4 * This file is part of BeRTOS.
6 * Bertos is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 * As a special exception, you may use this file as part of a free software
21 * library without restriction. Specifically, if other files instantiate
22 * templates or use macros or inline functions from this file, or you compile
23 * this file and link it with other files to produce an executable, this
24 * file does not by itself cause the resulting executable to be covered by
25 * the GNU General Public License. This exception does not however
26 * invalidate any other reasons why the executable file might be covered by
27 * the GNU General Public License.
29 * Copyright 2001, 2004 Develer S.r.l. (http://www.develer.com/)
30 * Copyright 1999, 2000, 2001, 2008 Bernie Innocenti <bernie@codewiz.org>
33 * \brief Process scheduler (public interface).
36 * \author Bernie Innocenti <bernie@codewiz.org>
41 #include "cfg/cfg_kern.h"
42 #include <cfg/compiler.h>
44 #if CONFIG_KERN_PREEMPT
45 #include <cfg/debug.h> // ASSERT()
48 #include <cpu/types.h> // cpustack_t
51 * Forward declaration. The definition of struct Process is private to the
52 * scheduler and hidden in proc_p.h.
56 /* Task scheduling services */
58 struct Process *proc_new_with_name(const char* name, void (*entry)(void), iptr_t data, size_t stacksize, cpustack_t *stack);
60 #if !CONFIG_KERN_MONITOR
61 #define proc_new(entry,data,size,stack) proc_new_with_name(NULL,(entry),(data),(size),(stack))
63 #define proc_new(entry,data,size,stack) proc_new_with_name(#entry,(entry),(data),(size),(stack))
67 void proc_yield(void);
68 #define proc_switch proc_yield /* OBSOLETE */
70 int proc_testSetup(void);
71 int proc_testRun(void);
72 int proc_testTearDown(void);
74 struct Process *proc_current(void);
75 iptr_t proc_currentUserData(void);
76 void proc_rename(struct Process *proc, const char *name);
77 const char *proc_name(struct Process *proc);
78 const char *proc_currentName(void);
81 void proc_setPri(struct Process *proc, int pri);
83 INLINE void proc_setPri(UNUSED_ARG(struct Process *,proc), UNUSED_ARG(int, pri))
89 * Disable preemptive task switching.
91 * The scheduler maintains a global nesting counter. Task switching is
92 * effectively re-enabled only when the number of calls to proc_permit()
93 * matches the number of calls to proc_forbid().
95 * \note Calling functions that could sleep while task switching is disabled
96 * is dangerous and unsupported.
98 * \note proc_permit() expands inline to 1-2 asm instructions, so it's a
99 * very efficient locking primitive in simple but performance-critical
100 * situations. In all other cases, semaphores offer a more flexible and
101 * fine-grained locking primitive.
105 INLINE void proc_forbid(void)
107 #if CONFIG_KERN_PREEMPT
108 // No need to protect against interrupts here.
109 extern int preempt_forbid_cnt;
110 ++preempt_forbid_cnt;
113 * Make sure preempt_forbid_cnt is flushed to memory so the
114 * preemption softirq will see the correct value from now on.
121 * Re-enable preemptive task switching.
125 INLINE void proc_permit(void)
127 #if CONFIG_KERN_PREEMPT
130 * This is to ensure any global state changed by the process gets
131 * flushed to memory before task switching is re-enabled.
135 /* No need to protect against interrupts here. */
136 extern int preempt_forbid_cnt;
137 --preempt_forbid_cnt;
138 ASSERT(preempt_forbid_cnt >= 0);
141 * This ensures preempt_forbid_cnt is flushed to memory immediately
142 * so the preemption interrupt sees the correct value.
151 * Execute a block of \a CODE atomically with respect to task scheduling.
153 #define PROC_ATOMIC(CODE) \
160 #ifndef CONFIG_KERN_MINSTACKSIZE
162 #if (ARCH & ARCH_EMUL)
163 /* We need a large stack because system libraries are bloated */
164 #define CONFIG_KERN_MINSTACKSIZE 65536
167 * Default stack size for each thread, in bytes.
169 * The goal here is to allow a minimal task to save all of its
170 * registers twice, plus push a maximum of 32 variables on the
173 * The actual size computed by the default formula is:
179 * Note that on most 16bit architectures, interrupts will also
180 * run on the stack of the currently running process. Nested
181 * interrupts will greatly increases the amount of stack space
182 * required per process. Use irqmanager to minimize stack
185 #define CONFIG_KERN_MINSTACKSIZE \
186 (CPU_SAVED_REGS_CNT * 2 * sizeof(cpustack_t) \
191 #define CONFIG_PROC_DEFSTACKSIZE CONFIG_KERN_MINSTACKSIZE // OBSOLETE
193 /* Memory fill codes to help debugging */
194 #if CONFIG_KERN_MONITOR
195 #include <cpu/types.h>
196 #if (SIZEOF_CPUSTACK_T == 1)
197 /* 8bit cpustack_t */
198 #define CONFIG_KERN_STACKFILLCODE 0xA5
199 #define CONFIG_KERN_MEMFILLCODE 0xDB
200 #elif (SIZEOF_CPUSTACK_T == 2)
201 /* 16bit cpustack_t */
202 #define CONFIG_KERN_STACKFILLCODE 0xA5A5
203 #define CONFIG_KERN_MEMFILLCODE 0xDBDB
204 #elif (SIZEOF_CPUSTACK_T == 4)
205 /* 32bit cpustack_t */
206 #define CONFIG_KERN_STACKFILLCODE 0xA5A5A5A5UL
207 #define CONFIG_KERN_MEMFILLCODE 0xDBDBDBDBUL
208 #elif (SIZEOF_CPUSTACK_T == 8)
209 /* 64bit cpustack_t */
210 #define CONFIG_KERN_STACKFILLCODE 0xA5A5A5A5A5A5A5A5ULL
211 #define CONFIG_KERN_MEMFILLCODE 0xDBDBDBDBDBDBDBDBULL
213 #error No cpustack_t size supported!
217 #endif /* KERN_PROC_H */