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authorMichael Brown2017-04-26 21:02:23 +0200
committerMichael Brown2017-04-26 21:15:39 +0200
commit648657b7762a9439879691e610f77afee4c56bcb (patch)
tree3bd4f02b3c3f69432a0ec162ccd56e873d77b06b /src/include/ipxe
parent[block] Provide sandev_read() and sandev_write() as global symbols (diff)
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[block] Provide abstraction to allow system to be quiesced
When performing a SAN boot via INT 13, there is no way for the operating system to indicate that it has finished using the INT 13 SAN device. We therefore have no opportunity to clean up state before the loaded operating system's native drivers take over. This can cause problems when booting Windows, which tends not to be forgiving of unexpected system state. Windows will typically write a flag to the SAN device as the last action before transferring control to the native drivers. We can use this as a heuristic to bring the system to a quiescent state (without performing a full shutdown); this provides us an opportunity to temporarily clean up state that could otherwise prevent a successful Windows boot. Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src/include/ipxe')
-rw-r--r--src/include/ipxe/quiesce.h31
1 files changed, 31 insertions, 0 deletions
diff --git a/src/include/ipxe/quiesce.h b/src/include/ipxe/quiesce.h
new file mode 100644
index 00000000..00b530b8
--- /dev/null
+++ b/src/include/ipxe/quiesce.h
@@ -0,0 +1,31 @@
+#ifndef _IPXE_QUIESCE_H
+#define _IPXE_QUIESCE_H
+
+/** @file
+ *
+ * Quiesce system
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/tables.h>
+
+/** A quiescer */
+struct quiescer {
+ /** Quiesce system */
+ void ( * quiesce ) ( void );
+ /** Unquiesce system */
+ void ( * unquiesce ) ( void );
+};
+
+/** Quiescer table */
+#define QUIESCERS __table ( struct quiescer, "quiescers" )
+
+/** Declare a quiescer */
+#define __quiescer __table_entry ( QUIESCERS, 01 )
+
+extern void quiesce ( void );
+extern void unquiesce ( void );
+
+#endif /* _IPXE_QUIESCE_H */