diff mbox

[3/3] arc: Add support for Newlib

Message ID 1475843870-11449-3-git-send-email-Anton.Kolesov@synopsys.com
State New
Headers show

Commit Message

Anton Kolesov Oct. 7, 2016, 12:37 p.m. UTC
Add support for Newlib as an OS/ABI.  The only thing that is specific to it
relatively to "generic" baremetal target is location of PC register in jump
buffer for longjump support.

Sniffer uses .ivt section to decide if ELF file is for ARC Newlib or not.

gdb/ChangeLog:

	* arc-newlib-tdep.c: New file.
	* configure.tgt: Add newlib support for ARC.
---
 gdb/arc-newlib-tdep.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++
 gdb/configure.tgt     |  7 +++++-
 2 files changed, 75 insertions(+), 1 deletion(-)
 create mode 100644 gdb/arc-newlib-tdep.c

Comments

Yao Qi Oct. 11, 2016, 2:14 p.m. UTC | #1
Anton Kolesov <Anton.Kolesov@synopsys.com> writes:

Hi Anton,

> +/* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */
> +
> +static void
> +arc_newlib_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
> +{
> +  if (arc_debug)
> +    debug_printf ("arc-newlib: Initialization.\n");
> +
> +  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> +
> +  /* Offset of original PC in longjmp jump buffer (in registers).  Value of PC
> +     offset can be found in newlib/libc/machine/arc/setjmp.S.  */
> +  tdep->jb_pc = 18;

What is jb_pc on arc-linux?  Is it 18 or a different one?  If it is 18
too, we can use arc_get_longjmp_target for both newlib and linux.  Patch
#1 is not needed.
Anton Kolesov Oct. 11, 2016, 3:34 p.m. UTC | #2
Hi Yao,

> -----Original Message-----

> From: Yao Qi [mailto:qiyaoltc@gmail.com]

> Sent: Tuesday, October 11, 2016 5:14 PM

> To: Anton Kolesov <Anton.Kolesov@synopsys.com>

> Cc: gdb-patches@sourceware.org; Francois Bedard <Francois.Bedard@synopsys.com>

> Subject: Re: [PATCH 3/3] arc: Add support for Newlib

> 

> Anton Kolesov <Anton.Kolesov@synopsys.com> writes:

> 

> Hi Anton,

> 

> > +/* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */

> > +

> > +static void

> > +arc_newlib_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)

> > +{

> > +  if (arc_debug)

> > +    debug_printf ("arc-newlib: Initialization.\n");

> > +

> > +  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

> > +

> > +  /* Offset of original PC in longjmp jump buffer (in registers).  Value of

> PC

> > +     offset can be found in newlib/libc/machine/arc/setjmp.S.  */

> > +  tdep->jb_pc = 18;

> 

> What is jb_pc on arc-linux?  Is it 18 or a different one?  If it is 18

> too, we can use arc_get_longjmp_target for both newlib and linux.  Patch

> #1 is not needed.


Unfortunately, it is different in our uClibc port [1] - jb_pc is 15 there.
uClibc saves r13-r25, fp (r27), sp (r28), blink (r31); newlib on the other
hand saves all registers from r13 through r31. Back in time ARC port of GDB
had an "if" inside the get_longjump_target which was selecting offset based
on OS/ABI, instead of using tdep->jb_pc. But using jb_pc, like in arm-tdep.c,
looks like a better solution architecturally.

[1] http://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/tree/libc/sysdeps/linux/arc/bits/setjmp.h

Anton

> 

> --

> Yao (齐尧)
Yao Qi Oct. 11, 2016, 4:25 p.m. UTC | #3
Anton Kolesov <Anton.Kolesov@synopsys.com> writes:

> Add support for Newlib as an OS/ABI.  The only thing that is specific to it
> relatively to "generic" baremetal target is location of PC register in jump
> buffer for longjump support.
>
> Sniffer uses .ivt section to decide if ELF file is for ARC Newlib or not.
>
> gdb/ChangeLog:
>
> 	* arc-newlib-tdep.c: New file.
> 	* configure.tgt: Add newlib support for ARC.

Patch is good to me.
Anton Kolesov Oct. 12, 2016, 11:54 a.m. UTC | #4
Hi,

> > Add support for Newlib as an OS/ABI.  The only thing that is specific to it

> > relatively to "generic" baremetal target is location of PC register in jump

> > buffer for longjump support.

> >

> > Sniffer uses .ivt section to decide if ELF file is for ARC Newlib or not.

> >

> > gdb/ChangeLog:

> >

> > 	* arc-newlib-tdep.c: New file.

> > 	* configure.tgt: Add newlib support for ARC.

> 

> Patch is good to me.



Patch series applied with requested fixes. Thanks for the review!

Anton


> 

> --

> Yao (齐尧)
diff mbox

Patch

diff --git a/gdb/arc-newlib-tdep.c b/gdb/arc-newlib-tdep.c
new file mode 100644
index 0000000..d93bf85
--- /dev/null
+++ b/gdb/arc-newlib-tdep.c
@@ -0,0 +1,69 @@ 
+/* Target-dependent code for Newlib ARC.
+
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   Contributed by Synopsys Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+
+#include "gdbarch.h"
+#include "arc-tdep.h"
+#include "osabi.h"
+
+/* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */
+
+static void
+arc_newlib_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
+{
+  if (arc_debug)
+    debug_printf ("arc-newlib: Initialization.\n");
+
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  /* Offset of original PC in longjmp jump buffer (in registers).  Value of PC
+     offset can be found in newlib/libc/machine/arc/setjmp.S.  */
+  tdep->jb_pc = 18;
+}
+
+/* Recognize ARC Newlib object files.  */
+
+static enum gdb_osabi
+arc_newlib_osabi_sniffer (bfd *abfd)
+{
+  if (arc_debug)
+    debug_printf ("arc-newlib: OS/ABI sniffer.\n");
+
+  /* crt0.S in libgloss for ARC defines .ivt section for interrupt handlers.
+     If this section is not present then this is likely not a newlib - could be
+     a Linux application or some non-newlib baremetal application.  */
+  if (bfd_get_section_by_name (abfd, ".ivt") != NULL)
+    return GDB_OSABI_NEWLIB;
+  else
+    return GDB_OSABI_UNKNOWN;
+}
+
+/* Provide a prototype to silence -Wmissing-prototypes.  */
+extern initialize_file_ftype _initialize_arc_newlib_tdep;
+
+void
+_initialize_arc_newlib_tdep (void)
+{
+  gdbarch_register_osabi_sniffer (bfd_arch_arc, bfd_target_elf_flavour,
+				  arc_newlib_osabi_sniffer);
+  gdbarch_register_osabi (bfd_arch_arc, 0, GDB_OSABI_NEWLIB,
+			  arc_newlib_init_osabi);
+}
diff --git a/gdb/configure.tgt b/gdb/configure.tgt
index ef041de..a64fe42 100644
--- a/gdb/configure.tgt
+++ b/gdb/configure.tgt
@@ -83,8 +83,13 @@  am33_2.0*-*-linux*)
 			solib-svr4.o"
 	;;
 
+arc*-*-elf32)
+	# Target: baremetal ARC elf32 (newlib) target
+	gdb_target_obs="arc-newlib-tdep.o arc-tdep.o"
+	;;
+
 arc*-*-*)
-	# Target: baremetal ARC elf32 target
+	# Target: Unidentified ARC target
 	gdb_target_obs="arc-tdep.o"
 	;;