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>
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 6d4dd22..295bf2d 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -17,6 +17,8 @@
select GENERIC_IRQ_SHOW
select GENERIC_SCHED_CLOCK
select GENERIC_SMP_IDLE_THREAD
+ select GENERIC_STRNCPY_FROM_USER
+ select GENERIC_STRNLEN_USER
select GENERIC_TIME_VSYSCALL
select HARDIRQS_SW_RESEND
select HAVE_ARCH_TRACEHOOK