Implement unsafe_clear_user() for powerpc.
It's a copy/paste of unsafe_copy_to_user() with value 0 as source.
It may be improved in a later patch by using 'dcbz' instruction
to zeroize full cache lines at once.
Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
arch/powerpc/include/asm/uaccess.h | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/arch/powerpc/include/asm/uaccess.h
b/arch/powerpc/include/asm/uaccess.h
index 22c79ab40006..962b675485ff 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -467,6 +467,26 @@ do {
\
unsafe_put_user(*(u8*)(_src + _i), (u8 __user *)(_dst + _i),
e); \
} while (0)
+#define unsafe_clear_user(d, l, e) \
+do { \
+ u8 __user *_dst = (u8 __user *)(d); \
+ size_t _len = (l); \
+ int _i; \
+ \
+ for (_i = 0; _i < (_len & ~(sizeof(u64) - 1)); _i += sizeof(u64)) \
+ unsafe_put_user(0, (u64 __user *)(_dst + _i), e); \
+ if (_len & 4) { \
+ unsafe_put_user(0, (u32 __user *)(_dst + _i), e); \
+ _i += 4; \
+ } \
+ if (_len & 2) { \
+ unsafe_put_user(0, (u16 __user *)(_dst + _i), e); \
+ _i += 2; \
+ } \
+ if (_len & 1) \
+ unsafe_put_user(0, (u8 __user *)(_dst + _i), e); \
+} while (0)
+
#define HAVE_GET_KERNEL_NOFAULT
#define __get_kernel_nofault(dst, src, type, err_label)
\
--
2.31.1
