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/arch/ia64/include/asm/uaccess.h

https://bitbucket.org/thekraven/iscream_thunderc-2.6.35
C++ Header | 401 lines | 264 code | 53 blank | 84 comment | 27 complexity | 29e2edda8d658179c1e43f41fd9ad53d MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
  1#ifndef _ASM_IA64_UACCESS_H
  2#define _ASM_IA64_UACCESS_H
  3
  4/*
  5 * This file defines various macros to transfer memory areas across
  6 * the user/kernel boundary.  This needs to be done carefully because
  7 * this code is executed in kernel mode and uses user-specified
  8 * addresses.  Thus, we need to be careful not to let the user to
  9 * trick us into accessing kernel memory that would normally be
 10 * inaccessible.  This code is also fairly performance sensitive,
 11 * so we want to spend as little time doing safety checks as
 12 * possible.
 13 *
 14 * To make matters a bit more interesting, these macros sometimes also
 15 * called from within the kernel itself, in which case the address
 16 * validity check must be skipped.  The get_fs() macro tells us what
 17 * to do: if get_fs()==USER_DS, checking is performed, if
 18 * get_fs()==KERNEL_DS, checking is bypassed.
 19 *
 20 * Note that even if the memory area specified by the user is in a
 21 * valid address range, it is still possible that we'll get a page
 22 * fault while accessing it.  This is handled by filling out an
 23 * exception handler fixup entry for each instruction that has the
 24 * potential to fault.  When such a fault occurs, the page fault
 25 * handler checks to see whether the faulting instruction has a fixup
 26 * associated and, if so, sets r8 to -EFAULT and clears r9 to 0 and
 27 * then resumes execution at the continuation point.
 28 *
 29 * Based on <asm-alpha/uaccess.h>.
 30 *
 31 * Copyright (C) 1998, 1999, 2001-2004 Hewlett-Packard Co
 32 *	David Mosberger-Tang <davidm@hpl.hp.com>
 33 */
 34
 35#include <linux/compiler.h>
 36#include <linux/errno.h>
 37#include <linux/sched.h>
 38#include <linux/page-flags.h>
 39#include <linux/mm.h>
 40
 41#include <asm/intrinsics.h>
 42#include <asm/pgtable.h>
 43#include <asm/io.h>
 44
 45/*
 46 * For historical reasons, the following macros are grossly misnamed:
 47 */
 48#define KERNEL_DS	((mm_segment_t) { ~0UL })		/* cf. access_ok() */
 49#define USER_DS		((mm_segment_t) { TASK_SIZE-1 })	/* cf. access_ok() */
 50
 51#define VERIFY_READ	0
 52#define VERIFY_WRITE	1
 53
 54#define get_ds()  (KERNEL_DS)
 55#define get_fs()  (current_thread_info()->addr_limit)
 56#define set_fs(x) (current_thread_info()->addr_limit = (x))
 57
 58#define segment_eq(a, b)	((a).seg == (b).seg)
 59
 60/*
 61 * When accessing user memory, we need to make sure the entire area really is in
 62 * user-level space.  In order to do this efficiently, we make sure that the page at
 63 * address TASK_SIZE is never valid.  We also need to make sure that the address doesn't
 64 * point inside the virtually mapped linear page table.
 65 */
 66#define __access_ok(addr, size, segment)						\
 67({											\
 68	__chk_user_ptr(addr);								\
 69	(likely((unsigned long) (addr) <= (segment).seg)				\
 70	 && ((segment).seg == KERNEL_DS.seg						\
 71	     || likely(REGION_OFFSET((unsigned long) (addr)) < RGN_MAP_LIMIT)));	\
 72})
 73#define access_ok(type, addr, size)	__access_ok((addr), (size), get_fs())
 74
 75/*
 76 * These are the main single-value transfer routines.  They automatically
 77 * use the right size if we just have the right pointer type.
 78 *
 79 * Careful to not
 80 * (a) re-use the arguments for side effects (sizeof/typeof is ok)
 81 * (b) require any knowledge of processes at this stage
 82 */
 83#define put_user(x, ptr)	__put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)), get_fs())
 84#define get_user(x, ptr)	__get_user_check((x), (ptr), sizeof(*(ptr)), get_fs())
 85
 86/*
 87 * The "__xxx" versions do not do address space checking, useful when
 88 * doing multiple accesses to the same area (the programmer has to do the
 89 * checks by hand with "access_ok()")
 90 */
 91#define __put_user(x, ptr)	__put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
 92#define __get_user(x, ptr)	__get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 93
 94extern long __put_user_unaligned_unknown (void);
 95
 96#define __put_user_unaligned(x, ptr)								\
 97({												\
 98	long __ret;										\
 99	switch (sizeof(*(ptr))) {								\
100		case 1: __ret = __put_user((x), (ptr)); break;					\
101		case 2: __ret = (__put_user((x), (u8 __user *)(ptr)))				\
102			| (__put_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break;		\
103		case 4: __ret = (__put_user((x), (u16 __user *)(ptr)))				\
104			| (__put_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break;		\
105		case 8: __ret = (__put_user((x), (u32 __user *)(ptr)))				\
106			| (__put_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break;		\
107		default: __ret = __put_user_unaligned_unknown();				\
108	}											\
109	__ret;											\
110})
111
112extern long __get_user_unaligned_unknown (void);
113
114#define __get_user_unaligned(x, ptr)								\
115({												\
116	long __ret;										\
117	switch (sizeof(*(ptr))) {								\
118		case 1: __ret = __get_user((x), (ptr)); break;					\
119		case 2: __ret = (__get_user((x), (u8 __user *)(ptr)))				\
120			| (__get_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break;		\
121		case 4: __ret = (__get_user((x), (u16 __user *)(ptr)))				\
122			| (__get_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break;		\
123		case 8: __ret = (__get_user((x), (u32 __user *)(ptr)))				\
124			| (__get_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break;		\
125		default: __ret = __get_user_unaligned_unknown();				\
126	}											\
127	__ret;											\
128})
129
130#ifdef ASM_SUPPORTED
131  struct __large_struct { unsigned long buf[100]; };
132# define __m(x) (*(struct __large_struct __user *)(x))
133
134/* We need to declare the __ex_table section before we can use it in .xdata.  */
135asm (".section \"__ex_table\", \"a\"\n\t.previous");
136
137# define __get_user_size(val, addr, n, err)							\
138do {												\
139	register long __gu_r8 asm ("r8") = 0;							\
140	register long __gu_r9 asm ("r9");							\
141	asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n"	\
142	     "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n"						\
143	     "[1:]"										\
144	     : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8));			\
145	(err) = __gu_r8;									\
146	(val) = __gu_r9;									\
147} while (0)
148
149/*
150 * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it.  This
151 * is because they do not write to any memory gcc knows about, so there are no aliasing
152 * issues.
153 */
154# define __put_user_size(val, addr, n, err)							\
155do {												\
156	register long __pu_r8 asm ("r8") = 0;							\
157	asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n"	\
158		      "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n"					\
159		      "[1:]"									\
160		      : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8));		\
161	(err) = __pu_r8;									\
162} while (0)
163
164#else /* !ASM_SUPPORTED */
165# define RELOC_TYPE	2	/* ip-rel */
166# define __get_user_size(val, addr, n, err)				\
167do {									\
168	__ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE);	\
169	(err) = ia64_getreg(_IA64_REG_R8);				\
170	(val) = ia64_getreg(_IA64_REG_R9);				\
171} while (0)
172# define __put_user_size(val, addr, n, err)							\
173do {												\
174	__st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE, (unsigned long) (val));	\
175	(err) = ia64_getreg(_IA64_REG_R8);							\
176} while (0)
177#endif /* !ASM_SUPPORTED */
178
179extern void __get_user_unknown (void);
180
181/*
182 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
183 * could clobber r8 and r9 (among others).  Thus, be careful not to evaluate it while
184 * using r8/r9.
185 */
186#define __do_get_user(check, x, ptr, size, segment)					\
187({											\
188	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);				\
189	__typeof__ (size) __gu_size = (size);						\
190	long __gu_err = -EFAULT;							\
191	unsigned long __gu_val = 0;							\
192	if (!check || __access_ok(__gu_ptr, size, segment))				\
193		switch (__gu_size) {							\
194		      case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break;	\
195		      case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break;	\
196		      case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break;	\
197		      case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break;	\
198		      default: __get_user_unknown(); break;				\
199		}									\
200	(x) = (__typeof__(*(__gu_ptr))) __gu_val;					\
201	__gu_err;									\
202})
203
204#define __get_user_nocheck(x, ptr, size)	__do_get_user(0, x, ptr, size, KERNEL_DS)
205#define __get_user_check(x, ptr, size, segment)	__do_get_user(1, x, ptr, size, segment)
206
207extern void __put_user_unknown (void);
208
209/*
210 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
211 * could clobber r8 (among others).  Thus, be careful not to evaluate them while using r8.
212 */
213#define __do_put_user(check, x, ptr, size, segment)					\
214({											\
215	__typeof__ (x) __pu_x = (x);							\
216	__typeof__ (*(ptr)) __user *__pu_ptr = (ptr);					\
217	__typeof__ (size) __pu_size = (size);						\
218	long __pu_err = -EFAULT;							\
219											\
220	if (!check || __access_ok(__pu_ptr, __pu_size, segment))			\
221		switch (__pu_size) {							\
222		      case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break;	\
223		      case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break;	\
224		      case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break;	\
225		      case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break;	\
226		      default: __put_user_unknown(); break;				\
227		}									\
228	__pu_err;									\
229})
230
231#define __put_user_nocheck(x, ptr, size)	__do_put_user(0, x, ptr, size, KERNEL_DS)
232#define __put_user_check(x, ptr, size, segment)	__do_put_user(1, x, ptr, size, segment)
233
234/*
235 * Complex access routines
236 */
237extern unsigned long __must_check __copy_user (void __user *to, const void __user *from,
238					       unsigned long count);
239
240static inline unsigned long
241__copy_to_user (void __user *to, const void *from, unsigned long count)
242{
243	return __copy_user(to, (__force void __user *) from, count);
244}
245
246static inline unsigned long
247__copy_from_user (void *to, const void __user *from, unsigned long count)
248{
249	return __copy_user((__force void __user *) to, from, count);
250}
251
252#define __copy_to_user_inatomic		__copy_to_user
253#define __copy_from_user_inatomic	__copy_from_user
254#define copy_to_user(to, from, n)							\
255({											\
256	void __user *__cu_to = (to);							\
257	const void *__cu_from = (from);							\
258	long __cu_len = (n);								\
259											\
260	if (__access_ok(__cu_to, __cu_len, get_fs()))					\
261		__cu_len = __copy_user(__cu_to, (__force void __user *) __cu_from, __cu_len);	\
262	__cu_len;									\
263})
264
265#define copy_from_user(to, from, n)							\
266({											\
267	void *__cu_to = (to);								\
268	const void __user *__cu_from = (from);						\
269	long __cu_len = (n);								\
270											\
271	__chk_user_ptr(__cu_from);							\
272	if (__access_ok(__cu_from, __cu_len, get_fs()))					\
273		__cu_len = __copy_user((__force void __user *) __cu_to, __cu_from, __cu_len);	\
274	__cu_len;									\
275})
276
277#define __copy_in_user(to, from, size)	__copy_user((to), (from), (size))
278
279static inline unsigned long
280copy_in_user (void __user *to, const void __user *from, unsigned long n)
281{
282	if (likely(access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n)))
283		n = __copy_user(to, from, n);
284	return n;
285}
286
287extern unsigned long __do_clear_user (void __user *, unsigned long);
288
289#define __clear_user(to, n)		__do_clear_user(to, n)
290
291#define clear_user(to, n)					\
292({								\
293	unsigned long __cu_len = (n);				\
294	if (__access_ok(to, __cu_len, get_fs()))		\
295		__cu_len = __do_clear_user(to, __cu_len);	\
296	__cu_len;						\
297})
298
299
300/*
301 * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else
302 * strlen.
303 */
304extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len);
305
306#define strncpy_from_user(to, from, n)					\
307({									\
308	const char __user * __sfu_from = (from);			\
309	long __sfu_ret = -EFAULT;					\
310	if (__access_ok(__sfu_from, 0, get_fs()))			\
311		__sfu_ret = __strncpy_from_user((to), __sfu_from, (n));	\
312	__sfu_ret;							\
313})
314
315/* Returns: 0 if bad, string length+1 (memory size) of string if ok */
316extern unsigned long __strlen_user (const char __user *);
317
318#define strlen_user(str)				\
319({							\
320	const char __user *__su_str = (str);		\
321	unsigned long __su_ret = 0;			\
322	if (__access_ok(__su_str, 0, get_fs()))		\
323		__su_ret = __strlen_user(__su_str);	\
324	__su_ret;					\
325})
326
327/*
328 * Returns: 0 if exception before NUL or reaching the supplied limit
329 * (N), a value greater than N if the limit would be exceeded, else
330 * strlen.
331 */
332extern unsigned long __strnlen_user (const char __user *, long);
333
334#define strnlen_user(str, len)					\
335({								\
336	const char __user *__su_str = (str);			\
337	unsigned long __su_ret = 0;				\
338	if (__access_ok(__su_str, 0, get_fs()))			\
339		__su_ret = __strnlen_user(__su_str, len);	\
340	__su_ret;						\
341})
342
343/* Generic code can't deal with the location-relative format that we use for compactness.  */
344#define ARCH_HAS_SORT_EXTABLE
345#define ARCH_HAS_SEARCH_EXTABLE
346
347struct exception_table_entry {
348	int addr;	/* location-relative address of insn this fixup is for */
349	int cont;	/* location-relative continuation addr.; if bit 2 is set, r9 is set to 0 */
350};
351
352extern void ia64_handle_exception (struct pt_regs *regs, const struct exception_table_entry *e);
353extern const struct exception_table_entry *search_exception_tables (unsigned long addr);
354
355static inline int
356ia64_done_with_exception (struct pt_regs *regs)
357{
358	const struct exception_table_entry *e;
359	e = search_exception_tables(regs->cr_iip + ia64_psr(regs)->ri);
360	if (e) {
361		ia64_handle_exception(regs, e);
362		return 1;
363	}
364	return 0;
365}
366
367#define ARCH_HAS_TRANSLATE_MEM_PTR	1
368static __inline__ char *
369xlate_dev_mem_ptr (unsigned long p)
370{
371	struct page *page;
372	char * ptr;
373
374	page = pfn_to_page(p >> PAGE_SHIFT);
375	if (PageUncached(page))
376		ptr = (char *)p + __IA64_UNCACHED_OFFSET;
377	else
378		ptr = __va(p);
379
380	return ptr;
381}
382
383/*
384 * Convert a virtual cached kernel memory pointer to an uncached pointer
385 */
386static __inline__ char *
387xlate_dev_kmem_ptr (char * p)
388{
389	struct page *page;
390	char * ptr;
391
392	page = virt_to_page((unsigned long)p);
393	if (PageUncached(page))
394		ptr = (char *)__pa(p) + __IA64_UNCACHED_OFFSET;
395	else
396		ptr = p;
397
398	return ptr;
399}
400
401#endif /* _ASM_IA64_UACCESS_H */