1.  Wind River Systems, Inc. 1997 Chapter - 15 Optional Products

2. 15-2 Optional Products 15.1 Overview WindView WindNet SNMP Shared Memory Objects (VxMP) Virtual Memory (VxVMI)

3. 15-3 Overview The following products may be purchased separately if desired. BSP Porting Kit Assists porting VxWorks to a new board on a supported architecture. VxSim VxWorks simulation on a UNIX workstation. Allows development, testing, and prototyping without target hardware. RtX-WINDOWS Scalable X windows / Motif package. Useful for applications which need to display data graphically. WindNet SNMP Provides remote network management of target via SNMP.

4. 15-4 Overview StethoScope Host based debugging tool with GUI. Monitor VxWorks program variables in real time, or store data and analyze later. Also contains a task profiler. VxMP High speed multiprocessing tools for distributed applications needing to communicate over the VMEbus. VxVMI Virtual memory support. Can restrict a tasks access to certain addresses. WindView Host based debugging tool with GUI. Allows monitoring of events like context switches, interrupts, semGive( ), msgQSend( ). Helps tune and debug system.

5. 15-5 Optional Products Overview 15.2 WindView WindNet SNMP Shared Memory Objects (VxMP) Virtual Memory (VxVMI)

6. 15-6 Overview  “Logic Analyzer” for VxWorks  Allows graphical viewing of multitasking application  Helps diagnose:  race conditions  deadlocks  missed deadlines  system crashes

7. 15-7 Host/Target Relationship  Event uploading can occur:  During run time, automatically or under program control  After system crash (for post-mortem debugging)

8. 15-8 Event Logging  Three modes with increasing information (and overhead):  Log context switches and interrupts only  Also log state transitions  Also log instrumented objects  Some objects which can be instrumented include:  semaphores  message queues  signals  tasks  Supports user defined events

9. 15-9 View Graph

10. 15-10 Zoom In on Task Exit

11. 15-11 Task States and Events  Task states are displayed as:  Events are displayed with icons, such as:

12. 15-12 Events  Event icons use a common paradigm:

13. 15-13 Priority Inversion Example

14. 15-14 Priority Inheritance Example

15. 15-15 Optional Products Overview WindView 15.3 WindNet SNMP Shared Memory Objects (VxMP) Virtual Memory (VxVMI)

16. 15-16 The Network Management Problem Administrators of internets face two main problems:  “Why can’t I communicate with Host A?”  “Why is the network so slow?”

17. 15-17 The SNMP Solution SNMP, The Simple Network Management Protocol, provides a standardized way for managing network nodes:  Supports management of all network devices  Query nodes to gather statistics on their health  Reconfigure a node remotely  Standard for the TCP/IP Protocol Suite

18. 15-18 The SNMP Management Paradigm

19. 15-19 WindNet SNMP Agent  Bilingual SNMP Agent which supports SNMPv1 and SNMPv2c  MIB-II TCP/IP statistics  Extensible agent which supports creating custom MIB extensions, scaling the agent MIB to include only relevant groups, and the WRS demo MIB.  Dynamic addition and removal of MIB variables.  Compatible with standard NMS’s such as SunNet Manager, HP OpenView, and Netview/6000.

20. 15-20 Optional Products Overview WindView WindNet SNMP 15.4 Shared Memory Objects (VxMP) Virtual Memory (VxVMI)

21. 15-21 VxMP Features  Allows multiprocessing on the VMEbus.  Faster than shared memory network.  Components: Name database Allows boards to share information on objects. Shared semaphores For mutual exclusion and synchronization. Shared message queues For message passing. Shared memory manager To dynamically allocate and free shared memory blocks.  Familiar interface (e.g., semGive( ), msgQSend( )).

22. 15-22 Example Usage  The tFooServer task on CPU1 wants to read requests from a shared message queue: 1. It first creates the message queue. 2. It then registers the MSG_Q_ID in the name database under the name “ServerSMQueue” 3. Finally, it reads and services requests in a loop.  The tFooClient task on CPU0 wants to send a request to tFooServer: 1. It first queries the name database to find the MSG_Q_ID under the name “ServerSMQueue” 2. This MSG_Q_ID is then used to send requests to the server.

23. 15-23 Registering Shared Objects STATUS smNameAdd (name, objId, type) name String used to name this object. objId Shared memory object identifier (e.g., SEM_ID or MSG_Q_ID). type The type of shared memory object (e.g. binary semaphore or message queue).  Registers the object in the name database.  Typically called right after object creation.

24. 15-24 Finding Shared Objects STATUS smNameFind (name, &objId, &type,wait) name Name to find in the database. objId Object id returned through this variable. type Object type returned. wait Wait until the object is created. Can be NO_WAIT or WAIT_FOREVER. Does not specify timeout in ticks.  Obtains the objId of an object created on another board.

25. 15-25 Shared Semaphores SEM_ID semBSmCreate (options, initialState) SEM_ID semCSmCreate (options, initialCount)  Creation routines similar to local semaphore creation routines, except options must be SEM_Q_FIFO.  Mutex semaphores are not provided.  Once created, semLib routines (e.g., semGive( ), semTake( )) work as before, except  Can not give a semaphore from an ISR.  May not delete semaphores.

26. 15-26 Shared Message Queues MSG_Q_ID msgQSmCreate (maxMsgs, maxMsgLen, options)  Creation routine similar to local message queue creation routine, except options must be MSG_Q_FIFO.  Once created, msgQLib routines (e.g., msgQSend( ), msgQReceive( )) work as before, except can not send a message from an ISR.

27. 15-27 Shared Memory Manager  Can dynamically allocate/free blocks of shared memory: void * smMemMalloc (nBytes) smMemFree (void * ptr)  These routines use local addresses. When exchanging address information through the name database, may need to call: void * smObjLocalToGlobal (localAdrs) void * smObjGlobalToLocal (globalAdrs)

28. 15-28 Creating Shared Memory Partitions  To creates additional shared memory partitions: PART_ID memPartSmCreate (pPool, poolSize) pPool Address of some shared memory. poolSize Size of this pool.  Manipulated with memPartLib routines (just like local partitions).

29. 15-29 Terminology Shared Memory Master - CPU 0. Initializes the shared memory objects data structures. Once initialized, all boards are peers. Shared Memory - Memory used for shared memory objects. Can be dual ported RAM on CPU0, or RAM on a memory card, but it must be accessible to all CPU’s. Anchor - Structure containing ready value and an offset to shared memory. Must be at an address known by all CPU’s. Heartbeat - Integer incremented once per second by CPU0, used to indicate that the shared memory objects system is alive. Ready Value - Stored in anchor by CPU0 to indicate that the shared memory objects facility is initialized.

30. 15-30 System Requirements  All boards must support an atomic read-modify-write cycle (e.g., test and set) in hardware.  Software implementation limits the number of CPU’s to 20 (CPU0 through CPU19). Hardware considerations may limit this number further.

31. 15-31 Caveats  Non-deterministic; exclusive access to shared memory object over the VMEbus is subject to unpredictable delays.  Slower than corresponding local objects; only use for distributed applications.  Increases interrupt latency; interrupts are locked out while shared memory object is updated.

32. 15-32 Initialization  Define INCLUDE_SM_OBJ in config.h.  If booting over the shared memory network, no extra initialization necessary.  If not booting over the shared memory network: 1. On CPU0, configure the location and size of the shared memory region. Boot CPU0. 2. Before another CPU can access shared memory objects, you must:  Calculate anchor address as seen by that board (as discussed in the shared memory network chapter).  Specify SM_ANCHOR_ADRS in config.h and rebuild VxWorks for that CPU.

33. 15-33 1. Shared Memory Location/Size (CPU0) Example wind/target/config/target/config.h stub for CPU0: #define SM_OFF_BOARD FALSE #if SM_OFF_BOARD #undef SM_ANCHOR_ADRS #define SM_ANCHOR_ADRS ((char *) 0xfb800000) #define SM_MEM_ADRS SM_ANCHOR_ADRS #define SM_MEM_SIZE 0x80000 /* 512K */ #define SM_OBJ_MEM_ADRS (SM_MEM_ADRS+SM_MEM_SIZE) #define SM_OBJ_MEM_SIZE 0x80000 /* 512K */ #else /* SM_OFF_BOARD */ #define SM_MEM_ADRS NONE /* NONE = malloc */ #define SM_MEM_SIZE 0x10000 /* 64K */ #define SM_OBJ_MEM_ADRS NONE /* NONE = malloc */ #define SM_OBJ_MEM_SIZE 0x10000 /* 64K */ #endif /* SM_OFF_BOARD */

34. 15-34 2: Calculating the Anchor Address (for other CPU’s) 1. If the anchor is in dual ported memory on CPU0, call sysLocalToBusAdrs( ) on CPU0 to calculate the VMEbus address of the anchor. 2. Call sysBusToLocalAdrs( ) on each other CPU board to calculate the local address which maps to the anchor’s VMEbus address. May need to examine source code for this routine if this CPU has not booted.

35. 15-35 Other Configuration Parameters The following configuration parameters are defined in configAll.h, and may be overridden in config.h: Constant Description (default value) SM_OBJ_MAX_TASK Maximum number of tasks using shared memory objects (40) SM_OBJ_MAX_SEM Maximum number of semaphores (30). SM_OBJ_MAX_MSG_Q Message queues (10). SM_OBJ_MAX_MEM_PART Memory partitions (4) SM_OBJ_MAX_NAME Names in database (100). SM_OBJ_MAX_TRIES Tries to obtain lock (100).

36. 15-36 Optional Products Overview WindView WindNet SNMP Shared Memory Objects (VxMP) 15.5 Virtual Memory (VxVMI)

37. 15-37 VxVMI Features  Allows write protecting:  The interrupt vector table.  Program text.  Crucial user data.  Makes application safer.  Makes debugging easier since writing to a protected area will incur a bus error.

38. 15-38 Virtual Addresses

39. 15-39 Default Virtual Memory Context  A mapping of virtual to physical addresses is called a virtual memory context.  A global mapping is defined at system start-up.  Local memory, on board devices, and some VME addresses are mapped.  Same as physical mapping, except some VME addresses are not mapped.  Controlled by sysPhysMemDesc structure in sysLib.c.  By default, all tasks use the global mapping.

40. 15-40 Other Uses of VxVMI  Can dynamically create new virtual memory contexts.  User is responsible for managing the contexts:  Initializing virtual to physical address maps in newly created contexts.  Swapping between contexts. Low level support routines provided.  Allows application to restrict a set of addresses to:  Only to one task.  Only to a select group of tasks.  Only through a library.

41. 15-41 Including VxVMI  Define INCLUDE_MMU_FULL in config.h.  Note: The symbol INCLUDE_MMU_BASIC is not part of VxVMI. It is bundled with VxWorks to provide support for cacheLib.

42. 15-42 Write Protection -Text and Vector Table  Define INCLUDE_PROTECT_VEC_TABLE to write protect the interrupt vector table.  Define INCLUDE_PROTECT_TEXT to write protect program text.  Prevents accidental modifications.  Intentional modification can still occur (e.g., via intConnect( )).

43. 15-43 Write Protection Overview-User Data 1. Allocate a page aligned buffer. 2. Fill buffer with data. 3. Modify the state of the page to be read-only.

44. 15-44 Allocating Page Aligned Buffers void * valloc (nBytes) nBytes Number of bytes to allocate.  Returns a pointer to allocated buffer, or NULL on error.  Allocated buffer will begin on a page boundary.  nBytes should be a multiple of VM_PAGE_SIZE. If not, then other data might get write protected when we try to write protect our buffer.

45. 15-45 Changing Page States STATUS vmStateSet (context, pVirtual, len, stateMask, state) context A VM_CONTEXT_ID, or NULL to use current context. pVirtual Virtual address of page to modify. len Number of pages affected (in bytes). stateMask Which states to modify. state State to set.

46. 15-46 Write Protection Example char *buf; /* Allocate physical memory on a page boundary */ buf = (char *)valloc (VM_PAGE_SIZE); /* fill buf with important data */... /* write protect virtual memory buf */ vmStateSet (NULL, buf, VM_PAGE_SIZE, VM_STATE_MASK_WRITABLE, VM_STATE_WRITABLE_NOT);