source: soft/giet_vm/giet_kernel/ctx_handler.c @ 765

Last change on this file since 765 was 725, checked in by alain, 9 years ago

Modify FBF_CMA syscall handlers to support chbufs containing more than two buffers.

  • Property svn:executable set to *
File size: 7.1 KB
Line 
1//////////////////////////////////////////////////////////////////////////////////
2// File     : ctx_handler.c
3// Date     : 01/04/2012
4// Authors  : alain greiner & joel porquet
5// Copyright (c) UPMC-LIP6
6//////////////////////////////////////////////////////////////////////////////////
7
8#include <ctx_handler.h>
9#include <sys_handler.h>
10#include <giet_config.h>
11#include <fat32.h>
12#include <hard_config.h>
13#include <utils.h>
14#include <tty0.h>
15#include <xcu_driver.h>
16#include <bdv_driver.h>
17
18/////////////////////////////////////////////////////////////////////////////////
19//     Extern variables and functions
20/////////////////////////////////////////////////////////////////////////////////
21
22// defined in giet_kernel/switch.s file
23extern void _thread_switch( thread_context_t* , thread_context_t* );
24
25// allocated in boot.c or kernel_init.c files
26extern static_scheduler_t* _schedulers[X_SIZE][Y_SIZE][NB_PROCS_MAX];
27
28// allocated in kernel_init.c file
29extern fat_desc_t  _fat;
30
31/////////////////////////////////////////////////////////////////////////////////
32// This function is called by the _ctx_switch() function.
33// It desactivates a thread that received a KILL signal.
34// We must release all ressources allocated to the thread
35// before the actual desactivation, that set the NORUN_MASK_THREAD
36// bit in the thread context.
37//////////////////////////////////////////////////////////////////////////////////
38static void _ctx_kill_thread( unsigned int x,
39                              unsigned int y,
40                              unsigned int p,
41                              unsigned int ltid )
42{
43    // get scheduler address
44    static_scheduler_t* psched = _schedulers[x][y][p];
45
46    // pretend the thread to kill is the currently scheduled thread
47    // (required by the _sys_***_release() calls)
48    unsigned int cur_thread = psched->current;
49    psched->current = ltid;
50
51    // release BDV lock if taken and reset BDV peripheral
52    if ( psched->context[ltid].slot[CTX_LOCKS_ID] & LOCKS_MASK_BDV ) 
53    {
54        _bdv_set_register( BLOCK_DEVICE_STATUS , 0 );
55        _spin_lock_release( &_bdv_lock );
56    }
57
58    // release FAT lock if taken
59    if ( psched->context[ltid].slot[CTX_LOCKS_ID] & LOCKS_MASK_FAT ) 
60    {
61       
62        _spin_lock_release( &_fat.fat_lock );
63    }
64
65    // release FBF lock if taken
66    if ( psched->context[ltid].slot[CTX_LOCKS_ID] & LOCKS_MASK_FBF ) 
67    {
68        _sys_fbf_release();
69    }
70
71    // release private TTY terminal if required
72    if ( psched->context[ltid].slot[CTX_TTY_ID] < NB_TTY_CHANNELS ) 
73        _sys_tty_release(); 
74
75    // release private TIM channel if required
76
77    if ( psched->context[ltid].slot[CTX_TIM_ID] < NB_TIM_CHANNELS )
78    {
79        _sys_tim_release();
80    }
81
82    // release private NIC_RX and CMA_RX channels if required
83    if ( psched->context[ltid].slot[CTX_NIC_RX_ID] < NB_NIC_CHANNELS )
84    {
85        _sys_nic_release( 1 );
86    }
87
88    // release private NIC_TX and CMA_TX channels if required
89    if ( psched->context[ltid].slot[CTX_NIC_TX_ID] < NB_NIC_CHANNELS )
90    {
91        _sys_nic_release( 0 );
92    }
93
94    // release private FBF_CMA channel if required
95    if ( psched->context[ltid].slot[CTX_CMA_FB_ID] < NB_CMA_CHANNELS )
96    {
97        _sys_fbf_cma_release();
98    }
99
100    // restore scheduled thread index
101    psched->current = cur_thread;
102
103    // set NORUN_MASK_THREAD bit to desactivate the target thread
104    psched->context[ltid].slot[CTX_NORUN_ID] = NORUN_MASK_THREAD;
105
106} // end _ctx_kill_thread()
107
108
109//////////////////
110void _ctx_switch() 
111{
112    unsigned int gpid       = _get_procid();
113    unsigned int cluster_xy = gpid >> P_WIDTH;
114    unsigned int x          = cluster_xy >> Y_WIDTH;
115    unsigned int y          = cluster_xy & ((1<<Y_WIDTH)-1);
116    unsigned int p          = gpid & ((1<<P_WIDTH)-1);
117
118    unsigned int ltid;     // index for loops on threads in scheduler
119
120    // get calling thread scheduler address
121    static_scheduler_t* psched = (static_scheduler_t*)_get_sched();
122
123    // get number of threads allocated to scheduler
124    unsigned int threads = psched->threads;
125
126    // get current thread ltid
127    unsigned int curr_thread_id = psched->current;
128
129    // first loop on threads: handle all pending KILL signals
130    for ( ltid = 0 ; ltid < threads ; ltid++ )
131    {
132        if ( psched->context[ltid].slot[CTX_SIGS_ID] & SIGS_MASK_KILL )
133        {
134            // acknowledge KILL signal
135            _atomic_and( &psched->context[ltid].slot[CTX_SIGS_ID], ~SIGS_MASK_KILL );
136
137            // desactivate the killed thread
138            _ctx_kill_thread( x , y , p , ltid );
139        }
140    }
141
142    // second loop: select next thread using a round-robin policy
143    unsigned int next_thread_id;
144    unsigned int found = 0;
145    for ( ltid = curr_thread_id + 1 ; ltid < (curr_thread_id + 1 + threads) ; ltid++ ) 
146    {
147        next_thread_id = ltid % threads;
148
149        // test if the thread is runable
150        if ( psched->context[next_thread_id].slot[CTX_NORUN_ID] == 0 )
151        {
152            found = 1;
153            break;
154        }
155    }
156
157    // launch idle_thread if no runable thread
158    if ( found == 0 ) next_thread_id = IDLE_THREAD_INDEX;
159
160    if ( curr_thread_id != next_thread_id )  // actual thread switch required
161    {
162
163#if GIET_DEBUG_SWITCH
164unsigned int x = cluster_xy >> Y_WIDTH;
165unsigned int y = cluster_xy & ((1<<Y_WIDTH)-1);
166if ( (_get_proctime() > GIET_DEBUG_SWITCH) && (x == 0) && (y == 0) && (p == 0) )
167_printf("\n[DEBUG SWITCH] (%d) -> (%d) on processor[%d,%d,%d] at cycle %d\n",
168        curr_thread_id, next_thread_id, x, y , p, _get_proctime() );
169#endif
170
171        thread_context_t* curr_ctx_vaddr = &(psched->context[curr_thread_id]);
172        thread_context_t* next_ctx_vaddr = &(psched->context[next_thread_id]);
173
174        // reset TICK timer counter.
175        _xcu_timer_reset_cpt( cluster_xy, p );
176
177        // set current thread index
178        psched->current = next_thread_id;
179
180        // makes context switch
181        _thread_switch( curr_ctx_vaddr , next_ctx_vaddr );
182    }
183} //end _ctx_switch()
184
185
186///////////////////
187void _idle_thread() 
188{
189    unsigned int gpid       = _get_procid();
190    unsigned int cluster_xy = gpid >> P_WIDTH;
191    unsigned int x          = cluster_xy >> Y_WIDTH;
192    unsigned int y          = cluster_xy & ((1<<Y_WIDTH)-1);
193    unsigned int p          = gpid & ((1<<P_WIDTH)-1);
194
195    while(1)
196    {
197        // initialize counter
198        unsigned int count = GIET_IDLE_THREAD_PERIOD;
199
200        // decounting loop
201        asm volatile(
202                "move   $3,   %0              \n"
203                "_idle_thread_loop:             \n"
204                "addi   $3,   $3,   -1        \n"
205                "bnez   $3,   _idle_thread_loop \n"
206                "nop                          \n"
207                :
208                : "r"(count)
209                : "$3" ); 
210
211        // warning message
212        _printf("\n[GIET WARNING] Processor[%d,%d,%d] still idle at cycle %d",
213                x , y , p , _get_proctime() );
214    }
215} // end ctx_idle()
216
217
218////////////////
219void _ctx_eret() 
220{
221    asm volatile("eret");
222}
223
224
225// Local Variables:
226// tab-width: 4
227// c-basic-offset: 4
228// c-file-offsets:((innamespace . 0)(inline-open . 0))
229// indent-tabs-mode: nil
230// End:
231// vim: filetype=c:expandtab:shiftwidth=4:tabstop=4:softtabstop=4
232
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