Synchronization, part II (#96)

* Add lock to logger.
* Add lock to page allocator.

include/kernel/infrastructure/i686/exports/spinlock.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2024 Philippe Aubertin.
+ * All rights reserved.
+
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 
+ * 3. Neither the name of the author nor the names of other contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef JINUE_KERNEL_INFRASTRUCTURE_I686_EXPORTS_SPINLOCK_H
+#define JINUE_KERNEL_INFRASTRUCTURE_I686_EXPORTS_SPINLOCK_H
+
+/** static initializer for a spinlock */
+#define SPINLOCK_INITIALIZER { .lock = 0 }
+
+#endif

include/kernel/infrastructure/i686/exports.h → include/kernel/infrastructure/i686/exports/types.h

@@ -29,8 +29,8 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef JINUE_KERNEL_INFRASTRUCTURE_I686_EXPORTS_H
-#define JINUE_KERNEL_INFRASTRUCTURE_I686_EXPORTS_H
+#ifndef JINUE_KERNEL_INFRASTRUCTURE_I686_EXPORTS_TYPES_H
+#define JINUE_KERNEL_INFRASTRUCTURE_I686_EXPORTS_TYPES_H
 
 #include <kernel/typedeps.h>
 

include/kernel/infrastructure/i686/types.h

@@ -33,7 +33,7 @@
 #define JINUE_KERNEL_INFRASTRUCTURE_I686_TYPES_H
 
 #include <kernel/infrastructure/i686/asm/descriptors.h>
-#include <kernel/infrastructure/i686/exports.h>
+#include <kernel/infrastructure/i686/exports/types.h>
 #include <kernel/machine/types.h>
 #include <kernel/types.h>
 #include <sys/elf.h>

include/kernel/machine/spinlock.h

@@ -34,7 +34,10 @@
 
 #include <kernel/machine/types.h>
 
-#define SPINLOCK_STATIC { .lock = 0 }
+/* Must define SPINLOCK_INITIALIZER. */
+#ifdef __i686__
+#include <kernel/infrastructure/i686/exports/spinlock.h>
+#endif
 
 void init_spinlock(spinlock_t *lock);
 
@@ -43,4 +46,3 @@ void spin_lock(spinlock_t *lock);
 void spin_unlock(spinlock_t *lock);
 
 #endif
-

include/kernel/machine/types.h

@@ -33,7 +33,7 @@
 #define JINUE_KERNEL_MACHINE_TYPES_H
 
 #ifdef __i686__
-#include <kernel/infrastructure/i686/exports.h>
+#include <kernel/infrastructure/i686/exports/types.h>
 #endif
 
 #endif

include/kernel/typedeps.h

@@ -40,7 +40,7 @@
  *      <kernel/typedeps.h>
  *          ^       ^
  *          |       |
- *          |   e.g. <kernel/infrastructure/i686/exports.h> for i686
+ *          |   e.g. <kernel/infrastructure/i686/exports/types.h> for i686
  *          |       ^
  *          |       |
  *          |   <kernel/machine/types.h>

include/kernel/utils/list.h

@@ -49,7 +49,7 @@ typedef struct  {
 
 typedef list_node_t **list_cursor_t;
 
-#define STATIC_LIST   {.head = NULL, .tail = NULL}
+#define LIST_INITIALIZER {.head = NULL, .tail = NULL}
 
 static inline void init_list(list_t *list) {
     list->head = NULL;

kernel/domain/alloc/page_alloc.c

@@ -34,6 +34,7 @@
 #include <kernel/domain/alloc/vmalloc.h>
 #include <kernel/machine/asm/machine.h>
 #include <kernel/machine/pmap.h>
+#include <kernel/machine/spinlock.h>
 #include <string.h>
 
 
@@ -43,7 +44,9 @@ struct alloc_page {
 
 static struct alloc_page *head_page = NULL;
 
-unsigned int page_count = 0;
+static unsigned int page_count = 0;
+
+static spinlock_t alloc_lock;
 
 /**
  * Allocate a page of kernel memory.
@@ -55,13 +58,17 @@ unsigned int page_count = 0;
  *
  * */
 void *page_alloc(void) {
+    spin_lock(&alloc_lock);
+
     struct alloc_page *alloc_page = head_page;
 
     if(alloc_page != NULL) {
         head_page = alloc_page->next;
         --page_count;
     }
 
+    spin_unlock(&alloc_lock);
+
     return alloc_page;
 }
 
@@ -79,10 +86,14 @@ void *page_alloc(void) {
  *
  * */
 void page_free(void *page) {
+    spin_lock(&alloc_lock);
+
     struct alloc_page *alloc_page = page;
     alloc_page->next    = head_page;
     head_page           = alloc_page;
     ++page_count;
+
+    spin_unlock(&alloc_lock);
 }
 
 /** 

kernel/domain/services/logging.c

@@ -31,17 +31,22 @@
 
 #include <jinue/shared/asm/logging.h>
 #include <kernel/domain/services/logging.h>
+#include <kernel/machine/spinlock.h>
 #include <kernel/utils/list.h>
 #include <kernel/types.h>
 #include <stdio.h>
 
-list_t loggers = STATIC_LIST;
+static list_t loggers = LIST_INITIALIZER;
+
+static spinlock_t logging_spinlock = SPINLOCK_INITIALIZER;
 
 void register_logger(logger_t *logger) {
     list_enqueue(&loggers, &logger->loggers);
 }
 
 static void log_message(int loglevel, const char *restrict format, va_list args) {
+    spin_lock(&logging_spinlock);
+
     /* TODO implement kernel logs ring buffer and get rid of this buffer
      *
      * This is static so it does not take a big chunk of the thread's stack. The
@@ -50,6 +55,8 @@ static void log_message(int loglevel, const char *restrict format, va_list args)
 
     size_t length = vsnprintf(message, sizeof(message), format, args);
     logging_add_message(loglevel, message, length);
+
+    spin_unlock(&logging_spinlock);
 }
 
 void logging_add_message(int loglevel, const char *message, size_t n) {

kernel/domain/services/scheduler.c

@@ -41,8 +41,8 @@ static struct {
     list_t          queue;
     spinlock_t      lock;
 } ready_queue = {
-    .queue  = STATIC_LIST,
-    .lock   = SPINLOCK_STATIC
+    .queue  = LIST_INITIALIZER,
+    .lock   = SPINLOCK_INITIALIZER
 };
 
 /**