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authorOlof Johansson <olof@lixom.net>2013-11-15 15:17:59 -0800
committerOlof Johansson <olof@lixom.net>2013-11-15 15:17:59 -0800
commit6886059f2ef5d62c73e87a905e84fa4f87d56074 (patch)
treedfe6e1611d7c50057df52db7b55eafbfb8e33a93 /include/asm-generic/preempt.h
parentca439c9b983ffa14e9eae6030e3ee80ad039388f (diff)
parent26273e02a0cf18eb72416559310d3294390a9024 (diff)
Merge tag 'omap-for-v3.13/fixes-for-merge-window-take2' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into fixes
Few clock fixes, a runtime PM fix, and pinctrl-single fix along with few other fixes that popped up during the merge window. * tag 'omap-for-v3.13/fixes-for-merge-window-take2' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap: ARM: OMAP2+: Fix build for dra7xx without omap4 and 5 ARM: OMAP2+: omap_device: maintain sane runtime pm status around suspend/resume doc: devicetree: Add bindings documentation for omap-des driver ARM: dts: doc: Document missing compatible property for omap-sham driver ARM: OMAP3: Beagle: fix return value check in beagle_opp_init() ARM: OMAP: devicetree: fix SPI node compatible property syntax items pinctrl: single: call pcs_soc->rearm() whenever IRQ mask is changed ARM: OMAP2+: smsc911x: fix return value check in gpmc_smsc911x_init() + sync with newer trunk
Diffstat (limited to 'include/asm-generic/preempt.h')
-rw-r--r--include/asm-generic/preempt.h105
1 files changed, 105 insertions, 0 deletions
diff --git a/include/asm-generic/preempt.h b/include/asm-generic/preempt.h
new file mode 100644
index 00000000000..ddf2b420ac8
--- /dev/null
+++ b/include/asm-generic/preempt.h
@@ -0,0 +1,105 @@
+#ifndef __ASM_PREEMPT_H
+#define __ASM_PREEMPT_H
+
+#include <linux/thread_info.h>
+
+/*
+ * We mask the PREEMPT_NEED_RESCHED bit so as not to confuse all current users
+ * that think a non-zero value indicates we cannot preempt.
+ */
+static __always_inline int preempt_count(void)
+{
+ return current_thread_info()->preempt_count & ~PREEMPT_NEED_RESCHED;
+}
+
+static __always_inline int *preempt_count_ptr(void)
+{
+ return &current_thread_info()->preempt_count;
+}
+
+/*
+ * We now loose PREEMPT_NEED_RESCHED and cause an extra reschedule; however the
+ * alternative is loosing a reschedule. Better schedule too often -- also this
+ * should be a very rare operation.
+ */
+static __always_inline void preempt_count_set(int pc)
+{
+ *preempt_count_ptr() = pc;
+}
+
+/*
+ * must be macros to avoid header recursion hell
+ */
+#define task_preempt_count(p) \
+ (task_thread_info(p)->preempt_count & ~PREEMPT_NEED_RESCHED)
+
+#define init_task_preempt_count(p) do { \
+ task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \
+} while (0)
+
+#define init_idle_preempt_count(p, cpu) do { \
+ task_thread_info(p)->preempt_count = PREEMPT_ENABLED; \
+} while (0)
+
+/*
+ * We fold the NEED_RESCHED bit into the preempt count such that
+ * preempt_enable() can decrement and test for needing to reschedule with a
+ * single instruction.
+ *
+ * We invert the actual bit, so that when the decrement hits 0 we know we both
+ * need to resched (the bit is cleared) and can resched (no preempt count).
+ */
+
+static __always_inline void set_preempt_need_resched(void)
+{
+ *preempt_count_ptr() &= ~PREEMPT_NEED_RESCHED;
+}
+
+static __always_inline void clear_preempt_need_resched(void)
+{
+ *preempt_count_ptr() |= PREEMPT_NEED_RESCHED;
+}
+
+static __always_inline bool test_preempt_need_resched(void)
+{
+ return !(*preempt_count_ptr() & PREEMPT_NEED_RESCHED);
+}
+
+/*
+ * The various preempt_count add/sub methods
+ */
+
+static __always_inline void __preempt_count_add(int val)
+{
+ *preempt_count_ptr() += val;
+}
+
+static __always_inline void __preempt_count_sub(int val)
+{
+ *preempt_count_ptr() -= val;
+}
+
+static __always_inline bool __preempt_count_dec_and_test(void)
+{
+ return !--*preempt_count_ptr();
+}
+
+/*
+ * Returns true when we need to resched and can (barring IRQ state).
+ */
+static __always_inline bool should_resched(void)
+{
+ return unlikely(!*preempt_count_ptr());
+}
+
+#ifdef CONFIG_PREEMPT
+extern asmlinkage void preempt_schedule(void);
+#define __preempt_schedule() preempt_schedule()
+
+#ifdef CONFIG_CONTEXT_TRACKING
+extern asmlinkage void preempt_schedule_context(void);
+#define __preempt_schedule_context() preempt_schedule_context()
+#endif
+#endif /* CONFIG_PREEMPT */
+
+#endif /* __ASM_PREEMPT_H */