \
({ \
__auto_type __pu_ptr = (ptr); \
typeof(*__pu_ptr) __pu_val = (typeof(*__pu_ptr))(x); \
access_ok(__pu_ptr, sizeof(*__pu_ptr)) ? \
__put_user_common(__pu_val, __pu_ptr) : \
-EFAULT; \
})
#endif /* _ASM_NIOS2_UACCESS_H */
Reference in New Issue View Git Blame Copy Permalink