Support catch syscall on aarch64 linux

Hi,
This patch is to support catch syscall on aarch64 linux.  We
implement gdbarch method get_syscall_number for aarch64-linux,
and add aarch64-linux.xml file, which looks straightforward, however
the changes to test case doesn't.

First of all, we enable catch-syscall.exp on aarch64-linux target,
but skip the multi_arch testing on current stage.  I plan to touch
multi arch debugging on aarch64-linux later.

Then, when I run catch-syscall.exp on aarch64-linux, gcc errors that
SYS_pipe isn't defined.  We find that aarch64 kernel only has pipe2
syscall and libc already convert pipe to pipe2.  As a result, I change
catch-syscall.c to use SYS_pipe if it is defined, otherwise use
SYS_pipe2 instead.  The vector all_syscalls in catch-syscall.exp can't
be pre-determined, so I add a new proc setup_all_syscalls to fill it,
according to the availability of SYS_pipe.

Regression tested on {x86_64, aarch64}-linux x {native, gdbserver}.

gdb:

2015-03-18  Yao Qi  <yao.qi@linaro.org>

	PR tdep/18107
	* aarch64-linux-tdep.c: Include xml-syscall.h
	(aarch64_linux_get_syscall_number): New function.
	(aarch64_linux_init_abi): Call
	set_gdbarch_get_syscall_number.
	* syscalls/aarch64-linux.xml: New file.

gdb/testsuite:

2015-03-18  Yao Qi  <yao.qi@linaro.org>

	PR tdep/18107
	* gdb.base/catch-syscall.c [!SYS_pipe] (pipe2_syscall): New
	variable.
	* gdb.base/catch-syscall.exp: Don't skip it on
	aarch64*-*-linux* target.  Remove elements in all_syscalls.
	(test_catch_syscall_multi_arch): Skip it on aarch64*-linux*
	target.
	(setup_all_syscalls): New proc.

2 files changed, 41 insertions, 4 deletions

diff --git a/gdb/testsuite/gdb.base/catch-syscall.c b/gdb/testsuite/gdb.base/catch-syscall.c
index ea33b93..4d0131c 100644
--- a/gdb/testsuite/gdb.base/catch-syscall.c
+++ b/gdb/testsuite/gdb.base/catch-syscall.c
@@ -21,7 +21,11 @@ int chroot_syscall = SYS_chroot;
    restart_syscall, which can't be called from userspace.  However,
    the "read" syscall is zero on x86_64.  */
 int read_syscall = SYS_read;
+#ifdef SYS_pipe
 int pipe_syscall = SYS_pipe;
+#else
+int pipe2_syscall = SYS_pipe2;
+#endif
 int write_syscall = SYS_write;
 int exit_group_syscall = SYS_exit_group;
 
diff --git a/gdb/testsuite/gdb.base/catch-syscall.exp b/gdb/testsuite/gdb.base/catch-syscall.exp
index 29e8109..df0004a 100644
--- a/gdb/testsuite/gdb.base/catch-syscall.exp
+++ b/gdb/testsuite/gdb.base/catch-syscall.exp
@@ -29,7 +29,7 @@ if { ![istarget "x86_64-*-linux*"] && ![istarget "i\[34567\]86-*-linux*"]
      && ![istarget "powerpc-*-linux*"] && ![istarget "powerpc64-*-linux*"]
      && ![istarget "sparc-*-linux*"] && ![istarget "sparc64-*-linux*"]
      && ![istarget "mips*-linux*"] && ![istarget "arm*-linux*"]
-     && ![istarget "s390*-linux*"] } {
+     && ![istarget "s390*-linux*"] && ![istarget "aarch64*-*-linux*"] } {
      continue
 }
 
@@ -40,9 +40,9 @@ if  { [prepare_for_testing ${testfile}.exp $testfile ${testfile}.c] } {
      return -1
 }
 
-# All (but the last) syscalls from the example code
-# They are ordered according to the file, so do not change this.
-set all_syscalls { "close" "chroot" "pipe" "write" "read" }
+# All (but the last) syscalls from the example code.  It is filled in
+# proc setup_all_syscalls.
+set all_syscalls { }
 set all_syscalls_numbers { }
 
 # The last syscall (exit()) does not return, so
@@ -402,6 +402,9 @@ proc test_catch_syscall_multi_arch {} {
 	# catch syscall supports only 32-bit ARM for now.
 	verbose "Not testing ARM for multi-arch syscall support"
 	return
+    } elseif { [istarget "aarch64*-linux*"] } {
+	verbose "Not testing AARCH64 for multi-arch syscall support"
+	return
     } elseif { [istarget "s390*-linux*"] } {
 	set arch1 "s390:31-bit"
 	set arch2 "s390:64-bit"
@@ -469,6 +472,36 @@ proc fill_all_syscalls_numbers {} {
     set last_syscall_number [get_integer_valueof "exit_group_syscall" -1]
 }
 
+# Set up the vector all_syscalls.
+
+proc setup_all_syscalls {} {
+    global all_syscalls
+    global gdb_prompt
+
+    # They are ordered according to the file, so do not change this.
+    lappend all_syscalls "close"
+    lappend all_syscalls "chroot"
+
+    # SYS_pipe doesn't exist on aarch64 kernel.
+    set test "check SYS_pipe"
+    gdb_test_multiple "p pipe_syscall" $test {
+	-re " = .*$gdb_prompt $" {
+	    pass $test
+	    lappend all_syscalls "pipe"
+	}
+	-re "No symbol .*$gdb_prompt $" {
+	    pass $test
+	    # SYS_pipe isn't defined, use SYS_pipe2 instead.
+	    lappend all_syscalls "pipe2"
+	}
+    }
+
+    lappend all_syscalls "write"
+    lappend all_syscalls "read"
+}
+
+setup_all_syscalls
+
 # Fill all the syscalls numbers before starting anything.
 fill_all_syscalls_numbers