Use kernel/Kconfig.preempt for ARM

before this patch ARM had it's own definition of CONFIG_PREEMPT.
Instead of that use the general definition provided in
kernel/Kconfig.preempt.

This patch changes the available options in *config.  Namely PREEMPT
isn't a stand alone bool anymore, but part of a 'choice' the
following Kconfig symbols are added:

	PREEMPT_NONE
	PREEMPT_VOLUNTARY

Selecting PREEMPT_NONE now produces exactly the code as not selecting
PREEMPT before (apart from a comment in
/sys/kernel/debug/tracing/(per_cpu/cpuX/)?trace).  The only difference
PREEMPT_VOLUNTARY does is that might_resched might reschedule.  Both
should't introduce regressions.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Russell King <linux@arm.linux.org.uk>

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index aef63c8e3d2dc99d53c8ab81564dce81b8c52b4d..eac1a927ca6e6ec17e9fed452e8252b8b5ea9bb3 100644 (file)
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -962,18 +962,7 @@ config LOCAL_TIMERS
          accounting to be spread across the timer interval, preventing a
          "thundering herd" at every timer tick.
 
-config PREEMPT
-       bool "Preemptible Kernel (EXPERIMENTAL)"
-       depends on EXPERIMENTAL
-       help
-         This option reduces the latency of the kernel when reacting to
-         real-time or interactive events by allowing a low priority process to
-         be preempted even if it is in kernel mode executing a system call.
-         This allows applications to run more reliably even when the system is
-         under load.
-
-         Say Y here if you are building a kernel for a desktop, embedded
-         or real-time system.  Say N if you are unsure.
+source kernel/Kconfig.preempt
 
 config HZ
        int