As of now these default to calling the arch provided __copy_{to,from}_user()
routines which being general purpose (w.r.t buffer alignment and lengths)
would lead to alignment checks in generated code (for arches which don't
support unaligned load/stores).
Given that in this case we already know that data involved is "unit"
sized and aligned, using the vanilla copy backend is a bit wasteful.
This change thus allows arches to over-ride the aforementioned routines.
Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
---
include/asm-generic/uaccess.h | 11 +++++++++++
1 files changed, 11 insertions(+), 0 deletions(-)
diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h
index 5f6ee61..c184aa8 100644
--- a/include/asm-generic/uaccess.h
+++ b/include/asm-generic/uaccess.h
@@ -169,12 +169,18 @@ static inline __must_check long __copy_to_user(void __user *to,
-EFAULT; \
})
+#ifndef __put_user_fn
+
static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
{
size = __copy_to_user(ptr, x, size);
return size ? -EFAULT : size;
}
+#define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
+
+#endif
+
extern int __put_user_bad(void) __attribute__((noreturn));
#define __get_user(x, ptr) \
@@ -225,12 +231,17 @@ extern int __put_user_bad(void) __attribute__((noreturn));
-EFAULT; \
})
+#ifndef __get_user_fn
static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
{
size = __copy_from_user(x, ptr, size);
return size ? -EFAULT : size;
}
+#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
+
+#endif
+
extern int __get_user_bad(void) __attribute__((noreturn));
#ifndef __copy_from_user_inatomic
--
1.7.4.1
--
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