Add libunwindstack support for Mips and Mips64

This patch requires v3.18 kernel or above, because v3.10 kernel
has a bug (as of 8/1/2017) in the ptrace(GETREGSET) function for mips
and mips64.

Change-Id: I004c1fa190193eebe1c84440b366289122a6bd8a
Signed-off-by: Douglas Leung <douglas.leung@mips.com>
Signed-off-by: Dejan Jovicevic <dejan.jovicevic@mips.com>
diff --git a/libunwindstack/UcontextMips.h b/libunwindstack/UcontextMips.h
new file mode 100644
index 0000000..27185e7
--- /dev/null
+++ b/libunwindstack/UcontextMips.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
+ * COPYRIGHT OWNER 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 _LIBUNWINDSTACK_UCONTEXT_MIPS_H
+#define _LIBUNWINDSTACK_UCONTEXT_MIPS_H
+
+#include <stdint.h>
+
+#include "MachineMips.h"
+
+namespace unwindstack {
+
+struct mips_stack_t {
+  uint32_t ss_sp;    // void __user*
+  uint32_t ss_size;  // size_t
+  int32_t ss_flags;  // int
+};
+
+struct mips_mcontext_t {
+  uint32_t sc_regmask;
+  uint32_t sc_status;
+  uint64_t sc_pc;
+  uint64_t sc_regs[32];
+  // Nothing else is used, so don't define it.
+};
+
+struct mips_ucontext_t {
+  uint32_t uc_flags;  // unsigned long
+  uint32_t uc_link;   // struct ucontext*
+  mips_stack_t uc_stack;
+  mips_mcontext_t uc_mcontext;
+  // Nothing else is used, so don't define it.
+};
+
+}  // namespace unwindstack
+
+#endif  // _LIBUNWINDSTACK_UCONTEXT_MIPS_H