1 /***************************************************************************
3 * Open \______ \ ____ ____ | | _\_ |__ _______ ___
4 * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
5 * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
6 * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
10 * Copyright (C) 2002 by Ulf Ralberg
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version 2
15 * of the License, or (at your option) any later version.
17 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
18 * KIND, either express or implied.
20 ****************************************************************************/
33 /****************************************************************************
35 * See notes below on implementing processor-specific portions! *
36 ***************************************************************************/
38 /* Define THREAD_EXTRA_CHECKS as 1 to enable additional state checks */
40 #define THREAD_EXTRA_CHECKS 1 /* Always 1 for DEBUG */
42 #define THREAD_EXTRA_CHECKS 0
46 * General locking order to guarantee progress. Order must be observed but
47 * all stages are not nescessarily obligatory. Going from 1) to 3) is
51 * This is first because of the likelyhood of having an interrupt occur that
52 * also accesses one of the objects farther down the list. Any non-blocking
53 * synchronization done may already have a lock on something during normal
54 * execution and if an interrupt handler running on the same processor as
55 * the one that has the resource locked were to attempt to access the
56 * resource, the interrupt handler would wait forever waiting for an unlock
57 * that will never happen. There is no danger if the interrupt occurs on
58 * a different processor because the one that has the lock will eventually
59 * unlock and the other processor's handler may proceed at that time. Not
60 * nescessary when the resource in question is definitely not available to
64 * 1) May be needed beforehand if the kernel object allows dual-use such as
65 * event queues. The kernel object must have a scheme to protect itself from
66 * access by another processor and is responsible for serializing the calls
67 * to block_thread(_w_tmo) and wakeup_thread both to themselves and to each
68 * other. Objects' queues are also protected here.
71 * This locks access to the thread's slot such that its state cannot be
72 * altered by another processor when a state change is in progress such as
73 * when it is in the process of going on a blocked list. An attempt to wake
74 * a thread while it is still blocking will likely desync its state with
75 * the other resources used for that state.
78 * These lists are specific to a particular processor core and are accessible
79 * by all processor cores and interrupt handlers. The running (rtr) list is
80 * the prime example where a thread may be added by any means.
83 /*---------------------------------------------------------------------------
84 * Processor specific: core_sleep/core_wake/misc. notes
87 * FIQ is not dealt with by the scheduler code and is simply restored if it
88 * must by masked for some reason - because threading modifies a register
89 * that FIQ may also modify and there's no way to accomplish it atomically.
90 * s3c2440 is such a case.
92 * Audio interrupts are generally treated at a higher priority than others
93 * usage of scheduler code with interrupts higher than HIGHEST_IRQ_LEVEL
94 * are not in general safe. Special cases may be constructed on a per-
95 * source basis and blocking operations are not available.
97 * core_sleep procedure to implement for any CPU to ensure an asychronous
98 * wakup never results in requiring a wait until the next tick (up to
99 * 10000uS!). May require assembly and careful instruction ordering.
101 * 1) On multicore, stay awake if directed to do so by another. If so, goto
103 * 2) If processor requires, atomically reenable interrupts and perform step
105 * 3) Sleep the CPU core. If wakeup itself enables interrupts (stop #0x2000
106 * on Coldfire) goto step 5.
107 * 4) Enable interrupts.
110 * core_wake and multprocessor notes for sleep/wake coordination:
111 * If possible, to wake up another processor, the forcing of an interrupt on
112 * the woken core by the waker core is the easiest way to ensure a non-
113 * delayed wake and immediate execution of any woken threads. If that isn't
114 * available then some careful non-blocking synchonization is needed (as on
115 * PP targets at the moment).
116 *---------------------------------------------------------------------------
119 /* Cast to the the machine pointer size, whose size could be < 4 or > 32
121 #define DEADBEEF ((uintptr_t)0xdeadbeefdeadbeefull)
122 struct core_entry cores
[NUM_CORES
] IBSS_ATTR
;
123 struct thread_entry threads
[MAXTHREADS
] IBSS_ATTR
;
125 static const char main_thread_name
[] = "main";
126 extern uintptr_t stackbegin
[];
127 extern uintptr_t stackend
[];
129 static inline void core_sleep(IF_COP_VOID(unsigned int core
))
130 __attribute__((always_inline
));
132 void check_tmo_threads(void)
133 __attribute__((noinline
));
135 static inline void block_thread_on_l(struct thread_entry
*thread
, unsigned state
)
136 __attribute__((always_inline
));
138 static void add_to_list_tmo(struct thread_entry
*thread
)
139 __attribute__((noinline
));
141 static void core_schedule_wakeup(struct thread_entry
*thread
)
142 __attribute__((noinline
));
145 static inline void run_blocking_ops(
146 unsigned int core
, struct thread_entry
*thread
)
147 __attribute__((always_inline
));
150 static void thread_stkov(struct thread_entry
*thread
)
151 __attribute__((noinline
));
153 static inline void store_context(void* addr
)
154 __attribute__((always_inline
));
156 static inline void load_context(const void* addr
)
157 __attribute__((always_inline
));
159 void switch_thread(void)
160 __attribute__((noinline
));
162 /****************************************************************************
163 * Processor-specific section
166 #if defined(MAX_PHYS_SECTOR_SIZE) && MEM == 64
167 /* Support a special workaround object for large-sector disks */
168 #define IF_NO_SKIP_YIELD(...) __VA_ARGS__
170 #define IF_NO_SKIP_YIELD(...)
174 /*---------------------------------------------------------------------------
175 * Start the thread running and terminate it if it returns
176 *---------------------------------------------------------------------------
178 static void __attribute__((naked
,used
)) start_thread(void)
182 "ldr sp, [r0, #32] \n" /* Load initial sp */
183 "ldr r4, [r0, #40] \n" /* start in r4 since it's non-volatile */
184 "mov r1, #0 \n" /* Mark thread as running */
185 "str r1, [r0, #40] \n"
187 "ldr r0, =cpucache_invalidate \n" /* Invalidate this core's cache. */
188 "mov lr, pc \n" /* This could be the first entry into */
189 "bx r0 \n" /* plugin or codec code for this core. */
191 "mov lr, pc \n" /* Call thread function */
193 ); /* No clobber list - new thread doesn't care */
195 //asm volatile (".ltorg"); /* Dump constant pool */
198 /* For startup, place context pointer in r4 slot, start_thread pointer in r5
199 * slot, and thread function pointer in context.start. See load_context for
200 * what happens when thread is initially going to run. */
201 #define THREAD_STARTUP_INIT(core, thread, function) \
202 ({ (thread)->context.r[0] = (uint32_t)&(thread)->context, \
203 (thread)->context.r[1] = (uint32_t)start_thread, \
204 (thread)->context.start = (uint32_t)function; })
206 /*---------------------------------------------------------------------------
207 * Store non-volatile context.
208 *---------------------------------------------------------------------------
210 static inline void store_context(void* addr
)
213 "stmia %0, { r4-r11, sp, lr } \n"
218 /*---------------------------------------------------------------------------
219 * Load non-volatile context.
220 *---------------------------------------------------------------------------
222 static inline void load_context(const void* addr
)
225 "ldr r0, [%0, #40] \n" /* Load start pointer */
226 "cmp r0, #0 \n" /* Check for NULL */
227 "ldmneia %0, { r0, pc } \n" /* If not already running, jump to start */
228 "ldmia %0, { r4-r11, sp, lr } \n" /* Load regs r4 to r14 from context */
229 : : "r" (addr
) : "r0" /* only! */
236 extern uintptr_t cpu_idlestackbegin
[];
237 extern uintptr_t cpu_idlestackend
[];
238 extern uintptr_t cop_idlestackbegin
[];
239 extern uintptr_t cop_idlestackend
[];
240 static uintptr_t * const idle_stacks
[NUM_CORES
] =
242 [CPU
] = cpu_idlestackbegin
,
243 [COP
] = cop_idlestackbegin
246 #if CONFIG_CPU == PP5002
247 /* Bytes to emulate the PP502x mailbox bits */
248 struct core_semaphores
250 volatile uint8_t intend_wake
; /* 00h */
251 volatile uint8_t stay_awake
; /* 01h */
252 volatile uint8_t intend_sleep
; /* 02h */
253 volatile uint8_t unused
; /* 03h */
256 static struct core_semaphores core_semaphores
[NUM_CORES
] IBSS_ATTR
;
257 #endif /* CONFIG_CPU == PP5002 */
259 #endif /* NUM_CORES */
261 #if CONFIG_CORELOCK == SW_CORELOCK
262 /* Software core locks using Peterson's mutual exclusion algorithm */
264 /*---------------------------------------------------------------------------
265 * Initialize the corelock structure.
266 *---------------------------------------------------------------------------
268 void corelock_init(struct corelock
*cl
)
270 memset(cl
, 0, sizeof (*cl
));
273 #if 1 /* Assembly locks to minimize overhead */
274 /*---------------------------------------------------------------------------
275 * Wait for the corelock to become free and acquire it when it does.
276 *---------------------------------------------------------------------------
278 void corelock_lock(struct corelock
*cl
) __attribute__((naked
));
279 void corelock_lock(struct corelock
*cl
)
281 /* Relies on the fact that core IDs are complementary bitmasks (0x55,0xaa) */
283 "mov r1, %0 \n" /* r1 = PROCESSOR_ID */
285 "strb r1, [r0, r1, lsr #7] \n" /* cl->myl[core] = core */
286 "eor r2, r1, #0xff \n" /* r2 = othercore */
287 "strb r2, [r0, #2] \n" /* cl->turn = othercore */
289 "ldrb r3, [r0, r2, lsr #7] \n" /* cl->myl[othercore] == 0 ? */
290 "cmp r3, #0 \n" /* yes? lock acquired */
292 "ldrb r3, [r0, #2] \n" /* || cl->turn == core ? */
294 "bxeq lr \n" /* yes? lock acquired */
295 "b 1b \n" /* keep trying */
296 : : "i"(&PROCESSOR_ID
)
301 /*---------------------------------------------------------------------------
302 * Try to aquire the corelock. If free, caller gets it, otherwise return 0.
303 *---------------------------------------------------------------------------
305 int corelock_try_lock(struct corelock
*cl
) __attribute__((naked
));
306 int corelock_try_lock(struct corelock
*cl
)
308 /* Relies on the fact that core IDs are complementary bitmasks (0x55,0xaa) */
310 "mov r1, %0 \n" /* r1 = PROCESSOR_ID */
313 "strb r1, [r0, r1, lsr #7] \n" /* cl->myl[core] = core */
314 "eor r2, r1, #0xff \n" /* r2 = othercore */
315 "strb r2, [r0, #2] \n" /* cl->turn = othercore */
316 "ldrb r0, [r3, r2, lsr #7] \n" /* cl->myl[othercore] == 0 ? */
317 "eors r0, r0, r2 \n" /* yes? lock acquired */
319 "ldrb r0, [r3, #2] \n" /* || cl->turn == core? */
321 "streqb r0, [r3, r1, lsr #7] \n" /* if not, cl->myl[core] = 0 */
322 "bx lr \n" /* return result */
323 : : "i"(&PROCESSOR_ID
)
330 /*---------------------------------------------------------------------------
331 * Release ownership of the corelock
332 *---------------------------------------------------------------------------
334 void corelock_unlock(struct corelock
*cl
) __attribute__((naked
));
335 void corelock_unlock(struct corelock
*cl
)
338 "mov r1, %0 \n" /* r1 = PROCESSOR_ID */
340 "mov r2, #0 \n" /* cl->myl[core] = 0 */
341 "strb r2, [r0, r1, lsr #7] \n"
343 : : "i"(&PROCESSOR_ID
)
347 #else /* C versions for reference */
348 /*---------------------------------------------------------------------------
349 * Wait for the corelock to become free and aquire it when it does.
350 *---------------------------------------------------------------------------
352 void corelock_lock(struct corelock
*cl
)
354 const unsigned int core
= CURRENT_CORE
;
355 const unsigned int othercore
= 1 - core
;
357 cl
->myl
[core
] = core
;
358 cl
->turn
= othercore
;
362 if (cl
->myl
[othercore
] == 0 || cl
->turn
== core
)
367 /*---------------------------------------------------------------------------
368 * Try to aquire the corelock. If free, caller gets it, otherwise return 0.
369 *---------------------------------------------------------------------------
371 int corelock_try_lock(struct corelock
*cl
)
373 const unsigned int core
= CURRENT_CORE
;
374 const unsigned int othercore
= 1 - core
;
376 cl
->myl
[core
] = core
;
377 cl
->turn
= othercore
;
379 if (cl
->myl
[othercore
] == 0 || cl
->turn
== core
)
388 /*---------------------------------------------------------------------------
389 * Release ownership of the corelock
390 *---------------------------------------------------------------------------
392 void corelock_unlock(struct corelock
*cl
)
394 cl
->myl
[CURRENT_CORE
] = 0;
396 #endif /* ASM / C selection */
398 #endif /* CONFIG_CORELOCK == SW_CORELOCK */
400 /*---------------------------------------------------------------------------
401 * Put core in a power-saving state if waking list wasn't repopulated and if
402 * no other core requested a wakeup for it to perform a task.
403 *---------------------------------------------------------------------------
407 static inline void core_sleep(void)
409 sleep_core(CURRENT_CORE
);
413 static inline void core_sleep(unsigned int core
)
417 "mov r0, #4 \n" /* r0 = 0x4 << core */
418 "mov r0, r0, lsl %[c] \n"
419 "str r0, [%[mbx], #4] \n" /* signal intent to sleep */
420 "ldr r1, [%[mbx], #0] \n" /* && !(MBX_MSG_STAT & (0x10<<core)) ? */
421 "tst r1, r0, lsl #2 \n"
422 "moveq r1, #0x80000000 \n" /* Then sleep */
423 "streq r1, [%[ctl], %[c], lsl #2] \n"
424 "moveq r1, #0 \n" /* Clear control reg */
425 "streq r1, [%[ctl], %[c], lsl #2] \n"
426 "orr r1, r0, r0, lsl #2 \n" /* Signal intent to wake - clear wake flag */
427 "str r1, [%[mbx], #8] \n"
428 "1: \n" /* Wait for wake procedure to finish */
429 "ldr r1, [%[mbx], #0] \n"
430 "tst r1, r0, lsr #2 \n"
433 : [ctl
]"r"(&CPU_CTL
), [mbx
]"r"(MBX_BASE
), [c
]"r"(core
)
435 #else /* C version for reference */
436 /* Signal intent to sleep */
437 MBX_MSG_SET
= 0x4 << core
;
439 /* Something waking or other processor intends to wake us? */
440 if ((MBX_MSG_STAT
& (0x10 << core
)) == 0)
446 /* Signal wake - clear wake flag */
447 MBX_MSG_CLR
= 0x14 << core
;
449 /* Wait for other processor to finish wake procedure */
450 while (MBX_MSG_STAT
& (0x1 << core
));
451 #endif /* ASM/C selection */
454 #endif /* NUM_CORES */
455 #elif CONFIG_CPU == PP5002
457 static inline void core_sleep(void)
459 sleep_core(CURRENT_CORE
);
463 /* PP5002 has no mailboxes - emulate using bytes */
464 static inline void core_sleep(unsigned int core
)
468 "mov r0, #1 \n" /* Signal intent to sleep */
469 "strb r0, [%[sem], #2] \n"
470 "ldrb r0, [%[sem], #1] \n" /* && stay_awake == 0? */
473 /* Sleep: PP5002 crashes if the instruction that puts it to sleep is
474 * located at 0xNNNNNNN0. 4/8/C works. This sequence makes sure
475 * that the correct alternative is executed. Don't change the order
476 * of the next 4 instructions! */
479 "strne r0, [%[ctl], %[c], lsl #2] \n"
480 "streq r0, [%[ctl], %[c], lsl #2] \n"
481 "nop \n" /* nop's needed because of pipeline */
485 "mov r0, #0 \n" /* Clear stay_awake and sleep intent */
486 "strb r0, [%[sem], #1] \n"
487 "strb r0, [%[sem], #2] \n"
488 "1: \n" /* Wait for wake procedure to finish */
489 "ldrb r0, [%[sem], #0] \n"
493 : [sem
]"r"(&core_semaphores
[core
]), [c
]"r"(core
),
497 #else /* C version for reference */
498 /* Signal intent to sleep */
499 core_semaphores
[core
].intend_sleep
= 1;
501 /* Something waking or other processor intends to wake us? */
502 if (core_semaphores
[core
].stay_awake
== 0)
507 /* Signal wake - clear wake flag */
508 core_semaphores
[core
].stay_awake
= 0;
509 core_semaphores
[core
].intend_sleep
= 0;
511 /* Wait for other processor to finish wake procedure */
512 while (core_semaphores
[core
].intend_wake
!= 0);
515 #endif /* ASM/C selection */
518 #endif /* NUM_CORES */
519 #endif /* PP CPU type */
521 /*---------------------------------------------------------------------------
522 * Wake another processor core that is sleeping or prevent it from doing so
523 * if it was already destined. FIQ, IRQ should be disabled before calling.
524 *---------------------------------------------------------------------------
527 /* Shared single-core build debugging version */
530 /* No wakey - core already wakey */
532 #elif defined (CPU_PP502x)
533 void core_wake(unsigned int othercore
)
536 /* avoid r0 since that contains othercore */
538 "mrs r3, cpsr \n" /* Disable IRQ */
539 "orr r1, r3, #0x80 \n"
541 "mov r2, #0x11 \n" /* r2 = (0x11 << othercore) */
542 "mov r2, r2, lsl %[oc] \n" /* Signal intent to wake othercore */
543 "str r2, [%[mbx], #4] \n"
544 "1: \n" /* If it intends to sleep, let it first */
545 "ldr r1, [%[mbx], #0] \n" /* (MSG_MSG_STAT & (0x4 << othercore)) != 0 ? */
546 "eor r1, r1, #0xc \n"
547 "tst r1, r2, lsr #2 \n"
548 "ldr r1, [%[ctl], %[oc], lsl #2] \n" /* && (PROC_CTL(othercore) & PROC_SLEEP) == 0 ? */
549 "tsteq r1, #0x80000000 \n"
550 "beq 1b \n" /* Wait for sleep or wake */
551 "tst r1, #0x80000000 \n" /* If sleeping, wake it */
553 "strne r1, [%[ctl], %[oc], lsl #2] \n"
554 "mov r1, r2, lsr #4 \n"
555 "str r1, [%[mbx], #8] \n" /* Done with wake procedure */
556 "msr cpsr_c, r3 \n" /* Restore IRQ */
558 : [ctl
]"r"(&PROC_CTL(CPU
)), [mbx
]"r"(MBX_BASE
),
561 #else /* C version for reference */
562 /* Disable interrupts - avoid reentrancy from the tick */
563 int oldlevel
= disable_irq_save();
565 /* Signal intent to wake other processor - set stay awake */
566 MBX_MSG_SET
= 0x11 << othercore
;
568 /* If it intends to sleep, wait until it does or aborts */
569 while ((MBX_MSG_STAT
& (0x4 << othercore
)) != 0 &&
570 (PROC_CTL(othercore
) & PROC_SLEEP
) == 0);
572 /* If sleeping, wake it up */
573 if (PROC_CTL(othercore
) & PROC_SLEEP
)
574 PROC_CTL(othercore
) = 0;
576 /* Done with wake procedure */
577 MBX_MSG_CLR
= 0x1 << othercore
;
578 restore_irq(oldlevel
);
579 #endif /* ASM/C selection */
581 #elif CONFIG_CPU == PP5002
582 /* PP5002 has no mailboxes - emulate using bytes */
583 void core_wake(unsigned int othercore
)
586 /* avoid r0 since that contains othercore */
588 "mrs r3, cpsr \n" /* Disable IRQ */
589 "orr r1, r3, #0x80 \n"
591 "mov r1, #1 \n" /* Signal intent to wake other core */
592 "orr r1, r1, r1, lsl #8 \n" /* and set stay_awake */
593 "strh r1, [%[sem], #0] \n"
595 "1: \n" /* If it intends to sleep, let it first */
596 "ldrb r1, [%[sem], #2] \n" /* intend_sleep != 0 ? */
598 "ldr r1, [%[st]] \n" /* && not sleeping ? */
599 "tsteq r1, r2, lsr %[oc] \n"
600 "beq 1b \n" /* Wait for sleep or wake */
601 "tst r1, r2, lsr %[oc] \n"
602 "ldrne r2, =0xcf004054 \n" /* If sleeping, wake it */
604 "strne r1, [r2, %[oc], lsl #2] \n"
605 "mov r1, #0 \n" /* Done with wake procedure */
606 "strb r1, [%[sem], #0] \n"
607 "msr cpsr_c, r3 \n" /* Restore IRQ */
609 : [sem
]"r"(&core_semaphores
[othercore
]),
614 #else /* C version for reference */
615 /* Disable interrupts - avoid reentrancy from the tick */
616 int oldlevel
= disable_irq_save();
618 /* Signal intent to wake other processor - set stay awake */
619 core_semaphores
[othercore
].intend_wake
= 1;
620 core_semaphores
[othercore
].stay_awake
= 1;
622 /* If it intends to sleep, wait until it does or aborts */
623 while (core_semaphores
[othercore
].intend_sleep
!= 0 &&
624 (PROC_STAT
& PROC_SLEEPING(othercore
)) == 0);
626 /* If sleeping, wake it up */
627 if (PROC_STAT
& PROC_SLEEPING(othercore
))
628 wake_core(othercore
);
630 /* Done with wake procedure */
631 core_semaphores
[othercore
].intend_wake
= 0;
632 restore_irq(oldlevel
);
633 #endif /* ASM/C selection */
635 #endif /* CPU type */
638 /*---------------------------------------------------------------------------
639 * Switches to a stack that always resides in the Rockbox core.
641 * Needed when a thread suicides on a core other than the main CPU since the
642 * stack used when idling is the stack of the last thread to run. This stack
643 * may not reside in the core firmware in which case the core will continue
644 * to use a stack from an unloaded module until another thread runs on it.
645 *---------------------------------------------------------------------------
647 static inline void switch_to_idle_stack(const unsigned int core
)
650 "str sp, [%0] \n" /* save original stack pointer on idle stack */
651 "mov sp, %0 \n" /* switch stacks */
652 : : "r"(&idle_stacks
[core
][IDLE_STACK_WORDS
-1]));
656 /*---------------------------------------------------------------------------
657 * Perform core switch steps that need to take place inside switch_thread.
659 * These steps must take place while before changing the processor and after
660 * having entered switch_thread since switch_thread may not do a normal return
661 * because the stack being used for anything the compiler saved will not belong
662 * to the thread's destination core and it may have been recycled for other
663 * purposes by the time a normal context load has taken place. switch_thread
664 * will also clobber anything stashed in the thread's context or stored in the
665 * nonvolatile registers if it is saved there before the call since the
666 * compiler's order of operations cannot be known for certain.
668 static void core_switch_blk_op(unsigned int core
, struct thread_entry
*thread
)
670 /* Flush our data to ram */
672 /* Stash thread in r4 slot */
673 thread
->context
.r
[0] = (uint32_t)thread
;
674 /* Stash restart address in r5 slot */
675 thread
->context
.r
[1] = thread
->context
.start
;
676 /* Save sp in context.sp while still running on old core */
677 thread
->context
.sp
= idle_stacks
[core
][IDLE_STACK_WORDS
-1];
680 /*---------------------------------------------------------------------------
681 * Machine-specific helper function for switching the processor a thread is
682 * running on. Basically, the thread suicides on the departing core and is
683 * reborn on the destination. Were it not for gcc's ill-behavior regarding
684 * naked functions written in C where it actually clobbers non-volatile
685 * registers before the intended prologue code, this would all be much
686 * simpler. Generic setup is done in switch_core itself.
689 /*---------------------------------------------------------------------------
690 * This actually performs the core switch.
692 static void __attribute__((naked
))
693 switch_thread_core(unsigned int core
, struct thread_entry
*thread
)
695 /* Pure asm for this because compiler behavior isn't sufficiently predictable.
696 * Stack access also isn't permitted until restoring the original stack and
699 "stmfd sp!, { r4-r12, lr } \n" /* Stack all non-volatile context on current core */
700 "ldr r2, =idle_stacks \n" /* r2 = &idle_stacks[core][IDLE_STACK_WORDS] */
701 "ldr r2, [r2, r0, lsl #2] \n"
702 "add r2, r2, %0*4 \n"
703 "stmfd r2!, { sp } \n" /* save original stack pointer on idle stack */
704 "mov sp, r2 \n" /* switch stacks */
705 "adr r2, 1f \n" /* r2 = new core restart address */
706 "str r2, [r1, #40] \n" /* thread->context.start = r2 */
707 "ldr pc, =switch_thread \n" /* r0 = thread after call - see load_context */
709 "ldr sp, [r0, #32] \n" /* Reload original sp from context structure */
710 "mov r1, #0 \n" /* Clear start address */
711 "str r1, [r0, #40] \n"
712 "ldr r0, =cpucache_invalidate \n" /* Invalidate new core's cache */
715 "ldmfd sp!, { r4-r12, pc } \n" /* Restore non-volatile context to new core and return */
716 ".ltorg \n" /* Dump constant pool */
717 : : "i"(IDLE_STACK_WORDS
)
719 (void)core
; (void)thread
;
722 /*---------------------------------------------------------------------------
723 * Do any device-specific inits for the threads and synchronize the kernel
725 *---------------------------------------------------------------------------
727 static void core_thread_init(unsigned int core
)
731 /* Wake up coprocessor and let it initialize kernel and threads */
736 /* Sleep until COP has finished */
741 /* Wake the CPU and return */
745 #endif /* NUM_CORES */
747 #elif defined(CPU_TCC780X) || defined(CPU_TCC77X) /* Single core only for now */ \
748 || CONFIG_CPU == IMX31L || CONFIG_CPU == DM320 || CONFIG_CPU == AS3525 \
749 || CONFIG_CPU == S3C2440
750 /* Use the generic ARMv4/v5/v6 wait for IRQ */
751 static inline void core_sleep(void)
754 "mcr p15, 0, %0, c7, c0, 4" /* Wait for interrupt */
760 static inline void core_sleep(void)
762 #warning core_sleep not implemented, battery life will be decreased
765 #endif /* CONFIG_CPU == */
767 #elif defined(CPU_COLDFIRE)
768 /*---------------------------------------------------------------------------
769 * Start the thread running and terminate it if it returns
770 *---------------------------------------------------------------------------
772 void start_thread(void); /* Provide C access to ASM label */
773 static void __attribute__((used
)) __start_thread(void)
775 /* a0=macsr, a1=context */
777 "start_thread: \n" /* Start here - no naked attribute */
778 "move.l %a0, %macsr \n" /* Set initial mac status reg */
779 "lea.l 48(%a1), %a1 \n"
780 "move.l (%a1)+, %sp \n" /* Set initial stack */
781 "move.l (%a1), %a2 \n" /* Fetch thread function pointer */
782 "clr.l (%a1) \n" /* Mark thread running */
783 "jsr (%a2) \n" /* Call thread function */
788 /* Set EMAC unit to fractional mode with saturation for each new thread,
789 * since that's what'll be the most useful for most things which the dsp
790 * will do. Codecs should still initialize their preferred modes
791 * explicitly. Context pointer is placed in d2 slot and start_thread
792 * pointer in d3 slot. thread function pointer is placed in context.start.
793 * See load_context for what happens when thread is initially going to
796 #define THREAD_STARTUP_INIT(core, thread, function) \
797 ({ (thread)->context.macsr = EMAC_FRACTIONAL | EMAC_SATURATE, \
798 (thread)->context.d[0] = (uint32_t)&(thread)->context, \
799 (thread)->context.d[1] = (uint32_t)start_thread, \
800 (thread)->context.start = (uint32_t)(function); })
802 /*---------------------------------------------------------------------------
803 * Store non-volatile context.
804 *---------------------------------------------------------------------------
806 static inline void store_context(void* addr
)
809 "move.l %%macsr,%%d0 \n"
810 "movem.l %%d0/%%d2-%%d7/%%a2-%%a7,(%0) \n"
811 : : "a" (addr
) : "d0" /* only! */
815 /*---------------------------------------------------------------------------
816 * Load non-volatile context.
817 *---------------------------------------------------------------------------
819 static inline void load_context(const void* addr
)
822 "move.l 52(%0), %%d0 \n" /* Get start address */
823 "beq.b 1f \n" /* NULL -> already running */
824 "movem.l (%0), %%a0-%%a2 \n" /* a0=macsr, a1=context, a2=start_thread */
825 "jmp (%%a2) \n" /* Start the thread */
827 "movem.l (%0), %%d0/%%d2-%%d7/%%a2-%%a7 \n" /* Load context */
828 "move.l %%d0, %%macsr \n"
829 : : "a" (addr
) : "d0" /* only! */
833 /*---------------------------------------------------------------------------
834 * Put core in a power-saving state if waking list wasn't repopulated.
835 *---------------------------------------------------------------------------
837 static inline void core_sleep(void)
839 /* Supervisor mode, interrupts enabled upon wakeup */
840 asm volatile ("stop #0x2000");
843 #elif CONFIG_CPU == SH7034
844 /*---------------------------------------------------------------------------
845 * Start the thread running and terminate it if it returns
846 *---------------------------------------------------------------------------
848 void start_thread(void); /* Provide C access to ASM label */
849 static void __attribute__((used
)) __start_thread(void)
853 "_start_thread: \n" /* Start here - no naked attribute */
854 "mov.l @(4, r8), r0 \n" /* Fetch thread function pointer */
855 "mov.l @(28, r8), r15 \n" /* Set initial sp */
856 "mov #0, r1 \n" /* Start the thread */
858 "mov.l r1, @(36, r8) \n" /* Clear start address */
863 /* Place context pointer in r8 slot, function pointer in r9 slot, and
864 * start_thread pointer in context_start */
865 #define THREAD_STARTUP_INIT(core, thread, function) \
866 ({ (thread)->context.r[0] = (uint32_t)&(thread)->context, \
867 (thread)->context.r[1] = (uint32_t)(function), \
868 (thread)->context.start = (uint32_t)start_thread; })
870 /*---------------------------------------------------------------------------
871 * Store non-volatile context.
872 *---------------------------------------------------------------------------
874 static inline void store_context(void* addr
)
877 "add #36, %0 \n" /* Start at last reg. By the time routine */
878 "sts.l pr, @-%0 \n" /* is done, %0 will have the original value */
891 /*---------------------------------------------------------------------------
892 * Load non-volatile context.
893 *---------------------------------------------------------------------------
895 static inline void load_context(const void* addr
)
898 "mov.l @(36, %0), r0 \n" /* Get start address */
900 "bt .running \n" /* NULL -> already running */
901 "jmp @r0 \n" /* r8 = context */
903 "mov.l @%0+, r8 \n" /* Executes in delay slot and outside it */
912 : : "r" (addr
) : "r0" /* only! */
916 /*---------------------------------------------------------------------------
917 * Put core in a power-saving state.
918 *---------------------------------------------------------------------------
920 static inline void core_sleep(void)
923 "and.b #0x7f, @(r0, gbr) \n" /* Clear SBY (bit 7) in SBYCR */
924 "mov #0, r1 \n" /* Enable interrupts */
925 "ldc r1, sr \n" /* Following instruction cannot be interrupted */
926 "sleep \n" /* Execute standby */
927 : : "z"(&SBYCR
-GBR
) : "r1");
932 /*---------------------------------------------------------------------------
933 * Start the thread running and terminate it if it returns
934 *---------------------------------------------------------------------------
937 void start_thread(void); /* Provide C access to ASM label */
938 static void __attribute__((used
)) _start_thread(void)
945 "lw $8, 4($9) \n" /* Fetch thread function pointer ($8 = $t0, $9 = $t1) */
946 "lw $29, 40($9) \n" /* Set initial sp(=$29) */
947 "sw $0, 48($9) \n" /* Clear start address */
948 "jr $8 \n" /* Start the thread */
956 /* Place context pointer in $s0 slot, function pointer in $s1 slot, and
957 * start_thread pointer in context_start */
958 #define THREAD_STARTUP_INIT(core, thread, function) \
959 ({ (thread)->context.r[0] = (uint32_t)&(thread)->context, \
960 (thread)->context.r[1] = (uint32_t)(function), \
961 (thread)->context.start = (uint32_t)start_thread; })
963 /*---------------------------------------------------------------------------
964 * Store non-volatile context.
965 *---------------------------------------------------------------------------
967 static inline void store_context(void* addr
)
973 "sw $16, 0($8) \n" /* $s0 */
974 "sw $17, 4($8) \n" /* $s1 */
975 "sw $18, 8($8) \n" /* $s2 */
976 "sw $19, 12($8) \n" /* $s3 */
977 "sw $20, 16($8) \n" /* $s4 */
978 "sw $21, 20($8) \n" /* $s5 */
979 "sw $22, 24($8) \n" /* $s6 */
980 "sw $23, 28($8) \n" /* $s7 */
981 "sw $28, 32($8) \n" /* gp */
982 "sw $30, 36($8) \n" /* fp */
983 "sw $29, 40($8) \n" /* sp */
984 "sw $31, 44($8) \n" /* ra */
987 : : "r" (addr
) : "t0"
991 /*---------------------------------------------------------------------------
992 * Load non-volatile context.
993 *---------------------------------------------------------------------------
995 static inline void load_context(const void* addr
)
1000 "lw $8, 48(%0) \n" /* Get start address ($8 = $t0) */
1001 "beqz $8, running \n" /* NULL -> already running */
1003 "move $9, %0 \n" /* $t1 = context */
1008 "lw $16, 0($8) \n" /* $s0 */
1009 "lw $17, 4($8) \n" /* $s1 */
1010 "lw $18, 8($8) \n" /* $s2 */
1011 "lw $19, 12($8) \n" /* $s3 */
1012 "lw $20, 16($8) \n" /* $s4 */
1013 "lw $21, 20($8) \n" /* $s5 */
1014 "lw $22, 24($8) \n" /* $s6 */
1015 "lw $23, 28($8) \n" /* $s7 */
1016 "lw $28, 32($8) \n" /* gp */
1017 "lw $30, 36($8) \n" /* fp */
1018 "lw $29, 40($8) \n" /* sp */
1019 "lw $31, 44($8) \n" /* ra */
1022 : : "r" (addr
) : "t0" /* only! */
1026 /*---------------------------------------------------------------------------
1027 * Put core in a power-saving state.
1028 *---------------------------------------------------------------------------
1030 static inline void core_sleep(void)
1032 #if CONFIG_CPU == JZ4732
1035 asm volatile(".set mips32r2 \n"
1036 "mfc0 $8, $12 \n" /* mfc $t0, $12 */
1037 "move $9, $8 \n" /* move $t1, $t0 */
1038 "la $10, 0x8000000 \n" /* la $t2, 0x8000000 */
1039 "or $8, $8, $10 \n" /* Enable reduced power mode */
1044 ::: "t0", "t1", "t2"
1050 #endif /* CONFIG_CPU == */
1053 * End Processor-specific section
1054 ***************************************************************************/
1056 #if THREAD_EXTRA_CHECKS
1057 static void thread_panicf(const char *msg
, struct thread_entry
*thread
)
1059 IF_COP( const unsigned int core
= thread
->core
; )
1060 static char name
[32];
1061 thread_get_name(name
, 32, thread
);
1062 panicf ("%s %s" IF_COP(" (%d)"), msg
, name
IF_COP(, core
));
1064 static void thread_stkov(struct thread_entry
*thread
)
1066 thread_panicf("Stkov", thread
);
1068 #define THREAD_PANICF(msg, thread) \
1069 thread_panicf(msg, thread)
1070 #define THREAD_ASSERT(exp, msg, thread) \
1071 ({ if (!({ exp; })) thread_panicf((msg), (thread)); })
1073 static void thread_stkov(struct thread_entry
*thread
)
1075 IF_COP( const unsigned int core
= thread
->core
; )
1076 static char name
[32];
1077 thread_get_name(name
, 32, thread
);
1078 panicf("Stkov %s" IF_COP(" (%d)"), name
IF_COP(, core
));
1080 #define THREAD_PANICF(msg, thread)
1081 #define THREAD_ASSERT(exp, msg, thread)
1082 #endif /* THREAD_EXTRA_CHECKS */
1084 /* Thread locking */
1086 #define LOCK_THREAD(thread) \
1087 ({ corelock_lock(&(thread)->slot_cl); })
1088 #define TRY_LOCK_THREAD(thread) \
1089 ({ corelock_try_lock(&thread->slot_cl); })
1090 #define UNLOCK_THREAD(thread) \
1091 ({ corelock_unlock(&(thread)->slot_cl); })
1092 #define UNLOCK_THREAD_AT_TASK_SWITCH(thread) \
1093 ({ unsigned int _core = (thread)->core; \
1094 cores[_core].blk_ops.flags |= TBOP_UNLOCK_CORELOCK; \
1095 cores[_core].blk_ops.cl_p = &(thread)->slot_cl; })
1097 #define LOCK_THREAD(thread) \
1099 #define TRY_LOCK_THREAD(thread) \
1101 #define UNLOCK_THREAD(thread) \
1103 #define UNLOCK_THREAD_AT_TASK_SWITCH(thread) \
1108 #define RTR_LOCK(core) \
1109 ({ corelock_lock(&cores[core].rtr_cl); })
1110 #define RTR_UNLOCK(core) \
1111 ({ corelock_unlock(&cores[core].rtr_cl); })
1113 #ifdef HAVE_PRIORITY_SCHEDULING
1114 #define rtr_add_entry(core, priority) \
1115 prio_add_entry(&cores[core].rtr, (priority))
1117 #define rtr_subtract_entry(core, priority) \
1118 prio_subtract_entry(&cores[core].rtr, (priority))
1120 #define rtr_move_entry(core, from, to) \
1121 prio_move_entry(&cores[core].rtr, (from), (to))
1123 #define rtr_add_entry(core, priority)
1124 #define rtr_add_entry_inl(core, priority)
1125 #define rtr_subtract_entry(core, priority)
1126 #define rtr_subtract_entry_inl(core, priotity)
1127 #define rtr_move_entry(core, from, to)
1128 #define rtr_move_entry_inl(core, from, to)
1131 /*---------------------------------------------------------------------------
1132 * Thread list structure - circular:
1133 * +------------------------------+
1135 * +--+---+<-+---+<-+---+<-+---+<-+
1136 * Head->| T | | T | | T | | T |
1137 * +->+---+->+---+->+---+->+---+--+
1139 * +------------------------------+
1140 *---------------------------------------------------------------------------
1143 /*---------------------------------------------------------------------------
1144 * Adds a thread to a list of threads using "insert last". Uses the "l"
1146 *---------------------------------------------------------------------------
1148 static void add_to_list_l(struct thread_entry
**list
,
1149 struct thread_entry
*thread
)
1151 struct thread_entry
*l
= *list
;
1155 /* Insert into unoccupied list */
1156 thread
->l
.prev
= thread
;
1157 thread
->l
.next
= thread
;
1163 thread
->l
.prev
= l
->l
.prev
;
1165 l
->l
.prev
->l
.next
= thread
;
1169 /*---------------------------------------------------------------------------
1170 * Removes a thread from a list of threads. Uses the "l" links.
1171 *---------------------------------------------------------------------------
1173 static void remove_from_list_l(struct thread_entry
**list
,
1174 struct thread_entry
*thread
)
1176 struct thread_entry
*prev
, *next
;
1178 next
= thread
->l
.next
;
1187 if (thread
== *list
)
1189 /* List becomes next item */
1193 prev
= thread
->l
.prev
;
1195 /* Fix links to jump over the removed entry. */
1196 next
->l
.prev
= prev
;
1197 prev
->l
.next
= next
;
1200 /*---------------------------------------------------------------------------
1201 * Timeout list structure - circular reverse (to make "remove item" O(1)),
1202 * NULL-terminated forward (to ease the far more common forward traversal):
1203 * +------------------------------+
1205 * +--+---+<-+---+<-+---+<-+---+<-+
1206 * Head->| T | | T | | T | | T |
1207 * +---+->+---+->+---+->+---+-X
1208 *---------------------------------------------------------------------------
1211 /*---------------------------------------------------------------------------
1212 * Add a thread from the core's timout list by linking the pointers in its
1214 *---------------------------------------------------------------------------
1216 static void add_to_list_tmo(struct thread_entry
*thread
)
1218 struct thread_entry
*tmo
= cores
[IF_COP_CORE(thread
->core
)].timeout
;
1219 THREAD_ASSERT(thread
->tmo
.prev
== NULL
,
1220 "add_to_list_tmo->already listed", thread
);
1222 thread
->tmo
.next
= NULL
;
1226 /* Insert into unoccupied list */
1227 thread
->tmo
.prev
= thread
;
1228 cores
[IF_COP_CORE(thread
->core
)].timeout
= thread
;
1233 thread
->tmo
.prev
= tmo
->tmo
.prev
;
1234 tmo
->tmo
.prev
->tmo
.next
= thread
;
1235 tmo
->tmo
.prev
= thread
;
1238 /*---------------------------------------------------------------------------
1239 * Remove a thread from the core's timout list by unlinking the pointers in
1240 * its tmo structure. Sets thread->tmo.prev to NULL to indicate the timeout
1242 *---------------------------------------------------------------------------
1244 static void remove_from_list_tmo(struct thread_entry
*thread
)
1246 struct thread_entry
**list
= &cores
[IF_COP_CORE(thread
->core
)].timeout
;
1247 struct thread_entry
*prev
= thread
->tmo
.prev
;
1248 struct thread_entry
*next
= thread
->tmo
.next
;
1250 THREAD_ASSERT(prev
!= NULL
, "remove_from_list_tmo->not listed", thread
);
1253 next
->tmo
.prev
= prev
;
1255 if (thread
== *list
)
1257 /* List becomes next item and empty if next == NULL */
1259 /* Mark as unlisted */
1260 thread
->tmo
.prev
= NULL
;
1265 (*list
)->tmo
.prev
= prev
;
1266 prev
->tmo
.next
= next
;
1267 /* Mark as unlisted */
1268 thread
->tmo
.prev
= NULL
;
1273 #ifdef HAVE_PRIORITY_SCHEDULING
1274 /*---------------------------------------------------------------------------
1275 * Priority distribution structure (one category for each possible priority):
1277 * +----+----+----+ ... +-----+
1278 * hist: | F0 | F1 | F2 | | F31 |
1279 * +----+----+----+ ... +-----+
1280 * mask: | b0 | b1 | b2 | | b31 |
1281 * +----+----+----+ ... +-----+
1283 * F = count of threads at priority category n (frequency)
1284 * b = bitmask of non-zero priority categories (occupancy)
1286 * / if H[n] != 0 : 1
1290 *---------------------------------------------------------------------------
1291 * Basic priority inheritance priotocol (PIP):
1293 * Mn = mutex n, Tn = thread n
1295 * A lower priority thread inherits the priority of the highest priority
1296 * thread blocked waiting for it to complete an action (such as release a
1297 * mutex or respond to a message via queue_send):
1301 * T1 owns M1, T2 is waiting for M1 to realease M1. If T2 has a higher
1302 * priority than T1 then T1 inherits the priority of T2.
1308 * Situation is like 1) but T2 and T3 are both queued waiting for M1 and so
1309 * T1 inherits the higher of T2 and T3.
1311 * 3) T3->M2->T2->M1->T1
1313 * T1 owns M1, T2 owns M2. If T3 has a higher priority than both T1 and T2,
1314 * then T1 inherits the priority of T3 through T2.
1316 * Blocking chains can grow arbitrarily complex (though it's best that they
1317 * not form at all very often :) and build-up from these units.
1318 *---------------------------------------------------------------------------
1321 /*---------------------------------------------------------------------------
1322 * Increment frequency at category "priority"
1323 *---------------------------------------------------------------------------
1325 static inline unsigned int prio_add_entry(
1326 struct priority_distribution
*pd
, int priority
)
1329 /* Enough size/instruction count difference for ARM makes it worth it to
1330 * use different code (192 bytes for ARM). Only thing better is ASM. */
1332 count
= pd
->hist
[priority
];
1334 pd
->mask
|= 1 << priority
;
1335 pd
->hist
[priority
] = count
;
1336 #else /* This one's better for Coldfire */
1337 if ((count
= ++pd
->hist
[priority
]) == 1)
1338 pd
->mask
|= 1 << priority
;
1344 /*---------------------------------------------------------------------------
1345 * Decrement frequency at category "priority"
1346 *---------------------------------------------------------------------------
1348 static inline unsigned int prio_subtract_entry(
1349 struct priority_distribution
*pd
, int priority
)
1354 count
= pd
->hist
[priority
];
1356 pd
->mask
&= ~(1 << priority
);
1357 pd
->hist
[priority
] = count
;
1359 if ((count
= --pd
->hist
[priority
]) == 0)
1360 pd
->mask
&= ~(1 << priority
);
1366 /*---------------------------------------------------------------------------
1367 * Remove from one category and add to another
1368 *---------------------------------------------------------------------------
1370 static inline void prio_move_entry(
1371 struct priority_distribution
*pd
, int from
, int to
)
1373 uint32_t mask
= pd
->mask
;
1378 count
= pd
->hist
[from
];
1380 mask
&= ~(1 << from
);
1381 pd
->hist
[from
] = count
;
1383 count
= pd
->hist
[to
];
1386 pd
->hist
[to
] = count
;
1388 if (--pd
->hist
[from
] == 0)
1389 mask
&= ~(1 << from
);
1391 if (++pd
->hist
[to
] == 1)
1398 /*---------------------------------------------------------------------------
1399 * Change the priority and rtr entry for a running thread
1400 *---------------------------------------------------------------------------
1402 static inline void set_running_thread_priority(
1403 struct thread_entry
*thread
, int priority
)
1405 const unsigned int core
= IF_COP_CORE(thread
->core
);
1407 rtr_move_entry(core
, thread
->priority
, priority
);
1408 thread
->priority
= priority
;
1412 /*---------------------------------------------------------------------------
1413 * Finds the highest priority thread in a list of threads. If the list is
1414 * empty, the PRIORITY_IDLE is returned.
1416 * It is possible to use the struct priority_distribution within an object
1417 * instead of scanning the remaining threads in the list but as a compromise,
1418 * the resulting per-object memory overhead is saved at a slight speed
1419 * penalty under high contention.
1420 *---------------------------------------------------------------------------
1422 static int find_highest_priority_in_list_l(
1423 struct thread_entry
* const thread
)
1425 if (LIKELY(thread
!= NULL
))
1427 /* Go though list until the ending up at the initial thread */
1428 int highest_priority
= thread
->priority
;
1429 struct thread_entry
*curr
= thread
;
1433 int priority
= curr
->priority
;
1435 if (priority
< highest_priority
)
1436 highest_priority
= priority
;
1438 curr
= curr
->l
.next
;
1440 while (curr
!= thread
);
1442 return highest_priority
;
1445 return PRIORITY_IDLE
;
1448 /*---------------------------------------------------------------------------
1449 * Register priority with blocking system and bubble it down the chain if
1450 * any until we reach the end or something is already equal or higher.
1452 * NOTE: A simultaneous circular wait could spin deadlock on multiprocessor
1453 * targets but that same action also guarantees a circular block anyway and
1454 * those are prevented, right? :-)
1455 *---------------------------------------------------------------------------
1457 static struct thread_entry
*
1458 blocker_inherit_priority(struct thread_entry
*current
)
1460 const int priority
= current
->priority
;
1461 struct blocker
*bl
= current
->blocker
;
1462 struct thread_entry
* const tstart
= current
;
1463 struct thread_entry
*bl_t
= bl
->thread
;
1465 /* Blocker cannot change since the object protection is held */
1470 struct thread_entry
*next
;
1471 int bl_pr
= bl
->priority
;
1473 if (priority
>= bl_pr
)
1474 break; /* Object priority already high enough */
1476 bl
->priority
= priority
;
1479 prio_add_entry(&bl_t
->pdist
, priority
);
1481 if (bl_pr
< PRIORITY_IDLE
)
1483 /* Not first waiter - subtract old one */
1484 prio_subtract_entry(&bl_t
->pdist
, bl_pr
);
1487 if (priority
>= bl_t
->priority
)
1488 break; /* Thread priority high enough */
1490 if (bl_t
->state
== STATE_RUNNING
)
1492 /* Blocking thread is a running thread therefore there are no
1493 * further blockers. Change the "run queue" on which it
1495 set_running_thread_priority(bl_t
, priority
);
1499 bl_t
->priority
= priority
;
1501 /* If blocking thread has a blocker, apply transitive inheritance */
1505 break; /* End of chain or object doesn't support inheritance */
1509 if (UNLIKELY(next
== tstart
))
1510 break; /* Full-circle - deadlock! */
1512 UNLOCK_THREAD(current
);
1519 /* Blocker could change - retest condition */
1520 if (LIKELY(bl
->thread
== next
))
1523 UNLOCK_THREAD(next
);
1531 UNLOCK_THREAD(bl_t
);
1536 /*---------------------------------------------------------------------------
1537 * Readjust priorities when waking a thread blocked waiting for another
1538 * in essence "releasing" the thread's effect on the object owner. Can be
1539 * performed from any context.
1540 *---------------------------------------------------------------------------
1542 struct thread_entry
*
1543 wakeup_priority_protocol_release(struct thread_entry
*thread
)
1545 const int priority
= thread
->priority
;
1546 struct blocker
*bl
= thread
->blocker
;
1547 struct thread_entry
* const tstart
= thread
;
1548 struct thread_entry
*bl_t
= bl
->thread
;
1550 /* Blocker cannot change since object will be locked */
1553 thread
->blocker
= NULL
; /* Thread not blocked */
1557 struct thread_entry
*next
;
1558 int bl_pr
= bl
->priority
;
1560 if (priority
> bl_pr
)
1561 break; /* Object priority higher */
1563 next
= *thread
->bqp
;
1567 /* No more threads in queue */
1568 prio_subtract_entry(&bl_t
->pdist
, bl_pr
);
1569 bl
->priority
= PRIORITY_IDLE
;
1573 /* Check list for highest remaining priority */
1574 int queue_pr
= find_highest_priority_in_list_l(next
);
1576 if (queue_pr
== bl_pr
)
1577 break; /* Object priority not changing */
1579 /* Change queue priority */
1580 prio_move_entry(&bl_t
->pdist
, bl_pr
, queue_pr
);
1581 bl
->priority
= queue_pr
;
1584 if (bl_pr
> bl_t
->priority
)
1585 break; /* thread priority is higher */
1587 bl_pr
= find_first_set_bit(bl_t
->pdist
.mask
);
1589 if (bl_pr
== bl_t
->priority
)
1590 break; /* Thread priority not changing */
1592 if (bl_t
->state
== STATE_RUNNING
)
1594 /* No further blockers */
1595 set_running_thread_priority(bl_t
, bl_pr
);
1599 bl_t
->priority
= bl_pr
;
1601 /* If blocking thread has a blocker, apply transitive inheritance */
1605 break; /* End of chain or object doesn't support inheritance */
1609 if (UNLIKELY(next
== tstart
))
1610 break; /* Full-circle - deadlock! */
1612 UNLOCK_THREAD(thread
);
1619 /* Blocker could change - retest condition */
1620 if (LIKELY(bl
->thread
== next
))
1623 UNLOCK_THREAD(next
);
1631 UNLOCK_THREAD(bl_t
);
1634 if (UNLIKELY(thread
!= tstart
))
1636 /* Relock original if it changed */
1637 LOCK_THREAD(tstart
);
1641 return cores
[CURRENT_CORE
].running
;
1644 /*---------------------------------------------------------------------------
1645 * Transfer ownership to a thread waiting for an objects and transfer
1646 * inherited priority boost from other waiters. This algorithm knows that
1647 * blocking chains may only unblock from the very end.
1649 * Only the owning thread itself may call this and so the assumption that
1650 * it is the running thread is made.
1651 *---------------------------------------------------------------------------
1653 struct thread_entry
*
1654 wakeup_priority_protocol_transfer(struct thread_entry
*thread
)
1656 /* Waking thread inherits priority boost from object owner */
1657 struct blocker
*bl
= thread
->blocker
;
1658 struct thread_entry
*bl_t
= bl
->thread
;
1659 struct thread_entry
*next
;
1662 THREAD_ASSERT(cores
[CURRENT_CORE
].running
== bl_t
,
1663 "UPPT->wrong thread", cores
[CURRENT_CORE
].running
);
1667 bl_pr
= bl
->priority
;
1669 /* Remove the object's boost from the owning thread */
1670 if (prio_subtract_entry(&bl_t
->pdist
, bl_pr
) == 0 &&
1671 bl_pr
<= bl_t
->priority
)
1673 /* No more threads at this priority are waiting and the old level is
1674 * at least the thread level */
1675 int priority
= find_first_set_bit(bl_t
->pdist
.mask
);
1677 if (priority
!= bl_t
->priority
)
1679 /* Adjust this thread's priority */
1680 set_running_thread_priority(bl_t
, priority
);
1684 next
= *thread
->bqp
;
1686 if (LIKELY(next
== NULL
))
1688 /* Expected shortcut - no more waiters */
1689 bl_pr
= PRIORITY_IDLE
;
1693 if (thread
->priority
<= bl_pr
)
1695 /* Need to scan threads remaining in queue */
1696 bl_pr
= find_highest_priority_in_list_l(next
);
1699 if (prio_add_entry(&thread
->pdist
, bl_pr
) == 1 &&
1700 bl_pr
< thread
->priority
)
1702 /* Thread priority must be raised */
1703 thread
->priority
= bl_pr
;
1707 bl
->thread
= thread
; /* This thread pwns */
1708 bl
->priority
= bl_pr
; /* Save highest blocked priority */
1709 thread
->blocker
= NULL
; /* Thread not blocked */
1711 UNLOCK_THREAD(bl_t
);
1716 /*---------------------------------------------------------------------------
1717 * No threads must be blocked waiting for this thread except for it to exit.
1718 * The alternative is more elaborate cleanup and object registration code.
1719 * Check this for risk of silent data corruption when objects with
1720 * inheritable blocking are abandoned by the owner - not precise but may
1722 *---------------------------------------------------------------------------
1724 static void check_for_obj_waiters(const char *function
, struct thread_entry
*thread
)
1726 /* Only one bit in the mask should be set with a frequency on 1 which
1727 * represents the thread's own base priority */
1728 uint32_t mask
= thread
->pdist
.mask
;
1729 if ((mask
& (mask
- 1)) != 0 ||
1730 thread
->pdist
.hist
[find_first_set_bit(mask
)] > 1)
1732 unsigned char name
[32];
1733 thread_get_name(name
, 32, thread
);
1734 panicf("%s->%s with obj. waiters", function
, name
);
1737 #endif /* HAVE_PRIORITY_SCHEDULING */
1739 /*---------------------------------------------------------------------------
1740 * Move a thread back to a running state on its core.
1741 *---------------------------------------------------------------------------
1743 static void core_schedule_wakeup(struct thread_entry
*thread
)
1745 const unsigned int core
= IF_COP_CORE(thread
->core
);
1749 thread
->state
= STATE_RUNNING
;
1751 add_to_list_l(&cores
[core
].running
, thread
);
1752 rtr_add_entry(core
, thread
->priority
);
1757 if (core
!= CURRENT_CORE
)
1762 /*---------------------------------------------------------------------------
1763 * Check the core's timeout list when at least one thread is due to wake.
1764 * Filtering for the condition is done before making the call. Resets the
1765 * tick when the next check will occur.
1766 *---------------------------------------------------------------------------
1768 void check_tmo_threads(void)
1770 const unsigned int core
= CURRENT_CORE
;
1771 const long tick
= current_tick
; /* snapshot the current tick */
1772 long next_tmo_check
= tick
+ 60*HZ
; /* minimum duration: once/minute */
1773 struct thread_entry
*next
= cores
[core
].timeout
;
1775 /* If there are no processes waiting for a timeout, just keep the check
1776 tick from falling into the past. */
1778 /* Break the loop once we have walked through the list of all
1779 * sleeping processes or have removed them all. */
1780 while (next
!= NULL
)
1782 /* Check sleeping threads. Allow interrupts between checks. */
1785 struct thread_entry
*curr
= next
;
1787 next
= curr
->tmo
.next
;
1789 /* Lock thread slot against explicit wakeup */
1793 unsigned state
= curr
->state
;
1795 if (state
< TIMEOUT_STATE_FIRST
)
1797 /* Cleanup threads no longer on a timeout but still on the
1799 remove_from_list_tmo(curr
);
1801 else if (LIKELY(TIME_BEFORE(tick
, curr
->tmo_tick
)))
1803 /* Timeout still pending - this will be the usual case */
1804 if (TIME_BEFORE(curr
->tmo_tick
, next_tmo_check
))
1806 /* Earliest timeout found so far - move the next check up
1808 next_tmo_check
= curr
->tmo_tick
;
1813 /* Sleep timeout has been reached so bring the thread back to
1815 if (state
== STATE_BLOCKED_W_TMO
)
1818 /* Lock the waiting thread's kernel object */
1819 struct corelock
*ocl
= curr
->obj_cl
;
1821 if (UNLIKELY(corelock_try_lock(ocl
) == 0))
1823 /* Need to retry in the correct order though the need is
1825 UNLOCK_THREAD(curr
);
1829 if (UNLIKELY(curr
->state
!= STATE_BLOCKED_W_TMO
))
1831 /* Thread was woken or removed explicitely while slot
1833 corelock_unlock(ocl
);
1834 remove_from_list_tmo(curr
);
1835 UNLOCK_THREAD(curr
);
1839 #endif /* NUM_CORES */
1841 remove_from_list_l(curr
->bqp
, curr
);
1843 #ifdef HAVE_WAKEUP_EXT_CB
1844 if (curr
->wakeup_ext_cb
!= NULL
)
1845 curr
->wakeup_ext_cb(curr
);
1848 #ifdef HAVE_PRIORITY_SCHEDULING
1849 if (curr
->blocker
!= NULL
)
1850 wakeup_priority_protocol_release(curr
);
1852 corelock_unlock(ocl
);
1854 /* else state == STATE_SLEEPING */
1856 remove_from_list_tmo(curr
);
1860 curr
->state
= STATE_RUNNING
;
1862 add_to_list_l(&cores
[core
].running
, curr
);
1863 rtr_add_entry(core
, curr
->priority
);
1868 UNLOCK_THREAD(curr
);
1871 cores
[core
].next_tmo_check
= next_tmo_check
;
1874 /*---------------------------------------------------------------------------
1875 * Performs operations that must be done before blocking a thread but after
1876 * the state is saved.
1877 *---------------------------------------------------------------------------
1880 static inline void run_blocking_ops(
1881 unsigned int core
, struct thread_entry
*thread
)
1883 struct thread_blk_ops
*ops
= &cores
[core
].blk_ops
;
1884 const unsigned flags
= ops
->flags
;
1886 if (LIKELY(flags
== TBOP_CLEAR
))
1891 case TBOP_SWITCH_CORE
:
1892 core_switch_blk_op(core
, thread
);
1894 case TBOP_UNLOCK_CORELOCK
:
1895 corelock_unlock(ops
->cl_p
);
1899 ops
->flags
= TBOP_CLEAR
;
1901 #endif /* NUM_CORES > 1 */
1904 void profile_thread(void)
1906 profstart(cores
[CURRENT_CORE
].running
- threads
);
1910 /*---------------------------------------------------------------------------
1911 * Prepares a thread to block on an object's list and/or for a specified
1912 * duration - expects object and slot to be appropriately locked if needed
1913 * and interrupts to be masked.
1914 *---------------------------------------------------------------------------
1916 static inline void block_thread_on_l(struct thread_entry
*thread
,
1919 /* If inlined, unreachable branches will be pruned with no size penalty
1920 because state is passed as a constant parameter. */
1921 const unsigned int core
= IF_COP_CORE(thread
->core
);
1923 /* Remove the thread from the list of running threads. */
1925 remove_from_list_l(&cores
[core
].running
, thread
);
1926 rtr_subtract_entry(core
, thread
->priority
);
1929 /* Add a timeout to the block if not infinite */
1933 case STATE_BLOCKED_W_TMO
:
1934 /* Put the thread into a new list of inactive threads. */
1935 add_to_list_l(thread
->bqp
, thread
);
1937 if (state
== STATE_BLOCKED
)
1941 case STATE_SLEEPING
:
1942 /* If this thread times out sooner than any other thread, update
1943 next_tmo_check to its timeout */
1944 if (TIME_BEFORE(thread
->tmo_tick
, cores
[core
].next_tmo_check
))
1946 cores
[core
].next_tmo_check
= thread
->tmo_tick
;
1949 if (thread
->tmo
.prev
== NULL
)
1951 add_to_list_tmo(thread
);
1953 /* else thread was never removed from list - just keep it there */
1957 /* Remember the the next thread about to block. */
1958 cores
[core
].block_task
= thread
;
1960 /* Report new state. */
1961 thread
->state
= state
;
1964 /*---------------------------------------------------------------------------
1965 * Switch thread in round robin fashion for any given priority. Any thread
1966 * that removed itself from the running list first must specify itself in
1969 * INTERNAL: Intended for use by kernel and not for programs.
1970 *---------------------------------------------------------------------------
1972 void switch_thread(void)
1975 const unsigned int core
= CURRENT_CORE
;
1976 struct thread_entry
*block
= cores
[core
].block_task
;
1977 struct thread_entry
*thread
= cores
[core
].running
;
1979 /* Get context to save - next thread to run is unknown until all wakeups
1983 cores
[core
].block_task
= NULL
;
1986 if (UNLIKELY(thread
== block
))
1988 /* This was the last thread running and another core woke us before
1989 * reaching here. Force next thread selection to give tmo threads or
1990 * other threads woken before this block a first chance. */
1996 /* Blocking task is the old one */
2002 profile_thread_stopped(thread
->id
& THREAD_ID_SLOT_MASK
);
2005 /* Begin task switching by saving our current context so that we can
2006 * restore the state of the current thread later to the point prior
2008 store_context(&thread
->context
);
2010 /* Check if the current thread stack is overflown */
2011 if (UNLIKELY(thread
->stack
[0] != DEADBEEF
))
2012 thread_stkov(thread
);
2015 /* Run any blocking operations requested before switching/sleeping */
2016 run_blocking_ops(core
, thread
);
2019 #ifdef HAVE_PRIORITY_SCHEDULING
2020 IF_NO_SKIP_YIELD( if (thread
->skip_count
!= -1) )
2021 /* Reset the value of thread's skip count */
2022 thread
->skip_count
= 0;
2027 /* If there are threads on a timeout and the earliest wakeup is due,
2028 * check the list and wake any threads that need to start running
2030 if (!TIME_BEFORE(current_tick
, cores
[core
].next_tmo_check
))
2032 check_tmo_threads();
2038 thread
= cores
[core
].running
;
2040 if (UNLIKELY(thread
== NULL
))
2042 /* Enter sleep mode to reduce power usage - woken up on interrupt
2043 * or wakeup request from another core - expected to enable
2046 core_sleep(IF_COP(core
));
2050 #ifdef HAVE_PRIORITY_SCHEDULING
2051 /* Select the new task based on priorities and the last time a
2052 * process got CPU time relative to the highest priority runnable
2054 struct priority_distribution
*pd
= &cores
[core
].rtr
;
2055 int max
= find_first_set_bit(pd
->mask
);
2059 /* Not switching on a block, tentatively select next thread */
2060 thread
= thread
->l
.next
;
2065 int priority
= thread
->priority
;
2068 /* This ridiculously simple method of aging seems to work
2069 * suspiciously well. It does tend to reward CPU hogs (under
2070 * yielding) but that's generally not desirable at all. On the
2071 * plus side, it, relatively to other threads, penalizes excess
2072 * yielding which is good if some high priority thread is
2073 * performing no useful work such as polling for a device to be
2074 * ready. Of course, aging is only employed when higher and lower
2075 * priority threads are runnable. The highest priority runnable
2076 * thread(s) are never skipped. */
2077 if (LIKELY(priority
<= max
) ||
2078 IF_NO_SKIP_YIELD( thread
->skip_count
== -1 || )
2079 (diff
= priority
- max
, ++thread
->skip_count
> diff
*diff
))
2081 cores
[core
].running
= thread
;
2085 thread
= thread
->l
.next
;
2088 /* Without priority use a simple FCFS algorithm */
2091 /* Not switching on a block, select next thread */
2092 thread
= thread
->l
.next
;
2093 cores
[core
].running
= thread
;
2095 #endif /* HAVE_PRIORITY_SCHEDULING */
2103 /* And finally give control to the next thread. */
2104 load_context(&thread
->context
);
2107 profile_thread_started(thread
->id
& THREAD_ID_SLOT_MASK
);
2112 /*---------------------------------------------------------------------------
2113 * Sleeps a thread for at least a specified number of ticks with zero being
2114 * a wait until the next tick.
2116 * INTERNAL: Intended for use by kernel and not for programs.
2117 *---------------------------------------------------------------------------
2119 void sleep_thread(int ticks
)
2121 struct thread_entry
*current
= cores
[CURRENT_CORE
].running
;
2123 LOCK_THREAD(current
);
2125 /* Set our timeout, remove from run list and join timeout list. */
2126 current
->tmo_tick
= current_tick
+ ticks
+ 1;
2127 block_thread_on_l(current
, STATE_SLEEPING
);
2129 UNLOCK_THREAD(current
);
2132 /*---------------------------------------------------------------------------
2133 * Indefinitely block a thread on a blocking queue for explicit wakeup.
2135 * INTERNAL: Intended for use by kernel objects and not for programs.
2136 *---------------------------------------------------------------------------
2138 void block_thread(struct thread_entry
*current
)
2140 /* Set the state to blocked and take us off of the run queue until we
2141 * are explicitly woken */
2142 LOCK_THREAD(current
);
2144 /* Set the list for explicit wakeup */
2145 block_thread_on_l(current
, STATE_BLOCKED
);
2147 #ifdef HAVE_PRIORITY_SCHEDULING
2148 if (current
->blocker
!= NULL
)
2150 /* Object supports PIP */
2151 current
= blocker_inherit_priority(current
);
2155 UNLOCK_THREAD(current
);
2158 /*---------------------------------------------------------------------------
2159 * Block a thread on a blocking queue for a specified time interval or until
2160 * explicitly woken - whichever happens first.
2162 * INTERNAL: Intended for use by kernel objects and not for programs.
2163 *---------------------------------------------------------------------------
2165 void block_thread_w_tmo(struct thread_entry
*current
, int timeout
)
2167 /* Get the entry for the current running thread. */
2168 LOCK_THREAD(current
);
2170 /* Set the state to blocked with the specified timeout */
2171 current
->tmo_tick
= current_tick
+ timeout
;
2173 /* Set the list for explicit wakeup */
2174 block_thread_on_l(current
, STATE_BLOCKED_W_TMO
);
2176 #ifdef HAVE_PRIORITY_SCHEDULING
2177 if (current
->blocker
!= NULL
)
2179 /* Object supports PIP */
2180 current
= blocker_inherit_priority(current
);
2184 UNLOCK_THREAD(current
);
2187 /*---------------------------------------------------------------------------
2188 * Explicitly wakeup a thread on a blocking queue. Only effects threads of
2189 * STATE_BLOCKED and STATE_BLOCKED_W_TMO.
2191 * This code should be considered a critical section by the caller meaning
2192 * that the object's corelock should be held.
2194 * INTERNAL: Intended for use by kernel objects and not for programs.
2195 *---------------------------------------------------------------------------
2197 unsigned int wakeup_thread(struct thread_entry
**list
)
2199 struct thread_entry
*thread
= *list
;
2200 unsigned int result
= THREAD_NONE
;
2202 /* Check if there is a blocked thread at all. */
2206 LOCK_THREAD(thread
);
2208 /* Determine thread's current state. */
2209 switch (thread
->state
)
2212 case STATE_BLOCKED_W_TMO
:
2213 remove_from_list_l(list
, thread
);
2217 #ifdef HAVE_PRIORITY_SCHEDULING
2218 struct thread_entry
*current
;
2219 struct blocker
*bl
= thread
->blocker
;
2223 /* No inheritance - just boost the thread by aging */
2224 IF_NO_SKIP_YIELD( if (thread
->skip_count
!= -1) )
2225 thread
->skip_count
= thread
->priority
;
2226 current
= cores
[CURRENT_CORE
].running
;
2230 /* Call the specified unblocking PIP */
2231 current
= bl
->wakeup_protocol(thread
);
2234 if (current
!= NULL
&& thread
->priority
< current
->priority
2235 IF_COP( && thread
->core
== current
->core
))
2237 /* Woken thread is higher priority and exists on the same CPU core;
2238 * recommend a task switch. Knowing if this is an interrupt call
2239 * would be helpful here. */
2240 result
|= THREAD_SWITCH
;
2242 #endif /* HAVE_PRIORITY_SCHEDULING */
2244 core_schedule_wakeup(thread
);
2247 /* Nothing to do. State is not blocked. */
2248 #if THREAD_EXTRA_CHECKS
2250 THREAD_PANICF("wakeup_thread->block invalid", thread
);
2257 UNLOCK_THREAD(thread
);
2261 /*---------------------------------------------------------------------------
2262 * Wakeup an entire queue of threads - returns bitwise-or of return bitmask
2263 * from each operation or THREAD_NONE of nothing was awakened. Object owning
2264 * the queue must be locked first.
2266 * INTERNAL: Intended for use by kernel objects and not for programs.
2267 *---------------------------------------------------------------------------
2269 unsigned int thread_queue_wake(struct thread_entry
**list
)
2271 unsigned result
= THREAD_NONE
;
2275 unsigned int rc
= wakeup_thread(list
);
2277 if (rc
== THREAD_NONE
)
2278 break; /* No more threads */
2286 /*---------------------------------------------------------------------------
2287 * Assign the thread slot a new ID. Version is 1-255.
2288 *---------------------------------------------------------------------------
2290 static void new_thread_id(unsigned int slot_num
,
2291 struct thread_entry
*thread
)
2293 unsigned int version
=
2294 (thread
->id
+ (1u << THREAD_ID_VERSION_SHIFT
))
2295 & THREAD_ID_VERSION_MASK
;
2297 /* If wrapped to 0, make it 1 */
2299 version
= 1u << THREAD_ID_VERSION_SHIFT
;
2301 thread
->id
= version
| (slot_num
& THREAD_ID_SLOT_MASK
);
2304 /*---------------------------------------------------------------------------
2305 * Find an empty thread slot or MAXTHREADS if none found. The slot returned
2306 * will be locked on multicore.
2307 *---------------------------------------------------------------------------
2309 static struct thread_entry
* find_empty_thread_slot(void)
2311 /* Any slot could be on an interrupt-accessible list */
2312 IF_COP( int oldlevel
= disable_irq_save(); )
2313 struct thread_entry
*thread
= NULL
;
2316 for (n
= 0; n
< MAXTHREADS
; n
++)
2318 /* Obtain current slot state - lock it on multicore */
2319 struct thread_entry
*t
= &threads
[n
];
2322 if (t
->state
== STATE_KILLED
IF_COP( && t
->name
!= THREAD_DESTRUCT
))
2324 /* Slot is empty - leave it locked and caller will unlock */
2329 /* Finished examining slot - no longer busy - unlock on multicore */
2333 IF_COP( restore_irq(oldlevel
); ) /* Reenable interrups - this slot is
2334 not accesible to them yet */
2338 /*---------------------------------------------------------------------------
2339 * Return the thread_entry pointer for a thread_id. Return the current
2340 * thread if the ID is 0 (alias for current).
2341 *---------------------------------------------------------------------------
2343 struct thread_entry
* thread_id_entry(unsigned int thread_id
)
2345 return (thread_id
== THREAD_ID_CURRENT
) ?
2346 cores
[CURRENT_CORE
].running
:
2347 &threads
[thread_id
& THREAD_ID_SLOT_MASK
];
2350 /*---------------------------------------------------------------------------
2351 * Place the current core in idle mode - woken up on interrupt or wake
2352 * request from another core.
2353 *---------------------------------------------------------------------------
2355 void core_idle(void)
2357 IF_COP( const unsigned int core
= CURRENT_CORE
; )
2359 core_sleep(IF_COP(core
));
2362 /*---------------------------------------------------------------------------
2363 * Create a thread. If using a dual core architecture, specify which core to
2364 * start the thread on.
2366 * Return ID if context area could be allocated, else NULL.
2367 *---------------------------------------------------------------------------
2369 unsigned int create_thread(void (*function
)(void),
2370 void* stack
, size_t stack_size
,
2371 unsigned flags
, const char *name
2372 IF_PRIO(, int priority
)
2373 IF_COP(, unsigned int core
))
2376 unsigned int stack_words
;
2377 uintptr_t stackptr
, stackend
;
2378 struct thread_entry
*thread
;
2382 thread
= find_empty_thread_slot();
2388 oldlevel
= disable_irq_save();
2390 /* Munge the stack to make it easy to spot stack overflows */
2391 stackptr
= ALIGN_UP((uintptr_t)stack
, sizeof (uintptr_t));
2392 stackend
= ALIGN_DOWN((uintptr_t)stack
+ stack_size
, sizeof (uintptr_t));
2393 stack_size
= stackend
- stackptr
;
2394 stack_words
= stack_size
/ sizeof (uintptr_t);
2396 for (i
= 0; i
< stack_words
; i
++)
2398 ((uintptr_t *)stackptr
)[i
] = DEADBEEF
;
2401 /* Store interesting information */
2402 thread
->name
= name
;
2403 thread
->stack
= (uintptr_t *)stackptr
;
2404 thread
->stack_size
= stack_size
;
2405 thread
->queue
= NULL
;
2406 #ifdef HAVE_WAKEUP_EXT_CB
2407 thread
->wakeup_ext_cb
= NULL
;
2409 #ifdef HAVE_SCHEDULER_BOOSTCTRL
2410 thread
->cpu_boost
= 0;
2412 #ifdef HAVE_PRIORITY_SCHEDULING
2413 memset(&thread
->pdist
, 0, sizeof(thread
->pdist
));
2414 thread
->blocker
= NULL
;
2415 thread
->base_priority
= priority
;
2416 thread
->priority
= priority
;
2417 thread
->skip_count
= priority
;
2418 prio_add_entry(&thread
->pdist
, priority
);
2422 thread
->core
= core
;
2424 /* Writeback stack munging or anything else before starting */
2425 if (core
!= CURRENT_CORE
)
2431 /* Thread is not on any timeout list but be a bit paranoid */
2432 thread
->tmo
.prev
= NULL
;
2434 state
= (flags
& CREATE_THREAD_FROZEN
) ?
2435 STATE_FROZEN
: STATE_RUNNING
;
2437 thread
->context
.sp
= (typeof (thread
->context
.sp
))stackend
;
2439 /* Load the thread's context structure with needed startup information */
2440 THREAD_STARTUP_INIT(core
, thread
, function
);
2442 thread
->state
= state
;
2443 i
= thread
->id
; /* Snapshot while locked */
2445 if (state
== STATE_RUNNING
)
2446 core_schedule_wakeup(thread
);
2448 UNLOCK_THREAD(thread
);
2449 restore_irq(oldlevel
);
2454 #ifdef HAVE_SCHEDULER_BOOSTCTRL
2455 /*---------------------------------------------------------------------------
2456 * Change the boost state of a thread boosting or unboosting the CPU
2458 *---------------------------------------------------------------------------
2460 static inline void boost_thread(struct thread_entry
*thread
, bool boost
)
2462 if ((thread
->cpu_boost
!= 0) != boost
)
2464 thread
->cpu_boost
= boost
;
2469 void trigger_cpu_boost(void)
2471 struct thread_entry
*current
= cores
[CURRENT_CORE
].running
;
2472 boost_thread(current
, true);
2475 void cancel_cpu_boost(void)
2477 struct thread_entry
*current
= cores
[CURRENT_CORE
].running
;
2478 boost_thread(current
, false);
2480 #endif /* HAVE_SCHEDULER_BOOSTCTRL */
2482 /*---------------------------------------------------------------------------
2483 * Block the current thread until another thread terminates. A thread may
2484 * wait on itself to terminate which prevents it from running again and it
2485 * will need to be killed externally.
2486 * Parameter is the ID as returned from create_thread().
2487 *---------------------------------------------------------------------------
2489 void thread_wait(unsigned int thread_id
)
2491 struct thread_entry
*current
= cores
[CURRENT_CORE
].running
;
2492 struct thread_entry
*thread
= thread_id_entry(thread_id
);
2494 /* Lock thread-as-waitable-object lock */
2495 corelock_lock(&thread
->waiter_cl
);
2497 /* Be sure it hasn't been killed yet */
2498 if (thread_id
== THREAD_ID_CURRENT
||
2499 (thread
->id
== thread_id
&& thread
->state
!= STATE_KILLED
))
2501 IF_COP( current
->obj_cl
= &thread
->waiter_cl
; )
2502 current
->bqp
= &thread
->queue
;
2505 block_thread(current
);
2507 corelock_unlock(&thread
->waiter_cl
);
2513 corelock_unlock(&thread
->waiter_cl
);
2516 /*---------------------------------------------------------------------------
2517 * Exit the current thread. The Right Way to Do Things (TM).
2518 *---------------------------------------------------------------------------
2520 void thread_exit(void)
2522 const unsigned int core
= CURRENT_CORE
;
2523 struct thread_entry
*current
= cores
[core
].running
;
2525 /* Cancel CPU boost if any */
2530 corelock_lock(¤t
->waiter_cl
);
2531 LOCK_THREAD(current
);
2533 #if defined (ALLOW_REMOVE_THREAD) && NUM_CORES > 1
2534 if (current
->name
== THREAD_DESTRUCT
)
2536 /* Thread being killed - become a waiter */
2537 unsigned int id
= current
->id
;
2538 UNLOCK_THREAD(current
);
2539 corelock_unlock(¤t
->waiter_cl
);
2541 THREAD_PANICF("thread_exit->WK:*R", current
);
2545 #ifdef HAVE_PRIORITY_SCHEDULING
2546 check_for_obj_waiters("thread_exit", current
);
2549 if (current
->tmo
.prev
!= NULL
)
2551 /* Cancel pending timeout list removal */
2552 remove_from_list_tmo(current
);
2555 /* Switch tasks and never return */
2556 block_thread_on_l(current
, STATE_KILLED
);
2559 /* Switch to the idle stack if not on the main core (where "main"
2560 * runs) - we can hope gcc doesn't need the old stack beyond this
2564 switch_to_idle_stack(core
);
2569 /* At this point, this thread isn't using resources allocated for
2570 * execution except the slot itself. */
2573 /* Update ID for this slot */
2574 new_thread_id(current
->id
, current
);
2575 current
->name
= NULL
;
2577 /* Signal this thread */
2578 thread_queue_wake(¤t
->queue
);
2579 corelock_unlock(¤t
->waiter_cl
);
2580 /* Slot must be unusable until thread is really gone */
2581 UNLOCK_THREAD_AT_TASK_SWITCH(current
);
2583 /* This should never and must never be reached - if it is, the
2584 * state is corrupted */
2585 THREAD_PANICF("thread_exit->K:*R", current
);
2588 #ifdef ALLOW_REMOVE_THREAD
2589 /*---------------------------------------------------------------------------
2590 * Remove a thread from the scheduler. Not The Right Way to Do Things in
2593 * Parameter is the ID as returned from create_thread().
2595 * Use with care on threads that are not under careful control as this may
2596 * leave various objects in an undefined state.
2597 *---------------------------------------------------------------------------
2599 void remove_thread(unsigned int thread_id
)
2602 /* core is not constant here because of core switching */
2603 unsigned int core
= CURRENT_CORE
;
2604 unsigned int old_core
= NUM_CORES
;
2605 struct corelock
*ocl
= NULL
;
2607 const unsigned int core
= CURRENT_CORE
;
2609 struct thread_entry
*current
= cores
[core
].running
;
2610 struct thread_entry
*thread
= thread_id_entry(thread_id
);
2615 if (thread
== current
)
2616 thread_exit(); /* Current thread - do normal exit */
2618 oldlevel
= disable_irq_save();
2620 corelock_lock(&thread
->waiter_cl
);
2621 LOCK_THREAD(thread
);
2623 state
= thread
->state
;
2625 if (thread
->id
!= thread_id
|| state
== STATE_KILLED
)
2629 if (thread
->name
== THREAD_DESTRUCT
)
2631 /* Thread being killed - become a waiter */
2632 UNLOCK_THREAD(thread
);
2633 corelock_unlock(&thread
->waiter_cl
);
2634 restore_irq(oldlevel
);
2635 thread_wait(thread_id
);
2639 thread
->name
= THREAD_DESTRUCT
; /* Slot can't be used for now */
2641 #ifdef HAVE_PRIORITY_SCHEDULING
2642 check_for_obj_waiters("remove_thread", thread
);
2645 if (thread
->core
!= core
)
2647 /* Switch cores and safely extract the thread there */
2648 /* Slot HAS to be unlocked or a deadlock could occur which means other
2649 * threads have to be guided into becoming thread waiters if they
2650 * attempt to remove it. */
2651 unsigned int new_core
= thread
->core
;
2653 corelock_unlock(&thread
->waiter_cl
);
2655 UNLOCK_THREAD(thread
);
2656 restore_irq(oldlevel
);
2658 old_core
= switch_core(new_core
);
2660 oldlevel
= disable_irq_save();
2662 corelock_lock(&thread
->waiter_cl
);
2663 LOCK_THREAD(thread
);
2665 state
= thread
->state
;
2667 /* Perform the extraction and switch ourselves back to the original
2670 #endif /* NUM_CORES > 1 */
2672 if (thread
->tmo
.prev
!= NULL
)
2674 /* Clean thread off the timeout list if a timeout check hasn't
2676 remove_from_list_tmo(thread
);
2679 #ifdef HAVE_SCHEDULER_BOOSTCTRL
2680 /* Cancel CPU boost if any */
2681 boost_thread(thread
, false);
2684 IF_COP( retry_state
: )
2690 /* Remove thread from ready to run tasks */
2691 remove_from_list_l(&cores
[core
].running
, thread
);
2692 rtr_subtract_entry(core
, thread
->priority
);
2696 case STATE_BLOCKED_W_TMO
:
2697 /* Remove thread from the queue it's blocked on - including its
2698 * own if waiting there */
2700 if (&thread
->waiter_cl
!= thread
->obj_cl
)
2702 ocl
= thread
->obj_cl
;
2704 if (UNLIKELY(corelock_try_lock(ocl
) == 0))
2706 UNLOCK_THREAD(thread
);
2708 LOCK_THREAD(thread
);
2710 if (UNLIKELY(thread
->state
!= state
))
2712 /* Something woke the thread */
2713 state
= thread
->state
;
2714 corelock_unlock(ocl
);
2720 remove_from_list_l(thread
->bqp
, thread
);
2722 #ifdef HAVE_WAKEUP_EXT_CB
2723 if (thread
->wakeup_ext_cb
!= NULL
)
2724 thread
->wakeup_ext_cb(thread
);
2727 #ifdef HAVE_PRIORITY_SCHEDULING
2728 if (thread
->blocker
!= NULL
)
2730 /* Remove thread's priority influence from its chain */
2731 wakeup_priority_protocol_release(thread
);
2737 corelock_unlock(ocl
);
2740 /* Otherwise thread is frozen and hasn't run yet */
2743 new_thread_id(thread_id
, thread
);
2744 thread
->state
= STATE_KILLED
;
2746 /* If thread was waiting on itself, it will have been removed above.
2747 * The wrong order would result in waking the thread first and deadlocking
2748 * since the slot is already locked. */
2749 thread_queue_wake(&thread
->queue
);
2751 thread
->name
= NULL
;
2753 thread_killed
: /* Thread was already killed */
2754 /* Removal complete - safe to unlock and reenable interrupts */
2755 corelock_unlock(&thread
->waiter_cl
);
2756 UNLOCK_THREAD(thread
);
2757 restore_irq(oldlevel
);
2760 if (old_core
< NUM_CORES
)
2762 /* Did a removal on another processor's thread - switch back to
2764 switch_core(old_core
);
2768 #endif /* ALLOW_REMOVE_THREAD */
2770 #ifdef HAVE_PRIORITY_SCHEDULING
2771 /*---------------------------------------------------------------------------
2772 * Sets the thread's relative base priority for the core it runs on. Any
2773 * needed inheritance changes also may happen.
2774 *---------------------------------------------------------------------------
2776 int thread_set_priority(unsigned int thread_id
, int priority
)
2778 int old_base_priority
= -1;
2779 struct thread_entry
*thread
= thread_id_entry(thread_id
);
2781 /* A little safety measure */
2782 if (priority
< HIGHEST_PRIORITY
|| priority
> LOWEST_PRIORITY
)
2785 /* Thread could be on any list and therefore on an interrupt accessible
2786 one - disable interrupts */
2787 int oldlevel
= disable_irq_save();
2789 LOCK_THREAD(thread
);
2791 /* Make sure it's not killed */
2792 if (thread_id
== THREAD_ID_CURRENT
||
2793 (thread
->id
== thread_id
&& thread
->state
!= STATE_KILLED
))
2795 int old_priority
= thread
->priority
;
2797 old_base_priority
= thread
->base_priority
;
2798 thread
->base_priority
= priority
;
2800 prio_move_entry(&thread
->pdist
, old_base_priority
, priority
);
2801 priority
= find_first_set_bit(thread
->pdist
.mask
);
2803 if (old_priority
== priority
)
2805 /* No priority change - do nothing */
2807 else if (thread
->state
== STATE_RUNNING
)
2809 /* This thread is running - change location on the run
2810 * queue. No transitive inheritance needed. */
2811 set_running_thread_priority(thread
, priority
);
2815 thread
->priority
= priority
;
2817 if (thread
->blocker
!= NULL
)
2819 /* Bubble new priority down the chain */
2820 struct blocker
*bl
= thread
->blocker
; /* Blocker struct */
2821 struct thread_entry
*bl_t
= bl
->thread
; /* Blocking thread */
2822 struct thread_entry
* const tstart
= thread
; /* Initial thread */
2823 const int highest
= MIN(priority
, old_priority
); /* Higher of new or old */
2827 struct thread_entry
*next
; /* Next thread to check */
2828 int bl_pr
; /* Highest blocked thread */
2829 int queue_pr
; /* New highest blocked thread */
2831 /* Owner can change but thread cannot be dislodged - thread
2832 * may not be the first in the queue which allows other
2833 * threads ahead in the list to be given ownership during the
2834 * operation. If thread is next then the waker will have to
2835 * wait for us and the owner of the object will remain fixed.
2836 * If we successfully grab the owner -- which at some point
2837 * is guaranteed -- then the queue remains fixed until we
2843 /* Double-check the owner - retry if it changed */
2844 if (LIKELY(bl
->thread
== bl_t
))
2847 UNLOCK_THREAD(bl_t
);
2851 bl_pr
= bl
->priority
;
2853 if (highest
> bl_pr
)
2854 break; /* Object priority won't change */
2856 /* This will include the thread being set */
2857 queue_pr
= find_highest_priority_in_list_l(*thread
->bqp
);
2859 if (queue_pr
== bl_pr
)
2860 break; /* Object priority not changing */
2862 /* Update thread boost for this object */
2863 bl
->priority
= queue_pr
;
2864 prio_move_entry(&bl_t
->pdist
, bl_pr
, queue_pr
);
2865 bl_pr
= find_first_set_bit(bl_t
->pdist
.mask
);
2867 if (bl_t
->priority
== bl_pr
)
2868 break; /* Blocking thread priority not changing */
2870 if (bl_t
->state
== STATE_RUNNING
)
2872 /* Thread not blocked - we're done */
2873 set_running_thread_priority(bl_t
, bl_pr
);
2877 bl_t
->priority
= bl_pr
;
2878 bl
= bl_t
->blocker
; /* Blocking thread has a blocker? */
2881 break; /* End of chain */
2885 if (UNLIKELY(next
== tstart
))
2886 break; /* Full-circle */
2888 UNLOCK_THREAD(thread
);
2894 UNLOCK_THREAD(bl_t
);
2899 UNLOCK_THREAD(thread
);
2901 restore_irq(oldlevel
);
2903 return old_base_priority
;
2906 /*---------------------------------------------------------------------------
2907 * Returns the current base priority for a thread.
2908 *---------------------------------------------------------------------------
2910 int thread_get_priority(unsigned int thread_id
)
2912 struct thread_entry
*thread
= thread_id_entry(thread_id
);
2913 int base_priority
= thread
->base_priority
;
2915 /* Simply check without locking slot. It may or may not be valid by the
2916 * time the function returns anyway. If all tests pass, it is the
2917 * correct value for when it was valid. */
2918 if (thread_id
!= THREAD_ID_CURRENT
&&
2919 (thread
->id
!= thread_id
|| thread
->state
== STATE_KILLED
))
2922 return base_priority
;
2924 #endif /* HAVE_PRIORITY_SCHEDULING */
2926 /*---------------------------------------------------------------------------
2927 * Starts a frozen thread - similar semantics to wakeup_thread except that
2928 * the thread is on no scheduler or wakeup queue at all. It exists simply by
2929 * virtue of the slot having a state of STATE_FROZEN.
2930 *---------------------------------------------------------------------------
2932 void thread_thaw(unsigned int thread_id
)
2934 struct thread_entry
*thread
= thread_id_entry(thread_id
);
2935 int oldlevel
= disable_irq_save();
2937 LOCK_THREAD(thread
);
2939 /* If thread is the current one, it cannot be frozen, therefore
2940 * there is no need to check that. */
2941 if (thread
->id
== thread_id
&& thread
->state
== STATE_FROZEN
)
2942 core_schedule_wakeup(thread
);
2944 UNLOCK_THREAD(thread
);
2945 restore_irq(oldlevel
);
2948 /*---------------------------------------------------------------------------
2949 * Return the ID of the currently executing thread.
2950 *---------------------------------------------------------------------------
2952 unsigned int thread_get_current(void)
2954 return cores
[CURRENT_CORE
].running
->id
;
2958 /*---------------------------------------------------------------------------
2959 * Switch the processor that the currently executing thread runs on.
2960 *---------------------------------------------------------------------------
2962 unsigned int switch_core(unsigned int new_core
)
2964 const unsigned int core
= CURRENT_CORE
;
2965 struct thread_entry
*current
= cores
[core
].running
;
2967 if (core
== new_core
)
2969 /* No change - just return same core */
2973 int oldlevel
= disable_irq_save();
2974 LOCK_THREAD(current
);
2976 if (current
->name
== THREAD_DESTRUCT
)
2978 /* Thread being killed - deactivate and let process complete */
2979 unsigned int id
= current
->id
;
2980 UNLOCK_THREAD(current
);
2981 restore_irq(oldlevel
);
2983 /* Should never be reached */
2984 THREAD_PANICF("switch_core->D:*R", current
);
2987 /* Get us off the running list for the current core */
2989 remove_from_list_l(&cores
[core
].running
, current
);
2990 rtr_subtract_entry(core
, current
->priority
);
2993 /* Stash return value (old core) in a safe place */
2994 current
->retval
= core
;
2996 /* If a timeout hadn't yet been cleaned-up it must be removed now or
2997 * the other core will likely attempt a removal from the wrong list! */
2998 if (current
->tmo
.prev
!= NULL
)
3000 remove_from_list_tmo(current
);
3003 /* Change the core number for this thread slot */
3004 current
->core
= new_core
;
3006 /* Do not use core_schedule_wakeup here since this will result in
3007 * the thread starting to run on the other core before being finished on
3008 * this one. Delay the list unlock to keep the other core stuck
3009 * until this thread is ready. */
3012 rtr_add_entry(new_core
, current
->priority
);
3013 add_to_list_l(&cores
[new_core
].running
, current
);
3015 /* Make a callback into device-specific code, unlock the wakeup list so
3016 * that execution may resume on the new core, unlock our slot and finally
3017 * restore the interrupt level */
3018 cores
[core
].blk_ops
.flags
= TBOP_SWITCH_CORE
;
3019 cores
[core
].blk_ops
.cl_p
= &cores
[new_core
].rtr_cl
;
3020 cores
[core
].block_task
= current
;
3022 UNLOCK_THREAD(current
);
3024 /* Alert other core to activity */
3025 core_wake(new_core
);
3027 /* Do the stack switching, cache_maintenence and switch_thread call -
3028 requires native code */
3029 switch_thread_core(core
, current
);
3031 /* Finally return the old core to caller */
3032 return current
->retval
;
3034 #endif /* NUM_CORES > 1 */
3036 /*---------------------------------------------------------------------------
3037 * Initialize threading API. This assumes interrupts are not yet enabled. On
3038 * multicore setups, no core is allowed to proceed until create_thread calls
3039 * are safe to perform.
3040 *---------------------------------------------------------------------------
3042 void init_threads(void)
3044 const unsigned int core
= CURRENT_CORE
;
3045 struct thread_entry
*thread
;
3049 /* Initialize core locks and IDs in all slots */
3051 for (n
= 0; n
< MAXTHREADS
; n
++)
3053 thread
= &threads
[n
];
3054 corelock_init(&thread
->waiter_cl
);
3055 corelock_init(&thread
->slot_cl
);
3056 thread
->id
= THREAD_ID_INIT(n
);
3060 /* CPU will initialize first and then sleep */
3061 thread
= find_empty_thread_slot();
3065 /* WTF? There really must be a slot available at this stage.
3066 * This can fail if, for example, .bss isn't zero'ed out by the loader
3067 * or threads is in the wrong section. */
3068 THREAD_PANICF("init_threads->no slot", NULL
);
3071 /* Initialize initially non-zero members of core */
3072 cores
[core
].next_tmo_check
= current_tick
; /* Something not in the past */
3074 /* Initialize initially non-zero members of slot */
3075 UNLOCK_THREAD(thread
); /* No sync worries yet */
3076 thread
->name
= main_thread_name
;
3077 thread
->state
= STATE_RUNNING
;
3078 IF_COP( thread
->core
= core
; )
3079 #ifdef HAVE_PRIORITY_SCHEDULING
3080 corelock_init(&cores
[core
].rtr_cl
);
3081 thread
->base_priority
= PRIORITY_USER_INTERFACE
;
3082 prio_add_entry(&thread
->pdist
, PRIORITY_USER_INTERFACE
);
3083 thread
->priority
= PRIORITY_USER_INTERFACE
;
3084 rtr_add_entry(core
, PRIORITY_USER_INTERFACE
);
3087 add_to_list_l(&cores
[core
].running
, thread
);
3091 thread
->stack
= stackbegin
;
3092 thread
->stack_size
= (uintptr_t)stackend
- (uintptr_t)stackbegin
;
3093 #if NUM_CORES > 1 /* This code path will not be run on single core targets */
3094 /* Wait for other processors to finish their inits since create_thread
3095 * isn't safe to call until the kernel inits are done. The first
3096 * threads created in the system must of course be created by CPU.
3097 * Another possible approach is to initialize all cores and slots
3098 * for each core by CPU, let the remainder proceed in parallel and
3099 * signal CPU when all are finished. */
3100 core_thread_init(CPU
);
3104 /* Initial stack is the idle stack */
3105 thread
->stack
= idle_stacks
[core
];
3106 thread
->stack_size
= IDLE_STACK_SIZE
;
3107 /* After last processor completes, it should signal all others to
3108 * proceed or may signal the next and call thread_exit(). The last one
3109 * to finish will signal CPU. */
3110 core_thread_init(core
);
3111 /* Other cores do not have a main thread - go idle inside switch_thread
3112 * until a thread can run on the core. */
3114 #endif /* NUM_CORES */
3118 /* Shared stack scan helper for thread_stack_usage and idle_stack_usage */
3120 static inline int stack_usage(uintptr_t *stackptr
, size_t stack_size
)
3122 static int stack_usage(uintptr_t *stackptr
, size_t stack_size
)
3125 unsigned int stack_words
= stack_size
/ sizeof (uintptr_t);
3129 for (i
= 0; i
< stack_words
; i
++)
3131 if (stackptr
[i
] != DEADBEEF
)
3133 usage
= ((stack_words
- i
) * 100) / stack_words
;
3141 /*---------------------------------------------------------------------------
3142 * Returns the maximum percentage of stack a thread ever used while running.
3143 * NOTE: Some large buffer allocations that don't use enough the buffer to
3144 * overwrite stackptr[0] will not be seen.
3145 *---------------------------------------------------------------------------
3147 int thread_stack_usage(const struct thread_entry
*thread
)
3149 return stack_usage(thread
->stack
, thread
->stack_size
);
3153 /*---------------------------------------------------------------------------
3154 * Returns the maximum percentage of the core's idle stack ever used during
3156 *---------------------------------------------------------------------------
3158 int idle_stack_usage(unsigned int core
)
3160 return stack_usage(idle_stacks
[core
], IDLE_STACK_SIZE
);
3164 /*---------------------------------------------------------------------------
3165 * Fills in the buffer with the specified thread's name. If the name is NULL,
3166 * empty, or the thread is in destruct state a formatted ID is written
3168 *---------------------------------------------------------------------------
3170 void thread_get_name(char *buffer
, int size
,
3171 struct thread_entry
*thread
)
3180 /* Display thread name if one or ID if none */
3181 const char *name
= thread
->name
;
3182 const char *fmt
= "%s";
3183 if (name
== NULL
IF_COP(|| name
== THREAD_DESTRUCT
) || *name
== '\0')
3185 name
= (const char *)thread
;
3188 snprintf(buffer
, size
, fmt
, name
);