alpha: Use new generic strncpy_from_user() and strnlen_user()
Similar to x86/sparc/powerpc implementations except:
1) we implement an extremely efficient has_zero()/find_zero()
sequence with both prep_zero_mask() and create_zero_mask()
no-operations.
2) Our output from prep_zero_mask() differs in that only the
lowest eight bits are used to represent the zero bytes
nevertheless it can be safely ORed with other similar masks
from prep_zero_mask() and forms input to create_zero_mask(),
the two fundamental properties prep_zero_mask() must satisfy.
Tests on EV67 and EV68 CPUs revealed that the generic code is
essentially as fast (to within 0.5% of CPU cycles) of the old
Alpha specific code for large quadword-aligned strings, despite
the 30% extra CPU instructions executed. In contrast, the
generic code for unaligned strings is substantially slower (by
more than a factor of 3) than the old Alpha specific code.
Signed-off-by: Michael Cree <mcree@orcon.net.nz>
Acked-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index d5b9b5e..9944ded 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -18,6 +18,8 @@
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select GENERIC_SMP_IDLE_THREAD
select GENERIC_CMOS_UPDATE
+ select GENERIC_STRNCPY_FROM_USER
+ select GENERIC_STRNLEN_USER
help
The Alpha is a 64-bit general-purpose processor designed and
marketed by the Digital Equipment Corporation of blessed memory,