arm64: use generic strnlen_user and strncpy_from_user functions

This patch implements the word-at-a-time interface for arm64 using the
same algorithm as ARM. We use the fls64 macro, which expands to a clz
instruction via a compiler builtin. Big-endian configurations make use
of the implementation from asm-generic.

With this implemented, we can replace our byte-at-a-time strnlen_user
and strncpy_from_user functions with the optimised generic versions.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 1 insertions, 4 deletions

diff --git a/arch/arm64/kernel/arm64ksyms.c b/arch/arm64/kernel/arm64ksyms.c
index e7ee770c0697..338b568cd8ae 100644
--- a/arch/arm64/kernel/arm64ksyms.c
+++ b/arch/arm64/kernel/arm64ksyms.c
@@ -29,13 +29,10 @@
 
 #include <asm/checksum.h>
 
-        /* user mem (segment) */
-EXPORT_SYMBOL(__strnlen_user);
-EXPORT_SYMBOL(__strncpy_from_user);
-
 EXPORT_SYMBOL(copy_page);
 EXPORT_SYMBOL(clear_page);
 
+        /* user mem (segment) */
 EXPORT_SYMBOL(__copy_from_user);
 EXPORT_SYMBOL(__copy_to_user);
 EXPORT_SYMBOL(__clear_user);