xtensa: Implement simcall

arch/xtensa/include/simcall.h

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+/****************************************************************************
+ * arch/xtensa/include/simcall.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __ARCH_XTENSA_INCLUDE_SIMCALL_H
+#define __ARCH_XTENSA_INCLUDE_SIMCALL_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define SIMCALL_SYS_READ    3
+#define SIMCALL_SYS_WRITE   4
+#define SIMCALL_SYS_OPEN    5
+#define SIMCALL_SYS_CLOSE   6
+#define SIMCALL_SYS_LSEEK   19
+
+/* fcntl O_xxx constants for simcall.
+ *
+ * Someone with the official spec should fix this and qemu.
+ * I made this CONFIG_HOST_xxx dependant because:
+ *  - the qemu implementation just pass them to the host OS
+ *  - I don't have an official documentation.
+ *  - I build NuttX and run qemu on the same host.
+ * I know this is wrong. But it works for me.
+ */
+
+#if CONFIG_HOST_MACOS
+#define SIMCALL_O_RDONLY   0x0000
+#define SIMCALL_O_WRONLY   0x0001
+#define SIMCALL_O_RDWR     0x0003
+#define SIMCALL_O_ACCMODE  0x0003
+#define SIMCALL_O_APPEND   0x0008
+#define SIMCALL_O_CREAT    0x0200
+#define SIMCALL_O_TRUNC    0x0400
+#define SIMCALL_O_EXCL     0x0800
+#else
+
+/* Assume Linux */
+
+#define SIMCALL_O_RDONLY   0x0000
+#define SIMCALL_O_WRONLY   0x0001
+#define SIMCALL_O_RDWR     0x0002
+#define SIMCALL_O_ACCMODE  0x0003
+#define SIMCALL_O_APPEND   0x0400
+#define SIMCALL_O_CREAT    0x0040
+#define SIMCALL_O_TRUNC    0x0200
+#define SIMCALL_O_EXCL     0x0080
+#endif
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Inline functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+int simcall(int nr, int param1, int param2, int param3, int *errp);
+
+#endif /* __ARCH_XTENSA_INCLUDE_SIMCALL_H */

arch/xtensa/src/common/xtensa_simcall.S

@@ -0,0 +1,60 @@
+/****************************************************************************
+ * arch/xtensa/src/common/xtensa_simcall.S
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include "xtensa_abi.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: simcall
+ *
+ * Description:
+ *   Execute a SIMCALL instruction
+ *
+ * Entry Conditions:
+ *   A2     - SIMCALL number
+ *   A3..A5 - SIMCALL arguments
+ *   A6     - the pointer to store errno
+ *
+ ****************************************************************************/
+
+    .global simcall
+    .type   simcall, @function
+
+simcall:
+    ENTRY0
+
+    simcall
+
+    /* A2 - return value
+     * A3 - errno
+     */
+
+    s32i	a3, a6, 0 /* store errno */
+
+    RET0