patch-2.4.20 linux-2.4.20/include/asm-x86_64/uaccess.h

• Lines: 255
• Date: Thu Nov 28 15:53:15 2002
• Orig file: linux-2.4.19/include/asm-x86_64/uaccess.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/include/asm-x86_64/uaccess.h linux-2.4.20/include/asm-x86_64/uaccess.h
@@ -0,0 +1,254 @@
+#ifndef __X86_64_UACCESS_H
+#define __X86_64_UACCESS_H
+
+/*
+ * User space memory access functions
+ */
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/prefetch.h>
+#include <asm/page.h>
+
+#define VERIFY_READ 0
+#define VERIFY_WRITE 1
+
+/*
+ * The fs value determines whether argument validity checking should be
+ * performed or not.  If get_fs() == USER_DS, checking is performed, with
+ * get_fs() == KERNEL_DS, checking is bypassed.
+ *
+ * For historical reasons, these macros are grossly misnamed.
+ */
+
+#define MAKE_MM_SEG(s)	((mm_segment_t) { (s) })
+
+#define KERNEL_DS	MAKE_MM_SEG(0xFFFFFFFFFFFFFFFF)
+#define USER_DS		MAKE_MM_SEG(PAGE_OFFSET)
+
+#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)
+
+#define __addr_ok(addr) (!((unsigned long)(addr) & (current->addr_limit.seg)))
+
+/*
+ * Uhhuh, this needs 65-bit arithmetic. We have a carry..
+ */
+#define __range_not_ok(addr,size) ({ \
+	unsigned long flag,sum; \
+	asm("# range_ok\n\r" \
+		"addq %3,%1 ; sbbq %0,%0 ; cmpq %1,%4 ; sbbq $0,%0"  \
+		:"=&r" (flag), "=r" (sum) \
+		:"1" (addr),"g" ((long)(size)),"g" (current->addr_limit.seg)); \
+	flag; })
+
+#define access_ok(type,addr,size) (__range_not_ok(addr,size) == 0)
+
+extern inline int verify_area(int type, const void * addr, unsigned long size)
+{
+	return access_ok(type,addr,size) ? 0 : -EFAULT;
+}
+
+
+/*
+ * The exception table consists of pairs of addresses: the first is the
+ * address of an instruction that is allowed to fault, and the second is
+ * the address at which the program should continue.  No registers are
+ * modified, so it is entirely up to the continuation code to figure out
+ * what to do.
+ *
+ * All the routines below use bits of fixup code that are out of line
+ * with the main instruction path.  This means when everything is well,
+ * we don't even have to jump over them.  Further, they do not intrude
+ * on our cache or tlb entries.
+ */
+
+struct exception_table_entry
+{
+	unsigned long insn, fixup;
+};
+
+/* Returns 0 if exception not found and fixup otherwise.  */
+extern unsigned long search_exception_table(unsigned long);
+
+
+/*
+ * These are the main single-value transfer routines.  They automatically
+ * use the right size if we just have the right pointer type.
+ *
+ * This gets kind of ugly. We want to return _two_ values in "get_user()"
+ * and yet we don't want to do any pointers, because that is too much
+ * of a performance impact. Thus we have a few rather ugly macros here,
+ * and hide all the uglyness from the user.
+ *
+ * The "__xxx" versions of the user access functions are versions that
+ * do not verify the address space, that must have been done previously
+ * with a separate "access_ok()" call (this is used when we do multiple
+ * accesses to the same area of user memory).
+ */
+
+extern void __get_user_1(void);
+extern void __get_user_2(void);
+extern void __get_user_4(void);
+extern void __get_user_8(void);
+
+#define __get_user_x(size,ret,x,ptr) \
+	__asm__ __volatile__("call __get_user_" #size \
+		:"=a" (ret),"=d" (x) \
+		:"0" (ptr) \
+		:"rbx")
+
+/* Careful: we have to cast the result to the type of the pointer for sign reasons */
+#define get_user(x,ptr)							\
+({	long __ret_gu,__val_gu;						\
+	switch(sizeof (*(ptr))) {					\
+	case 1:  __get_user_x(1,__ret_gu,__val_gu,ptr); break;		\
+	case 2:  __get_user_x(2,__ret_gu,__val_gu,ptr); break;		\
+	case 4:  __get_user_x(4,__ret_gu,__val_gu,ptr); break;		\
+	case 8:  __get_user_x(8,__ret_gu,__val_gu,ptr); break;		\
+	default: __get_user_bad(); break;				\
+	}								\
+	(x) = (__typeof__(*(ptr)))__val_gu;				\
+	__ret_gu;							\
+})
+
+extern void __put_user_1(void);
+extern void __put_user_2(void);
+extern void __put_user_4(void);
+extern void __put_user_8(void);
+
+extern void __put_user_bad(void);
+
+#define __put_user_x(size,ret,x,ptr)					\
+	__asm__ __volatile__("call __put_user_" #size			\
+		:"=a" (ret)						\
+		:"0" (ptr),"d" (x)					\
+		:"rbx")
+
+#define put_user(x,ptr)							\
+  __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
+
+#define __get_user(x,ptr) \
+  __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
+#define __put_user(x,ptr) \
+  __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
+
+#define __put_user_nocheck(x,ptr,size)			\
+({							\
+	long __pu_err;					\
+	__put_user_size((x),(ptr),(size),__pu_err);	\
+	__pu_err;					\
+})
+
+
+#define __put_user_check(x,ptr,size)			\
+({							\
+	long __pu_err = -EFAULT;			\
+	__typeof__(*(ptr)) *__pu_addr = (ptr);		\
+	if (access_ok(VERIFY_WRITE,__pu_addr,size))	\
+		__put_user_size((x),__pu_addr,(size),__pu_err);	\
+	__pu_err;					\
+})
+
+#define __put_user_size(x,ptr,size,retval)				\
+do {									\
+	retval = 0;							\
+	switch (size) {							\
+	  case 1: __put_user_asm(x,ptr,retval,"b","b","iq"); break;	\
+	  case 2: __put_user_asm(x,ptr,retval,"w","w","ir"); break;	\
+	  case 4: __put_user_asm(x,ptr,retval,"l","k","ir"); break;	\
+	  case 8: __put_user_asm(x,ptr,retval,"q","","ir"); break;	\
+	  default: __put_user_bad();					\
+	}								\
+} while (0)
+
+/* FIXME: this hack is definitely wrong -AK */
+struct __large_struct { unsigned long buf[100]; };
+#define __m(x) (*(struct __large_struct *)(x))
+
+/*
+ * Tell gcc we read from memory instead of writing: this is because
+ * we do not write to any memory gcc knows about, so there are no
+ * aliasing issues.
+ */
+#define __put_user_asm(x, addr, err, itype, rtype, ltype)	\
+	__asm__ __volatile__(				\
+		"1:	mov"itype" %"rtype"1,%2\n"	\
+		"2:\n"							\
+		".section .fixup,\"ax\"\n"		\
+		"3:	movq %3,%0\n"				\
+		"	jmp 2b\n"					\
+		".previous\n"					\
+		".section __ex_table,\"a\"\n"	\
+		"	.align 8\n"					\
+		"	.quad 1b,3b\n"				\
+		".previous"						\
+		: "=r"(err)						\
+		: ltype (x), "m"(__m(addr)), "i"(-EFAULT), "0"(err))
+
+
+#define __get_user_nocheck(x,ptr,size)				\
+({								\
+	long __gu_err, __gu_val;				\
+	__get_user_size(__gu_val,(ptr),(size),__gu_err);	\
+	(x) = (__typeof__(*(ptr)))__gu_val;			\
+	__gu_err;						\
+})
+
+extern long __get_user_bad(void);
+
+#define __get_user_size(x,ptr,size,retval)				\
+do {									\
+	retval = 0;							\
+	switch (size) {							\
+	  case 1: __get_user_asm(x,ptr,retval,"b","b","=q"); break;	\
+	  case 2: __get_user_asm(x,ptr,retval,"w","w","=r"); break;	\
+	  case 4: __get_user_asm(x,ptr,retval,"l","k","=r"); break;	\
+	  case 8: __get_user_asm(x,ptr,retval,"q","","=r"); break;	\
+	  default: (x) = __get_user_bad();				\
+	}								\
+} while (0)
+
+#define __get_user_asm(x, addr, err, itype, rtype, ltype)	\
+	__asm__ __volatile__(					\
+		"1:	mov"itype" %2,%"rtype"1\n"		\
+		"2:\n"						\
+		".section .fixup,\"ax\"\n"			\
+		"3:	mov %3,%0\n"				\
+		"	xor"itype" %"rtype"1,%"rtype"1\n"	\
+		"	jmp 2b\n"				\
+		".previous\n"					\
+		".section __ex_table,\"a\"\n"			\
+		"	.align 8\n"				\
+		"	.quad 1b,3b\n"				\
+		".previous"					\
+		: "=r"(err), ltype (x)				\
+		: "m"(__m(addr)), "i"(-EFAULT), "0"(err))
+
+/*
+ * Copy To/From Userspace
+ * 
+ * This relies on an optimized common worker function.
+ * 
+ * Could do special inline versions for small constant copies, but avoid this
+ * for now. It's not clear it is worth it. 
+ */
+
+extern unsigned long copy_user_generic(void *to, const void *from, unsigned len); 
+
+extern unsigned long copy_to_user(void *to, const void *from, unsigned len); 
+extern unsigned long copy_from_user(void *to, const void *from, unsigned len); 
+#define __copy_to_user copy_user_generic
+#define __copy_from_user copy_user_generic
+
+long strncpy_from_user(char *dst, const char *src, long count);
+long __strncpy_from_user(char *dst, const char *src, long count);
+#define strlen_user(str) strnlen_user(str, ~0UL >> 1)
+long strnlen_user(const char *str, long n);
+unsigned long clear_user(void *mem, unsigned long len);
+unsigned long __clear_user(void *mem, unsigned long len);
+
+#endif /* __X86_64_UACCESS_H */