Joachim Eastwood reports that commit fbfb872f5f41 "ARM: 8148/1: flush
TLS and thumbee register state during exec" causes a boot-time crash
on a Cortex-M4 nommu system:
The problem is that set_tls is attempting to clear the TLS location in
the kernel-user helper page, which isn't set up on V7M.
Fix this by guarding the write to the kuser helper page with
a CONFIG_KUSER_HELPERS ifdef.
Fixes: fbfb872f5f41 ARM: 8148/1: flush TLS and thumbee register state during exec Reported-by: Joachim Eastwood <manabian@gmail.com> Tested-by: Joachim Eastwood <manabian@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>