Non-SFI mode: Add Linux asynchronous signal support

src/nonsfi/linux/irt_signal_handling.h

Index: src/nonsfi/linux/irt_signal_handling.h
diff --git a/src/nonsfi/linux/irt_signal_handling.h b/src/nonsfi/linux/irt_signal_handling.h
new file mode 100644
index 0000000000000000000000000000000000000000..42e7f9e3af01f2ff97ddf6ed547dd22dea40d4bb
--- /dev/null
+++ b/src/nonsfi/linux/irt_signal_handling.h
@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 2015 The Native Client Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef NATIVE_CLIENT_SRC_NONSFI_LINUX_IRT_SIGNAL_HANDLING_H_
+#define NATIVE_CLIENT_SRC_NONSFI_LINUX_IRT_SIGNAL_HANDLING_H_ 1
+
+#include <pthread.h>
+
+#include "native_client/src/include/nacl/nacl_exception.h"
+
+EXTERN_C_BEGIN
+
+#if defined(__i386__)
+
+/* From linux/arch/x86/include/uapi/asm/sigcontext32.h */
+struct sigcontext_ia32 {
+  unsigned short gs, __gsh;
+  unsigned short fs, __fsh;
+  unsigned short es, __esh;
+  unsigned short ds, __dsh;
+  unsigned int di;
+  unsigned int si;
+  unsigned int bp;
+  unsigned int sp;
+  unsigned int bx;
+  unsigned int dx;
+  unsigned int cx;
+  unsigned int ax;
+  unsigned int trapno;
+  unsigned int err;
+  unsigned int ip;
+  unsigned short cs, __csh;
+  unsigned int flags;
+  unsigned int sp_at_signal;
+  unsigned short ss, __ssh;
+  unsigned int fpstate;
+  unsigned int oldmask;
+  unsigned int cr2;
+};
+
+typedef struct sigcontext_ia32 linux_mcontext_t;
+
+#elif defined(__arm__)
+
+/* From linux/arch/arm/include/uapi/asm/sigcontext.h */
+struct sigcontext_arm {
+  uint32_t trap_no;
+  uint32_t error_code;
+  uint32_t oldmask;
+  uint32_t arm_r0;
+  uint32_t arm_r1;
+  uint32_t arm_r2;
+  uint32_t arm_r3;
+  uint32_t arm_r4;
+  uint32_t arm_r5;
+  uint32_t arm_r6;
+  uint32_t arm_r7;
+  uint32_t arm_r8;
+  uint32_t arm_r9;
+  uint32_t arm_r10;
+  uint32_t arm_r11;  /* fp */
+  uint32_t arm_r12;  /* ip */
+  uint32_t arm_sp;
+  uint32_t arm_lr;
+  uint32_t arm_pc;
+  uint32_t arm_cpsr;
+  uint32_t fault_address;
+};
+
+typedef struct sigcontext_arm linux_mcontext_t;
+
+#else
+#error "unsupported architecture"
+#endif
+
+struct NonSfiExceptionFrame {
+  struct NaClExceptionContext context;
+  struct NaClExceptionPortableContext portable;
+};
+
+extern pthread_mutex_t g_signal_handler_mutex;
+void nonsfi_initialize_signal_handler_locked(void);
+void nonsfi_install_exception_handler_locked(void);
+void exception_frame_from_signal_context(
+    struct NonSfiExceptionFrame *frame,
+    const void *raw_ctx);
+
+EXTERN_C_END
+
+#endif