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authorRussell King <rmk@dyn-67.arm.linux.org.uk>2006-06-21 16:31:52 +0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2006-06-22 13:24:18 +0400
commitd6551e884cf66de072b81f8b6d23259462c40baf (patch)
treefd8af193bd045e4b16ce911d392d7ffd109d7284 /include/asm-arm
parent52ab3f3dc711eeccbfbcc5d4f5c5d9b9ff59650f (diff)
downloadlinux-d6551e884cf66de072b81f8b6d23259462c40baf.tar.xz
[ARM] Add thread_notify infrastructure
Some machine classes need to allow VFP support to be built into the kernel, but still allow the kernel to run even though VFP isn't present. Unfortunately, the kernel hard-codes VFP instructions into the thread switch, which prevents this being run-time selectable. Solve this by introducing a notifier which things such as VFP can hook into to be informed of events which affect the VFP subsystem (eg, creation and destruction of threads, switches between threads.) Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'include/asm-arm')
-rw-r--r--include/asm-arm/thread_notify.h48
1 files changed, 48 insertions, 0 deletions
diff --git a/include/asm-arm/thread_notify.h b/include/asm-arm/thread_notify.h
new file mode 100644
index 000000000000..8866e5216840
--- /dev/null
+++ b/include/asm-arm/thread_notify.h
@@ -0,0 +1,48 @@
+/*
+ * linux/include/asm-arm/thread_notify.h
+ *
+ * Copyright (C) 2006 Russell King.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef ASMARM_THREAD_NOTIFY_H
+#define ASMARM_THREAD_NOTIFY_H
+
+#ifdef __KERNEL__
+
+#ifndef __ASSEMBLY__
+
+#include <linux/notifier.h>
+#include <asm/thread_info.h>
+
+static inline int thread_register_notifier(struct notifier_block *n)
+{
+ extern struct atomic_notifier_head thread_notify_head;
+ return atomic_notifier_chain_register(&thread_notify_head, n);
+}
+
+static inline void thread_unregister_notifier(struct notifier_block *n)
+{
+ extern struct atomic_notifier_head thread_notify_head;
+ atomic_notifier_chain_unregister(&thread_notify_head, n);
+}
+
+static inline void thread_notify(unsigned long rc, struct thread_info *thread)
+{
+ extern struct atomic_notifier_head thread_notify_head;
+ atomic_notifier_call_chain(&thread_notify_head, rc, thread);
+}
+
+#endif
+
+/*
+ * These are the reason codes for the thread notifier.
+ */
+#define THREAD_NOTIFY_FLUSH 0
+#define THREAD_NOTIFY_RELEASE 1
+#define THREAD_NOTIFY_SWITCH 2
+
+#endif
+#endif