OpenRISC: Memory management

Signed-off-by: Jonas Bonn <jonas@southpole.se>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 355 insertions, 0 deletions

diff --git a/arch/openrisc/include/asm/uaccess.h b/arch/openrisc/include/asm/uaccess.h
new file mode 100644
index 00000000000..c310e45b538
--- /dev/null
+++ b/arch/openrisc/include/asm/uaccess.h
@@ -0,0 +1,355 @@
+/*
+ * OpenRISC Linux
+ *
+ * Linux architectural port borrowing liberally from similar works of
+ * others.  All original copyrights apply as per the original source
+ * declaration.
+ *
+ * OpenRISC implementation:
+ * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
+ * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
+ * et al.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __ASM_OPENRISC_UACCESS_H
+#define __ASM_OPENRISC_UACCESS_H
+
+/*
+ * User space memory access functions
+ */
+#include <linux/errno.h>
+#include <linux/thread_info.h>
+#include <linux/prefetch.h>
+#include <linux/string.h>
+#include <linux/thread_info.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.
+ */
+
+/* addr_limit is the maximum accessible address for the task. we misuse
+ * the KERNEL_DS and USER_DS values to both assign and compare the
+ * addr_limit values through the equally misnamed get/set_fs macros.
+ * (see above)
+ */
+
+#define KERNEL_DS	(~0UL)
+#define get_ds()	(KERNEL_DS)
+
+#define USER_DS		(TASK_SIZE)
+#define get_fs()	(current_thread_info()->addr_limit)
+#define set_fs(x)	(current_thread_info()->addr_limit = (x))
+
+#define segment_eq(a, b)	((a) == (b))
+
+/* Ensure that the range from addr to addr+size is all within the process'
+ * address space
+ */
+#define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs()-size))
+
+/* Ensure that addr is below task's addr_limit */
+#define __addr_ok(addr) ((unsigned long) addr < get_fs())
+
+#define access_ok(type, addr, size) \
+	__range_ok((unsigned long)addr, (unsigned long)size)
+
+/*
+ * 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);
+extern void sort_exception_table(void);
+
+/*
+ * 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).
+ *
+ * As we use the same address space for kernel and user data on the
+ * PowerPC, we can just do these as direct assignments.  (Of course, the
+ * exception handling means that it's no longer "just"...)
+ */
+#define get_user(x, ptr) \
+	__get_user_check((x), (ptr), sizeof(*(ptr)))
+#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)))
+
+extern long __put_user_bad(void);
+
+#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, "l.sb"); break;		\
+	case 2: __put_user_asm(x, ptr, retval, "l.sh"); break;		\
+	case 4: __put_user_asm(x, ptr, retval, "l.sw"); break;		\
+	case 8: __put_user_asm2(x, ptr, retval); break;			\
+	default: __put_user_bad();					\
+	}								\
+} while (0)
+
+struct __large_struct {
+	unsigned long buf[100];
+};
+#define __m(x) (*(struct __large_struct *)(x))
+
+/*
+ * We don't tell gcc that we are accessing memory, but this is OK
+ * because we do not write to any memory gcc knows about, so there
+ * are no aliasing issues.
+ */
+#define __put_user_asm(x, addr, err, op)			\
+	__asm__ __volatile__(					\
+		"1:	"op" 0(%2),%1\n"			\
+		"2:\n"						\
+		".section .fixup,\"ax\"\n"			\
+		"3:	l.addi %0,r0,%3\n"			\
+		"	l.j 2b\n"				\
+		"	l.nop\n"				\
+		".previous\n"					\
+		".section __ex_table,\"a\"\n"			\
+		"	.align 2\n"				\
+		"	.long 1b,3b\n"				\
+		".previous"					\
+		: "=r"(err)					\
+		: "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
+
+#define __put_user_asm2(x, addr, err)				\
+	__asm__ __volatile__(					\
+		"1:	l.sw 0(%2),%1\n"			\
+		"2:	l.sw 4(%2),%H1\n"			\
+		"3:\n"						\
+		".section .fixup,\"ax\"\n"			\
+		"4:	l.addi %0,r0,%3\n"			\
+		"	l.j 3b\n"				\
+		"	l.nop\n"				\
+		".previous\n"					\
+		".section __ex_table,\"a\"\n"			\
+		"	.align 2\n"				\
+		"	.long 1b,4b\n"				\
+		"	.long 2b,4b\n"				\
+		".previous"					\
+		: "=r"(err)					\
+		: "r"(x), "r"(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;						\
+})
+
+#define __get_user_check(x, ptr, size)					\
+({									\
+	long __gu_err = -EFAULT, __gu_val = 0;				\
+	const __typeof__(*(ptr)) * __gu_addr = (ptr);			\
+	if (access_ok(VERIFY_READ, __gu_addr, size))			\
+		__get_user_size(__gu_val, __gu_addr, (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, "l.lbz"); break;		\
+	case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break;		\
+	case 4: __get_user_asm(x, ptr, retval, "l.lwz"); break;		\
+	case 8: __get_user_asm2(x, ptr, retval);			\
+	default: (x) = __get_user_bad();				\
+	}								\
+} while (0)
+
+#define __get_user_asm(x, addr, err, op)		\
+	__asm__ __volatile__(				\
+		"1:	"op" %1,0(%2)\n"		\
+		"2:\n"					\
+		".section .fixup,\"ax\"\n"		\
+		"3:	l.addi %0,r0,%3\n"		\
+		"	l.addi %1,r0,0\n"		\
+		"	l.j 2b\n"			\
+		"	l.nop\n"			\
+		".previous\n"				\
+		".section __ex_table,\"a\"\n"		\
+		"	.align 2\n"			\
+		"	.long 1b,3b\n"			\
+		".previous"				\
+		: "=r"(err), "=r"(x)			\
+		: "r"(addr), "i"(-EFAULT), "0"(err))
+
+#define __get_user_asm2(x, addr, err)			\
+	__asm__ __volatile__(				\
+		"1:	l.lwz %1,0(%2)\n"		\
+		"2:	l.lwz %H1,4(%2)\n"		\
+		"3:\n"					\
+		".section .fixup,\"ax\"\n"		\
+		"4:	l.addi %0,r0,%3\n"		\
+		"	l.addi %1,r0,0\n"		\
+		"	l.addi %H1,r0,0\n"		\
+		"	l.j 3b\n"			\
+		"	l.nop\n"			\
+		".previous\n"				\
+		".section __ex_table,\"a\"\n"		\
+		"	.align 2\n"			\
+		"	.long 1b,4b\n"			\
+		"	.long 2b,4b\n"			\
+		".previous"				\
+		: "=r"(err), "=&r"(x)			\
+		: "r"(addr), "i"(-EFAULT), "0"(err))
+
+/* more complex routines */
+
+extern unsigned long __must_check
+__copy_tofrom_user(void *to, const void *from, unsigned long size);
+
+#define __copy_from_user(to, from, size) \
+	__copy_tofrom_user(to, from, size)
+#define __copy_to_user(to, from, size) \
+	__copy_tofrom_user(to, from, size)
+
+#define __copy_to_user_inatomic __copy_to_user
+#define __copy_from_user_inatomic __copy_from_user
+
+static inline unsigned long
+copy_from_user(void *to, const void *from, unsigned long n)
+{
+	unsigned long over;
+
+	if (access_ok(VERIFY_READ, from, n))
+		return __copy_tofrom_user(to, from, n);
+	if ((unsigned long)from < TASK_SIZE) {
+		over = (unsigned long)from + n - TASK_SIZE;
+		return __copy_tofrom_user(to, from, n - over) + over;
+	}
+	return n;
+}
+
+static inline unsigned long
+copy_to_user(void *to, const void *from, unsigned long n)
+{
+	unsigned long over;
+
+	if (access_ok(VERIFY_WRITE, to, n))
+		return __copy_tofrom_user(to, from, n);
+	if ((unsigned long)to < TASK_SIZE) {
+		over = (unsigned long)to + n - TASK_SIZE;
+		return __copy_tofrom_user(to, from, n - over) + over;
+	}
+	return n;
+}
+
+extern unsigned long __clear_user(void *addr, unsigned long size);
+
+static inline __must_check unsigned long
+clear_user(void *addr, unsigned long size)
+{
+
+	if (access_ok(VERIFY_WRITE, addr, size))
+		return __clear_user(addr, size);
+	if ((unsigned long)addr < TASK_SIZE) {
+		unsigned long over = (unsigned long)addr + size - TASK_SIZE;
+		return __clear_user(addr, size - over) + over;
+	}
+	return size;
+}
+
+extern int __strncpy_from_user(char *dst, const char *src, long count);
+
+static inline long strncpy_from_user(char *dst, const char *src, long count)
+{
+	if (access_ok(VERIFY_READ, src, 1))
+		return __strncpy_from_user(dst, src, count);
+	return -EFAULT;
+}
+
+/*
+ * Return the size of a string (including the ending 0)
+ *
+ * Return 0 for error
+ */
+
+extern int __strnlen_user(const char *str, long len, unsigned long top);
+
+/*
+ * Returns the length of the string at str (including the null byte),
+ * or 0 if we hit a page we can't access,
+ * or something > len if we didn't find a null byte.
+ *
+ * The `top' parameter to __strnlen_user is to make sure that
+ * we can never overflow from the user area into kernel space.
+ */
+static inline long strnlen_user(const char __user *str, long len)
+{
+	unsigned long top = (unsigned long)get_fs();
+	unsigned long res = 0;
+
+	if (__addr_ok(str))
+		res = __strnlen_user(str, len, top);
+
+	return res;
+}
+
+#define strlen_user(str) strnlen_user(str, TASK_SIZE-1)
+
+#endif /* __ASM_OPENRISC_UACCESS_H */