Add qemu 2.4.0

[kvmfornfv.git] / qemu / roms / ipxe / src / core / process.c

diff --git a/qemu/roms/ipxe/src/core/process.c b/qemu/roms/ipxe/src/core/process.c
new file mode 100644 (file)
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+++ b/qemu/roms/ipxe/src/core/process.c
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+/*
+ * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <ipxe/list.h>
+#include <ipxe/init.h>
+#include <ipxe/process.h>
+
+/** @file
+ *
+ * Processes
+ *
+ * We implement a trivial form of cooperative multitasking, in which
+ * all processes share a single stack and address space.
+ */
+
+/** Process run queue */
+static LIST_HEAD ( run_queue );
+
+/**
+ * Get pointer to object containing process
+ *
+ * @v process          Process
+ * @ret object         Containing object
+ */
+void * process_object ( struct process *process ) {
+       return ( ( ( void * ) process ) - process->desc->offset );
+}
+
+/**
+ * Add process to process list
+ *
+ * @v process          Process
+ *
+ * It is safe to call process_add() multiple times; further calls will
+ * have no effect.
+ */
+void process_add ( struct process *process ) {
+       if ( ! process_running ( process ) ) {
+               DBGC ( PROC_COL ( process ), "PROCESS " PROC_FMT
+                      " starting\n", PROC_DBG ( process ) );
+               ref_get ( process->refcnt );
+               list_add_tail ( &process->list, &run_queue );
+       } else {
+               DBGC ( PROC_COL ( process ), "PROCESS " PROC_FMT
+                      " already started\n", PROC_DBG ( process ) );
+       }
+}
+
+/**
+ * Remove process from process list
+ *
+ * @v process          Process
+ *
+ * It is safe to call process_del() multiple times; further calls will
+ * have no effect.
+ */
+void process_del ( struct process *process ) {
+       if ( process_running ( process ) ) {
+               DBGC ( PROC_COL ( process ), "PROCESS " PROC_FMT
+                      " stopping\n", PROC_DBG ( process ) );
+               list_del ( &process->list );
+               INIT_LIST_HEAD ( &process->list );
+               ref_put ( process->refcnt );
+       } else {
+               DBGC ( PROC_COL ( process ), "PROCESS " PROC_FMT
+                      " already stopped\n", PROC_DBG ( process ) );
+       }
+}
+
+/**
+ * Single-step a single process
+ *
+ * This executes a single step of the first process in the run queue,
+ * and moves the process to the end of the run queue.
+ */
+void step ( void ) {
+       struct process *process;
+       struct process_descriptor *desc;
+       void *object;
+
+       if ( ( process = list_first_entry ( &run_queue, struct process,
+                                           list ) ) ) {
+               ref_get ( process->refcnt ); /* Inhibit destruction mid-step */
+               desc = process->desc;
+               object = process_object ( process );
+               if ( desc->reschedule ) {
+                       list_del ( &process->list );
+                       list_add_tail ( &process->list, &run_queue );
+               } else {
+                       process_del ( process );
+               }
+               DBGC2 ( PROC_COL ( process ), "PROCESS " PROC_FMT
+                       " executing\n", PROC_DBG ( process ) );
+               desc->step ( object );
+               DBGC2 ( PROC_COL ( process ), "PROCESS " PROC_FMT
+                       " finished executing\n", PROC_DBG ( process ) );
+               ref_put ( process->refcnt ); /* Allow destruction */
+       }
+}
+
+/**
+ * Initialise processes
+ *
+ */
+static void init_processes ( void ) {
+       struct process *process;
+
+       for_each_table_entry ( process, PERMANENT_PROCESSES )
+               process_add ( process );
+}
+
+/** Process initialiser */
+struct init_fn process_init_fn __init_fn ( INIT_NORMAL ) = {
+       .initialise = init_processes,
+};