Changeset db4d6de in mainline for kernel/generic/include

Timestamp:

2009-11-28T16:30:43Z (17 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/fix-logger-deadlock, topic/msim-upgrade, topic/simplify-dev-export

Children:

c4702804

Parents:

ba8f8cb (diff), 67392fa (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge mainline changes.

Location:

kernel/generic/include

Files:

• context.h (modified) (2 diffs)
• ipc/ipc.h (modified) (3 diffs)
• proc/task.h (modified) (2 diffs)

kernel/generic/include/context.h

@@ -51 +51 @@
 /** Save register context.
  *
- * Save current register context (including stack pointers)
- * to context structure.
- *
- * Note that call to context_restore() will return at the same
+ * Save the current register context (including stack pointer) to a context
+ * structure. A subsequent call to context_restore() will return to the same
  * address as the corresponding call to context_save().
  *
- * This MUST be a macro, gcc -O0 does not inline functions even
- * if they are marked inline and context_save_arch must be called
- * from level <= that when context_restore is called.
+ * Note that context_save_arch() must reuse the stack frame of the function
+ * which called context_save(). We guarantee this by:
  *
- * @param c Context structure.
+ *   a) implementing context_save_arch() in assembly so that it does not create
+ *      its own stack frame, and by
+ *   b) defining context_save() as a macro because the inline keyword is just a
+ *      hint for the compiler, not a real constraint; the application of a macro
+ *      will definitely not create a stack frame either.
  *
- * @return context_save() returns 1, context_restore() returns 0.
+ * To imagine what could happen if there were some extra stack frames created
+ * either by context_save() or context_save_arch(), we need to realize that the
+ * sp saved in the contex_t structure points to the current stack frame as it
+ * existed when context_save_arch() was executing. After the return from
+ * context_save_arch() and context_save(), any extra stack frames created by
+ * these functions will be destroyed and their contents sooner or later
+ * overwritten by functions called next. Any attempt to restore to a context
+ * saved like that would therefore lead to a disaster.
+ *
+ * @param c             Context structure.
+ *
+ * @return              context_save() returns 1, context_restore() returns 0.
  */
 #define context_save(c)   context_save_arch(c)
@@ -69 +81 @@
 /** Restore register context.
  *
- * Restore previously saved register context (including stack pointers)
- * from context structure.
+ * Restore a previously saved register context (including stack pointer) from
+ * a context structure.
  *
- * Note that this function does not normally return.
- * Instead, it returns at the same address as the
- * corresponding call to context_save(), the only
- * difference being return value.
+ * Note that this function does not normally return.  Instead, it returns to the
+ * same address as the corresponding call to context_save(), the only difference
+ * being return value.
  *
- * @param c Context structure.
+ * @param c             Context structure.
  */
 static inline void context_restore(context_t *c)

kernel/generic/include/ipc/ipc.h

@@ -51 +51 @@
 /** This is answer to a call */
 #define IPC_CALL_ANSWERED       (1 << 0)
-/** This call will not be freed on error */
-#define IPC_CALL_STATIC_ALLOC   (1 << 1)
 /** Answer will not be passed to userspace, will be discarded */
-#define IPC_CALL_DISCARD_ANSWER (1 << 2)
+#define IPC_CALL_DISCARD_ANSWER (1 << 1)
 /** Call was forwarded */
-#define IPC_CALL_FORWARDED      (1 << 3)
+#define IPC_CALL_FORWARDED      (1 << 2)
 /** Identify connect_me_to answer */
-#define IPC_CALL_CONN_ME_TO     (1 << 4)
+#define IPC_CALL_CONN_ME_TO     (1 << 3)
 /** Interrupt notification */
-#define IPC_CALL_NOTIF          (1 << 5)
+#define IPC_CALL_NOTIF          (1 << 4)
 
 /*
@@ -267 +265 @@
         waitq_t wq;
 
+        /** Linkage for the list of task's synchronous answerboxes. */
+        link_t sync_box_link;
+
         /** Phones connected to this answerbox. */
         link_t connected_phones;
@@ -316 +317 @@
 } call_t;
 
+
+extern answerbox_t *ipc_phone_0;
+
+
 extern void ipc_init(void);
-extern call_t * ipc_wait_for_call(answerbox_t *, uint32_t, int);
-extern void ipc_answer(answerbox_t *, call_t *);
+
+extern call_t * ipc_call_alloc(int);
+extern void ipc_call_free(call_t *);
+
 extern int ipc_call(phone_t *, call_t *);
 extern int ipc_call_sync(phone_t *, call_t *);
+extern call_t * ipc_wait_for_call(answerbox_t *, uint32_t, int);
+extern int ipc_forward(call_t *, phone_t *, answerbox_t *, int);
+extern void ipc_answer(answerbox_t *, call_t *);
+
 extern void ipc_phone_init(phone_t *);
 extern void ipc_phone_connect(phone_t *, answerbox_t *);
-extern void ipc_call_free(call_t *);
-extern call_t * ipc_call_alloc(int);
+extern int ipc_phone_hangup(phone_t *);
+
 extern void ipc_answerbox_init(answerbox_t *, struct task *);
-extern void ipc_call_static_init(call_t *);
-extern void task_print_list(void);
-extern int ipc_forward(call_t *, phone_t *, answerbox_t *, int);
+
 extern void ipc_cleanup(void);
-extern int ipc_phone_hangup(phone_t *);
 extern void ipc_backsend_err(phone_t *, call_t *, unative_t);
-extern void ipc_print_task(task_id_t);
 extern void ipc_answerbox_slam_phones(answerbox_t *, bool);
 extern void ipc_cleanup_call_list(link_t *);
 
-extern answerbox_t *ipc_phone_0;
+extern void ipc_print_task(task_id_t);
 
 #endif

kernel/generic/include/proc/task.h

@@ -98 +98 @@
          */
         atomic_t active_calls;
+        /** List of synchronous answerboxes. */
+        link_t sync_box_head;
 
 #ifdef CONFIG_UDEBUG
@@ -132 +134 @@
 extern int task_kill(task_id_t id);
 extern uint64_t task_get_accounting(task_t *t);
+extern void task_print_list(void);
 
 extern void cap_set(task_t *t, cap_t caps);