[PATCH 12/27] asm-generic: add a NOMMU uaccess.h

Arnd Bergmann
2009-04-30T15:45:44Z

This uaccess.h can be used by all NOMMU architectures,
but it does not provide exception handlers that would
be needed for an architecture with an MMU.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com>
---
arch/parisc/include/asm/uaccess.h | 2 +-
arch/sparc/include/asm/uaccess_64.h | 2 +-
.../asm-generic/{uaccess.h => uaccess-unaligned.h} | 6 +-
include/asm-generic/uaccess.h | 235 +++++++++++++++++---
4 files changed, 214 insertions(+), 31 deletions(-)
rename include/asm-generic/{uaccess.h => uaccess-unaligned.h} (82%)
rewrite include/asm-generic/uaccess.h (96%)

diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h
index cd4c0b2..7cf799d 100644
--- a/arch/parisc/include/asm/uaccess.h
+++ b/arch/parisc/include/asm/uaccess.h
@@ -7,7 +7,7 @@
#include <asm/page.h>
#include <asm/system.h>
#include <asm/cache.h>
-#include <asm-generic/uaccess.h>
+#include <asm-generic/uaccess-unaligned.h>

#define VERIFY_READ 0
#define VERIFY_WRITE 1
diff --git a/arch/sparc/include/asm/uaccess_64.h b/arch/sparc/include/asm/uaccess_64.h
index c64e767..a38c032 100644
--- a/arch/sparc/include/asm/uaccess_64.h
+++ b/arch/sparc/include/asm/uaccess_64.h
@@ -12,7 +12,7 @@
#include <asm/asi.h>
#include <asm/system.h>
#include <asm/spitfire.h>
-#include <asm-generic/uaccess.h>
+#include <asm-generic/uaccess-unaligned.h>
#endif

#ifndef __ASSEMBLY__
diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess-unaligned.h
similarity index 82%
rename from include/asm-generic/uaccess.h
rename to include/asm-generic/uaccess-unaligned.h
index 549cb3a..67deb89 100644
--- a/include/asm-generic/uaccess.h
+++ b/include/asm-generic/uaccess-unaligned.h
@@ -1,5 +1,5 @@
-#ifndef _ASM_GENERIC_UACCESS_H_
-#define _ASM_GENERIC_UACCESS_H_
+#ifndef __ASM_GENERIC_UACCESS_UNALIGNED_H
+#define __ASM_GENERIC_UACCESS_UNALIGNED_H

/*
* This macro should be used instead of __get_user() when accessing
@@ -23,4 +23,4 @@
__copy_to_user((ptr), &__x, sizeof(*(ptr))) ? -EFAULT : 0; \
})

-#endif /* _ASM_GENERIC_UACCESS_H */
+#endif /* __ASM_GENERIC_UACCESS_UNALIGNED_H */
diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h
dissimilarity index 96%
index 549cb3a..ebeacd9 100644
--- a/include/asm-generic/uaccess.h
+++ b/include/asm-generic/uaccess.h
@@ -1,26 +1,209 @@
-#ifndef _ASM_GENERIC_UACCESS_H_
-#define _ASM_GENERIC_UACCESS_H_
-
-/*
- * This macro should be used instead of __get_user() when accessing
- * values at locations that are not known to be aligned.
- */
-#define __get_user_unaligned(x, ptr) \
-({ \
- __typeof__ (*(ptr)) __x; \
- __copy_from_user(&__x, (ptr), sizeof(*(ptr))) ? -EFAULT : 0; \
- (x) = __x; \
-})
-
-
-/*
- * This macro should be used instead of __put_user() when accessing
- * values at locations that are not known to be aligned.
- */
-#define __put_user_unaligned(x, ptr) \
-({ \
- __typeof__ (*(ptr)) __x = (x); \
- __copy_to_user((ptr), &__x, sizeof(*(ptr))) ? -EFAULT : 0; \
-})
-
-#endif /* _ASM_GENERIC_UACCESS_H */
+#ifndef __ASM_GENERIC_UACCESS_H
+#define __ASM_GENERIC_UACCESS_H
+
+/*
+ * User space memory access functions, these should work
+ * on a ny machine that has kernel and user data in the same
+ * address space, e.g. all NOMMU machines.
+ */
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+
+#include <asm/segment.h>
+
+#ifndef get_fs
+#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
+#define KERNEL_DS MAKE_MM_SEG(~0UL)
+#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
+
+#define get_ds() (KERNEL_DS)
+#define get_fs() (current_thread_info()->addr_limit)
+
+static inline void set_fs(mm_segment_t fs)
+{
+ current_thread_info()->addr_limit = fs;
+}
+#endif
+
+#define segment_eq(a, b) ((a).seg == (b).seg)
+
+#define VERIFY_READ 0
+#define VERIFY_WRITE 1
+
+#define access_ok(type, addr, size) _access_ok((unsigned long)(addr),(size))
+
+/*
+ * The architecture should really override this if possible, at least
+ * doing a check on the get_fs()
+ */
+#ifndef _access_ok
+static inline int _access_ok(unsigned long addr, unsigned long size)
+{
+ return 1;
+}
+#endif
+
+/*
+ * 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.
+ */
+#ifndef __put_user
+#define __put_user(x, ptr) \
+({ \
+ int __pu_err = 0; \
+ typeof(*(ptr)) __pu_val = (x); \
+ switch (sizeof (*(ptr))) { \
+ case 1: \
+ case 2: \
+ case 4: \
+ *(ptr) = (__pu_val); \
+ break; \
+ case 8: \
+ memcpy(ptr, &__pu_val, sizeof (*(ptr)));\
+ break; \
+ default: \
+ __pu_err = __put_user_bad(); \
+ break; \
+ } \
+ __pu_err; \
+})
+extern int __put_user_bad(void);
+#endif
+
+#define put_user(x, ptr) ( \
+ access_ok(VERIFY_WRITE, ptr, sizeof (*ptr)) ? \
+ __put_user(x, ptr) : \
+ -EFAULT)
+
+#ifndef __get_user
+#define __get_user(x, ptr) \
+({ \
+ int __gu_err = 0; \
+ unsigned long __gu_val = (unsigned long)*ptr; \
+ switch (sizeof(*(ptr))) { \
+ case 1: \
+ case 2: \
+ case 4: \
+ case 8: \
+ break; \
+ default: \
+ __gu_err = __get_user_bad(); \
+ __gu_val = 0; \
+ break; \
+ } \
+ (x) = (typeof(*ptr))__gu_val; \
+ __gu_err; \
+})
+extern int __get_user_bad(void);
+#endif
+
+#define get_user(x, ptr) ( \
+ access_ok(VERIFY_READ, ptr, sizeof (*ptr)) ? \
+ __get_user(x, ptr) : \
+ -EFAULT)
+
+#define __copy_from_user(to, from, n) (memcpy(to, from, n), 0)
+#define __copy_to_user(to, from, n) (memcpy(to, from, n), 0)
+#define __copy_to_user_inatomic __copy_to_user
+#define __copy_from_user_inatomic __copy_from_user
+
+#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; })
+
+static inline long copy_from_user(void *to,
+ const void __user * from, unsigned long n)
+{
+ if (access_ok(VERIFY_READ, from, n))
+ __copy_from_user(to, from, n);
+ else
+ return n;
+ return 0;
+}
+
+static inline long copy_to_user(void *to,
+ const void __user * from, unsigned long n)
+{
+ if (access_ok(VERIFY_WRITE, to, n))
+ __copy_to_user(to, from, n);
+ else
+ return n;
+ return 0;
+}
+
+/*
+ * Copy a null terminated string from userspace.
+ */
+
+static inline long
+__do_strncpy_from_user(char *dst, const char __user *src, long count)
+{
+ char *tmp;
+ strncpy(dst, src, count);
+ for (tmp = dst; *tmp && count > 0; tmp++, count--)
+ ;
+ return (tmp - dst);
+}
+
+static inline long
+strncpy_from_user(char *dst, const char __user *src, long count)
+{
+ if (!access_ok(VERIFY_READ, src, 1))
+ return -EFAULT;
+ return __do_strncpy_from_user(dst, src, count);
+}
+
+static inline long
+__strncpy_from_user(char *dst, const char __user *src, long count)
+{
+ return __do_strncpy_from_user(dst, src, count);
+}
+
+/*
+ * Return the size of a string (including the ending 0)
+ *
+ * Return 0 on exception, a value greater than N if too long
+ */
+static inline long strnlen_user(const char *src, long n)
+{
+ return strlen(src) + 1;
+}
+
+#define strlen_user(str) strnlen_user(str, 32767)
+
+/*
+ * Zero Userspace
+ */
+
+static inline unsigned long
+__clear_user(void *to, unsigned long n)
+{
+ memset(to, 0, n);
+ return 0;
+}
+
+#define clear_user(to, n) __clear_user(to, n)
+
+#endif /* __ASM_GENERIC_UACCESS_H */
--
1.5.6.3