[RFC] [PATCH] [v2] AArch64 - Add parameter to __mount routine and register signal handler for profiling.

[Venkataramanan Kumar <venkataramanan.kumar@linaro.org>]

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Hi Maintainers,

This is version 2 patch that supports profiling in AArch64.
 Ref: https://sourceware.org/ml/libc-ports/2013-09/msg00090.html

This patch in addition to the previous patch, includes changes needed
to register signal handler "profil_counter " for profiling in AArch64.

For execution time profiling for gprof, we need to register the
"profile_counter" signal handler in the same way as other port does in
"sigcontextinfo.h".

I have started cross tests in ARMV8 foundation model.

2013-09-20  Venkataramanan Kumar  <venkataramanan.kumar@linaro.org>

        * sysdeps/aarch64/machine-gmon.h (__mcount): Accept parameter and
          pass it to mcount_internal.
       * sysdeps/unix/sysv/linux/sigcontextinfo.h: New file

regards,
Venkat

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diff --git a/ports/sysdeps/aarch64/machine-gmon.h b/ports/sysdeps/aarch64/machine-gmon.h
index 4425965..5cc2941 100644
--- a/ports/sysdeps/aarch64/machine-gmon.h
+++ b/ports/sysdeps/aarch64/machine-gmon.h
@@ -16,10 +16,9 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-/* GCC version 2 gives us a perfect magical function to get
-   just the information we need:
-     void *__builtin_return_address (unsigned int N)
-   returns the return address of the frame N frames up.  */
+/* Accept 'frompc' address as argument from the function that calls
+   __mcount for profiling.  Use  __builtin_return_address (0)
+   for the 'selfpc' address.  */
 
 #include <sysdep.h>
 
@@ -28,8 +27,8 @@ static void mcount_internal (u_long frompc, u_long selfpc);
 #define _MCOUNT_DECL(frompc, selfpc) \
 static inline void mcount_internal (u_long frompc, u_long selfpc)
 
-#define MCOUNT \
-void __mcount (void)							      \
-{									      \
-  mcount_internal ((u_long) RETURN_ADDRESS (1), (u_long) RETURN_ADDRESS (0)); \
+#define MCOUNT                                                    \
+void __mcount (void *frompc)                                      \
+{                                                                 \
+  mcount_internal ((u_long) frompc, (u_long) RETURN_ADDRESS (0)); \
 }
diff --git a/ports/sysdeps/unix/sysv/linux/aarch64/sigcontextinfo.h b/ports/sysdeps/unix/sysv/linux/aarch64/sigcontextinfo.h
new file mode 100644
index 0000000..f660d1e
--- /dev/null
+++ b/ports/sysdeps/unix/sysv/linux/aarch64/sigcontextinfo.h
@@ -0,0 +1,36 @@
+/* AArch64 definitions for profiling support.
+   Copyright (C) 1996-2013 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sys/ucontext.h>
+#include "kernel-features.h"
+
+#define SIGCONTEXT siginfo_t *_si, struct ucontext *
+#define GET_PC(ctx)	((void *) (ctx)->uc_mcontext.pc)
+
+/* There is no reliable way to get the sigcontext unless we use a
+   three-argument signal handler.  */
+#define __sigaction(sig, act, oact) ({ \
+  (act)->sa_flags |= SA_SIGINFO; \
+  (__sigaction) (sig, act, oact); \
+})
+
+#define sigaction(sig, act, oact) ({ \
+  (act)->sa_flags |= SA_SIGINFO; \
+  (sigaction) (sig, act, oact); \
+})
+