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 "jalr $8 \n" /* Start the thread */
948 "sw $0, 48($9) \n" /* Clear start address */
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
)
972 "sw $16, 0(%0) \n" /* s0 */
973 "sw $17, 4(%0) \n" /* s1 */
974 "sw $18, 8(%0) \n" /* s2 */
975 "sw $19, 12(%0) \n" /* s3 */
976 "sw $20, 16(%0) \n" /* s4 */
977 "sw $21, 20(%0) \n" /* s5 */
978 "sw $22, 24(%0) \n" /* s6 */
979 "sw $23, 28(%0) \n" /* s7 */
980 "sw $28, 32(%0) \n" /* gp */
981 "sw $30, 36(%0) \n" /* fp */
982 "sw $29, 40(%0) \n" /* sp */
983 "sw $31, 44(%0) \n" /* ra */
990 /*---------------------------------------------------------------------------
991 * Load non-volatile context.
992 *---------------------------------------------------------------------------
994 static inline void load_context(const void* addr
)
999 "lw $8, 48(%0) \n" /* Get start address ($8 = t0) */
1000 "beqz $8, running \n" /* NULL -> already running */
1003 "move $9, %0 \n" /* t1 = context */
1005 "lw $16, 0(%0) \n" /* s0 */
1006 "lw $17, 4(%0) \n" /* s1 */
1007 "lw $18, 8(%0) \n" /* s2 */
1008 "lw $19, 12(%0) \n" /* s3 */
1009 "lw $20, 16(%0) \n" /* s4 */
1010 "lw $21, 20(%0) \n" /* s5 */
1011 "lw $22, 24(%0) \n" /* s6 */
1012 "lw $23, 28(%0) \n" /* s7 */
1013 "lw $28, 32(%0) \n" /* gp */
1014 "lw $30, 36(%0) \n" /* fp */
1015 "lw $29, 40(%0) \n" /* sp */
1016 "lw $31, 44(%0) \n" /* ra */
1019 : : "r" (addr
) : "t0", "t1"
1023 /*---------------------------------------------------------------------------
1024 * Put core in a power-saving state.
1025 *---------------------------------------------------------------------------
1027 static inline void core_sleep(void)
1029 #if CONFIG_CPU == JZ4732
1032 asm volatile(".set mips32r2 \n"
1033 "mfc0 $8, $12 \n" /* mfc t0, $12 */
1034 "move $9, $8 \n" /* move t1, t0 */
1035 "la $10, 0x8000000 \n" /* la t2, 0x8000000 */
1036 "or $8, $8, $10 \n" /* Enable reduced power mode */
1041 ::: "t0", "t1", "t2"
1047 #endif /* CONFIG_CPU == */
1050 * End Processor-specific section
1051 ***************************************************************************/
1053 #if THREAD_EXTRA_CHECKS
1054 static void thread_panicf(const char *msg
, struct thread_entry
*thread
)
1056 IF_COP( const unsigned int core
= thread
->core
; )
1057 static char name
[32];
1058 thread_get_name(name
, 32, thread
);
1059 panicf ("%s %s" IF_COP(" (%d)"), msg
, name
IF_COP(, core
));
1061 static void thread_stkov(struct thread_entry
*thread
)
1063 thread_panicf("Stkov", thread
);
1065 #define THREAD_PANICF(msg, thread) \
1066 thread_panicf(msg, thread)
1067 #define THREAD_ASSERT(exp, msg, thread) \
1068 ({ if (!({ exp; })) thread_panicf((msg), (thread)); })
1070 static void thread_stkov(struct thread_entry
*thread
)
1072 IF_COP( const unsigned int core
= thread
->core
; )
1073 static char name
[32];
1074 thread_get_name(name
, 32, thread
);
1075 panicf("Stkov %s" IF_COP(" (%d)"), name
IF_COP(, core
));
1077 #define THREAD_PANICF(msg, thread)
1078 #define THREAD_ASSERT(exp, msg, thread)
1079 #endif /* THREAD_EXTRA_CHECKS */
1081 /* Thread locking */
1083 #define LOCK_THREAD(thread) \
1084 ({ corelock_lock(&(thread)->slot_cl); })
1085 #define TRY_LOCK_THREAD(thread) \
1086 ({ corelock_try_lock(&thread->slot_cl); })
1087 #define UNLOCK_THREAD(thread) \
1088 ({ corelock_unlock(&(thread)->slot_cl); })
1089 #define UNLOCK_THREAD_AT_TASK_SWITCH(thread) \
1090 ({ unsigned int _core = (thread)->core; \
1091 cores[_core].blk_ops.flags |= TBOP_UNLOCK_CORELOCK; \
1092 cores[_core].blk_ops.cl_p = &(thread)->slot_cl; })
1094 #define LOCK_THREAD(thread) \
1096 #define TRY_LOCK_THREAD(thread) \
1098 #define UNLOCK_THREAD(thread) \
1100 #define UNLOCK_THREAD_AT_TASK_SWITCH(thread) \
1105 #define RTR_LOCK(core) \
1106 ({ corelock_lock(&cores[core].rtr_cl); })
1107 #define RTR_UNLOCK(core) \
1108 ({ corelock_unlock(&cores[core].rtr_cl); })
1110 #ifdef HAVE_PRIORITY_SCHEDULING
1111 #define rtr_add_entry(core, priority) \
1112 prio_add_entry(&cores[core].rtr, (priority))
1114 #define rtr_subtract_entry(core, priority) \
1115 prio_subtract_entry(&cores[core].rtr, (priority))
1117 #define rtr_move_entry(core, from, to) \
1118 prio_move_entry(&cores[core].rtr, (from), (to))
1120 #define rtr_add_entry(core, priority)
1121 #define rtr_add_entry_inl(core, priority)
1122 #define rtr_subtract_entry(core, priority)
1123 #define rtr_subtract_entry_inl(core, priotity)
1124 #define rtr_move_entry(core, from, to)
1125 #define rtr_move_entry_inl(core, from, to)
1128 /*---------------------------------------------------------------------------
1129 * Thread list structure - circular:
1130 * +------------------------------+
1132 * +--+---+<-+---+<-+---+<-+---+<-+
1133 * Head->| T | | T | | T | | T |
1134 * +->+---+->+---+->+---+->+---+--+
1136 * +------------------------------+
1137 *---------------------------------------------------------------------------
1140 /*---------------------------------------------------------------------------
1141 * Adds a thread to a list of threads using "insert last". Uses the "l"
1143 *---------------------------------------------------------------------------
1145 static void add_to_list_l(struct thread_entry
**list
,
1146 struct thread_entry
*thread
)
1148 struct thread_entry
*l
= *list
;
1152 /* Insert into unoccupied list */
1153 thread
->l
.prev
= thread
;
1154 thread
->l
.next
= thread
;
1160 thread
->l
.prev
= l
->l
.prev
;
1162 l
->l
.prev
->l
.next
= thread
;
1166 /*---------------------------------------------------------------------------
1167 * Removes a thread from a list of threads. Uses the "l" links.
1168 *---------------------------------------------------------------------------
1170 static void remove_from_list_l(struct thread_entry
**list
,
1171 struct thread_entry
*thread
)
1173 struct thread_entry
*prev
, *next
;
1175 next
= thread
->l
.next
;
1184 if (thread
== *list
)
1186 /* List becomes next item */
1190 prev
= thread
->l
.prev
;
1192 /* Fix links to jump over the removed entry. */
1193 next
->l
.prev
= prev
;
1194 prev
->l
.next
= next
;
1197 /*---------------------------------------------------------------------------
1198 * Timeout list structure - circular reverse (to make "remove item" O(1)),
1199 * NULL-terminated forward (to ease the far more common forward traversal):
1200 * +------------------------------+
1202 * +--+---+<-+---+<-+---+<-+---+<-+
1203 * Head->| T | | T | | T | | T |
1204 * +---+->+---+->+---+->+---+-X
1205 *---------------------------------------------------------------------------
1208 /*---------------------------------------------------------------------------
1209 * Add a thread from the core's timout list by linking the pointers in its
1211 *---------------------------------------------------------------------------
1213 static void add_to_list_tmo(struct thread_entry
*thread
)
1215 struct thread_entry
*tmo
= cores
[IF_COP_CORE(thread
->core
)].timeout
;
1216 THREAD_ASSERT(thread
->tmo
.prev
== NULL
,
1217 "add_to_list_tmo->already listed", thread
);
1219 thread
->tmo
.next
= NULL
;
1223 /* Insert into unoccupied list */
1224 thread
->tmo
.prev
= thread
;
1225 cores
[IF_COP_CORE(thread
->core
)].timeout
= thread
;
1230 thread
->tmo
.prev
= tmo
->tmo
.prev
;
1231 tmo
->tmo
.prev
->tmo
.next
= thread
;
1232 tmo
->tmo
.prev
= thread
;
1235 /*---------------------------------------------------------------------------
1236 * Remove a thread from the core's timout list by unlinking the pointers in
1237 * its tmo structure. Sets thread->tmo.prev to NULL to indicate the timeout
1239 *---------------------------------------------------------------------------
1241 static void remove_from_list_tmo(struct thread_entry
*thread
)
1243 struct thread_entry
**list
= &cores
[IF_COP_CORE(thread
->core
)].timeout
;
1244 struct thread_entry
*prev
= thread
->tmo
.prev
;
1245 struct thread_entry
*next
= thread
->tmo
.next
;
1247 THREAD_ASSERT(prev
!= NULL
, "remove_from_list_tmo->not listed", thread
);
1250 next
->tmo
.prev
= prev
;
1252 if (thread
== *list
)
1254 /* List becomes next item and empty if next == NULL */
1256 /* Mark as unlisted */
1257 thread
->tmo
.prev
= NULL
;
1262 (*list
)->tmo
.prev
= prev
;
1263 prev
->tmo
.next
= next
;
1264 /* Mark as unlisted */
1265 thread
->tmo
.prev
= NULL
;
1270 #ifdef HAVE_PRIORITY_SCHEDULING
1271 /*---------------------------------------------------------------------------
1272 * Priority distribution structure (one category for each possible priority):
1274 * +----+----+----+ ... +-----+
1275 * hist: | F0 | F1 | F2 | | F31 |
1276 * +----+----+----+ ... +-----+
1277 * mask: | b0 | b1 | b2 | | b31 |
1278 * +----+----+----+ ... +-----+
1280 * F = count of threads at priority category n (frequency)
1281 * b = bitmask of non-zero priority categories (occupancy)
1283 * / if H[n] != 0 : 1
1287 *---------------------------------------------------------------------------
1288 * Basic priority inheritance priotocol (PIP):
1290 * Mn = mutex n, Tn = thread n
1292 * A lower priority thread inherits the priority of the highest priority
1293 * thread blocked waiting for it to complete an action (such as release a
1294 * mutex or respond to a message via queue_send):
1298 * T1 owns M1, T2 is waiting for M1 to realease M1. If T2 has a higher
1299 * priority than T1 then T1 inherits the priority of T2.
1305 * Situation is like 1) but T2 and T3 are both queued waiting for M1 and so
1306 * T1 inherits the higher of T2 and T3.
1308 * 3) T3->M2->T2->M1->T1
1310 * T1 owns M1, T2 owns M2. If T3 has a higher priority than both T1 and T2,
1311 * then T1 inherits the priority of T3 through T2.
1313 * Blocking chains can grow arbitrarily complex (though it's best that they
1314 * not form at all very often :) and build-up from these units.
1315 *---------------------------------------------------------------------------
1318 /*---------------------------------------------------------------------------
1319 * Increment frequency at category "priority"
1320 *---------------------------------------------------------------------------
1322 static inline unsigned int prio_add_entry(
1323 struct priority_distribution
*pd
, int priority
)
1326 /* Enough size/instruction count difference for ARM makes it worth it to
1327 * use different code (192 bytes for ARM). Only thing better is ASM. */
1329 count
= pd
->hist
[priority
];
1331 pd
->mask
|= 1 << priority
;
1332 pd
->hist
[priority
] = count
;
1333 #else /* This one's better for Coldfire */
1334 if ((count
= ++pd
->hist
[priority
]) == 1)
1335 pd
->mask
|= 1 << priority
;
1341 /*---------------------------------------------------------------------------
1342 * Decrement frequency at category "priority"
1343 *---------------------------------------------------------------------------
1345 static inline unsigned int prio_subtract_entry(
1346 struct priority_distribution
*pd
, int priority
)
1351 count
= pd
->hist
[priority
];
1353 pd
->mask
&= ~(1 << priority
);
1354 pd
->hist
[priority
] = count
;
1356 if ((count
= --pd
->hist
[priority
]) == 0)
1357 pd
->mask
&= ~(1 << priority
);
1363 /*---------------------------------------------------------------------------
1364 * Remove from one category and add to another
1365 *---------------------------------------------------------------------------
1367 static inline void prio_move_entry(
1368 struct priority_distribution
*pd
, int from
, int to
)
1370 uint32_t mask
= pd
->mask
;
1375 count
= pd
->hist
[from
];
1377 mask
&= ~(1 << from
);
1378 pd
->hist
[from
] = count
;
1380 count
= pd
->hist
[to
];
1383 pd
->hist
[to
] = count
;
1385 if (--pd
->hist
[from
] == 0)
1386 mask
&= ~(1 << from
);
1388 if (++pd
->hist
[to
] == 1)
1395 /*---------------------------------------------------------------------------
1396 * Change the priority and rtr entry for a running thread
1397 *---------------------------------------------------------------------------
1399 static inline void set_running_thread_priority(
1400 struct thread_entry
*thread
, int priority
)
1402 const unsigned int core
= IF_COP_CORE(thread
->core
);
1404 rtr_move_entry(core
, thread
->priority
, priority
);
1405 thread
->priority
= priority
;
1409 /*---------------------------------------------------------------------------
1410 * Finds the highest priority thread in a list of threads. If the list is
1411 * empty, the PRIORITY_IDLE is returned.
1413 * It is possible to use the struct priority_distribution within an object
1414 * instead of scanning the remaining threads in the list but as a compromise,
1415 * the resulting per-object memory overhead is saved at a slight speed
1416 * penalty under high contention.
1417 *---------------------------------------------------------------------------
1419 static int find_highest_priority_in_list_l(
1420 struct thread_entry
* const thread
)
1422 if (LIKELY(thread
!= NULL
))
1424 /* Go though list until the ending up at the initial thread */
1425 int highest_priority
= thread
->priority
;
1426 struct thread_entry
*curr
= thread
;
1430 int priority
= curr
->priority
;
1432 if (priority
< highest_priority
)
1433 highest_priority
= priority
;
1435 curr
= curr
->l
.next
;
1437 while (curr
!= thread
);
1439 return highest_priority
;
1442 return PRIORITY_IDLE
;
1445 /*---------------------------------------------------------------------------
1446 * Register priority with blocking system and bubble it down the chain if
1447 * any until we reach the end or something is already equal or higher.
1449 * NOTE: A simultaneous circular wait could spin deadlock on multiprocessor
1450 * targets but that same action also guarantees a circular block anyway and
1451 * those are prevented, right? :-)
1452 *---------------------------------------------------------------------------
1454 static struct thread_entry
*
1455 blocker_inherit_priority(struct thread_entry
*current
)
1457 const int priority
= current
->priority
;
1458 struct blocker
*bl
= current
->blocker
;
1459 struct thread_entry
* const tstart
= current
;
1460 struct thread_entry
*bl_t
= bl
->thread
;
1462 /* Blocker cannot change since the object protection is held */
1467 struct thread_entry
*next
;
1468 int bl_pr
= bl
->priority
;
1470 if (priority
>= bl_pr
)
1471 break; /* Object priority already high enough */
1473 bl
->priority
= priority
;
1476 prio_add_entry(&bl_t
->pdist
, priority
);
1478 if (bl_pr
< PRIORITY_IDLE
)
1480 /* Not first waiter - subtract old one */
1481 prio_subtract_entry(&bl_t
->pdist
, bl_pr
);
1484 if (priority
>= bl_t
->priority
)
1485 break; /* Thread priority high enough */
1487 if (bl_t
->state
== STATE_RUNNING
)
1489 /* Blocking thread is a running thread therefore there are no
1490 * further blockers. Change the "run queue" on which it
1492 set_running_thread_priority(bl_t
, priority
);
1496 bl_t
->priority
= priority
;
1498 /* If blocking thread has a blocker, apply transitive inheritance */
1502 break; /* End of chain or object doesn't support inheritance */
1506 if (UNLIKELY(next
== tstart
))
1507 break; /* Full-circle - deadlock! */
1509 UNLOCK_THREAD(current
);
1516 /* Blocker could change - retest condition */
1517 if (LIKELY(bl
->thread
== next
))
1520 UNLOCK_THREAD(next
);
1528 UNLOCK_THREAD(bl_t
);
1533 /*---------------------------------------------------------------------------
1534 * Readjust priorities when waking a thread blocked waiting for another
1535 * in essence "releasing" the thread's effect on the object owner. Can be
1536 * performed from any context.
1537 *---------------------------------------------------------------------------
1539 struct thread_entry
*
1540 wakeup_priority_protocol_release(struct thread_entry
*thread
)
1542 const int priority
= thread
->priority
;
1543 struct blocker
*bl
= thread
->blocker
;
1544 struct thread_entry
* const tstart
= thread
;
1545 struct thread_entry
*bl_t
= bl
->thread
;
1547 /* Blocker cannot change since object will be locked */
1550 thread
->blocker
= NULL
; /* Thread not blocked */
1554 struct thread_entry
*next
;
1555 int bl_pr
= bl
->priority
;
1557 if (priority
> bl_pr
)
1558 break; /* Object priority higher */
1560 next
= *thread
->bqp
;
1564 /* No more threads in queue */
1565 prio_subtract_entry(&bl_t
->pdist
, bl_pr
);
1566 bl
->priority
= PRIORITY_IDLE
;
1570 /* Check list for highest remaining priority */
1571 int queue_pr
= find_highest_priority_in_list_l(next
);
1573 if (queue_pr
== bl_pr
)
1574 break; /* Object priority not changing */
1576 /* Change queue priority */
1577 prio_move_entry(&bl_t
->pdist
, bl_pr
, queue_pr
);
1578 bl
->priority
= queue_pr
;
1581 if (bl_pr
> bl_t
->priority
)
1582 break; /* thread priority is higher */
1584 bl_pr
= find_first_set_bit(bl_t
->pdist
.mask
);
1586 if (bl_pr
== bl_t
->priority
)
1587 break; /* Thread priority not changing */
1589 if (bl_t
->state
== STATE_RUNNING
)
1591 /* No further blockers */
1592 set_running_thread_priority(bl_t
, bl_pr
);
1596 bl_t
->priority
= bl_pr
;
1598 /* If blocking thread has a blocker, apply transitive inheritance */
1602 break; /* End of chain or object doesn't support inheritance */
1606 if (UNLIKELY(next
== tstart
))
1607 break; /* Full-circle - deadlock! */
1609 UNLOCK_THREAD(thread
);
1616 /* Blocker could change - retest condition */
1617 if (LIKELY(bl
->thread
== next
))
1620 UNLOCK_THREAD(next
);
1628 UNLOCK_THREAD(bl_t
);
1631 if (UNLIKELY(thread
!= tstart
))
1633 /* Relock original if it changed */
1634 LOCK_THREAD(tstart
);
1638 return cores
[CURRENT_CORE
].running
;
1641 /*---------------------------------------------------------------------------
1642 * Transfer ownership to a thread waiting for an objects and transfer
1643 * inherited priority boost from other waiters. This algorithm knows that
1644 * blocking chains may only unblock from the very end.
1646 * Only the owning thread itself may call this and so the assumption that
1647 * it is the running thread is made.
1648 *---------------------------------------------------------------------------
1650 struct thread_entry
*
1651 wakeup_priority_protocol_transfer(struct thread_entry
*thread
)
1653 /* Waking thread inherits priority boost from object owner */
1654 struct blocker
*bl
= thread
->blocker
;
1655 struct thread_entry
*bl_t
= bl
->thread
;
1656 struct thread_entry
*next
;
1659 THREAD_ASSERT(cores
[CURRENT_CORE
].running
== bl_t
,
1660 "UPPT->wrong thread", cores
[CURRENT_CORE
].running
);
1664 bl_pr
= bl
->priority
;
1666 /* Remove the object's boost from the owning thread */
1667 if (prio_subtract_entry(&bl_t
->pdist
, bl_pr
) == 0 &&
1668 bl_pr
<= bl_t
->priority
)
1670 /* No more threads at this priority are waiting and the old level is
1671 * at least the thread level */
1672 int priority
= find_first_set_bit(bl_t
->pdist
.mask
);
1674 if (priority
!= bl_t
->priority
)
1676 /* Adjust this thread's priority */
1677 set_running_thread_priority(bl_t
, priority
);
1681 next
= *thread
->bqp
;
1683 if (LIKELY(next
== NULL
))
1685 /* Expected shortcut - no more waiters */
1686 bl_pr
= PRIORITY_IDLE
;
1690 if (thread
->priority
<= bl_pr
)
1692 /* Need to scan threads remaining in queue */
1693 bl_pr
= find_highest_priority_in_list_l(next
);
1696 if (prio_add_entry(&thread
->pdist
, bl_pr
) == 1 &&
1697 bl_pr
< thread
->priority
)
1699 /* Thread priority must be raised */
1700 thread
->priority
= bl_pr
;
1704 bl
->thread
= thread
; /* This thread pwns */
1705 bl
->priority
= bl_pr
; /* Save highest blocked priority */
1706 thread
->blocker
= NULL
; /* Thread not blocked */
1708 UNLOCK_THREAD(bl_t
);
1713 /*---------------------------------------------------------------------------
1714 * No threads must be blocked waiting for this thread except for it to exit.
1715 * The alternative is more elaborate cleanup and object registration code.
1716 * Check this for risk of silent data corruption when objects with
1717 * inheritable blocking are abandoned by the owner - not precise but may
1719 *---------------------------------------------------------------------------
1721 static void check_for_obj_waiters(const char *function
, struct thread_entry
*thread
)
1723 /* Only one bit in the mask should be set with a frequency on 1 which
1724 * represents the thread's own base priority */
1725 uint32_t mask
= thread
->pdist
.mask
;
1726 if ((mask
& (mask
- 1)) != 0 ||
1727 thread
->pdist
.hist
[find_first_set_bit(mask
)] > 1)
1729 unsigned char name
[32];
1730 thread_get_name(name
, 32, thread
);
1731 panicf("%s->%s with obj. waiters", function
, name
);
1734 #endif /* HAVE_PRIORITY_SCHEDULING */
1736 /*---------------------------------------------------------------------------
1737 * Move a thread back to a running state on its core.
1738 *---------------------------------------------------------------------------
1740 static void core_schedule_wakeup(struct thread_entry
*thread
)
1742 const unsigned int core
= IF_COP_CORE(thread
->core
);
1746 thread
->state
= STATE_RUNNING
;
1748 add_to_list_l(&cores
[core
].running
, thread
);
1749 rtr_add_entry(core
, thread
->priority
);
1754 if (core
!= CURRENT_CORE
)
1759 /*---------------------------------------------------------------------------
1760 * Check the core's timeout list when at least one thread is due to wake.
1761 * Filtering for the condition is done before making the call. Resets the
1762 * tick when the next check will occur.
1763 *---------------------------------------------------------------------------
1765 void check_tmo_threads(void)
1767 const unsigned int core
= CURRENT_CORE
;
1768 const long tick
= current_tick
; /* snapshot the current tick */
1769 long next_tmo_check
= tick
+ 60*HZ
; /* minimum duration: once/minute */
1770 struct thread_entry
*next
= cores
[core
].timeout
;
1772 /* If there are no processes waiting for a timeout, just keep the check
1773 tick from falling into the past. */
1775 /* Break the loop once we have walked through the list of all
1776 * sleeping processes or have removed them all. */
1777 while (next
!= NULL
)
1779 /* Check sleeping threads. Allow interrupts between checks. */
1782 struct thread_entry
*curr
= next
;
1784 next
= curr
->tmo
.next
;
1786 /* Lock thread slot against explicit wakeup */
1790 unsigned state
= curr
->state
;
1792 if (state
< TIMEOUT_STATE_FIRST
)
1794 /* Cleanup threads no longer on a timeout but still on the
1796 remove_from_list_tmo(curr
);
1798 else if (LIKELY(TIME_BEFORE(tick
, curr
->tmo_tick
)))
1800 /* Timeout still pending - this will be the usual case */
1801 if (TIME_BEFORE(curr
->tmo_tick
, next_tmo_check
))
1803 /* Earliest timeout found so far - move the next check up
1805 next_tmo_check
= curr
->tmo_tick
;
1810 /* Sleep timeout has been reached so bring the thread back to
1812 if (state
== STATE_BLOCKED_W_TMO
)
1815 /* Lock the waiting thread's kernel object */
1816 struct corelock
*ocl
= curr
->obj_cl
;
1818 if (UNLIKELY(corelock_try_lock(ocl
) == 0))
1820 /* Need to retry in the correct order though the need is
1822 UNLOCK_THREAD(curr
);
1826 if (UNLIKELY(curr
->state
!= STATE_BLOCKED_W_TMO
))
1828 /* Thread was woken or removed explicitely while slot
1830 corelock_unlock(ocl
);
1831 remove_from_list_tmo(curr
);
1832 UNLOCK_THREAD(curr
);
1836 #endif /* NUM_CORES */
1838 remove_from_list_l(curr
->bqp
, curr
);
1840 #ifdef HAVE_WAKEUP_EXT_CB
1841 if (curr
->wakeup_ext_cb
!= NULL
)
1842 curr
->wakeup_ext_cb(curr
);
1845 #ifdef HAVE_PRIORITY_SCHEDULING
1846 if (curr
->blocker
!= NULL
)
1847 wakeup_priority_protocol_release(curr
);
1849 corelock_unlock(ocl
);
1851 /* else state == STATE_SLEEPING */
1853 remove_from_list_tmo(curr
);
1857 curr
->state
= STATE_RUNNING
;
1859 add_to_list_l(&cores
[core
].running
, curr
);
1860 rtr_add_entry(core
, curr
->priority
);
1865 UNLOCK_THREAD(curr
);
1868 cores
[core
].next_tmo_check
= next_tmo_check
;
1871 /*---------------------------------------------------------------------------
1872 * Performs operations that must be done before blocking a thread but after
1873 * the state is saved.
1874 *---------------------------------------------------------------------------
1877 static inline void run_blocking_ops(
1878 unsigned int core
, struct thread_entry
*thread
)
1880 struct thread_blk_ops
*ops
= &cores
[core
].blk_ops
;
1881 const unsigned flags
= ops
->flags
;
1883 if (LIKELY(flags
== TBOP_CLEAR
))
1888 case TBOP_SWITCH_CORE
:
1889 core_switch_blk_op(core
, thread
);
1891 case TBOP_UNLOCK_CORELOCK
:
1892 corelock_unlock(ops
->cl_p
);
1896 ops
->flags
= TBOP_CLEAR
;
1898 #endif /* NUM_CORES > 1 */
1901 void profile_thread(void)
1903 profstart(cores
[CURRENT_CORE
].running
- threads
);
1907 /*---------------------------------------------------------------------------
1908 * Prepares a thread to block on an object's list and/or for a specified
1909 * duration - expects object and slot to be appropriately locked if needed
1910 * and interrupts to be masked.
1911 *---------------------------------------------------------------------------
1913 static inline void block_thread_on_l(struct thread_entry
*thread
,
1916 /* If inlined, unreachable branches will be pruned with no size penalty
1917 because state is passed as a constant parameter. */
1918 const unsigned int core
= IF_COP_CORE(thread
->core
);
1920 /* Remove the thread from the list of running threads. */
1922 remove_from_list_l(&cores
[core
].running
, thread
);
1923 rtr_subtract_entry(core
, thread
->priority
);
1926 /* Add a timeout to the block if not infinite */
1930 case STATE_BLOCKED_W_TMO
:
1931 /* Put the thread into a new list of inactive threads. */
1932 add_to_list_l(thread
->bqp
, thread
);
1934 if (state
== STATE_BLOCKED
)
1938 case STATE_SLEEPING
:
1939 /* If this thread times out sooner than any other thread, update
1940 next_tmo_check to its timeout */
1941 if (TIME_BEFORE(thread
->tmo_tick
, cores
[core
].next_tmo_check
))
1943 cores
[core
].next_tmo_check
= thread
->tmo_tick
;
1946 if (thread
->tmo
.prev
== NULL
)
1948 add_to_list_tmo(thread
);
1950 /* else thread was never removed from list - just keep it there */
1954 /* Remember the the next thread about to block. */
1955 cores
[core
].block_task
= thread
;
1957 /* Report new state. */
1958 thread
->state
= state
;
1961 /*---------------------------------------------------------------------------
1962 * Switch thread in round robin fashion for any given priority. Any thread
1963 * that removed itself from the running list first must specify itself in
1966 * INTERNAL: Intended for use by kernel and not for programs.
1967 *---------------------------------------------------------------------------
1969 void switch_thread(void)
1972 const unsigned int core
= CURRENT_CORE
;
1973 struct thread_entry
*block
= cores
[core
].block_task
;
1974 struct thread_entry
*thread
= cores
[core
].running
;
1976 /* Get context to save - next thread to run is unknown until all wakeups
1980 cores
[core
].block_task
= NULL
;
1983 if (UNLIKELY(thread
== block
))
1985 /* This was the last thread running and another core woke us before
1986 * reaching here. Force next thread selection to give tmo threads or
1987 * other threads woken before this block a first chance. */
1993 /* Blocking task is the old one */
1999 profile_thread_stopped(thread
->id
& THREAD_ID_SLOT_MASK
);
2002 /* Begin task switching by saving our current context so that we can
2003 * restore the state of the current thread later to the point prior
2005 store_context(&thread
->context
);
2007 /* Check if the current thread stack is overflown */
2008 if (UNLIKELY(thread
->stack
[0] != DEADBEEF
))
2009 thread_stkov(thread
);
2012 /* Run any blocking operations requested before switching/sleeping */
2013 run_blocking_ops(core
, thread
);
2016 #ifdef HAVE_PRIORITY_SCHEDULING
2017 IF_NO_SKIP_YIELD( if (thread
->skip_count
!= -1) )
2018 /* Reset the value of thread's skip count */
2019 thread
->skip_count
= 0;
2024 /* If there are threads on a timeout and the earliest wakeup is due,
2025 * check the list and wake any threads that need to start running
2027 if (!TIME_BEFORE(current_tick
, cores
[core
].next_tmo_check
))
2029 check_tmo_threads();
2035 thread
= cores
[core
].running
;
2037 if (UNLIKELY(thread
== NULL
))
2039 /* Enter sleep mode to reduce power usage - woken up on interrupt
2040 * or wakeup request from another core - expected to enable
2043 core_sleep(IF_COP(core
));
2047 #ifdef HAVE_PRIORITY_SCHEDULING
2048 /* Select the new task based on priorities and the last time a
2049 * process got CPU time relative to the highest priority runnable
2051 struct priority_distribution
*pd
= &cores
[core
].rtr
;
2052 int max
= find_first_set_bit(pd
->mask
);
2056 /* Not switching on a block, tentatively select next thread */
2057 thread
= thread
->l
.next
;
2062 int priority
= thread
->priority
;
2065 /* This ridiculously simple method of aging seems to work
2066 * suspiciously well. It does tend to reward CPU hogs (under
2067 * yielding) but that's generally not desirable at all. On the
2068 * plus side, it, relatively to other threads, penalizes excess
2069 * yielding which is good if some high priority thread is
2070 * performing no useful work such as polling for a device to be
2071 * ready. Of course, aging is only employed when higher and lower
2072 * priority threads are runnable. The highest priority runnable
2073 * thread(s) are never skipped. */
2074 if (LIKELY(priority
<= max
) ||
2075 IF_NO_SKIP_YIELD( thread
->skip_count
== -1 || )
2076 (diff
= priority
- max
, ++thread
->skip_count
> diff
*diff
))
2078 cores
[core
].running
= thread
;
2082 thread
= thread
->l
.next
;
2085 /* Without priority use a simple FCFS algorithm */
2088 /* Not switching on a block, select next thread */
2089 thread
= thread
->l
.next
;
2090 cores
[core
].running
= thread
;
2092 #endif /* HAVE_PRIORITY_SCHEDULING */
2100 /* And finally give control to the next thread. */
2101 load_context(&thread
->context
);
2104 profile_thread_started(thread
->id
& THREAD_ID_SLOT_MASK
);
2109 /*---------------------------------------------------------------------------
2110 * Sleeps a thread for at least a specified number of ticks with zero being
2111 * a wait until the next tick.
2113 * INTERNAL: Intended for use by kernel and not for programs.
2114 *---------------------------------------------------------------------------
2116 void sleep_thread(int ticks
)
2118 struct thread_entry
*current
= cores
[CURRENT_CORE
].running
;
2120 LOCK_THREAD(current
);
2122 /* Set our timeout, remove from run list and join timeout list. */
2123 current
->tmo_tick
= current_tick
+ ticks
+ 1;
2124 block_thread_on_l(current
, STATE_SLEEPING
);
2126 UNLOCK_THREAD(current
);
2129 /*---------------------------------------------------------------------------
2130 * Indefinitely block a thread on a blocking queue for explicit wakeup.
2132 * INTERNAL: Intended for use by kernel objects and not for programs.
2133 *---------------------------------------------------------------------------
2135 void block_thread(struct thread_entry
*current
)
2137 /* Set the state to blocked and take us off of the run queue until we
2138 * are explicitly woken */
2139 LOCK_THREAD(current
);
2141 /* Set the list for explicit wakeup */
2142 block_thread_on_l(current
, STATE_BLOCKED
);
2144 #ifdef HAVE_PRIORITY_SCHEDULING
2145 if (current
->blocker
!= NULL
)
2147 /* Object supports PIP */
2148 current
= blocker_inherit_priority(current
);
2152 UNLOCK_THREAD(current
);
2155 /*---------------------------------------------------------------------------
2156 * Block a thread on a blocking queue for a specified time interval or until
2157 * explicitly woken - whichever happens first.
2159 * INTERNAL: Intended for use by kernel objects and not for programs.
2160 *---------------------------------------------------------------------------
2162 void block_thread_w_tmo(struct thread_entry
*current
, int timeout
)
2164 /* Get the entry for the current running thread. */
2165 LOCK_THREAD(current
);
2167 /* Set the state to blocked with the specified timeout */
2168 current
->tmo_tick
= current_tick
+ timeout
;
2170 /* Set the list for explicit wakeup */
2171 block_thread_on_l(current
, STATE_BLOCKED_W_TMO
);
2173 #ifdef HAVE_PRIORITY_SCHEDULING
2174 if (current
->blocker
!= NULL
)
2176 /* Object supports PIP */
2177 current
= blocker_inherit_priority(current
);
2181 UNLOCK_THREAD(current
);
2184 /*---------------------------------------------------------------------------
2185 * Explicitly wakeup a thread on a blocking queue. Only effects threads of
2186 * STATE_BLOCKED and STATE_BLOCKED_W_TMO.
2188 * This code should be considered a critical section by the caller meaning
2189 * that the object's corelock should be held.
2191 * INTERNAL: Intended for use by kernel objects and not for programs.
2192 *---------------------------------------------------------------------------
2194 unsigned int wakeup_thread(struct thread_entry
**list
)
2196 struct thread_entry
*thread
= *list
;
2197 unsigned int result
= THREAD_NONE
;
2199 /* Check if there is a blocked thread at all. */
2203 LOCK_THREAD(thread
);
2205 /* Determine thread's current state. */
2206 switch (thread
->state
)
2209 case STATE_BLOCKED_W_TMO
:
2210 remove_from_list_l(list
, thread
);
2214 #ifdef HAVE_PRIORITY_SCHEDULING
2215 struct thread_entry
*current
;
2216 struct blocker
*bl
= thread
->blocker
;
2220 /* No inheritance - just boost the thread by aging */
2221 IF_NO_SKIP_YIELD( if (thread
->skip_count
!= -1) )
2222 thread
->skip_count
= thread
->priority
;
2223 current
= cores
[CURRENT_CORE
].running
;
2227 /* Call the specified unblocking PIP */
2228 current
= bl
->wakeup_protocol(thread
);
2231 if (current
!= NULL
&& thread
->priority
< current
->priority
2232 IF_COP( && thread
->core
== current
->core
))
2234 /* Woken thread is higher priority and exists on the same CPU core;
2235 * recommend a task switch. Knowing if this is an interrupt call
2236 * would be helpful here. */
2237 result
|= THREAD_SWITCH
;
2239 #endif /* HAVE_PRIORITY_SCHEDULING */
2241 core_schedule_wakeup(thread
);
2244 /* Nothing to do. State is not blocked. */
2245 #if THREAD_EXTRA_CHECKS
2247 THREAD_PANICF("wakeup_thread->block invalid", thread
);
2254 UNLOCK_THREAD(thread
);
2258 /*---------------------------------------------------------------------------
2259 * Wakeup an entire queue of threads - returns bitwise-or of return bitmask
2260 * from each operation or THREAD_NONE of nothing was awakened. Object owning
2261 * the queue must be locked first.
2263 * INTERNAL: Intended for use by kernel objects and not for programs.
2264 *---------------------------------------------------------------------------
2266 unsigned int thread_queue_wake(struct thread_entry
**list
)
2268 unsigned result
= THREAD_NONE
;
2272 unsigned int rc
= wakeup_thread(list
);
2274 if (rc
== THREAD_NONE
)
2275 break; /* No more threads */
2283 /*---------------------------------------------------------------------------
2284 * Assign the thread slot a new ID. Version is 1-255.
2285 *---------------------------------------------------------------------------
2287 static void new_thread_id(unsigned int slot_num
,
2288 struct thread_entry
*thread
)
2290 unsigned int version
=
2291 (thread
->id
+ (1u << THREAD_ID_VERSION_SHIFT
))
2292 & THREAD_ID_VERSION_MASK
;
2294 /* If wrapped to 0, make it 1 */
2296 version
= 1u << THREAD_ID_VERSION_SHIFT
;
2298 thread
->id
= version
| (slot_num
& THREAD_ID_SLOT_MASK
);
2301 /*---------------------------------------------------------------------------
2302 * Find an empty thread slot or MAXTHREADS if none found. The slot returned
2303 * will be locked on multicore.
2304 *---------------------------------------------------------------------------
2306 static struct thread_entry
* find_empty_thread_slot(void)
2308 /* Any slot could be on an interrupt-accessible list */
2309 IF_COP( int oldlevel
= disable_irq_save(); )
2310 struct thread_entry
*thread
= NULL
;
2313 for (n
= 0; n
< MAXTHREADS
; n
++)
2315 /* Obtain current slot state - lock it on multicore */
2316 struct thread_entry
*t
= &threads
[n
];
2319 if (t
->state
== STATE_KILLED
IF_COP( && t
->name
!= THREAD_DESTRUCT
))
2321 /* Slot is empty - leave it locked and caller will unlock */
2326 /* Finished examining slot - no longer busy - unlock on multicore */
2330 IF_COP( restore_irq(oldlevel
); ) /* Reenable interrups - this slot is
2331 not accesible to them yet */
2335 /*---------------------------------------------------------------------------
2336 * Return the thread_entry pointer for a thread_id. Return the current
2337 * thread if the ID is 0 (alias for current).
2338 *---------------------------------------------------------------------------
2340 struct thread_entry
* thread_id_entry(unsigned int thread_id
)
2342 return (thread_id
== THREAD_ID_CURRENT
) ?
2343 cores
[CURRENT_CORE
].running
:
2344 &threads
[thread_id
& THREAD_ID_SLOT_MASK
];
2347 /*---------------------------------------------------------------------------
2348 * Place the current core in idle mode - woken up on interrupt or wake
2349 * request from another core.
2350 *---------------------------------------------------------------------------
2352 void core_idle(void)
2354 IF_COP( const unsigned int core
= CURRENT_CORE
; )
2356 core_sleep(IF_COP(core
));
2359 /*---------------------------------------------------------------------------
2360 * Create a thread. If using a dual core architecture, specify which core to
2361 * start the thread on.
2363 * Return ID if context area could be allocated, else NULL.
2364 *---------------------------------------------------------------------------
2366 unsigned int create_thread(void (*function
)(void),
2367 void* stack
, size_t stack_size
,
2368 unsigned flags
, const char *name
2369 IF_PRIO(, int priority
)
2370 IF_COP(, unsigned int core
))
2373 unsigned int stack_words
;
2374 uintptr_t stackptr
, stackend
;
2375 struct thread_entry
*thread
;
2379 thread
= find_empty_thread_slot();
2385 oldlevel
= disable_irq_save();
2387 /* Munge the stack to make it easy to spot stack overflows */
2388 stackptr
= ALIGN_UP((uintptr_t)stack
, sizeof (uintptr_t));
2389 stackend
= ALIGN_DOWN((uintptr_t)stack
+ stack_size
, sizeof (uintptr_t));
2390 stack_size
= stackend
- stackptr
;
2391 stack_words
= stack_size
/ sizeof (uintptr_t);
2393 for (i
= 0; i
< stack_words
; i
++)
2395 ((uintptr_t *)stackptr
)[i
] = DEADBEEF
;
2398 /* Store interesting information */
2399 thread
->name
= name
;
2400 thread
->stack
= (uintptr_t *)stackptr
;
2401 thread
->stack_size
= stack_size
;
2402 thread
->queue
= NULL
;
2403 #ifdef HAVE_WAKEUP_EXT_CB
2404 thread
->wakeup_ext_cb
= NULL
;
2406 #ifdef HAVE_SCHEDULER_BOOSTCTRL
2407 thread
->cpu_boost
= 0;
2409 #ifdef HAVE_PRIORITY_SCHEDULING
2410 memset(&thread
->pdist
, 0, sizeof(thread
->pdist
));
2411 thread
->blocker
= NULL
;
2412 thread
->base_priority
= priority
;
2413 thread
->priority
= priority
;
2414 thread
->skip_count
= priority
;
2415 prio_add_entry(&thread
->pdist
, priority
);
2419 thread
->core
= core
;
2421 /* Writeback stack munging or anything else before starting */
2422 if (core
!= CURRENT_CORE
)
2428 /* Thread is not on any timeout list but be a bit paranoid */
2429 thread
->tmo
.prev
= NULL
;
2431 state
= (flags
& CREATE_THREAD_FROZEN
) ?
2432 STATE_FROZEN
: STATE_RUNNING
;
2434 thread
->context
.sp
= (typeof (thread
->context
.sp
))stackend
;
2436 /* Load the thread's context structure with needed startup information */
2437 THREAD_STARTUP_INIT(core
, thread
, function
);
2439 thread
->state
= state
;
2440 i
= thread
->id
; /* Snapshot while locked */
2442 if (state
== STATE_RUNNING
)
2443 core_schedule_wakeup(thread
);
2445 UNLOCK_THREAD(thread
);
2446 restore_irq(oldlevel
);
2451 #ifdef HAVE_SCHEDULER_BOOSTCTRL
2452 /*---------------------------------------------------------------------------
2453 * Change the boost state of a thread boosting or unboosting the CPU
2455 *---------------------------------------------------------------------------
2457 static inline void boost_thread(struct thread_entry
*thread
, bool boost
)
2459 if ((thread
->cpu_boost
!= 0) != boost
)
2461 thread
->cpu_boost
= boost
;
2466 void trigger_cpu_boost(void)
2468 struct thread_entry
*current
= cores
[CURRENT_CORE
].running
;
2469 boost_thread(current
, true);
2472 void cancel_cpu_boost(void)
2474 struct thread_entry
*current
= cores
[CURRENT_CORE
].running
;
2475 boost_thread(current
, false);
2477 #endif /* HAVE_SCHEDULER_BOOSTCTRL */
2479 /*---------------------------------------------------------------------------
2480 * Block the current thread until another thread terminates. A thread may
2481 * wait on itself to terminate which prevents it from running again and it
2482 * will need to be killed externally.
2483 * Parameter is the ID as returned from create_thread().
2484 *---------------------------------------------------------------------------
2486 void thread_wait(unsigned int thread_id
)
2488 struct thread_entry
*current
= cores
[CURRENT_CORE
].running
;
2489 struct thread_entry
*thread
= thread_id_entry(thread_id
);
2491 /* Lock thread-as-waitable-object lock */
2492 corelock_lock(&thread
->waiter_cl
);
2494 /* Be sure it hasn't been killed yet */
2495 if (thread_id
== THREAD_ID_CURRENT
||
2496 (thread
->id
== thread_id
&& thread
->state
!= STATE_KILLED
))
2498 IF_COP( current
->obj_cl
= &thread
->waiter_cl
; )
2499 current
->bqp
= &thread
->queue
;
2502 block_thread(current
);
2504 corelock_unlock(&thread
->waiter_cl
);
2510 corelock_unlock(&thread
->waiter_cl
);
2513 /*---------------------------------------------------------------------------
2514 * Exit the current thread. The Right Way to Do Things (TM).
2515 *---------------------------------------------------------------------------
2517 void thread_exit(void)
2519 const unsigned int core
= CURRENT_CORE
;
2520 struct thread_entry
*current
= cores
[core
].running
;
2522 /* Cancel CPU boost if any */
2527 corelock_lock(¤t
->waiter_cl
);
2528 LOCK_THREAD(current
);
2530 #if defined (ALLOW_REMOVE_THREAD) && NUM_CORES > 1
2531 if (current
->name
== THREAD_DESTRUCT
)
2533 /* Thread being killed - become a waiter */
2534 unsigned int id
= current
->id
;
2535 UNLOCK_THREAD(current
);
2536 corelock_unlock(¤t
->waiter_cl
);
2538 THREAD_PANICF("thread_exit->WK:*R", current
);
2542 #ifdef HAVE_PRIORITY_SCHEDULING
2543 check_for_obj_waiters("thread_exit", current
);
2546 if (current
->tmo
.prev
!= NULL
)
2548 /* Cancel pending timeout list removal */
2549 remove_from_list_tmo(current
);
2552 /* Switch tasks and never return */
2553 block_thread_on_l(current
, STATE_KILLED
);
2556 /* Switch to the idle stack if not on the main core (where "main"
2557 * runs) - we can hope gcc doesn't need the old stack beyond this
2561 switch_to_idle_stack(core
);
2566 /* At this point, this thread isn't using resources allocated for
2567 * execution except the slot itself. */
2570 /* Update ID for this slot */
2571 new_thread_id(current
->id
, current
);
2572 current
->name
= NULL
;
2574 /* Signal this thread */
2575 thread_queue_wake(¤t
->queue
);
2576 corelock_unlock(¤t
->waiter_cl
);
2577 /* Slot must be unusable until thread is really gone */
2578 UNLOCK_THREAD_AT_TASK_SWITCH(current
);
2580 /* This should never and must never be reached - if it is, the
2581 * state is corrupted */
2582 THREAD_PANICF("thread_exit->K:*R", current
);
2585 #ifdef ALLOW_REMOVE_THREAD
2586 /*---------------------------------------------------------------------------
2587 * Remove a thread from the scheduler. Not The Right Way to Do Things in
2590 * Parameter is the ID as returned from create_thread().
2592 * Use with care on threads that are not under careful control as this may
2593 * leave various objects in an undefined state.
2594 *---------------------------------------------------------------------------
2596 void remove_thread(unsigned int thread_id
)
2599 /* core is not constant here because of core switching */
2600 unsigned int core
= CURRENT_CORE
;
2601 unsigned int old_core
= NUM_CORES
;
2602 struct corelock
*ocl
= NULL
;
2604 const unsigned int core
= CURRENT_CORE
;
2606 struct thread_entry
*current
= cores
[core
].running
;
2607 struct thread_entry
*thread
= thread_id_entry(thread_id
);
2612 if (thread
== current
)
2613 thread_exit(); /* Current thread - do normal exit */
2615 oldlevel
= disable_irq_save();
2617 corelock_lock(&thread
->waiter_cl
);
2618 LOCK_THREAD(thread
);
2620 state
= thread
->state
;
2622 if (thread
->id
!= thread_id
|| state
== STATE_KILLED
)
2626 if (thread
->name
== THREAD_DESTRUCT
)
2628 /* Thread being killed - become a waiter */
2629 UNLOCK_THREAD(thread
);
2630 corelock_unlock(&thread
->waiter_cl
);
2631 restore_irq(oldlevel
);
2632 thread_wait(thread_id
);
2636 thread
->name
= THREAD_DESTRUCT
; /* Slot can't be used for now */
2638 #ifdef HAVE_PRIORITY_SCHEDULING
2639 check_for_obj_waiters("remove_thread", thread
);
2642 if (thread
->core
!= core
)
2644 /* Switch cores and safely extract the thread there */
2645 /* Slot HAS to be unlocked or a deadlock could occur which means other
2646 * threads have to be guided into becoming thread waiters if they
2647 * attempt to remove it. */
2648 unsigned int new_core
= thread
->core
;
2650 corelock_unlock(&thread
->waiter_cl
);
2652 UNLOCK_THREAD(thread
);
2653 restore_irq(oldlevel
);
2655 old_core
= switch_core(new_core
);
2657 oldlevel
= disable_irq_save();
2659 corelock_lock(&thread
->waiter_cl
);
2660 LOCK_THREAD(thread
);
2662 state
= thread
->state
;
2664 /* Perform the extraction and switch ourselves back to the original
2667 #endif /* NUM_CORES > 1 */
2669 if (thread
->tmo
.prev
!= NULL
)
2671 /* Clean thread off the timeout list if a timeout check hasn't
2673 remove_from_list_tmo(thread
);
2676 #ifdef HAVE_SCHEDULER_BOOSTCTRL
2677 /* Cancel CPU boost if any */
2678 boost_thread(thread
, false);
2681 IF_COP( retry_state
: )
2687 /* Remove thread from ready to run tasks */
2688 remove_from_list_l(&cores
[core
].running
, thread
);
2689 rtr_subtract_entry(core
, thread
->priority
);
2693 case STATE_BLOCKED_W_TMO
:
2694 /* Remove thread from the queue it's blocked on - including its
2695 * own if waiting there */
2697 if (&thread
->waiter_cl
!= thread
->obj_cl
)
2699 ocl
= thread
->obj_cl
;
2701 if (UNLIKELY(corelock_try_lock(ocl
) == 0))
2703 UNLOCK_THREAD(thread
);
2705 LOCK_THREAD(thread
);
2707 if (UNLIKELY(thread
->state
!= state
))
2709 /* Something woke the thread */
2710 state
= thread
->state
;
2711 corelock_unlock(ocl
);
2717 remove_from_list_l(thread
->bqp
, thread
);
2719 #ifdef HAVE_WAKEUP_EXT_CB
2720 if (thread
->wakeup_ext_cb
!= NULL
)
2721 thread
->wakeup_ext_cb(thread
);
2724 #ifdef HAVE_PRIORITY_SCHEDULING
2725 if (thread
->blocker
!= NULL
)
2727 /* Remove thread's priority influence from its chain */
2728 wakeup_priority_protocol_release(thread
);
2734 corelock_unlock(ocl
);
2737 /* Otherwise thread is frozen and hasn't run yet */
2740 new_thread_id(thread_id
, thread
);
2741 thread
->state
= STATE_KILLED
;
2743 /* If thread was waiting on itself, it will have been removed above.
2744 * The wrong order would result in waking the thread first and deadlocking
2745 * since the slot is already locked. */
2746 thread_queue_wake(&thread
->queue
);
2748 thread
->name
= NULL
;
2750 thread_killed
: /* Thread was already killed */
2751 /* Removal complete - safe to unlock and reenable interrupts */
2752 corelock_unlock(&thread
->waiter_cl
);
2753 UNLOCK_THREAD(thread
);
2754 restore_irq(oldlevel
);
2757 if (old_core
< NUM_CORES
)
2759 /* Did a removal on another processor's thread - switch back to
2761 switch_core(old_core
);
2765 #endif /* ALLOW_REMOVE_THREAD */
2767 #ifdef HAVE_PRIORITY_SCHEDULING
2768 /*---------------------------------------------------------------------------
2769 * Sets the thread's relative base priority for the core it runs on. Any
2770 * needed inheritance changes also may happen.
2771 *---------------------------------------------------------------------------
2773 int thread_set_priority(unsigned int thread_id
, int priority
)
2775 int old_base_priority
= -1;
2776 struct thread_entry
*thread
= thread_id_entry(thread_id
);
2778 /* A little safety measure */
2779 if (priority
< HIGHEST_PRIORITY
|| priority
> LOWEST_PRIORITY
)
2782 /* Thread could be on any list and therefore on an interrupt accessible
2783 one - disable interrupts */
2784 int oldlevel
= disable_irq_save();
2786 LOCK_THREAD(thread
);
2788 /* Make sure it's not killed */
2789 if (thread_id
== THREAD_ID_CURRENT
||
2790 (thread
->id
== thread_id
&& thread
->state
!= STATE_KILLED
))
2792 int old_priority
= thread
->priority
;
2794 old_base_priority
= thread
->base_priority
;
2795 thread
->base_priority
= priority
;
2797 prio_move_entry(&thread
->pdist
, old_base_priority
, priority
);
2798 priority
= find_first_set_bit(thread
->pdist
.mask
);
2800 if (old_priority
== priority
)
2802 /* No priority change - do nothing */
2804 else if (thread
->state
== STATE_RUNNING
)
2806 /* This thread is running - change location on the run
2807 * queue. No transitive inheritance needed. */
2808 set_running_thread_priority(thread
, priority
);
2812 thread
->priority
= priority
;
2814 if (thread
->blocker
!= NULL
)
2816 /* Bubble new priority down the chain */
2817 struct blocker
*bl
= thread
->blocker
; /* Blocker struct */
2818 struct thread_entry
*bl_t
= bl
->thread
; /* Blocking thread */
2819 struct thread_entry
* const tstart
= thread
; /* Initial thread */
2820 const int highest
= MIN(priority
, old_priority
); /* Higher of new or old */
2824 struct thread_entry
*next
; /* Next thread to check */
2825 int bl_pr
; /* Highest blocked thread */
2826 int queue_pr
; /* New highest blocked thread */
2828 /* Owner can change but thread cannot be dislodged - thread
2829 * may not be the first in the queue which allows other
2830 * threads ahead in the list to be given ownership during the
2831 * operation. If thread is next then the waker will have to
2832 * wait for us and the owner of the object will remain fixed.
2833 * If we successfully grab the owner -- which at some point
2834 * is guaranteed -- then the queue remains fixed until we
2840 /* Double-check the owner - retry if it changed */
2841 if (LIKELY(bl
->thread
== bl_t
))
2844 UNLOCK_THREAD(bl_t
);
2848 bl_pr
= bl
->priority
;
2850 if (highest
> bl_pr
)
2851 break; /* Object priority won't change */
2853 /* This will include the thread being set */
2854 queue_pr
= find_highest_priority_in_list_l(*thread
->bqp
);
2856 if (queue_pr
== bl_pr
)
2857 break; /* Object priority not changing */
2859 /* Update thread boost for this object */
2860 bl
->priority
= queue_pr
;
2861 prio_move_entry(&bl_t
->pdist
, bl_pr
, queue_pr
);
2862 bl_pr
= find_first_set_bit(bl_t
->pdist
.mask
);
2864 if (bl_t
->priority
== bl_pr
)
2865 break; /* Blocking thread priority not changing */
2867 if (bl_t
->state
== STATE_RUNNING
)
2869 /* Thread not blocked - we're done */
2870 set_running_thread_priority(bl_t
, bl_pr
);
2874 bl_t
->priority
= bl_pr
;
2875 bl
= bl_t
->blocker
; /* Blocking thread has a blocker? */
2878 break; /* End of chain */
2882 if (UNLIKELY(next
== tstart
))
2883 break; /* Full-circle */
2885 UNLOCK_THREAD(thread
);
2891 UNLOCK_THREAD(bl_t
);
2896 UNLOCK_THREAD(thread
);
2898 restore_irq(oldlevel
);
2900 return old_base_priority
;
2903 /*---------------------------------------------------------------------------
2904 * Returns the current base priority for a thread.
2905 *---------------------------------------------------------------------------
2907 int thread_get_priority(unsigned int thread_id
)
2909 struct thread_entry
*thread
= thread_id_entry(thread_id
);
2910 int base_priority
= thread
->base_priority
;
2912 /* Simply check without locking slot. It may or may not be valid by the
2913 * time the function returns anyway. If all tests pass, it is the
2914 * correct value for when it was valid. */
2915 if (thread_id
!= THREAD_ID_CURRENT
&&
2916 (thread
->id
!= thread_id
|| thread
->state
== STATE_KILLED
))
2919 return base_priority
;
2921 #endif /* HAVE_PRIORITY_SCHEDULING */
2923 /*---------------------------------------------------------------------------
2924 * Starts a frozen thread - similar semantics to wakeup_thread except that
2925 * the thread is on no scheduler or wakeup queue at all. It exists simply by
2926 * virtue of the slot having a state of STATE_FROZEN.
2927 *---------------------------------------------------------------------------
2929 void thread_thaw(unsigned int thread_id
)
2931 struct thread_entry
*thread
= thread_id_entry(thread_id
);
2932 int oldlevel
= disable_irq_save();
2934 LOCK_THREAD(thread
);
2936 /* If thread is the current one, it cannot be frozen, therefore
2937 * there is no need to check that. */
2938 if (thread
->id
== thread_id
&& thread
->state
== STATE_FROZEN
)
2939 core_schedule_wakeup(thread
);
2941 UNLOCK_THREAD(thread
);
2942 restore_irq(oldlevel
);
2945 /*---------------------------------------------------------------------------
2946 * Return the ID of the currently executing thread.
2947 *---------------------------------------------------------------------------
2949 unsigned int thread_get_current(void)
2951 return cores
[CURRENT_CORE
].running
->id
;
2955 /*---------------------------------------------------------------------------
2956 * Switch the processor that the currently executing thread runs on.
2957 *---------------------------------------------------------------------------
2959 unsigned int switch_core(unsigned int new_core
)
2961 const unsigned int core
= CURRENT_CORE
;
2962 struct thread_entry
*current
= cores
[core
].running
;
2964 if (core
== new_core
)
2966 /* No change - just return same core */
2970 int oldlevel
= disable_irq_save();
2971 LOCK_THREAD(current
);
2973 if (current
->name
== THREAD_DESTRUCT
)
2975 /* Thread being killed - deactivate and let process complete */
2976 unsigned int id
= current
->id
;
2977 UNLOCK_THREAD(current
);
2978 restore_irq(oldlevel
);
2980 /* Should never be reached */
2981 THREAD_PANICF("switch_core->D:*R", current
);
2984 /* Get us off the running list for the current core */
2986 remove_from_list_l(&cores
[core
].running
, current
);
2987 rtr_subtract_entry(core
, current
->priority
);
2990 /* Stash return value (old core) in a safe place */
2991 current
->retval
= core
;
2993 /* If a timeout hadn't yet been cleaned-up it must be removed now or
2994 * the other core will likely attempt a removal from the wrong list! */
2995 if (current
->tmo
.prev
!= NULL
)
2997 remove_from_list_tmo(current
);
3000 /* Change the core number for this thread slot */
3001 current
->core
= new_core
;
3003 /* Do not use core_schedule_wakeup here since this will result in
3004 * the thread starting to run on the other core before being finished on
3005 * this one. Delay the list unlock to keep the other core stuck
3006 * until this thread is ready. */
3009 rtr_add_entry(new_core
, current
->priority
);
3010 add_to_list_l(&cores
[new_core
].running
, current
);
3012 /* Make a callback into device-specific code, unlock the wakeup list so
3013 * that execution may resume on the new core, unlock our slot and finally
3014 * restore the interrupt level */
3015 cores
[core
].blk_ops
.flags
= TBOP_SWITCH_CORE
;
3016 cores
[core
].blk_ops
.cl_p
= &cores
[new_core
].rtr_cl
;
3017 cores
[core
].block_task
= current
;
3019 UNLOCK_THREAD(current
);
3021 /* Alert other core to activity */
3022 core_wake(new_core
);
3024 /* Do the stack switching, cache_maintenence and switch_thread call -
3025 requires native code */
3026 switch_thread_core(core
, current
);
3028 /* Finally return the old core to caller */
3029 return current
->retval
;
3031 #endif /* NUM_CORES > 1 */
3033 /*---------------------------------------------------------------------------
3034 * Initialize threading API. This assumes interrupts are not yet enabled. On
3035 * multicore setups, no core is allowed to proceed until create_thread calls
3036 * are safe to perform.
3037 *---------------------------------------------------------------------------
3039 void init_threads(void)
3041 const unsigned int core
= CURRENT_CORE
;
3042 struct thread_entry
*thread
;
3046 /* Initialize core locks and IDs in all slots */
3048 for (n
= 0; n
< MAXTHREADS
; n
++)
3050 thread
= &threads
[n
];
3051 corelock_init(&thread
->waiter_cl
);
3052 corelock_init(&thread
->slot_cl
);
3053 thread
->id
= THREAD_ID_INIT(n
);
3057 /* CPU will initialize first and then sleep */
3058 thread
= find_empty_thread_slot();
3062 /* WTF? There really must be a slot available at this stage.
3063 * This can fail if, for example, .bss isn't zero'ed out by the loader
3064 * or threads is in the wrong section. */
3065 THREAD_PANICF("init_threads->no slot", NULL
);
3068 /* Initialize initially non-zero members of core */
3069 cores
[core
].next_tmo_check
= current_tick
; /* Something not in the past */
3071 /* Initialize initially non-zero members of slot */
3072 UNLOCK_THREAD(thread
); /* No sync worries yet */
3073 thread
->name
= main_thread_name
;
3074 thread
->state
= STATE_RUNNING
;
3075 IF_COP( thread
->core
= core
; )
3076 #ifdef HAVE_PRIORITY_SCHEDULING
3077 corelock_init(&cores
[core
].rtr_cl
);
3078 thread
->base_priority
= PRIORITY_USER_INTERFACE
;
3079 prio_add_entry(&thread
->pdist
, PRIORITY_USER_INTERFACE
);
3080 thread
->priority
= PRIORITY_USER_INTERFACE
;
3081 rtr_add_entry(core
, PRIORITY_USER_INTERFACE
);
3084 add_to_list_l(&cores
[core
].running
, thread
);
3088 thread
->stack
= stackbegin
;
3089 thread
->stack_size
= (uintptr_t)stackend
- (uintptr_t)stackbegin
;
3090 #if NUM_CORES > 1 /* This code path will not be run on single core targets */
3091 /* Wait for other processors to finish their inits since create_thread
3092 * isn't safe to call until the kernel inits are done. The first
3093 * threads created in the system must of course be created by CPU.
3094 * Another possible approach is to initialize all cores and slots
3095 * for each core by CPU, let the remainder proceed in parallel and
3096 * signal CPU when all are finished. */
3097 core_thread_init(CPU
);
3101 /* Initial stack is the idle stack */
3102 thread
->stack
= idle_stacks
[core
];
3103 thread
->stack_size
= IDLE_STACK_SIZE
;
3104 /* After last processor completes, it should signal all others to
3105 * proceed or may signal the next and call thread_exit(). The last one
3106 * to finish will signal CPU. */
3107 core_thread_init(core
);
3108 /* Other cores do not have a main thread - go idle inside switch_thread
3109 * until a thread can run on the core. */
3111 #endif /* NUM_CORES */
3115 /* Shared stack scan helper for thread_stack_usage and idle_stack_usage */
3117 static inline int stack_usage(uintptr_t *stackptr
, size_t stack_size
)
3119 static int stack_usage(uintptr_t *stackptr
, size_t stack_size
)
3122 unsigned int stack_words
= stack_size
/ sizeof (uintptr_t);
3126 for (i
= 0; i
< stack_words
; i
++)
3128 if (stackptr
[i
] != DEADBEEF
)
3130 usage
= ((stack_words
- i
) * 100) / stack_words
;
3138 /*---------------------------------------------------------------------------
3139 * Returns the maximum percentage of stack a thread ever used while running.
3140 * NOTE: Some large buffer allocations that don't use enough the buffer to
3141 * overwrite stackptr[0] will not be seen.
3142 *---------------------------------------------------------------------------
3144 int thread_stack_usage(const struct thread_entry
*thread
)
3146 return stack_usage(thread
->stack
, thread
->stack_size
);
3150 /*---------------------------------------------------------------------------
3151 * Returns the maximum percentage of the core's idle stack ever used during
3153 *---------------------------------------------------------------------------
3155 int idle_stack_usage(unsigned int core
)
3157 return stack_usage(idle_stacks
[core
], IDLE_STACK_SIZE
);
3161 /*---------------------------------------------------------------------------
3162 * Fills in the buffer with the specified thread's name. If the name is NULL,
3163 * empty, or the thread is in destruct state a formatted ID is written
3165 *---------------------------------------------------------------------------
3167 void thread_get_name(char *buffer
, int size
,
3168 struct thread_entry
*thread
)
3177 /* Display thread name if one or ID if none */
3178 const char *name
= thread
->name
;
3179 const char *fmt
= "%s";
3180 if (name
== NULL
IF_COP(|| name
== THREAD_DESTRUCT
) || *name
== '\0')
3182 name
= (const char *)thread
;
3185 snprintf(buffer
, size
, fmt
, name
);