sh: fix futex/robust_list on nommu models

The futex cmpxchg runtime testing in kernel/futex.c depends on
accesses to address 0 producing EFAULT, which obviously does not work
on nommu. Since SH always has cmpxchg, disable the broken runtime
detection.

At some point this should be fixed at the kernel/futex.c level. UP
machines can always provide a working cmpxchg with interrupt masking,
and SMP cannot function without a working cmpxchg anyway.

Signed-off-by: Rich Felker <dalias@libc.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index ceeda5c1a70a..e6d88f9e978a 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -45,6 +45,7 @@ config SUPERH
         select OLD_SIGSUSPEND
         select OLD_SIGACTION
         select HAVE_ARCH_AUDITSYSCALL
+        select HAVE_FUTEX_CMPXCHG if FUTEX
         select HAVE_NMI
         help
           The SuperH is a RISC processor targeted for use in embedded systems