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001 /* Copyright (C) 2004 David Decotigny 001 /* Copyright (C) 2004 David Decotigny 002 002 003 This program is free software; you can redi 003 This program is free software; you can redistribute it and/or 004 modify it under the terms of the GNU Genera 004 modify it under the terms of the GNU General Public License 005 as published by the Free Software Foundatio 005 as published by the Free Software Foundation; either version 2 006 of the License, or (at your option) any lat 006 of the License, or (at your option) any later version. 007 007 008 This program is distributed in the hope tha 008 This program is distributed in the hope that it will be useful, 009 but WITHOUT ANY WARRANTY; without even the 009 but WITHOUT ANY WARRANTY; without even the implied warranty of 010 MERCHANTABILITY or FITNESS FOR A PARTICULAR 010 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 011 GNU General Public License for more details 011 GNU General Public License for more details. 012 012 013 You should have received a copy of the GNU 013 You should have received a copy of the GNU General Public License 014 along with this program; if not, write to t 014 along with this program; if not, write to the Free Software 015 Foundation, Inc., 59 Temple Place - Suite 3 015 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 016 USA. 016 USA. 017 */ 017 */ 018 018 019 019 020 #include <hwcore/irq.h> 020 #include <hwcore/irq.h> >> 021 #include <sos/assert.h> 021 022 022 023 023 #include "ksynch.h" 024 #include "ksynch.h" 024 025 025 026 026 sos_ret_t sos_ksema_init(struct sos_ksema *sem 027 sos_ret_t sos_ksema_init(struct sos_ksema *sema, const char *name, 027 int initial_value) !! 028 int initial_value, >> 029 sos_kwaitq_ordering_t ordering) 028 { 030 { 029 sema->value = initial_value; 031 sema->value = initial_value; 030 return sos_kwaitq_init(& sema->kwaitq, name) !! 032 return sos_kwaitq_init(& sema->kwaitq, name, ordering); 031 } 033 } 032 034 033 035 034 sos_ret_t sos_ksema_dispose(struct sos_ksema * 036 sos_ret_t sos_ksema_dispose(struct sos_ksema *sema) 035 { 037 { 036 return sos_kwaitq_dispose(& sema->kwaitq); 038 return sos_kwaitq_dispose(& sema->kwaitq); 037 } 039 } 038 040 039 041 040 sos_ret_t sos_ksema_down(struct sos_ksema *sem 042 sos_ret_t sos_ksema_down(struct sos_ksema *sema, 041 struct sos_time *time 043 struct sos_time *timeout) 042 { 044 { 043 sos_ui32_t flags; 045 sos_ui32_t flags; 044 sos_ret_t retval; 046 sos_ret_t retval; 045 047 046 sos_disable_IRQs(flags); 048 sos_disable_IRQs(flags); 047 retval = SOS_OK; 049 retval = SOS_OK; 048 050 049 sema->value --; 051 sema->value --; 050 if (sema->value < 0) 052 if (sema->value < 0) 051 { 053 { 052 /* Wait for somebody to wake us */ 054 /* Wait for somebody to wake us */ 053 retval = sos_kwaitq_wait(& sema->kwaitq, 055 retval = sos_kwaitq_wait(& sema->kwaitq, timeout); 054 056 055 /* Something wrong happened (timeout, ex 057 /* Something wrong happened (timeout, external wakeup, ...) ? */ 056 if (SOS_OK != retval) 058 if (SOS_OK != retval) 057 { 059 { 058 /* Yes: pretend we did not ask for t 060 /* Yes: pretend we did not ask for the semaphore */ 059 sema->value ++; 061 sema->value ++; 060 } 062 } 061 } 063 } 062 064 063 sos_restore_IRQs(flags); 065 sos_restore_IRQs(flags); 064 return retval; 066 return retval; 065 } 067 } 066 068 067 069 068 sos_ret_t sos_ksema_trydown(struct sos_ksema * 070 sos_ret_t sos_ksema_trydown(struct sos_ksema *sema) 069 { 071 { 070 sos_ui32_t flags; 072 sos_ui32_t flags; 071 sos_ret_t retval; 073 sos_ret_t retval; 072 074 073 sos_disable_IRQs(flags); 075 sos_disable_IRQs(flags); 074 076 075 /* Can we take the semaphore without blockin 077 /* Can we take the semaphore without blocking ? */ 076 if (sema->value >= 1) 078 if (sema->value >= 1) 077 { 079 { 078 /* Yes: we take it now */ 080 /* Yes: we take it now */ 079 sema->value --; 081 sema->value --; 080 retval = SOS_OK; 082 retval = SOS_OK; 081 } 083 } 082 else 084 else 083 { 085 { 084 /* No: we signal it */ 086 /* No: we signal it */ 085 retval = -SOS_EBUSY; 087 retval = -SOS_EBUSY; 086 } 088 } 087 089 088 sos_restore_IRQs(flags); 090 sos_restore_IRQs(flags); 089 return retval; 091 return retval; 090 } 092 } 091 093 092 094 093 sos_ret_t sos_ksema_up(struct sos_ksema *sema) 095 sos_ret_t sos_ksema_up(struct sos_ksema *sema) 094 { 096 { 095 sos_ui32_t flags; 097 sos_ui32_t flags; 096 sos_ret_t retval; 098 sos_ret_t retval; 097 099 098 sos_disable_IRQs(flags); 100 sos_disable_IRQs(flags); 099 101 100 sema->value ++; 102 sema->value ++; 101 retval = sos_kwaitq_wakeup(& sema->kwaitq, 1 103 retval = sos_kwaitq_wakeup(& sema->kwaitq, 1, SOS_OK); 102 104 103 sos_restore_IRQs(flags); 105 sos_restore_IRQs(flags); 104 return retval; 106 return retval; 105 } 107 } 106 108 107 109 108 sos_ret_t sos_kmutex_init(struct sos_kmutex *m !! 110 sos_ret_t sos_kmutex_init(struct sos_kmutex *mutex, const char *name, >> 111 sos_kwaitq_ordering_t ordering) 109 { 112 { 110 mutex->owner = NULL; 113 mutex->owner = NULL; 111 return sos_kwaitq_init(& mutex->kwaitq, name !! 114 return sos_kwaitq_init(& mutex->kwaitq, name, ordering); 112 } 115 } 113 116 114 117 115 sos_ret_t sos_kmutex_dispose(struct sos_kmutex 118 sos_ret_t sos_kmutex_dispose(struct sos_kmutex *mutex) 116 { 119 { 117 return sos_kwaitq_dispose(& mutex->kwaitq); 120 return sos_kwaitq_dispose(& mutex->kwaitq); 118 } 121 } 119 122 120 123 121 /* 124 /* 122 * Implementation based on ownership transfer 125 * Implementation based on ownership transfer (ie no while() 123 * loop). The only assumption is that the thre 126 * loop). The only assumption is that the thread awoken by 124 * kmutex_unlock is not suppressed before effe 127 * kmutex_unlock is not suppressed before effectively waking up: in 125 * that case the mutex will be forever locked 128 * that case the mutex will be forever locked AND unlockable (by 126 * nobody other than the owner, but this is no 129 * nobody other than the owner, but this is not natural since this 127 * owner already issued an unlock()...). The s 130 * owner already issued an unlock()...). The same problem happens with 128 * the semaphores, but in a less obvious manne 131 * the semaphores, but in a less obvious manner. 129 */ 132 */ 130 sos_ret_t sos_kmutex_lock(struct sos_kmutex *m 133 sos_ret_t sos_kmutex_lock(struct sos_kmutex *mutex, 131 struct sos_time *tim 134 struct sos_time *timeout) 132 { 135 { 133 __label__ exit_kmutex_lock; 136 __label__ exit_kmutex_lock; 134 sos_ui32_t flags; 137 sos_ui32_t flags; 135 sos_ret_t retval; 138 sos_ret_t retval; 136 139 137 sos_disable_IRQs(flags); 140 sos_disable_IRQs(flags); 138 retval = SOS_OK; 141 retval = SOS_OK; 139 142 140 /* Mutex already owned ? */ 143 /* Mutex already owned ? */ 141 if (NULL != mutex->owner) 144 if (NULL != mutex->owner) 142 { 145 { 143 /* Owned by us or by someone else ? */ 146 /* Owned by us or by someone else ? */ 144 if (sos_thread_get_current() == mutex->o 147 if (sos_thread_get_current() == mutex->owner) 145 { 148 { 146 /* Owned by us: do nothing */ 149 /* Owned by us: do nothing */ 147 retval = -SOS_EBUSY; 150 retval = -SOS_EBUSY; 148 goto exit_kmutex_lock; 151 goto exit_kmutex_lock; 149 } 152 } 150 153 151 /* Wait for somebody to wake us */ 154 /* Wait for somebody to wake us */ 152 retval = sos_kwaitq_wait(& mutex->kwaitq 155 retval = sos_kwaitq_wait(& mutex->kwaitq, timeout); 153 156 154 /* Something wrong happened ? */ 157 /* Something wrong happened ? */ 155 if (SOS_OK != retval) 158 if (SOS_OK != retval) 156 { 159 { 157 goto exit_kmutex_lock; 160 goto exit_kmutex_lock; 158 } 161 } 159 } 162 } 160 163 161 /* Ok, the mutex is available to us: take it 164 /* Ok, the mutex is available to us: take it */ 162 mutex->owner = sos_thread_get_current(); 165 mutex->owner = sos_thread_get_current(); 163 166 164 exit_kmutex_lock: 167 exit_kmutex_lock: 165 sos_restore_IRQs(flags); 168 sos_restore_IRQs(flags); 166 return retval; 169 return retval; 167 } 170 } 168 171 169 172 >> 173 sos_bool_t sos_kmutex_owned_by_me(struct sos_kmutex const* mutex) >> 174 { >> 175 sos_ui32_t flags; >> 176 sos_bool_t retval; >> 177 >> 178 sos_disable_IRQs(flags); >> 179 retval = (sos_thread_get_current() == mutex->owner); >> 180 sos_restore_IRQs(flags); >> 181 >> 182 return retval; >> 183 } >> 184 >> 185 170 sos_ret_t sos_kmutex_trylock(struct sos_kmutex 186 sos_ret_t sos_kmutex_trylock(struct sos_kmutex *mutex) 171 { 187 { 172 sos_ui32_t flags; 188 sos_ui32_t flags; 173 sos_ret_t retval; 189 sos_ret_t retval; 174 190 175 sos_disable_IRQs(flags); 191 sos_disable_IRQs(flags); 176 192 177 /* Mutex available to us ? */ 193 /* Mutex available to us ? */ 178 if (NULL == mutex->owner) 194 if (NULL == mutex->owner) 179 { 195 { 180 /* Great ! Take it now */ 196 /* Great ! Take it now */ 181 mutex->owner = sos_thread_get_current(); 197 mutex->owner = sos_thread_get_current(); 182 198 183 retval = SOS_OK; 199 retval = SOS_OK; 184 } 200 } 185 else 201 else 186 { 202 { 187 /* No: signal it */ 203 /* No: signal it */ 188 retval = -SOS_EBUSY; 204 retval = -SOS_EBUSY; 189 } 205 } 190 206 191 sos_restore_IRQs(flags); 207 sos_restore_IRQs(flags); 192 return retval; 208 return retval; 193 } 209 } 194 210 195 211 196 sos_ret_t sos_kmutex_unlock(struct sos_kmutex 212 sos_ret_t sos_kmutex_unlock(struct sos_kmutex *mutex) 197 { 213 { 198 sos_ui32_t flags; 214 sos_ui32_t flags; 199 sos_ret_t retval; 215 sos_ret_t retval; 200 216 201 sos_disable_IRQs(flags); 217 sos_disable_IRQs(flags); 202 218 203 if (sos_thread_get_current() != mutex->owner 219 if (sos_thread_get_current() != mutex->owner) 204 retval = -SOS_EPERM; 220 retval = -SOS_EPERM; 205 221 206 else if (sos_kwaitq_is_empty(& mutex->kwaitq 222 else if (sos_kwaitq_is_empty(& mutex->kwaitq)) 207 { 223 { 208 /* 224 /* 209 * There is NOT ANY thread waiting => we 225 * There is NOT ANY thread waiting => we really mark the mutex 210 * as FREE 226 * as FREE 211 */ 227 */ 212 mutex->owner = NULL; 228 mutex->owner = NULL; 213 retval = SOS_OK; 229 retval = SOS_OK; 214 } 230 } 215 else 231 else 216 { 232 { 217 /* 233 /* 218 * There is at least 1 thread waiting => 234 * There is at least 1 thread waiting => we DO NOT mark the 219 * mutex as free ! 235 * mutex as free ! 220 * Actually, we should have written: 236 * Actually, we should have written: 221 * mutex->owner = thread_that_is_woken 237 * mutex->owner = thread_that_is_woken_up; 222 * But the real Id of the next thread ow 238 * But the real Id of the next thread owning the mutex is not 223 * that important. What is important her 239 * that important. What is important here is that mutex->owner 224 * IS NOT NULL. Otherwise there will be !! 240 * IS NOT NULL and does not correspond to any existing thread >> 241 * (address 0x43 is a good candidate because, in SOS, addresses >> 242 * below 4kB are never mapped in order to catch invalid >> 243 * pointers). Otherwise there will be a possibility for the 225 * thread woken up here to have the mute 244 * thread woken up here to have the mutex stolen by a thread 226 * locking the mutex in the meantime. 245 * locking the mutex in the meantime. 227 */ 246 */ >> 247 #define MUTEX_STILL_LOCKED ((struct sos_thread*) 0x43) >> 248 mutex->owner = MUTEX_STILL_LOCKED; >> 249 >> 250 /* We wake up ONE thread ONLY */ 228 retval = sos_kwaitq_wakeup(& mutex->kwai 251 retval = sos_kwaitq_wakeup(& mutex->kwaitq, 1, SOS_OK); 229 } 252 } 230 253 231 sos_restore_IRQs(flags); 254 sos_restore_IRQs(flags); 232 return retval; 255 return retval; 233 } 256 }
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