[PATCH] MIPS SDE OS ABI support

[PATCH] MIPS SDE OS ABI support

[Yao Qi]

This patch is to add SDE OS ABI support in GDB, which has been used in
codesourcery gdb tree for some years.

gdb:

2014-12-15  Maciej W. Rozycki  <macro@codesourcery.com>
	    Nigel Stephens  <nigel@mips.com>
	    Chris Dearman  <chris@mips.com>
	    Luis Machado  <lgustavo@codesourcery.com>

	* sde-mips-tdep.c: New file containg SDE specific code.
	* configure.tgt (mips*-sde*-elf*): Add sde-mips-tdep.o to
	gdb_target_obs.
	* defs.h (gdb_osabi): Add GDB_OSABI_SDE.
	* osabi.c (gdb_osabi_names): Add SDE.
	* NEWS: Mention the change.
---
 gdb/Makefile.in     |   3 +-
 gdb/NEWS            |   4 +
 gdb/configure.tgt   |   5 ++
 gdb/defs.h          |   1 +
 gdb/mips-sde-tdep.c | 252 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 gdb/osabi.c         |   1 +
 6 files changed, 265 insertions(+), 1 deletion(-)
 create mode 100644 gdb/mips-sde-tdep.c

diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 2f69eb2..be69b6f 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -664,7 +664,7 @@ ALL_TARGET_OBS = \
 	m88k-tdep.o \
 	mep-tdep.o \
 	microblaze-tdep.o microblaze-linux-tdep.o \
-	mips-linux-tdep.o \
+	mips-linux-tdep.o mips-sde-tdep.o \
 	mipsnbsd-tdep.o mips-tdep.o \
 	mn10300-linux-tdep.o mn10300-tdep.o \
 	moxie-tdep.o \
@@ -1682,6 +1682,7 @@ ALLDEPFILES = \
 	microblaze-tdep.c microblaze-linux-tdep.c \
 	mingw-hdep.c \
 	mips-linux-nat.c mips-linux-tdep.c \
+	mips-sde-tdep.c \
 	mips-tdep.c \
 	mipsnbsd-nat.c mipsnbsd-tdep.c \
 	mips64obsd-nat.c mips64obsd-tdep.c \
diff --git a/gdb/NEWS b/gdb/NEWS
index a6789bd..ac2b175 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -11,6 +11,10 @@
   ** gdb.events.memory_changed: A memory location has been altered.
   ** gdb.events.register_changed: A register has been altered.
 
+* New targets
+
+MIPS SDE			mips*-sde*-elf*
+
 *** Changes since GDB 7.8
 
 * GDB now supports hardware watchpoints on x86 GNU Hurd.
diff --git a/gdb/configure.tgt b/gdb/configure.tgt
index 1d7f54b..065e797 100644
--- a/gdb/configure.tgt
+++ b/gdb/configure.tgt
@@ -364,6 +364,11 @@ mips64*-*-openbsd*)
 	# Target: OpenBSD/mips64
 	gdb_target_obs="mips-tdep.o mips64obsd-tdep.o obsd-tdep.o solib-svr4.o"
 	;;
+mips*-sde*-elf*)
+	# Target: MIPS SDE
+	gdb_target_obs="mips-tdep.o mips-sde-tdep.o remote-mips.o"
+	gdb_sim=../sim/mips/libsim.a
+	;;
 mips*-*-elf)
 	# Target: MIPS ELF
 	gdb_target_obs="mips-tdep.o remote-mips.o"
diff --git a/gdb/defs.h b/gdb/defs.h
index 7920938..d440afb 100644
--- a/gdb/defs.h
+++ b/gdb/defs.h
@@ -562,6 +562,7 @@ enum gdb_osabi
   GDB_OSABI_OPENVMS,
   GDB_OSABI_LYNXOS178,
   GDB_OSABI_NEWLIB,
+  GDB_OSABI_SDE,
 
   GDB_OSABI_INVALID		/* keep this last */
 };
diff --git a/gdb/mips-sde-tdep.c b/gdb/mips-sde-tdep.c
new file mode 100644
index 0000000..06d10cc
--- /dev/null
+++ b/gdb/mips-sde-tdep.c
@@ -0,0 +1,252 @@
+/* Target-dependent code for SDE on MIPS processors.
+
+   Copyright (C) 2014 Free Software Foundation, 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 "osabi.h"
+#include "elf-bfd.h"
+#include "block.h"
+#include "symtab.h"
+
+#include "frame.h"
+#include "frame-unwind.h"
+#include "frame-base.h"
+#include "trad-frame.h"
+
+#include "mips-tdep.h"
+
+static struct trad_frame_cache *
+mips_sde_frame_cache (struct frame_info *this_frame, void **this_cache)
+{
+  struct gdbarch *gdbarch = get_frame_arch (this_frame);
+  const struct mips_regnum *regs = mips_regnum (gdbarch);
+  const int sizeof_reg_t = mips_abi_regsize (gdbarch);
+						/* FIXME: Is this correct?  */
+  enum mips_abi abi = mips_abi (gdbarch);
+  struct trad_frame_cache *cache;
+  CORE_ADDR xcpt_frame;
+  CORE_ADDR start_addr;
+  CORE_ADDR stack_addr;
+  CORE_ADDR pc;
+  int i;
+
+  if (*this_cache != NULL)
+    return *this_cache;
+  cache = trad_frame_cache_zalloc (this_frame);
+  *this_cache = cache;
+
+  /* The previous registers are held in struct xcptcontext
+     which is at $sp+offs
+
+     struct xcptcontext {
+       reg_t	sr;		CP0 Status
+       reg_t	cr;		CP0 Cause
+       reg_t	epc;		CP0 EPC
+       reg_t	vaddr;		CP0 BadVAddr
+       reg_t	regs[32];	General registers
+       reg_t	mdlo;		LO
+       reg_t	mdhi;		HI
+       reg_t	mdex;		ACX
+       ...
+     };
+  */
+
+  stack_addr = get_frame_register_signed (this_frame,
+					  gdbarch_sp_regnum (gdbarch));
+  switch (abi)
+    {
+    case MIPS_ABI_O32:
+      /* 40: XCPTCONTEXT
+	 24: xcpt_gen() argspace		(16 bytes)
+	 16: _xcptcall() saved ra, rounded up	( 8 bytes)
+	 00: _xcptcall() argspace 		(16 bytes)  */
+      xcpt_frame = stack_addr + 40;
+      break;
+    case MIPS_ABI_N32:
+    case MIPS_ABI_N64:
+    default:			/* Wild guess.  */
+      /* 16: XCPTCONTEXT
+	 16: xcpt_gen() argspace 		( 0 bytes)
+	 00: _xcptcall() saved ra, rounded up	(16 bytes)  */
+      xcpt_frame = stack_addr + 16;
+      break;
+    }
+
+  trad_frame_set_reg_addr (cache,
+			   MIPS_PS_REGNUM + gdbarch_num_regs (gdbarch),
+			   xcpt_frame + 0 * sizeof_reg_t);
+  trad_frame_set_reg_addr (cache,
+			   regs->cause + gdbarch_num_regs (gdbarch),
+			   xcpt_frame + 1 * sizeof_reg_t);
+  trad_frame_set_reg_addr (cache,
+			   regs->pc + gdbarch_num_regs (gdbarch),
+			   xcpt_frame + 2 * sizeof_reg_t);
+  trad_frame_set_reg_addr (cache,
+			   regs->badvaddr + gdbarch_num_regs (gdbarch),
+			   xcpt_frame + 3 * sizeof_reg_t);
+  for (i = 0; i < MIPS_NUMREGS; i++)
+    trad_frame_set_reg_addr (cache,
+			     i + MIPS_ZERO_REGNUM + gdbarch_num_regs (gdbarch),
+			     xcpt_frame + (4 + i) * sizeof_reg_t);
+  trad_frame_set_reg_addr (cache,
+			   regs->lo + gdbarch_num_regs (gdbarch),
+			   xcpt_frame + 36 * sizeof_reg_t);
+  trad_frame_set_reg_addr (cache,
+			   regs->hi + gdbarch_num_regs (gdbarch),
+			   xcpt_frame + 37 * sizeof_reg_t);
+
+  pc = get_frame_pc (this_frame);
+  find_pc_partial_function (pc, NULL, &start_addr, NULL);
+  trad_frame_set_id (cache, frame_id_build (start_addr, stack_addr));
+
+  return cache;
+}
+
+static void
+mips_sde_frame_this_id (struct frame_info *this_frame, void **this_cache,
+			struct frame_id *this_id)
+{
+  struct trad_frame_cache *this_trad_cache
+    = mips_sde_frame_cache (this_frame, this_cache);
+  trad_frame_get_id (this_trad_cache, this_id);
+}
+
+static struct value *
+mips_sde_frame_prev_register (struct frame_info *this_frame,
+			      void **this_cache,
+			      int prev_regnum)
+{
+  struct trad_frame_cache *trad_cache
+    = mips_sde_frame_cache (this_frame, this_cache);
+  return trad_frame_get_register (trad_cache, this_frame, prev_regnum);
+}
+
+static int
+mips_sde_frame_sniffer (const struct frame_unwind *self,
+			struct frame_info *this_frame,
+			void **this_cache)
+{
+  CORE_ADDR pc = get_frame_pc (this_frame);
+  const char *name;
+
+  find_pc_partial_function (pc, &name, NULL, NULL);
+  return (name
+	  && (strcmp (name, "_xcptcall") == 0
+	      || strcmp (name, "_sigtramp") == 0));
+}
+
+static const struct frame_unwind mips_sde_frame_unwind =
+{
+  SIGTRAMP_FRAME,
+  default_frame_unwind_stop_reason,
+  mips_sde_frame_this_id,
+  mips_sde_frame_prev_register,
+  NULL,
+  mips_sde_frame_sniffer
+};
+
+static CORE_ADDR
+mips_sde_frame_base_address (struct frame_info *this_frame, void **this_cache)
+{
+  struct trad_frame_cache *this_trad_cache
+    = mips_sde_frame_cache (this_frame, this_cache);
+  return trad_frame_get_this_base (this_trad_cache);
+}
+
+static const struct frame_base mips_sde_frame_base =
+{
+  &mips_sde_frame_unwind,
+  mips_sde_frame_base_address,
+  mips_sde_frame_base_address,
+  mips_sde_frame_base_address
+};
+
+static const struct frame_base *
+mips_sde_frame_base_sniffer (struct frame_info *this_frame)
+{
+  if (mips_sde_frame_sniffer (&mips_sde_frame_unwind, this_frame, NULL))
+    return &mips_sde_frame_base;
+  else
+    return NULL;
+}
+
+static void
+mips_sde_elf_osabi_sniff_abi_tag_sections (bfd *abfd, asection *sect,
+					   void *obj)
+{
+  enum gdb_osabi *os_ident_ptr = obj;
+  const char *name;
+
+  name = bfd_get_section_name (abfd, sect);
+
+  /* The presence of a section with a ".sde" prefix is indicative
+     of an SDE binary.  */
+  if (strncmp (name, ".sde", 4) == 0)
+    *os_ident_ptr = GDB_OSABI_SDE;
+}
+
+static enum gdb_osabi
+mips_sde_elf_osabi_sniffer (bfd *abfd)
+{
+  enum gdb_osabi osabi = GDB_OSABI_UNKNOWN;
+  unsigned int elfosabi;
+
+  /* If the generic sniffer gets a hit, return and let other sniffers
+     get a crack at it.  */
+  bfd_map_over_sections (abfd,
+			 generic_elf_osabi_sniff_abi_tag_sections,
+			 &osabi);
+  if (osabi != GDB_OSABI_UNKNOWN)
+    return GDB_OSABI_UNKNOWN;
+
+  elfosabi = elf_elfheader (abfd)->e_ident[EI_OSABI];
+
+  if (elfosabi == ELFOSABI_NONE)
+    {
+      /* When elfosabi is ELFOSABI_NONE (0), then the ELF structures in the
+         file are conforming to the base specification for that machine
+         (there are no OS-specific extensions).  In order to determine the
+         real OS in use we must look for OS notes that have been added.
+
+         For SDE, we simply look for sections named with .sde as prefixes.  */
+      bfd_map_over_sections (abfd,
+			     mips_sde_elf_osabi_sniff_abi_tag_sections,
+			     &osabi);
+    }
+  return osabi;
+}
+
+static void
+mips_sde_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
+{
+  frame_unwind_append_unwinder (gdbarch, &mips_sde_frame_unwind);
+  frame_base_append_sniffer (gdbarch, mips_sde_frame_base_sniffer);
+}
+
+/* Provide a prototype to silence -Wmissing-prototypes.  */
+extern initialize_file_ftype _initialize_mips_sde_tdep;
+
+void
+_initialize_mips_sde_tdep (void)
+{
+  gdbarch_register_osabi_sniffer (bfd_arch_mips,
+				  bfd_target_elf_flavour,
+				  mips_sde_elf_osabi_sniffer);
+
+  gdbarch_register_osabi (bfd_arch_mips, 0, GDB_OSABI_SDE, mips_sde_init_abi);
+}
diff --git a/gdb/osabi.c b/gdb/osabi.c
index 50d391a..895b476 100644
--- a/gdb/osabi.c
+++ b/gdb/osabi.c
@@ -83,6 +83,7 @@ static const struct osabi_names gdb_osabi_names[] =
   { "OpenVMS", NULL },
   { "LynxOS178", NULL },
   { "Newlib", NULL },
+  { "SDE", NULL },
 
   { "<invalid>", NULL }
 };
-- 
1.9.3

Re: [PATCH] MIPS SDE OS ABI support

[Yao Qi]

Yao Qi <yao@codesourcery.com> writes:

> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -11,6 +11,10 @@
>    ** gdb.events.memory_changed: A memory location has been altered.
>    ** gdb.events.register_changed: A register has been altered.
>  
> +* New targets
> +
> +MIPS SDE			mips*-sde*-elf*
> +
>  *** Changes since GDB 7.8

Ur, I add this entry in the wrong section.  Move it back to the
"Changes since GDB 7.8" section.

-- 
Yao (齐尧)

diff --git a/gdb/NEWS b/gdb/NEWS
index a6789bd..168e810 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -91,6 +91,10 @@ compile file [-r|-raw] filename
   ** The -list-thread-groups command outputs an exit-code field for
      inferiors that have exited.
 
+* New targets
+
+MIPS SDE                       mips*-sde*-elf*
+
 * Removed targets
 
 Support for these obsolete configurations has been removed.

Re: [PATCH] MIPS SDE OS ABI support

[Joel Brobecker]

> 2014-12-15  Maciej W. Rozycki  <macro@codesourcery.com>
> 	    Nigel Stephens  <nigel@mips.com>
> 	    Chris Dearman  <chris@mips.com>
> 	    Luis Machado  <lgustavo@codesourcery.com>
> 
> 	* sde-mips-tdep.c: New file containg SDE specific code.
> 	* configure.tgt (mips*-sde*-elf*): Add sde-mips-tdep.o to
> 	gdb_target_obs.
> 	* defs.h (gdb_osabi): Add GDB_OSABI_SDE.
> 	* osabi.c (gdb_osabi_names): Add SDE.
> 	* NEWS: Mention the change.

I just skimmed through that patch, and noticed a few things, all
of fairly trivial nature. So, as soon as fixed, I think the patch
can go in (modulo NEWS to be approved by Eli).

> +static struct trad_frame_cache *
> +mips_sde_frame_cache (struct frame_info *this_frame, void **this_cache)

All functions should have an introductory comment. Since these
implement callbacks/"methods", the usual one-liner that describe
which callback they implement should be used.

> +static void
> +mips_sde_frame_this_id (struct frame_info *this_frame, void **this_cache,
> +			struct frame_id *this_id)
> +{
> +  struct trad_frame_cache *this_trad_cache
> +    = mips_sde_frame_cache (this_frame, this_cache);
> +  trad_frame_get_id (this_trad_cache, this_id);

Empty line between variable declaration and the rest of the code.

> +static struct value *
> +mips_sde_frame_prev_register (struct frame_info *this_frame,
> +			      void **this_cache,
> +			      int prev_regnum)
> +{
> +  struct trad_frame_cache *trad_cache
> +    = mips_sde_frame_cache (this_frame, this_cache);
> +  return trad_frame_get_register (trad_cache, this_frame, prev_regnum);

Likewise.

> +static CORE_ADDR
> +mips_sde_frame_base_address (struct frame_info *this_frame, void **this_cache)
> +{
> +  struct trad_frame_cache *this_trad_cache
> +    = mips_sde_frame_cache (this_frame, this_cache);
> +  return trad_frame_get_this_base (this_trad_cache);

Same here.

-- 
Joel

Re: [PATCH] MIPS SDE OS ABI support

[Yao Qi]

Yao Qi <yao@codesourcery.com> writes:

> diff --git a/gdb/NEWS b/gdb/NEWS
> index a6789bd..168e810 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -91,6 +91,10 @@ compile file [-r|-raw] filename
>    ** The -list-thread-groups command outputs an exit-code field for
>       inferiors that have exited.
>  
> +* New targets
> +
> +MIPS SDE                       mips*-sde*-elf*
> +
>  * Removed targets
>  
>  Support for these obsolete configurations has been removed.

Hi Eli,
How about the NEWS entry?

-- 
Yao (齐尧)

Re: [PATCH] MIPS SDE OS ABI support

[Eli Zaretskii]

> From: Yao Qi <yao@codesourcery.com>
> CC: <eliz@gnu.org>
> Date: Thu, 18 Dec 2014 21:30:43 +0800
> 
> Yao Qi <yao@codesourcery.com> writes:
> 
> > diff --git a/gdb/NEWS b/gdb/NEWS
> > index a6789bd..168e810 100644
> > --- a/gdb/NEWS
> > +++ b/gdb/NEWS
> > @@ -91,6 +91,10 @@ compile file [-r|-raw] filename
> >    ** The -list-thread-groups command outputs an exit-code field for
> >       inferiors that have exited.
> >  
> > +* New targets
> > +
> > +MIPS SDE                       mips*-sde*-elf*
> > +
> >  * Removed targets
> >  
> >  Support for these obsolete configurations has been removed.
> 
> Hi Eli,
> How about the NEWS entry?

It's fine, thanks.

Re: [PATCH] MIPS SDE OS ABI support

[Pedro Alves]

On 12/15/2014 01:10 PM, Joel Brobecker wrote:
>> 	* sde-mips-tdep.c: New file containg SDE specific code.

Nit: I noticed the file was named oddly here,

>> 	* configure.tgt (mips*-sde*-elf*): Add sde-mips-tdep.o to

and here, but then the actual file name looks "regular":

>  gdb/mips-sde-tdep.c | 252


BTW, OOC, I looked around the web for MIPS SDE, and not much
comes out.  What is it exactly?

Thanks,
Pedro Alves

Re: [PATCH] MIPS SDE OS ABI support

[Yao Qi]

Pedro Alves <palves@redhat.com> writes:

>>> 	* sde-mips-tdep.c: New file containg SDE specific code.
>
> Nit: I noticed the file was named oddly here,
>

Sorry, it should be mips-sde-tdep.c ...

>>> 	* configure.tgt (mips*-sde*-elf*): Add sde-mips-tdep.o to
>
> and here, but then the actual file name looks "regular":
>

... and mips-sde-tdep.o.


>>  gdb/mips-sde-tdep.c | 252
>
>
> BTW, OOC, I looked around the web for MIPS SDE, and not much
> comes out.  What is it exactly?

I don't see much either.  Looks MIPS SDE lite has been discontinued
<http://forum.imgtec.com/discussion/2794/mips-sde-lite>
We develop toolchain, which is integrated in MIPS Navigator ICS
<http://community.imgtec.com/developers/mips/tools/mips-navigator-ics/>.
Both SDE ELF and Linux toolchain are used in it
<http://navigatorics.mips.com/2.9.2/GettingStartedGuide-2.9.2.10356.pdf>

Patch below is pushed in.

-- 
Yao (齐尧)

Subject: [PATCH] MIPS SDE OS ABI support

This patch is to add SDE OS ABI support in GDB, which has been used in
codesourcery gdb tree for some years.

gdb:

2014-12-19  Maciej W. Rozycki  <macro@codesourcery.com>
	    Nigel Stephens  <nigel@mips.com>
	    Chris Dearman  <chris@mips.com>
	    Luis Machado  <lgustavo@codesourcery.com>

	* Makefile.in (ALL_TARGET_OBS): Add mips-sde-tdep.o.
	(ALLDEPFILES): Add mips-sde-tdep.c.
	* mips-sde-tdep.c: New file containg SDE specific code.
	* configure.tgt (mips*-sde*-elf*): Add mips-sde-dep.o to
	gdb_target_obs.
	* defs.h (gdb_osabi): Add GDB_OSABI_SDE.
	* osabi.c (gdb_osabi_names): Add SDE.
	* NEWS: Mention the change.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index adb24d4..2f34a31 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,17 @@
+2014-12-19  Maciej W. Rozycki  <macro@codesourcery.com>
+	    Nigel Stephens  <nigel@mips.com>
+	    Chris Dearman  <chris@mips.com>
+	    Luis Machado  <lgustavo@codesourcery.com>
+
+	* Makefile.in (ALL_TARGET_OBS): Add mips-sde-tdep.o.
+	(ALLDEPFILES): Add mips-sde-tdep.c.
+	* mips-sde-tdep.c: New file containg SDE specific code.
+	* configure.tgt (mips*-sde*-elf*): Add mips-sde-dep.o to
+	gdb_target_obs.
+	* defs.h (gdb_osabi): Add GDB_OSABI_SDE.
+	* osabi.c (gdb_osabi_names): Add SDE.
+	* NEWS: Mention the change.
+
 2014-12-18  Simon Marchi  <simon.marchi@ericsson.com>
 
 	* elfread.c (elf_symfile_init): Remove stale comment.
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 2f69eb2..be69b6f 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -664,7 +664,7 @@ ALL_TARGET_OBS = \
 	m88k-tdep.o \
 	mep-tdep.o \
 	microblaze-tdep.o microblaze-linux-tdep.o \
-	mips-linux-tdep.o \
+	mips-linux-tdep.o mips-sde-tdep.o \
 	mipsnbsd-tdep.o mips-tdep.o \
 	mn10300-linux-tdep.o mn10300-tdep.o \
 	moxie-tdep.o \
@@ -1682,6 +1682,7 @@ ALLDEPFILES = \
 	microblaze-tdep.c microblaze-linux-tdep.c \
 	mingw-hdep.c \
 	mips-linux-nat.c mips-linux-tdep.c \
+	mips-sde-tdep.c \
 	mips-tdep.c \
 	mipsnbsd-nat.c mipsnbsd-tdep.c \
 	mips64obsd-nat.c mips64obsd-tdep.c \
diff --git a/gdb/NEWS b/gdb/NEWS
index 955dd23..c34cf2b 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -95,6 +95,10 @@ show debug symbol-lookup
   ** The -list-thread-groups command outputs an exit-code field for
      inferiors that have exited.
 
+* New targets
+
+MIPS SDE			mips*-sde*-elf*
+
 * Removed targets
 
 Support for these obsolete configurations has been removed.
diff --git a/gdb/configure.tgt b/gdb/configure.tgt
index 1d7f54b..065e797 100644
--- a/gdb/configure.tgt
+++ b/gdb/configure.tgt
@@ -364,6 +364,11 @@ mips64*-*-openbsd*)
 	# Target: OpenBSD/mips64
 	gdb_target_obs="mips-tdep.o mips64obsd-tdep.o obsd-tdep.o solib-svr4.o"
 	;;
+mips*-sde*-elf*)
+	# Target: MIPS SDE
+	gdb_target_obs="mips-tdep.o mips-sde-tdep.o remote-mips.o"
+	gdb_sim=../sim/mips/libsim.a
+	;;
 mips*-*-elf)
 	# Target: MIPS ELF
 	gdb_target_obs="mips-tdep.o remote-mips.o"
diff --git a/gdb/defs.h b/gdb/defs.h
index 7b5bc06..d74cc3c 100644
--- a/gdb/defs.h
+++ b/gdb/defs.h
@@ -562,6 +562,7 @@ enum gdb_osabi
   GDB_OSABI_OPENVMS,
   GDB_OSABI_LYNXOS178,
   GDB_OSABI_NEWLIB,
+  GDB_OSABI_SDE,
 
   GDB_OSABI_INVALID		/* keep this last */
 };
diff --git a/gdb/mips-sde-tdep.c b/gdb/mips-sde-tdep.c
new file mode 100644
index 0000000..fa4d2a0
--- /dev/null
+++ b/gdb/mips-sde-tdep.c
@@ -0,0 +1,270 @@
+/* Target-dependent code for SDE on MIPS processors.
+
+   Copyright (C) 2014 Free Software Foundation, 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 "osabi.h"
+#include "elf-bfd.h"
+#include "block.h"
+#include "symtab.h"
+
+#include "frame.h"
+#include "frame-unwind.h"
+#include "frame-base.h"
+#include "trad-frame.h"
+
+#include "mips-tdep.h"
+
+/* Fill in the register cache *THIS_CACHE for THIS_FRAME for use
+   in the SDE frame unwinder.  */
+
+static struct trad_frame_cache *
+mips_sde_frame_cache (struct frame_info *this_frame, void **this_cache)
+{
+  struct gdbarch *gdbarch = get_frame_arch (this_frame);
+  const struct mips_regnum *regs = mips_regnum (gdbarch);
+  const int sizeof_reg_t = mips_abi_regsize (gdbarch);
+  enum mips_abi abi = mips_abi (gdbarch);
+  struct trad_frame_cache *cache;
+  CORE_ADDR xcpt_frame;
+  CORE_ADDR start_addr;
+  CORE_ADDR stack_addr;
+  CORE_ADDR pc;
+  int i;
+
+  if (*this_cache != NULL)
+    return *this_cache;
+  cache = trad_frame_cache_zalloc (this_frame);
+  *this_cache = cache;
+
+  /* The previous registers are held in struct xcptcontext
+     which is at $sp+offs
+
+     struct xcptcontext {
+       reg_t	sr;		CP0 Status
+       reg_t	cr;		CP0 Cause
+       reg_t	epc;		CP0 EPC
+       reg_t	vaddr;		CP0 BadVAddr
+       reg_t	regs[32];	General registers
+       reg_t	mdlo;		LO
+       reg_t	mdhi;		HI
+       reg_t	mdex;		ACX
+       ...
+     };
+  */
+
+  stack_addr = get_frame_register_signed (this_frame,
+					  gdbarch_sp_regnum (gdbarch));
+  switch (abi)
+    {
+    case MIPS_ABI_O32:
+      /* 40: XCPTCONTEXT
+	 24: xcpt_gen() argspace		(16 bytes)
+	 16: _xcptcall() saved ra, rounded up	( 8 bytes)
+	 00: _xcptcall() argspace 		(16 bytes)  */
+      xcpt_frame = stack_addr + 40;
+      break;
+    case MIPS_ABI_N32:
+    case MIPS_ABI_N64:
+    default:			/* Wild guess.  */
+      /* 16: XCPTCONTEXT
+	 16: xcpt_gen() argspace 		( 0 bytes)
+	 00: _xcptcall() saved ra, rounded up	(16 bytes)  */
+      xcpt_frame = stack_addr + 16;
+      break;
+    }
+
+  trad_frame_set_reg_addr (cache,
+			   MIPS_PS_REGNUM + gdbarch_num_regs (gdbarch),
+			   xcpt_frame + 0 * sizeof_reg_t);
+  trad_frame_set_reg_addr (cache,
+			   regs->cause + gdbarch_num_regs (gdbarch),
+			   xcpt_frame + 1 * sizeof_reg_t);
+  trad_frame_set_reg_addr (cache,
+			   regs->pc + gdbarch_num_regs (gdbarch),
+			   xcpt_frame + 2 * sizeof_reg_t);
+  trad_frame_set_reg_addr (cache,
+			   regs->badvaddr + gdbarch_num_regs (gdbarch),
+			   xcpt_frame + 3 * sizeof_reg_t);
+  for (i = 0; i < MIPS_NUMREGS; i++)
+    trad_frame_set_reg_addr (cache,
+			     i + MIPS_ZERO_REGNUM + gdbarch_num_regs (gdbarch),
+			     xcpt_frame + (4 + i) * sizeof_reg_t);
+  trad_frame_set_reg_addr (cache,
+			   regs->lo + gdbarch_num_regs (gdbarch),
+			   xcpt_frame + 36 * sizeof_reg_t);
+  trad_frame_set_reg_addr (cache,
+			   regs->hi + gdbarch_num_regs (gdbarch),
+			   xcpt_frame + 37 * sizeof_reg_t);
+
+  pc = get_frame_pc (this_frame);
+  find_pc_partial_function (pc, NULL, &start_addr, NULL);
+  trad_frame_set_id (cache, frame_id_build (start_addr, stack_addr));
+
+  return cache;
+}
+
+/* Implement the this_id function for the SDE frame unwinder.  */
+
+static void
+mips_sde_frame_this_id (struct frame_info *this_frame, void **this_cache,
+			struct frame_id *this_id)
+{
+  struct trad_frame_cache *this_trad_cache
+    = mips_sde_frame_cache (this_frame, this_cache);
+
+  trad_frame_get_id (this_trad_cache, this_id);
+}
+
+/* Implement the prev_register function for the SDE frame unwinder.  */
+
+static struct value *
+mips_sde_frame_prev_register (struct frame_info *this_frame,
+			      void **this_cache,
+			      int prev_regnum)
+{
+  struct trad_frame_cache *trad_cache
+    = mips_sde_frame_cache (this_frame, this_cache);
+
+  return trad_frame_get_register (trad_cache, this_frame, prev_regnum);
+}
+
+/* Implement the sniffer function for the SDE frame unwinder.  */
+
+static int
+mips_sde_frame_sniffer (const struct frame_unwind *self,
+			struct frame_info *this_frame,
+			void **this_cache)
+{
+  CORE_ADDR pc = get_frame_pc (this_frame);
+  const char *name;
+
+  find_pc_partial_function (pc, &name, NULL, NULL);
+  return (name
+	  && (strcmp (name, "_xcptcall") == 0
+	      || strcmp (name, "_sigtramp") == 0));
+}
+
+/* Data structure for the SDE frame unwinder.  */
+
+static const struct frame_unwind mips_sde_frame_unwind =
+{
+  SIGTRAMP_FRAME,
+  default_frame_unwind_stop_reason,
+  mips_sde_frame_this_id,
+  mips_sde_frame_prev_register,
+  NULL,
+  mips_sde_frame_sniffer
+};
+
+/* Implement the this_base, this_locals, and this_args hooks
+   for the normal unwinder.  */
+
+static CORE_ADDR
+mips_sde_frame_base_address (struct frame_info *this_frame, void **this_cache)
+{
+  struct trad_frame_cache *this_trad_cache
+    = mips_sde_frame_cache (this_frame, this_cache);
+
+  return trad_frame_get_this_base (this_trad_cache);
+}
+
+static const struct frame_base mips_sde_frame_base =
+{
+  &mips_sde_frame_unwind,
+  mips_sde_frame_base_address,
+  mips_sde_frame_base_address,
+  mips_sde_frame_base_address
+};
+
+static const struct frame_base *
+mips_sde_frame_base_sniffer (struct frame_info *this_frame)
+{
+  if (mips_sde_frame_sniffer (&mips_sde_frame_unwind, this_frame, NULL))
+    return &mips_sde_frame_base;
+  else
+    return NULL;
+}
+
+static void
+mips_sde_elf_osabi_sniff_abi_tag_sections (bfd *abfd, asection *sect,
+					   void *obj)
+{
+  enum gdb_osabi *os_ident_ptr = obj;
+  const char *name;
+
+  name = bfd_get_section_name (abfd, sect);
+
+  /* The presence of a section with a ".sde" prefix is indicative
+     of an SDE binary.  */
+  if (strncmp (name, ".sde", 4) == 0)
+    *os_ident_ptr = GDB_OSABI_SDE;
+}
+
+/* OSABI sniffer for MIPS SDE.  */
+
+static enum gdb_osabi
+mips_sde_elf_osabi_sniffer (bfd *abfd)
+{
+  enum gdb_osabi osabi = GDB_OSABI_UNKNOWN;
+  unsigned int elfosabi;
+
+  /* If the generic sniffer gets a hit, return and let other sniffers
+     get a crack at it.  */
+  bfd_map_over_sections (abfd,
+			 generic_elf_osabi_sniff_abi_tag_sections,
+			 &osabi);
+  if (osabi != GDB_OSABI_UNKNOWN)
+    return GDB_OSABI_UNKNOWN;
+
+  elfosabi = elf_elfheader (abfd)->e_ident[EI_OSABI];
+
+  if (elfosabi == ELFOSABI_NONE)
+    {
+      /* When elfosabi is ELFOSABI_NONE (0), then the ELF structures in the
+	 file are conforming to the base specification for that machine
+	 (there are no OS-specific extensions).  In order to determine the
+	 real OS in use we must look for OS notes that have been added.
+
+	 For SDE, we simply look for sections named with .sde as prefixes.  */
+      bfd_map_over_sections (abfd,
+			     mips_sde_elf_osabi_sniff_abi_tag_sections,
+			     &osabi);
+    }
+  return osabi;
+}
+
+static void
+mips_sde_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
+{
+  frame_unwind_append_unwinder (gdbarch, &mips_sde_frame_unwind);
+  frame_base_append_sniffer (gdbarch, mips_sde_frame_base_sniffer);
+}
+
+/* Provide a prototype to silence -Wmissing-prototypes.  */
+extern initialize_file_ftype _initialize_mips_sde_tdep;
+
+void
+_initialize_mips_sde_tdep (void)
+{
+  gdbarch_register_osabi_sniffer (bfd_arch_mips,
+				  bfd_target_elf_flavour,
+				  mips_sde_elf_osabi_sniffer);
+
+  gdbarch_register_osabi (bfd_arch_mips, 0, GDB_OSABI_SDE, mips_sde_init_abi);
+}
diff --git a/gdb/osabi.c b/gdb/osabi.c
index 50d391a..895b476 100644
--- a/gdb/osabi.c
+++ b/gdb/osabi.c
@@ -83,6 +83,7 @@ static const struct osabi_names gdb_osabi_names[] =
   { "OpenVMS", NULL },
   { "LynxOS178", NULL },
   { "Newlib", NULL },
+  { "SDE", NULL },
 
   { "<invalid>", NULL }
 };

Re: [PATCH] MIPS SDE OS ABI support

[Maciej W. Rozycki]

On Fri, 19 Dec 2014, Yao Qi wrote:

> > BTW, OOC, I looked around the web for MIPS SDE, and not much
> > comes out.  What is it exactly?
> 
> I don't see much either.  Looks MIPS SDE lite has been discontinued
> <http://forum.imgtec.com/discussion/2794/mips-sde-lite>
> We develop toolchain, which is integrated in MIPS Navigator ICS
> <http://community.imgtec.com/developers/mips/tools/mips-navigator-ics/>.
> Both SDE ELF and Linux toolchain are used in it
> <http://navigatorics.mips.com/2.9.2/GettingStartedGuide-2.9.2.10356.pdf>

 SDE (Software Development Environment) was a bare-metal MIPS toolchain 
developed by a UK company called Algorithmics who, from 1988, provided 
development support for the MIPS platform -- in the form of both hardware, 
such as system controller IP or development boards, as well as software.  
The toolchain comprised GNU toolchain components (Binutils, GCC, 
GDB/Insight) and a proprietary C library including low-level hardware 
support (e.g. to map Posix semantics onto MIPS MT hardware threading 
support or to handle individual development boards), all together defining 
a bare-metal MIPS ABI.

 The toolchain was taken over by MIPS Technologies together with 
Algorithmics in 2002 and maintained by them until the maintenance was 
handed over to CodeSourcery (now Mentor Graphics) in 2007.  The original 
SDE C library was still included in CodeSourcery's Sourcery G++ 4.2 
toolchain for MIPS/ELF, but then it was replaced with a combination of 
Newlib and proprietary hardware support code.  The ABI has been retained 
though and the toolchain has been since maintained by Mentor Graphics.

 Here's programmer's documentation for the last version (6.06.01) of the 
original SDE toolchain released by MIPS Technologies:

<http://web.archive.org/web/20130315203850/http://mips.com/media/files/MD00428%2D2B%2DSDE6X%2DSUM%2D01.17.pdf>

Older stuff can be found in the archive, collected from the original 
Algorithmics web site that used to be there at http://www.algor.co.uk/.  
Their corresponding FTP site is I believe regrettably gone for good.

 The `mips-sde-elf' configuration triplet has been used across the GNU 
toolchain to select the specifics of this ABI.

  Maciej