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28 * Authors: Nathan Binkert
32 * System Console Backdoor Interface
35 #ifndef __DEV_ALPHA_BACKDOOR_HH__
36 #define __DEV_ALPHA_BACKDOOR_HH__
38 #include "base/types.hh"
39 #include "dev/alpha/access.h"
40 #include "dev/io_device.hh"
41 #include "params/AlphaBackdoor.hh"
42 #include "sim/sim_object.hh"
50 * Memory mapped interface to the system console. This device
51 * represents a shared data region between the OS Kernel and the
52 * System Console Backdoor.
54 * The system console is a small standalone program that is initially
55 * run when the system boots. It contains the necessary code to
56 * access the boot disk, to read/write from the console, and to pass
57 * boot parameters to the kernel.
59 * This version of the system console is very different from the one
60 * that would be found in a real system. Many of the functions use
61 * some sort of backdoor to get their job done. For example, reading
62 * from the boot device on a real system would require a minimal
63 * device driver to access the disk controller, but since we have a
64 * simulator here, we are able to bypass the disk controller and
65 * access the disk image directly. There are also some things like
66 * reading the kernel off the disk image into memory that are normally
67 * taken care of by the console that are now taken care of by the
70 * These shortcuts are acceptable since the system console is
71 * primarily used doing boot before the kernel has loaded its device
74 class AlphaBackdoor : public BasicPioDevice
77 struct Access : public AlphaAccess, public Serializable
79 void serialize(CheckpointOut &cp) const override;
80 void unserialize(CheckpointIn &cp) override;
88 /** the disk must be accessed from the console */
91 /** the system console (the terminal) is accessable from the console */
94 /** a pointer to the system we are running in */
97 /** a pointer to the CPU boot cpu */
101 typedef AlphaBackdoorParams Params;
102 AlphaBackdoor(const Params *p);
107 return dynamic_cast<const Params *>(_params);
110 void startup() override;
113 * memory mapped reads and writes
115 Tick read(PacketPtr pkt) override;
116 Tick write(PacketPtr pkt) override;
119 * standard serialization routines for checkpointing
121 void serialize(CheckpointOut &cp) const override;
122 void unserialize(CheckpointIn &cp) override;
125 #endif // __DEV_ALPHA_BACKDOOR_HH__