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authorArnd Bergmann <arnd@arndb.de>2013-05-06 23:38:00 +0200
committerArnd Bergmann <arnd@arndb.de>2013-05-06 23:38:00 +0200
commit4183bef2e093a2f0aab45f2d5fed82b0e02aeacf (patch)
treee84c484db3746a0f3ead0fb7a2bb9e5a42b89e85 /include/linux/preempt.h
parent662478d060a39b8faf2b1fe2fbbb212556c2e052 (diff)
parent775c4f66fd855e68a98fc5049003810fe98e2e20 (diff)
Merge branch 'late/dt' into next/dt2
This is support for the ARM Chromebook, originally scheduled as a "late" pull request. Since it's already late now, we can combine this into the existing next/dt2 branch. * late/dt: ARM: exynos: dts: cros5250: add EC device ARM: dts: Add sbs-battery for exynos5250-snow ARM: dts: Add i2c-arbitrator bus for exynos5250-snow ARM: dts: Add chip-id controller node on Exynos4/5 SoC ARM: EXYNOS: Create virtual I/O mapping for Chip-ID controller using device tree
Diffstat (limited to 'include/linux/preempt.h')
-rw-r--r--include/linux/preempt.h22
1 files changed, 14 insertions, 8 deletions
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 5a710b9c578e..87a03c746f17 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -93,14 +93,20 @@ do { \
#else /* !CONFIG_PREEMPT_COUNT */
-#define preempt_disable() do { } while (0)
-#define sched_preempt_enable_no_resched() do { } while (0)
-#define preempt_enable_no_resched() do { } while (0)
-#define preempt_enable() do { } while (0)
-
-#define preempt_disable_notrace() do { } while (0)
-#define preempt_enable_no_resched_notrace() do { } while (0)
-#define preempt_enable_notrace() do { } while (0)
+/*
+ * Even if we don't have any preemption, we need preempt disable/enable
+ * to be barriers, so that we don't have things like get_user/put_user
+ * that can cause faults and scheduling migrate into our preempt-protected
+ * region.
+ */
+#define preempt_disable() barrier()
+#define sched_preempt_enable_no_resched() barrier()
+#define preempt_enable_no_resched() barrier()
+#define preempt_enable() barrier()
+
+#define preempt_disable_notrace() barrier()
+#define preempt_enable_no_resched_notrace() barrier()
+#define preempt_enable_notrace() barrier()
#endif /* CONFIG_PREEMPT_COUNT */