/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_IA64_UACCESS_H
#define _ASM_IA64_UACCESS_H
/*
* This file defines various macros to transfer memory areas across
* the user/kernel boundary. This needs to be done carefully because
* this code is executed in kernel mode and uses user-specified
* addresses. Thus, we need to be careful not to let the user to
* trick us into accessing kernel memory that would normally be
* inaccessible. This code is also fairly performance sensitive,
* so we want to spend as little time doing safety checks as
* possible.
*
* To make matters a bit more interesting, these macros sometimes also
* called from within the kernel itself, in which case the address
* validity check must be skipped. The get_fs() macro tells us what
* to do: if get_fs()==USER_DS, checking is performed, if
* get_fs()==KERNEL_DS, checking is bypassed.
*
* Note that even if the memory area specified by the user is in a
* valid address range, it is still possible that we'll get a page
* fault while accessing it. This is handled by filling out an
* exception handler fixup entry for each instruction that has the
* potential to fault. When such a fault occurs, the page fault
* handler checks to see whether the faulting instruction has a fixup
* associated and, if so, sets r8 to -EFAULT and clears r9 to 0 and
* then resumes execution at the continuation point.
*
* Based on <asm-alpha/uaccess.h>.
*
* Copyright (C) 1998, 1999, 2001-2004 Hewlett-Packard Co
* David Mosberger-Tang <davidm@hpl.hp.com>
*/
#include <linux/compiler.h>
#include <linux/page-flags.h>
#include <linux/mm.h>
#include <asm/intrinsics.h>
#include <asm/pgtable.h>
#include <asm/io.h>
#include <asm/extable.h>
/*
* For historical reasons, the following macros are grossly misnamed:
*/
#define KERNEL_DS ((mm_segment_t) { ~0UL }) /* cf. access_ok() */
#define USER_DS ((mm_segment_t) { TASK_SIZE-1 }) /* cf. access_ok() */
#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)
/*
* When accessing user memory, we need to make sure the entire area really is in
* user-level space. In order to do this efficiently, we make sure that the page at
* address TASK_SIZE is never valid. We also need to make sure that the address doesn't
* point inside the virtually mapped linear page table.
*/
static inline int __access_ok(const void __user *p, unsigned long size)
{
unsigned long addr = (unsigned long)p;
unsigned long seg = get_fs().seg;
return likely(addr <= seg) &&
(seg == KERNEL_DS.seg || likely(REGION_OFFSET(addr) < RGN_MAP_LIMIT));
}
#define access_ok(addr, size) __access_ok((addr), (size))
/*
* These are the main single-value transfer routines. They automatically
* use the right size if we just have the right pointer type.
*
* Careful to not
* (a) re-use the arguments for side effects (sizeof/typeof is ok)
* (b) require any knowledge of processes at this stage
*/
#define put_user(x, ptr) __put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
#define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)))
/*
* The "__xxx" versions do not do address space checking, useful when
* doing multiple accesses to the same area (the programmer has to do the
* checks by hand with "access_ok()")
*/
#define __put_user(x, ptr) __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
#define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
#ifdef ASM_SUPPORTED
struct __large_struct { unsigned long buf[100]; };
# define __m(x) (*(struct __large_struct __user *)(x))
/* We need to declare the __ex_table section before we can use it in .xdata. */
asm (".section \"__ex_table\", \"a\"\n\t.previous");
# define __get_user_size(val, addr, n, err) \
do { \
register long __gu_r8 asm ("r8") = 0; \
register long __gu_r9 asm ("r9"); \
asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n" \
"\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n" \
"[1:]" \
: "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8)); \
(err) = __gu_r8; \
(val) = __gu_r9; \
} while (0)
/*
* The "__put_user_size()" macro tells gcc it reads from memory instead of writing it. This
* is because they do not write to any memory gcc knows about, so there are no aliasing
* issues.
*/
# define __put_user_size(val, addr, n, err) \
do { \
register long __pu_r8 asm ("r8") = 0; \
asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \
"\t.xdata4 \"__ex_table\", 1b-., 1f-.\n" \
"[1:]" \
: "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8)); \
(err) = __pu_r8; \
} while (0)
#else /* !ASM_SUPPORTED */
# define RELOC_TYPE 2 /* ip-rel */
# define __get_user_size(val, addr, n, err) \
do { \
__ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE); \
(err) = ia64_getreg(_IA64_REG_R8); \
(val) = ia64_getreg(_IA64_REG_R9); \
} while (0)
# define __put_user_size(val, addr, n, err) \
do { \
__st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE, \
(__force unsigned long) (val)); \
(err) = ia64_getreg(_IA64_REG_R8); \
} while (0)
#endif /* !ASM_SUPPORTED */
extern void __get_user_unknown (void);
/*
* Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
* could clobber r8 and r9 (among others). Thus, be careful not to evaluate it while
* using r8/r9.
*/
#define __do_get_user(check, x, ptr, size) \
({ \
const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
__typeof__ (size) __gu_size = (size); \
long __gu_err = -EFAULT; \
unsigned long __gu_val = 0; \
if (!check || __access_ok(__gu_ptr, size)) \
switch (__gu_size) { \
case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break; \
case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break; \
case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break; \
case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break; \
default: __get_user_unknown(); break; \
} \
(x) = (__force __typeof__(*(__gu_ptr))) __gu_val; \
__gu_err; \
})
#define __get_user_nocheck(x, ptr, size) __do_get_user(0, x, ptr, size)
#define __get_user_check(x, ptr, size) __do_get_user(1, x, ptr, size)
extern void __put_user_unknown (void);
/*
* Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
* could clobber r8 (among others). Thus, be careful not to evaluate them while using r8.
*/
#define __do_put_user(check, x, ptr, size) \
({ \
__typeof__ (x) __pu_x = (x); \
__typeof__ (*(ptr)) __user *__pu_ptr = (ptr); \
__typeof__ (size) __pu_size = (size); \
long __pu_err = -EFAULT; \
\
if (!check || __access_ok(__pu_ptr, __pu_size)) \
switch (__pu_size) { \
case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break; \
case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break; \
case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break; \
case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break; \
default: __put_user_unknown(); break; \
} \
__pu_err; \
})
#define __put_user_nocheck(x, ptr, size) __do_put_user(0, x, ptr, size)
#define __put_user_check(x, ptr, size) __do_put_user(1, x, ptr, size)
/*
* Complex access routines
*/
extern unsigned long __must_check __copy_user (void __user *to, const void __user *from,
unsigned long count);
static inline unsigned long
raw_copy_to_user(void __user *to, const void *from, unsigned long count)
{
return __copy_user(to, (__force void __user *) from, count);
}
static inline unsigned long
raw_copy_from_user(void *to, const void __user *from, unsigned long count)
{
return __copy_user((__force void __user *) to, from, count);
}
#define INLINE_COPY_FROM_USER
#define INLINE_COPY_TO_USER
extern unsigned long __do_clear_user (void __user *, unsigned long);
#define __clear_user(to, n) __do_clear_user(to, n)
#define clear_user(to, n) \
({ \
unsigned long __cu_len = (n); \
if (__access_ok(to, __cu_len)) \
__cu_len = __do_clear_user(to, __cu_len); \
__cu_len; \
})
/*
* Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else
* strlen.
*/
extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len);
#define strncpy_from_user(to, from, n) \
({ \
const char __user * __sfu_from = (from); \
long __sfu_ret = -EFAULT; \
if (__access_ok(__sfu_from, 0)) \
__sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \
__sfu_ret; \
})
/*
* Returns: 0 if exception before NUL or reaching the supplied limit
* (N), a value greater than N if the limit would be exceeded, else
* strlen.
*/
extern unsigned long __strnlen_user (const char __user *, long);
#define strnlen_user(str, len) \
({ \
const char __user *__su_str = (str); \
unsigned long __su_ret = 0; \
if (__access_ok(__su_str, 0)) \
__su_ret = __strnlen_user(__su_str, len); \
__su_ret; \
})
#define ARCH_HAS_TRANSLATE_MEM_PTR 1
static __inline__ void *
xlate_dev_mem_ptr(phys_addr_t p)
{
struct page *page;
void *ptr;
page = pfn_to_page(p >> PAGE_SHIFT);
if (PageUncached(page))
ptr = (void *)p + __IA64_UNCACHED_OFFSET;
else
ptr = __va(p);
return ptr;
}
/*
* Convert a virtual cached kernel memory pointer to an uncached pointer
*/
static __inline__ void *
xlate_dev_kmem_ptr(void *p)
{
struct page *page;
void *ptr;
page = virt_to_page((unsigned long)p);
if (PageUncached(page))
ptr = (void *)__pa(p) + __IA64_UNCACHED_OFFSET;
else
ptr = p;
return ptr;
}
#endif /* _ASM_IA64_UACCESS_H */