diff options
| author | Michael Cree <mcree@orcon.net.nz> | 2012-08-19 14:40:58 +1200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-08-19 08:41:18 -0700 |
| commit | f2db633d301b4b50f5f93de0e8314cc81e9bc7de (patch) | |
| tree | aafa01b17e83221ca92ee58e66d7e6783808a224 /arch/alpha/kernel | |
| parent | d8d5da129857bfd54b603771fca5409062167392 (diff) | |
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>
Diffstat (limited to 'arch/alpha/kernel')
| -rw-r--r-- | arch/alpha/kernel/alpha_ksyms.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/alpha/kernel/alpha_ksyms.c b/arch/alpha/kernel/alpha_ksyms.c index d96e742d4dc2..a354277bbaa7 100644 --- a/arch/alpha/kernel/alpha_ksyms.c +++ b/arch/alpha/kernel/alpha_ksyms.c @@ -74,8 +74,6 @@ EXPORT_SYMBOL(alpha_fp_emul); */ EXPORT_SYMBOL(__copy_user); EXPORT_SYMBOL(__do_clear_user); -EXPORT_SYMBOL(__strncpy_from_user); -EXPORT_SYMBOL(__strnlen_user); /* * SMP-specific symbols. |