4.104.114.95
Last change
on this file since 252dea2f was
252dea2f,
checked in by Joel Sherrill <joel.sherrill@…>, on 09/05/08 at 21:33:41
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2008-09-05 Joel Sherrill <joel.sherrill@…>
- shmsupp/lock.c: Disable CPU interrupts when we have the shared memory
locked. This is necessary to prevent deadlock.
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-
Property mode set to
100644
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File size:
1.4 KB
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1 | /* Shared Memory Lock Routines |
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2 | * |
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3 | * This shared memory locked queue support routine need to be |
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4 | * able to lock the specified locked queue. Interrupts are |
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5 | * disabled while the queue is locked to prevent preemption |
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6 | * and deadlock when two tasks poll for the same lock. |
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7 | * previous level. |
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8 | * |
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9 | * COPYRIGHT (c) 1989-2008. |
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10 | * On-Line Applications Research Corporation (OAR). |
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11 | * |
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12 | * The license and distribution terms for this file may in |
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13 | * the file LICENSE in this distribution or at |
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14 | * http://www.rtems.com/license/LICENSE. |
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15 | * |
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16 | * $Id$ |
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17 | */ |
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18 | |
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19 | #include <rtems.h> |
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20 | #include <bsp.h> |
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21 | #include <shm_driver.h> |
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22 | #include <psim.h> |
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23 | |
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24 | /* |
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25 | * Shm_Initialize_lock |
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26 | * |
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27 | * Initialize the lock for the specified locked queue. |
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28 | */ |
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29 | |
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30 | void Shm_Initialize_lock( |
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31 | Shm_Locked_queue_Control *lq_cb |
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32 | ) |
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33 | { |
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34 | /* nothing required -- done implicitly by device tree */ |
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35 | } |
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36 | |
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37 | /* void _Shm_Lock( &lq_cb ) |
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38 | * |
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39 | * This shared memory locked queue support routine locks the |
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40 | * specified locked queue. It disables interrupts to prevent |
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41 | * a deadlock condition. |
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42 | */ |
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43 | |
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44 | static rtems_interrupt_level level; |
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45 | |
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46 | void Shm_Lock( |
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47 | Shm_Locked_queue_Control *lq_cb |
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48 | ) |
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49 | { |
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50 | rtems_interrupt_disable( level ); |
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51 | (void) PSIM.Semaphore.lock; |
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52 | } |
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53 | |
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54 | /* |
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55 | * Shm_Unlock |
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56 | * |
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57 | * Unlock the lock for the specified locked queue. |
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58 | */ |
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59 | |
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60 | void Shm_Unlock( |
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61 | Shm_Locked_queue_Control *lq_cb |
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62 | ) |
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63 | { |
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64 | (void) PSIM.Semaphore.unlock; |
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65 | rtems_interrupt_enable( level ); |
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66 | } |
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