1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_IA64_UACCESS_H
3#define _ASM_IA64_UACCESS_H
4
5/*
6 * This file defines various macros to transfer memory areas across
7 * the user/kernel boundary.  This needs to be done carefully because
8 * this code is executed in kernel mode and uses user-specified
9 * addresses.  Thus, we need to be careful not to let the user to
10 * trick us into accessing kernel memory that would normally be
11 * inaccessible.  This code is also fairly performance sensitive,
12 * so we want to spend as little time doing safety checks as
13 * possible.
14 *
15 * To make matters a bit more interesting, these macros sometimes also
16 * called from within the kernel itself, in which case the address
17 * validity check must be skipped.  The get_fs() macro tells us what
18 * to do: if get_fs()==USER_DS, checking is performed, if
19 * get_fs()==KERNEL_DS, checking is bypassed.
20 *
21 * Note that even if the memory area specified by the user is in a
22 * valid address range, it is still possible that we'll get a page
23 * fault while accessing it.  This is handled by filling out an
24 * exception handler fixup entry for each instruction that has the
25 * potential to fault.  When such a fault occurs, the page fault
26 * handler checks to see whether the faulting instruction has a fixup
27 * associated and, if so, sets r8 to -EFAULT and clears r9 to 0 and
28 * then resumes execution at the continuation point.
29 *
30 * Based on <asm-alpha/uaccess.h>.
31 *
32 * Copyright (C) 1998, 1999, 2001-2004 Hewlett-Packard Co
33 *	David Mosberger-Tang <davidm@hpl.hp.com>
34 */
35
36#include <linux/compiler.h>
37#include <linux/page-flags.h>
38
39#include <asm/intrinsics.h>
40#include <linux/pgtable.h>
41#include <asm/io.h>
42#include <asm/extable.h>
43
44/*
45 * When accessing user memory, we need to make sure the entire area really is
46 * in user-level space.  We also need to make sure that the address doesn't
47 * point inside the virtually mapped linear page table.
48 */
49static inline int __access_ok(const void __user *p, unsigned long size)
50{
51	unsigned long limit = TASK_SIZE;
52	unsigned long addr = (unsigned long)p;
53
54	return likely((size <= limit) && (addr <= (limit - size)) &&
55		 likely(REGION_OFFSET(addr) < RGN_MAP_LIMIT));
56}
57#define __access_ok __access_ok
58#include <asm-generic/access_ok.h>
59
60/*
61 * These are the main single-value transfer routines.  They automatically
62 * use the right size if we just have the right pointer type.
63 *
64 * Careful to not
65 * (a) re-use the arguments for side effects (sizeof/typeof is ok)
66 * (b) require any knowledge of processes at this stage
67 */
68#define put_user(x, ptr)	__put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
69#define get_user(x, ptr)	__get_user_check((x), (ptr), sizeof(*(ptr)))
70
71/*
72 * The "__xxx" versions do not do address space checking, useful when
73 * doing multiple accesses to the same area (the programmer has to do the
74 * checks by hand with "access_ok()")
75 */
76#define __put_user(x, ptr)	__put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
77#define __get_user(x, ptr)	__get_user_nocheck((x), (ptr), sizeof(*(ptr)))
78
79#ifdef ASM_SUPPORTED
80  struct __large_struct { unsigned long buf[100]; };
81# define __m(x) (*(struct __large_struct __user *)(x))
82
83/* We need to declare the __ex_table section before we can use it in .xdata.  */
84asm (".section \"__ex_table\", \"a\"\n\t.previous");
85
86# define __get_user_size(val, addr, n, err)							\
87do {												\
88	register long __gu_r8 asm ("r8") = 0;							\
89	register long __gu_r9 asm ("r9");							\
90	asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n"	\
91	     "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n"						\
92	     "[1:]"										\
93	     : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8));			\
94	(err) = __gu_r8;									\
95	(val) = __gu_r9;									\
96} while (0)
97
98/*
99 * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it.  This
100 * is because they do not write to any memory gcc knows about, so there are no aliasing
101 * issues.
102 */
103# define __put_user_size(val, addr, n, err)							\
104do {												\
105	register long __pu_r8 asm ("r8") = 0;							\
106	asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n"	\
107		      "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n"					\
108		      "[1:]"									\
109		      : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8));		\
110	(err) = __pu_r8;									\
111} while (0)
112
113#else /* !ASM_SUPPORTED */
114# define RELOC_TYPE	2	/* ip-rel */
115# define __get_user_size(val, addr, n, err)				\
116do {									\
117	__ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE);	\
118	(err) = ia64_getreg(_IA64_REG_R8);				\
119	(val) = ia64_getreg(_IA64_REG_R9);				\
120} while (0)
121# define __put_user_size(val, addr, n, err)				\
122do {									\
123	__st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE,	\
124		  (__force unsigned long) (val));			\
125	(err) = ia64_getreg(_IA64_REG_R8);				\
126} while (0)
127#endif /* !ASM_SUPPORTED */
128
129extern void __get_user_unknown (void);
130
131/*
132 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
133 * could clobber r8 and r9 (among others).  Thus, be careful not to evaluate it while
134 * using r8/r9.
135 */
136#define __do_get_user(check, x, ptr, size)						\
137({											\
138	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);				\
139	__typeof__ (size) __gu_size = (size);						\
140	long __gu_err = -EFAULT;							\
141	unsigned long __gu_val = 0;							\
142	if (!check || __access_ok(__gu_ptr, size))					\
143		switch (__gu_size) {							\
144		      case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break;	\
145		      case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break;	\
146		      case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break;	\
147		      case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break;	\
148		      default: __get_user_unknown(); break;				\
149		}									\
150	(x) = (__force __typeof__(*(__gu_ptr))) __gu_val;				\
151	__gu_err;									\
152})
153
154#define __get_user_nocheck(x, ptr, size)	__do_get_user(0, x, ptr, size)
155#define __get_user_check(x, ptr, size)	__do_get_user(1, x, ptr, size)
156
157extern void __put_user_unknown (void);
158
159/*
160 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
161 * could clobber r8 (among others).  Thus, be careful not to evaluate them while using r8.
162 */
163#define __do_put_user(check, x, ptr, size)						\
164({											\
165	__typeof__ (x) __pu_x = (x);							\
166	__typeof__ (*(ptr)) __user *__pu_ptr = (ptr);					\
167	__typeof__ (size) __pu_size = (size);						\
168	long __pu_err = -EFAULT;							\
169											\
170	if (!check || __access_ok(__pu_ptr, __pu_size))					\
171		switch (__pu_size) {							\
172		      case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break;	\
173		      case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break;	\
174		      case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break;	\
175		      case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break;	\
176		      default: __put_user_unknown(); break;				\
177		}									\
178	__pu_err;									\
179})
180
181#define __put_user_nocheck(x, ptr, size)	__do_put_user(0, x, ptr, size)
182#define __put_user_check(x, ptr, size)	__do_put_user(1, x, ptr, size)
183
184/*
185 * Complex access routines
186 */
187extern unsigned long __must_check __copy_user (void __user *to, const void __user *from,
188					       unsigned long count);
189
190static inline unsigned long
191raw_copy_to_user(void __user *to, const void *from, unsigned long count)
192{
193	return __copy_user(to, (__force void __user *) from, count);
194}
195
196static inline unsigned long
197raw_copy_from_user(void *to, const void __user *from, unsigned long count)
198{
199	return __copy_user((__force void __user *) to, from, count);
200}
201
202#define INLINE_COPY_FROM_USER
203#define INLINE_COPY_TO_USER
204
205extern unsigned long __do_clear_user (void __user *, unsigned long);
206
207#define __clear_user(to, n)		__do_clear_user(to, n)
208
209#define clear_user(to, n)					\
210({								\
211	unsigned long __cu_len = (n);				\
212	if (__access_ok(to, __cu_len))				\
213		__cu_len = __do_clear_user(to, __cu_len);	\
214	__cu_len;						\
215})
216
217
218/*
219 * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else
220 * strlen.
221 */
222extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len);
223
224#define strncpy_from_user(to, from, n)					\
225({									\
226	const char __user * __sfu_from = (from);			\
227	long __sfu_ret = -EFAULT;					\
228	if (__access_ok(__sfu_from, 0))					\
229		__sfu_ret = __strncpy_from_user((to), __sfu_from, (n));	\
230	__sfu_ret;							\
231})
232
233/*
234 * Returns: 0 if exception before NUL or reaching the supplied limit
235 * (N), a value greater than N if the limit would be exceeded, else
236 * strlen.
237 */
238extern unsigned long __strnlen_user (const char __user *, long);
239
240#define strnlen_user(str, len)					\
241({								\
242	const char __user *__su_str = (str);			\
243	unsigned long __su_ret = 0;				\
244	if (__access_ok(__su_str, 0))				\
245		__su_ret = __strnlen_user(__su_str, len);	\
246	__su_ret;						\
247})
248
249#define ARCH_HAS_TRANSLATE_MEM_PTR	1
250static __inline__ void *
251xlate_dev_mem_ptr(phys_addr_t p)
252{
253	struct page *page;
254	void *ptr;
255
256	page = pfn_to_page(p >> PAGE_SHIFT);
257	if (PageUncached(page))
258		ptr = (void *)p + __IA64_UNCACHED_OFFSET;
259	else
260		ptr = __va(p);
261
262	return ptr;
263}
264
265#endif /* _ASM_IA64_UACCESS_H */
266