libc/machine/xtensa: add mcount implementation for gprof

Add the implementation of _mcount() to meet the requirements of gprof.

Signed-off-by: chenxiaoyi <chenxiaoyi@xiaomi.com>

libs/libc/machine/xtensa/CMakeLists.txt

@@ -55,4 +55,8 @@ if(CONFIG_XTENSA_STRCMP)
   list(APPEND CSRCS arch_strcmp.S)
 endif()
 
+if(NOT CONFIG_PROFILE_NONE)
+  list(APPEND CSRCS arch_mcount.c)
+endif()
+
 target_sources(c PRIVATE ${CSRCS})

libs/libc/machine/xtensa/Make.defs

@@ -56,6 +56,10 @@ ifeq ($(CONFIG_XTENSA_STRCMP),y)
 ASRCS += arch_strcmp.S
 endif
 
+ifeq ($(CONFIG_PROFILE_NONE),)
+CSRCS += arch_mcount.c
+endif
+
 DEPPATH += --dep-path machine/xtensa
 VPATH += :machine/xtensa
 

libs/libc/machine/xtensa/arch_mcount.c

@@ -0,0 +1,68 @@
+/****************************************************************************
+ * libs/libc/machine/xtensa/arch_mcount.c
+ *
+ * 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 <sys/gmon.h>
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: _mcount
+ *
+ * Description:
+ *   This is the Xtensa mcount function.  It is called by the profiling logic
+ *   to record the call.
+ *
+ * Input Parameters:
+ *   frompc - The address of the calling instruction
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+noinstrument_function
+void _mcount(uintptr_t from_pc)
+{
+#ifndef __XTENSA_CALL0_ABI__
+  uint32_t high_bit_mask = (0x03 << 30);
+  uint32_t low_bit_mask = ~high_bit_mask;
+  uint32_t pc_high_bits = ((uint32_t)_mcount) & high_bit_mask;
+#endif
+  uintptr_t self_pc;
+
+  __asm__ __volatile__
+  (
+    "mov %0, a0\n"
+    : "=r" (self_pc)
+  );
+
+#ifndef __XTENSA_CALL0_ABI__
+  self_pc = pc_high_bits | (self_pc & low_bit_mask);
+  from_pc = pc_high_bits | (from_pc & low_bit_mask);
+#endif
+
+  mcount_internal(from_pc, self_pc);
+}