patch-2.3.43 linux/include/asm-ia64/uaccess.h

• Lines: 367
• Date: Sun Feb 6 18:42:40 2000
• Orig file: v2.3.42/linux/include/asm-ia64/uaccess.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.42/linux/include/asm-ia64/uaccess.h linux/include/asm-ia64/uaccess.h
@@ -0,0 +1,366 @@
+#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 saftey 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.
+ * 
+ * Copyright (C) 1998, 1999 Hewlett-Packard Co
+ * Copyright (C) 1998, 1999 David Mosberger-Tang <davidm@hpl.hp.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/sched.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 VERIFY_READ	0
+#define VERIFY_WRITE	1
+
+#define get_ds()  (KERNEL_DS)
+#define get_fs()  (current->addr_limit)
+#define set_fs(x) (current->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 do
+ * this by selecting VMALLOC_START as TASK_SIZE+PAGE_SIZE).  This way,
+ * we can simply check whether the starting address is < TASK_SIZE
+ * and, if so, start accessing the memory.  If the user specified bad
+ * length, we will fault on the NaT page and then return the
+ * appropriate error.
+ */
+#define __access_ok(addr,size,segment)	(((unsigned long) (addr)) <= (segment).seg)
+#define access_ok(type,addr,size)	__access_ok((addr),(size),get_fs())
+
+extern inline int
+verify_area (int type, const void *addr, unsigned long size)
+{
+	return access_ok(type,addr,size) ? 0 : -EFAULT;
+}
+
+/*
+ * These are the main single-value transfer routines.  They automatically
+ * use the right size if we just have the right pointer type.
+ *
+ * As the alpha uses the same address space for kernel and user
+ * data, we can just do these as direct assignments.  (Of course, the
+ * exception handling means that it's no longer "just"...)
+ *
+ * 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)),get_fs())
+#define get_user(x,ptr)	__get_user_check((x),(ptr),sizeof(*(ptr)),get_fs())
+
+/*
+ * 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)))
+  
+/*
+ * The "xxx_ret" versions return constant specified in third argument, if
+ * something bad happens. These macros can be optimized for the
+ * case of just returning from the function xxx_ret is used.
+ */
+#define put_user_ret(x,ptr,ret)		({ if (put_user(x,ptr)) return ret; })
+#define get_user_ret(x,ptr,ret)		({ if (get_user(x,ptr)) return ret; })
+#define __put_user_ret(x,ptr,ret)	({ if (__put_user(x,ptr)) return ret; })
+#define __get_user_ret(x,ptr,ret)	({ if (__get_user(x,ptr)) return ret; })
+
+extern void __get_user_unknown (void);
+
+#define __get_user_nocheck(x,ptr,size)				\
+({								\
+	register long __gu_err __asm__ ("r8") = 0;		\
+	register long __gu_val __asm__ ("r9") = 0;		\
+	switch (size) {						\
+	  case 1: __get_user_8(ptr); break;			\
+	  case 2: __get_user_16(ptr); break;			\
+	  case 4: __get_user_32(ptr); break;			\
+	  case 8: __get_user_64(ptr); break;			\
+	  default: __get_user_unknown(); break;			\
+	}							\
+	(x) = (__typeof__(*(ptr))) __gu_val;			\
+	__gu_err;						\
+})
+
+#define __get_user_check(x,ptr,size,segment)			\
+({								\
+	register long __gu_err __asm__ ("r8") = -EFAULT;	\
+	register long __gu_val __asm__ ("r9") = 0;		\
+	const __typeof__(*(ptr)) *__gu_addr = (ptr);		\
+	if (__access_ok((long)__gu_addr,size,segment)) {	\
+		__gu_err = 0;					\
+		switch (size) {					\
+		  case 1: __get_user_8(__gu_addr); break;	\
+		  case 2: __get_user_16(__gu_addr); break;	\
+		  case 4: __get_user_32(__gu_addr); break;	\
+		  case 8: __get_user_64(__gu_addr); break;	\
+		  default: __get_user_unknown(); break;		\
+		}						\
+	}							\
+	(x) = (__typeof__(*(ptr))) __gu_val;			\
+	__gu_err;						\
+})
+
+struct __large_struct { unsigned long buf[100]; };
+#define __m(x) (*(struct __large_struct *)(x))
+
+#define __get_user_64(addr)								\
+	__asm__ ("\n1:\tld8 %0=%2\t// %0 and %1 get overwritten by exception handler\n"	\
+		 "2:\n"									\
+		 "\t.section __ex_table,\"a\"\n"					\
+		 "\t\tdata4 @gprel(1b)\n"						\
+		 "\t\tdata4 (2b-1b)|1\n"						\
+		 "\t.previous"								\
+		: "=r"(__gu_val), "=r"(__gu_err)					\
+		: "m"(__m(addr)), "1"(__gu_err));
+
+#define __get_user_32(addr)								\
+	__asm__ ("\n1:\tld4 %0=%2\t// %0 and %1 get overwritten by exception handler\n"	\
+		 "2:\n"									\
+		 "\t.section __ex_table,\"a\"\n"					\
+		 "\t\tdata4 @gprel(1b)\n"						\
+		 "\t\tdata4 (2b-1b)|1\n"						\
+		 "\t.previous"								\
+		: "=r"(__gu_val), "=r"(__gu_err)					\
+		: "m"(__m(addr)), "1"(__gu_err));
+
+#define __get_user_16(addr)								\
+	__asm__ ("\n1:\tld2 %0=%2\t// %0 and %1 get overwritten by exception handler\n"	\
+		 "2:\n"									\
+		 "\t.section __ex_table,\"a\"\n"					\
+		 "\t\tdata4 @gprel(1b)\n"						\
+		 "\t\tdata4 (2b-1b)|1\n"						\
+		 "\t.previous"								\
+		: "=r"(__gu_val), "=r"(__gu_err)					\
+		: "m"(__m(addr)), "1"(__gu_err));
+
+#define __get_user_8(addr)								\
+	__asm__ ("\n1:\tld1 %0=%2\t// %0 and %1 get overwritten by exception handler\n"	\
+		 "2:\n"									\
+		 "\t.section __ex_table,\"a\"\n"					\
+		 "\t\tdata4 @gprel(1b)\n"						\
+		 "\t\tdata4 (2b-1b)|1\n"						\
+		 "\t.previous"								\
+		: "=r"(__gu_val), "=r"(__gu_err)					\
+		: "m"(__m(addr)), "1"(__gu_err));
+
+
+extern void __put_user_unknown (void);
+
+#define __put_user_nocheck(x,ptr,size)				\
+({								\
+	register long __pu_err __asm__ ("r8") = 0;		\
+	switch (size) {						\
+	  case 1: __put_user_8(x,ptr); break;			\
+	  case 2: __put_user_16(x,ptr); break;			\
+	  case 4: __put_user_32(x,ptr); break;			\
+	  case 8: __put_user_64(x,ptr); break;			\
+	  default: __put_user_unknown(); break;			\
+	}							\
+	__pu_err;						\
+})
+
+#define __put_user_check(x,ptr,size,segment)			\
+({								\
+	register long __pu_err __asm__ ("r8") = -EFAULT;	\
+	__typeof__(*(ptr)) *__pu_addr = (ptr);			\
+	if (__access_ok((long)__pu_addr,size,segment)) {	\
+		__pu_err = 0;					\
+		switch (size) {					\
+		  case 1: __put_user_8(x,__pu_addr); break;	\
+		  case 2: __put_user_16(x,__pu_addr); break;	\
+		  case 4: __put_user_32(x,__pu_addr); break;	\
+		  case 8: __put_user_64(x,__pu_addr); break;	\
+		  default: __put_user_unknown(); break;		\
+		}						\
+	}							\
+	__pu_err;						\
+})
+
+/*
+ * The "__put_user_xx()" macros tell gcc they read from memory
+ * instead of writing: this is because they do not write to
+ * any memory gcc knows about, so there are no aliasing issues
+ */
+#define __put_user_64(x,addr)								\
+	__asm__ __volatile__ (								\
+		 "\n1:\tst8 %1=%r2\t// %0 gets overwritten by exception handler\n"	\
+		 "2:\n"									\
+		 "\t.section __ex_table,\"a\"\n"					\
+		 "\t\tdata4 @gprel(1b)\n"						\
+		 "\t\tdata4 2b-1b\n"							\
+		 "\t.previous"								\
+		: "=r"(__pu_err)							\
+		: "m"(__m(addr)), "rO"(x), "0"(__pu_err))
+
+#define __put_user_32(x,addr)								\
+	__asm__ __volatile__ (								\
+		 "\n1:\tst4 %1=%r2\t// %0 gets overwritten by exception handler\n"	\
+		 "2:\n"									\
+		 "\t.section __ex_table,\"a\"\n"					\
+		 "\t\tdata4 @gprel(1b)\n"						\
+		 "\t\tdata4 2b-1b\n"							\
+		 "\t.previous"								\
+		: "=r"(__pu_err)							\
+		: "m"(__m(addr)), "rO"(x), "0"(__pu_err))
+
+#define __put_user_16(x,addr)								\
+	__asm__ __volatile__ (								\
+		 "\n1:\tst2 %1=%r2\t// %0 gets overwritten by exception handler\n"	\
+		 "2:\n"									\
+		 "\t.section __ex_table,\"a\"\n"					\
+		 "\t\tdata4 @gprel(1b)\n"						\
+		 "\t\tdata4 2b-1b\n"							\
+		 "\t.previous"								\
+		: "=r"(__pu_err)							\
+		: "m"(__m(addr)), "rO"(x), "0"(__pu_err))
+
+#define __put_user_8(x,addr)								\
+	__asm__ __volatile__ (								\
+		 "\n1:\tst1 %1=%r2\t// %0 gets overwritten by exception handler\n"	\
+		 "2:\n"									\
+		 "\t.section __ex_table,\"a\"\n"					\
+		 "\t\tdata4 @gprel(1b)\n"						\
+		 "\t\tdata4 2b-1b\n"							\
+		 "\t.previous"								\
+		: "=r"(__pu_err)							\
+		: "m"(__m(addr)), "rO"(x), "0"(__pu_err))
+
+/*
+ * Complex access routines
+ */
+extern unsigned long __copy_user (void *to, const void *from, unsigned long count);
+
+#define __copy_to_user(to,from,n)	__copy_user((to), (from), (n))
+#define __copy_from_user(to,from,n) 	__copy_user((to), (from), (n))
+
+#define copy_to_user(to,from,n)   __copy_tofrom_user((to), (from), (n), 1)
+#define copy_from_user(to,from,n) __copy_tofrom_user((to), (from), (n), 0)
+
+#define __copy_tofrom_user(to,from,n,check_to)							\
+({												\
+	void *__cu_to = (to);									\
+	const void *__cu_from = (from);								\
+	long __cu_len = (n);									\
+												\
+	if (__access_ok((long) ((check_to) ? __cu_to : __cu_from), __cu_len, get_fs())) {	\
+		__cu_len = __copy_user(__cu_to, __cu_from, __cu_len);				\
+	}											\
+	__cu_len;										\
+})
+
+#define copy_to_user_ret(to,from,n,retval)	\
+({						\
+	if (copy_to_user(to,from,n))		\
+		return retval;			\
+})
+
+#define copy_from_user_ret(to,from,n,retval)	\
+({						\
+	if (copy_from_user(to,from,n))		\
+		return retval;			\
+})
+
+extern unsigned long __do_clear_user (void *, 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((long) to, __cu_len, get_fs())) {	\
+		__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 __strncpy_from_user (char *to, const char *from, long to_len);
+
+#define strncpy_from_user(to,from,n)					\
+({									\
+	const char * __sfu_from = (from);				\
+	long __sfu_ret = -EFAULT;					\
+	if (__access_ok((long) __sfu_from, 0, get_fs()))		\
+		__sfu_ret = __strncpy_from_user((to), __sfu_from, (n));	\
+	__sfu_ret;							\
+})
+
+/* Returns: 0 if bad, string length+1 (memory size) of string if ok */
+extern unsigned long __strlen_user (const char *);
+
+#define strlen_user(str)				\
+({							\
+	const char *__su_str = (str);			\
+	unsigned long __su_ret = 0;			\
+	if (__access_ok((long) __su_str, 0, get_fs()))	\
+		__su_ret = __strlen_user(__su_str);	\
+	__su_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 *, long);
+
+#define strnlen_user(str, len)					\
+({								\
+	const char *__su_str = (str);				\
+	unsigned long __su_ret = 0;				\
+	if (__access_ok((long) __su_str, 0, get_fs()))		\
+		__su_ret = __strnlen_user(__su_str, len);	\
+	__su_ret;						\
+})
+
+struct exception_table_entry {
+	int addr;	/* gp-relative address of insn this fixup is for */
+	int skip;	/* number of bytes to skip to get to the continuation point.
+			   Bit 0 tells us if r9 should be cleared to 0*/
+};
+
+extern const struct exception_table_entry *search_exception_table (unsigned long addr);
+
+#endif /* _ASM_IA64_UACCESS_H */