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author | Thomas Martitz <kugel@rockbox.org> | 2012-01-04 18:07:21 +0100 |
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committer | Thomas Martitz <kugel@rockbox.org> | 2012-01-22 18:46:44 +0100 |
commit | 991ae1e39553172a7dd6cd8c634aebfce892e261 (patch) | |
tree | 672a4583af663def399c4fefdbad060605397fbc /firmware/target/hosted/thread-unix.c | |
parent | eaa83bd64775b87e943d345e2810deed44408776 (diff) | |
download | rockbox-991ae1e39553172a7dd6cd8c634aebfce892e261.tar.gz rockbox-991ae1e39553172a7dd6cd8c634aebfce892e261.zip |
Create fimrware/asm directory for assembly optimized stuff.
This dir is suitable for stuff that doesn't fit the target tree, e.g. because
it also builds on hosted or otherwise. It also has a generic subfolder for
fallback C implementations so that not all archs need to provide asm files.
SOURCES should only contain "foo.c" where foo.c includes the specific
<arch>/foo.c files from the subdirs using the preprocessor. This way automatic
selection of asm versions or generic C verion is possible.
For the start, the thread support files are moved, since ASM threads can
be used on hosted platforms as well. Since core_sleep() remains platform
specific it's moved to the corresponding system.h headers.
Change-Id: Iebff272f3407a6eaafeb7656ceb0ae9eca3f7cb9
Diffstat (limited to 'firmware/target/hosted/thread-unix.c')
-rw-r--r-- | firmware/target/hosted/thread-unix.c | 316 |
1 files changed, 0 insertions, 316 deletions
diff --git a/firmware/target/hosted/thread-unix.c b/firmware/target/hosted/thread-unix.c deleted file mode 100644 index 79310e0600..0000000000 --- a/firmware/target/hosted/thread-unix.c +++ /dev/null | |||
@@ -1,316 +0,0 @@ | |||
1 | /*************************************************************************** | ||
2 | * __________ __ ___. | ||
3 | * Open \______ \ ____ ____ | | _\_ |__ _______ ___ | ||
4 | * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / | ||
5 | * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < | ||
6 | * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ | ||
7 | * \/ \/ \/ \/ \/ | ||
8 | * $Id$ | ||
9 | * | ||
10 | * Copyright (C) 2011 by Thomas Martitz | ||
11 | * | ||
12 | * Generic unix threading support | ||
13 | * | ||
14 | * This program is free software; you can redistribute it and/or | ||
15 | * modify it under the terms of the GNU General Public License | ||
16 | * as published by the Free Software Foundation; either version 2 | ||
17 | * of the License, or (at your option) any later version. | ||
18 | * | ||
19 | * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY | ||
20 | * KIND, either express or implied. | ||
21 | * | ||
22 | ****************************************************************************/ | ||
23 | |||
24 | #include <stdlib.h> | ||
25 | #include <stdbool.h> | ||
26 | #include <signal.h> | ||
27 | #include <stdio.h> | ||
28 | #include <setjmp.h> | ||
29 | #include <unistd.h> | ||
30 | #include <pthread.h> | ||
31 | #include <errno.h> | ||
32 | #include "debug.h" | ||
33 | |||
34 | static volatile bool sig_handler_called; | ||
35 | static volatile jmp_buf tramp_buf; | ||
36 | static volatile jmp_buf bootstrap_buf; | ||
37 | static void (*thread_func)(void); | ||
38 | static const int trampoline_sig = SIGUSR1; | ||
39 | static pthread_t main_thread; | ||
40 | |||
41 | static struct ctx { | ||
42 | jmp_buf thread_buf; | ||
43 | } thread_bufs[MAXTHREADS]; | ||
44 | static struct ctx* thread_context, *target_context; | ||
45 | static int curr_uc; | ||
46 | |||
47 | static void trampoline(int sig); | ||
48 | static void bootstrap_context(void) __attribute__((noinline)); | ||
49 | |||
50 | /* The *_context functions are heavily based on Gnu pth | ||
51 | * http://www.gnu.org/software/pth/ | ||
52 | * | ||
53 | * adjusted to work in a multi-thread environment to | ||
54 | * offer a ucontext-like API | ||
55 | */ | ||
56 | |||
57 | /* | ||
58 | * VARIANT 2: THE SIGNAL STACK TRICK | ||
59 | * | ||
60 | * This uses sigstack/sigaltstack() and friends and is really the | ||
61 | * most tricky part of Pth. When you understand the following | ||
62 | * stuff you're a good Unix hacker and then you've already | ||
63 | * understood the gory ingredients of Pth. So, either welcome to | ||
64 | * the club of hackers, or do yourself a favor and skip this ;) | ||
65 | * | ||
66 | * The ingenious fact is that this variant runs really on _all_ POSIX | ||
67 | * compliant systems without special platform kludges. But be _VERY_ | ||
68 | * carefully when you change something in the following code. The slightest | ||
69 | * change or reordering can lead to horribly broken code. Really every | ||
70 | * function call in the following case is intended to be how it is, doubt | ||
71 | * me... | ||
72 | * | ||
73 | * For more details we strongly recommend you to read the companion | ||
74 | * paper ``Portable Multithreading -- The Signal Stack Trick for | ||
75 | * User-Space Thread Creation'' from Ralf S. Engelschall. A copy of the | ||
76 | * draft of this paper you can find in the file rse-pmt.ps inside the | ||
77 | * GNU Pth distribution. | ||
78 | */ | ||
79 | |||
80 | static int make_context(struct ctx *ctx, void (*f)(void), char *sp, size_t stack_size) | ||
81 | { | ||
82 | struct sigaction sa; | ||
83 | struct sigaction osa; | ||
84 | stack_t ss; | ||
85 | stack_t oss; | ||
86 | sigset_t osigs; | ||
87 | sigset_t sigs; | ||
88 | |||
89 | disable_irq(); | ||
90 | /* | ||
91 | * Preserve the trampoline_sig signal state, block trampoline_sig, | ||
92 | * and establish our signal handler. The signal will | ||
93 | * later transfer control onto the signal stack. | ||
94 | */ | ||
95 | sigemptyset(&sigs); | ||
96 | sigaddset(&sigs, trampoline_sig); | ||
97 | sigprocmask(SIG_BLOCK, &sigs, &osigs); | ||
98 | sa.sa_handler = trampoline; | ||
99 | sigemptyset(&sa.sa_mask); | ||
100 | sa.sa_flags = SA_ONSTACK; | ||
101 | if (sigaction(trampoline_sig, &sa, &osa) != 0) | ||
102 | { | ||
103 | DEBUGF("%s(): %s\n", __func__, strerror(errno)); | ||
104 | return false; | ||
105 | } | ||
106 | /* | ||
107 | * Set the new stack. | ||
108 | * | ||
109 | * For sigaltstack we're lucky [from sigaltstack(2) on | ||
110 | * FreeBSD 3.1]: ``Signal stacks are automatically adjusted | ||
111 | * for the direction of stack growth and alignment | ||
112 | * requirements'' | ||
113 | * | ||
114 | * For sigstack we have to decide ourself [from sigstack(2) | ||
115 | * on Solaris 2.6]: ``The direction of stack growth is not | ||
116 | * indicated in the historical definition of struct sigstack. | ||
117 | * The only way to portably establish a stack pointer is for | ||
118 | * the application to determine stack growth direction.'' | ||
119 | */ | ||
120 | ss.ss_sp = sp; | ||
121 | ss.ss_size = stack_size; | ||
122 | ss.ss_flags = 0; | ||
123 | if (sigaltstack(&ss, &oss) < 0) | ||
124 | { | ||
125 | DEBUGF("%s(): %s\n", __func__, strerror(errno)); | ||
126 | return false; | ||
127 | } | ||
128 | |||
129 | /* | ||
130 | * Now transfer control onto the signal stack and set it up. | ||
131 | * It will return immediately via "return" after the setjmp() | ||
132 | * was performed. Be careful here with race conditions. The | ||
133 | * signal can be delivered the first time sigsuspend() is | ||
134 | * called. | ||
135 | */ | ||
136 | sig_handler_called = false; | ||
137 | main_thread = pthread_self(); | ||
138 | sigfillset(&sigs); | ||
139 | sigdelset(&sigs, trampoline_sig); | ||
140 | pthread_kill(main_thread, trampoline_sig); | ||
141 | while(!sig_handler_called) | ||
142 | sigsuspend(&sigs); | ||
143 | |||
144 | /* | ||
145 | * Inform the system that we are back off the signal stack by | ||
146 | * removing the alternative signal stack. Be careful here: It | ||
147 | * first has to be disabled, before it can be removed. | ||
148 | */ | ||
149 | sigaltstack(NULL, &ss); | ||
150 | ss.ss_flags = SS_DISABLE; | ||
151 | if (sigaltstack(&ss, NULL) < 0) | ||
152 | { | ||
153 | DEBUGF("%s(): %s\n", __func__, strerror(errno)); | ||
154 | return false; | ||
155 | } | ||
156 | sigaltstack(NULL, &ss); | ||
157 | if (!(ss.ss_flags & SS_DISABLE)) | ||
158 | { | ||
159 | DEBUGF("%s(): %s\n", __func__, strerror(errno)); | ||
160 | return false; | ||
161 | } | ||
162 | if (!(oss.ss_flags & SS_DISABLE)) | ||
163 | sigaltstack(&oss, NULL); | ||
164 | |||
165 | /* | ||
166 | * Restore the old trampoline_sig signal handler and mask | ||
167 | */ | ||
168 | sigaction(trampoline_sig, &osa, NULL); | ||
169 | sigprocmask(SIG_SETMASK, &osigs, NULL); | ||
170 | |||
171 | /* | ||
172 | * Tell the trampoline and bootstrap function where to dump | ||
173 | * the new machine context, and what to do afterwards... | ||
174 | */ | ||
175 | thread_func = f; | ||
176 | thread_context = ctx; | ||
177 | |||
178 | /* | ||
179 | * Now enter the trampoline again, but this time not as a signal | ||
180 | * handler. Instead we jump into it directly. The functionally | ||
181 | * redundant ping-pong pointer arithmentic is neccessary to avoid | ||
182 | * type-conversion warnings related to the `volatile' qualifier and | ||
183 | * the fact that `jmp_buf' usually is an array type. | ||
184 | */ | ||
185 | if (setjmp(*((jmp_buf *)&bootstrap_buf)) == 0) | ||
186 | longjmp(*((jmp_buf *)&tramp_buf), 1); | ||
187 | |||
188 | /* | ||
189 | * Ok, we returned again, so now we're finished | ||
190 | */ | ||
191 | enable_irq(); | ||
192 | return true; | ||
193 | } | ||
194 | |||
195 | static void trampoline(int sig) | ||
196 | { | ||
197 | (void)sig; | ||
198 | /* sanity check, no other thread should be here */ | ||
199 | if (pthread_self() != main_thread) | ||
200 | return; | ||
201 | |||
202 | if (setjmp(*((jmp_buf *)&tramp_buf)) == 0) | ||
203 | { | ||
204 | sig_handler_called = true; | ||
205 | return; | ||
206 | } | ||
207 | /* longjump'd back in */ | ||
208 | bootstrap_context(); | ||
209 | } | ||
210 | |||
211 | void bootstrap_context(void) | ||
212 | { | ||
213 | /* copy to local storage so we can spawn further threads | ||
214 | * in the meantime */ | ||
215 | void (*thread_entry)(void) = thread_func; | ||
216 | struct ctx *t = thread_context; | ||
217 | |||
218 | /* | ||
219 | * Save current machine state (on new stack) and | ||
220 | * go back to caller until we're scheduled for real... | ||
221 | */ | ||
222 | if (setjmp(t->thread_buf) == 0) | ||
223 | longjmp(*((jmp_buf *)&bootstrap_buf), 1); | ||
224 | |||
225 | /* | ||
226 | * The new thread is now running: GREAT! | ||
227 | * Now we just invoke its init function.... | ||
228 | */ | ||
229 | thread_entry(); | ||
230 | DEBUGF("thread left\n"); | ||
231 | thread_exit(); | ||
232 | } | ||
233 | |||
234 | static inline void set_context(struct ctx *c) | ||
235 | { | ||
236 | longjmp(c->thread_buf, 1); | ||
237 | } | ||
238 | |||
239 | static inline void swap_context(struct ctx *old, struct ctx *new) | ||
240 | { | ||
241 | if (setjmp(old->thread_buf) == 0) | ||
242 | longjmp(new->thread_buf, 1); | ||
243 | } | ||
244 | |||
245 | static inline void get_context(struct ctx *c) | ||
246 | { | ||
247 | setjmp(c->thread_buf); | ||
248 | } | ||
249 | |||
250 | |||
251 | static void setup_thread(struct regs *context); | ||
252 | |||
253 | #define INIT_MAIN_THREAD | ||
254 | static void init_main_thread(void *addr) | ||
255 | { | ||
256 | /* get a context for the main thread so that we can jump to it from | ||
257 | * other threads */ | ||
258 | struct regs *context = (struct regs*)addr; | ||
259 | context->uc = &thread_bufs[curr_uc++]; | ||
260 | get_context(context->uc); | ||
261 | } | ||
262 | |||
263 | #define THREAD_STARTUP_INIT(core, thread, function) \ | ||
264 | ({ (thread)->context.stack_size = (thread)->stack_size, \ | ||
265 | (thread)->context.stack = (uintptr_t)(thread)->stack; \ | ||
266 | (thread)->context.start = function; }) | ||
267 | |||
268 | |||
269 | |||
270 | /* | ||
271 | * Prepare context to make the thread runnable by calling swapcontext on it | ||
272 | */ | ||
273 | static void setup_thread(struct regs *context) | ||
274 | { | ||
275 | void (*fn)(void) = context->start; | ||
276 | context->uc = &thread_bufs[curr_uc++]; | ||
277 | while (!make_context(context->uc, fn, (char*)context->stack, context->stack_size)) | ||
278 | DEBUGF("Thread creation failed. Retrying"); | ||
279 | } | ||
280 | |||
281 | |||
282 | /* | ||
283 | * Save the ucontext_t pointer for later use in swapcontext() | ||
284 | * | ||
285 | * Cannot do getcontext() here, because jumping back to the context | ||
286 | * resumes after the getcontext call (i.e. store_context), but we need | ||
287 | * to resume from load_context() | ||
288 | */ | ||
289 | static inline void store_context(void* addr) | ||
290 | { | ||
291 | struct regs *r = (struct regs*)addr; | ||
292 | target_context = r->uc; | ||
293 | } | ||
294 | |||
295 | /* | ||
296 | * Perform context switch | ||
297 | */ | ||
298 | static inline void load_context(const void* addr) | ||
299 | { | ||
300 | struct regs *r = (struct regs*)addr; | ||
301 | if (UNLIKELY(r->start)) | ||
302 | { | ||
303 | setup_thread(r); | ||
304 | r->start = NULL; | ||
305 | } | ||
306 | swap_context(target_context, r->uc); | ||
307 | } | ||
308 | |||
309 | /* | ||
310 | * play nice with the host and sleep while waiting for the tick */ | ||
311 | extern void wait_for_interrupt(void); | ||
312 | static inline void core_sleep(void) | ||
313 | { | ||
314 | enable_irq(); | ||
315 | wait_for_interrupt(); | ||
316 | } | ||