[PATCH] Handle OpenBSD/sparc signal trampolines

[Mark Kettenis <kettenis at chello dot nl>]

Similar to what I did to OpenBSD/sparc64 yesterday.  Core file support
remains to be done.

Committed,

Mark


Index: ChangeLog
from  Mark Kettenis  <kettenis@gnu.org>
 
	* sparc-tdep.h (sparc32nbsd_sigcontext_saved_regs): New prototype.
	* sparcnbsd-tdep.c (sparc32nbsd_sigcontext_saved_regs): New
	function with code split out from
	sparc32nbsd_sigcontext_frame_cache.
	(sparc32nbsd_sigcontext_frame_cache): Use
	sparc32nbsd_sigcontext_saved_regs.
	(_initialize_sparc32nbsd_tdep): Don't register OS ABI handler for
	OpenBSD.
	* sparcobsd-tdep.c: New file.
	* Makefile.in (ALLDEPFILES): Add sparcobsd-tdep.c.
	(sparcobsd-tdep.o): New dependency.
	* configure.tgt (sparc-*-openbsd*): Set gdb_target to obsd.
	* config/sparc/obsd.mt: New file.

Index: sparc-tdep.h
===================================================================
RCS file: /cvs/src/src/gdb/sparc-tdep.h,v
retrieving revision 1.6
diff -u -p -r1.6 sparc-tdep.h
--- sparc-tdep.h 12 Jan 2004 18:33:47 -0000 1.6
+++ sparc-tdep.h 25 Jan 2004 11:43:55 -0000
@@ -22,11 +22,11 @@
 #ifndef SPARC_TDEP_H
 #define SPARC_TDEP_H 1
 
+struct frame_info;
 struct gdbarch;
 struct regcache;
 struct regset;
 struct trad_frame_saved_reg;
-struct frame_info;
 
 /* Register offsets for the general-purpose register set.  */
 
@@ -194,5 +194,8 @@ extern void sparc32_sol2_init_abi (struc
 
 /* Register offsets for NetBSD.  */
 extern const struct sparc_gregset sparc32nbsd_gregset;
+
+extern struct trad_frame_saved_reg *
+  sparc32nbsd_sigcontext_saved_regs (struct frame_info *next_frame);
 
 #endif /* sparc-tdep.h */
Index: sparcnbsd-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/sparcnbsd-tdep.c,v
retrieving revision 1.12
diff -u -p -r1.12 sparcnbsd-tdep.c
--- sparcnbsd-tdep.c 24 Jan 2004 20:55:41 -0000 1.12
+++ sparcnbsd-tdep.c 25 Jan 2004 11:43:55 -0000
@@ -90,92 +90,104 @@ sparc32nbsd_pc_in_sigtramp (CORE_ADDR pc
   return nbsd_pc_in_sigtramp (pc, name);
 }
 
-static struct sparc_frame_cache *
-sparc32nbsd_sigcontext_frame_cache (struct frame_info *next_frame,
-				    void **this_cache)
+struct trad_frame_saved_reg *
+sparc32nbsd_sigcontext_saved_regs (struct frame_info *next_frame)
 {
-  struct sparc_frame_cache *cache;
+  struct trad_frame_saved_reg *saved_regs;
   CORE_ADDR addr, sigcontext_addr;
-  LONGEST psr;
   int regnum, delta;
+  ULONGEST psr;
 
-  if (*this_cache)
-    return *this_cache;
+  saved_regs = trad_frame_alloc_saved_regs (next_frame);
 
-  cache = sparc_frame_cache (next_frame, this_cache);
-  gdb_assert (cache == *this_cache);
+  /* We find the appropriate instance of `struct sigcontext' at a
+     fixed offset in the signal frame.  */
+  addr = frame_unwind_register_unsigned (next_frame, SPARC_FP_REGNUM);
+  sigcontext_addr = addr + 64 + 16;
 
   /* The registers are saved in bits and pieces scattered all over the
      place.  The code below records their location on the assumption
      that the part of the signal trampoline that saves the state has
      been executed.  */
 
-  /* If we couldn't find the frame's function, we're probably dealing
-     with an on-stack signal trampoline.  */
-  if (cache->pc == 0)
-    {
-      cache->pc = sparc32nbsd_sigtramp_start;
-
-      /* Since we couldn't find the frame's function, the cache was
-         initialized under the assumption that we're frameless.  */
-      cache->frameless_p = 0;
-      addr = frame_unwind_register_unsigned (next_frame, SPARC_FP_REGNUM);
-      cache->base = addr;
-    }
-
-  cache->saved_regs = trad_frame_alloc_saved_regs (next_frame);
-
-  /* We find the appropriate instance of `struct sigcontext' at a
-     fixed offset in the signal frame.  */
-  sigcontext_addr = cache->base + 64 + 16;
-
-  cache->saved_regs[SPARC_SP_REGNUM].addr = sigcontext_addr + 8;
-  cache->saved_regs[SPARC32_PC_REGNUM].addr = sigcontext_addr + 12;
-  cache->saved_regs[SPARC32_NPC_REGNUM].addr = sigcontext_addr + 16;
-  cache->saved_regs[SPARC32_PSR_REGNUM].addr = sigcontext_addr + 20;
-  cache->saved_regs[SPARC_G1_REGNUM].addr = sigcontext_addr + 24;
-  cache->saved_regs[SPARC_O0_REGNUM].addr = sigcontext_addr + 28;
+  saved_regs[SPARC_SP_REGNUM].addr = sigcontext_addr + 8;
+  saved_regs[SPARC32_PC_REGNUM].addr = sigcontext_addr + 12;
+  saved_regs[SPARC32_NPC_REGNUM].addr = sigcontext_addr + 16;
+  saved_regs[SPARC32_PSR_REGNUM].addr = sigcontext_addr + 20;
+  saved_regs[SPARC_G1_REGNUM].addr = sigcontext_addr + 24;
+  saved_regs[SPARC_O0_REGNUM].addr = sigcontext_addr + 28;
 
   /* The remaining `global' registers and %y are saved in the `local'
      registers.  */
   delta = SPARC_L0_REGNUM - SPARC_G0_REGNUM;
   for (regnum = SPARC_G2_REGNUM; regnum <= SPARC_G7_REGNUM; regnum++)
-    cache->saved_regs[regnum].realreg = regnum + delta;
-  cache->saved_regs[SPARC32_Y_REGNUM].realreg = SPARC_L1_REGNUM;
+    saved_regs[regnum].realreg = regnum + delta;
+  saved_regs[SPARC32_Y_REGNUM].realreg = SPARC_L1_REGNUM;
 
   /* The remaining `out' registers can be found in the current frame's
      `in' registers.  */
   delta = SPARC_I0_REGNUM - SPARC_O0_REGNUM;
   for (regnum = SPARC_O1_REGNUM; regnum <= SPARC_O5_REGNUM; regnum++)
-    cache->saved_regs[regnum].realreg = regnum + delta;
-  cache->saved_regs[SPARC_O7_REGNUM].realreg = SPARC_I7_REGNUM;
+    saved_regs[regnum].realreg = regnum + delta;
+  saved_regs[SPARC_O7_REGNUM].realreg = SPARC_I7_REGNUM;
 
   /* The `local' and `in' registers have been saved in the register
      save area.  */
-  addr = cache->saved_regs[SPARC_SP_REGNUM].addr;
+  addr = saved_regs[SPARC_SP_REGNUM].addr;
   addr = get_frame_memory_unsigned (next_frame, addr, 4);
   for (regnum = SPARC_L0_REGNUM;
        regnum <= SPARC_I7_REGNUM; regnum++, addr += 4)
-    cache->saved_regs[regnum].addr = addr;
+    saved_regs[regnum].addr = addr;
 
   /* The floating-point registers are only saved if the EF bit in %prs
      has been set.  */
 
 #define PSR_EF	0x00001000
 
-  addr = cache->saved_regs[SPARC32_PSR_REGNUM].addr;
+  addr = saved_regs[SPARC32_PSR_REGNUM].addr;
   psr = get_frame_memory_unsigned (next_frame, addr, 4);
   if (psr & PSR_EF)
     {
       CORE_ADDR sp;
 
       sp = frame_unwind_register_unsigned (next_frame, SPARC_SP_REGNUM);
-      cache->saved_regs[SPARC32_FSR_REGNUM].addr = sp + 96;
+      saved_regs[SPARC32_FSR_REGNUM].addr = sp + 96;
       for (regnum = SPARC_F0_REGNUM, addr = sp + 96 + 8;
 	   regnum <= SPARC_F31_REGNUM; regnum++, addr += 4)
-	cache->saved_regs[regnum].addr = addr;
+	saved_regs[regnum].addr = addr;
     }
 
+  return saved_regs;
+}
+
+static struct sparc_frame_cache *
+sparc32nbsd_sigcontext_frame_cache (struct frame_info *next_frame,
+				    void **this_cache)
+{
+  struct sparc_frame_cache *cache;
+  CORE_ADDR addr;
+
+  if (*this_cache)
+    return *this_cache;
+
+  cache = sparc_frame_cache (next_frame, this_cache);
+  gdb_assert (cache == *this_cache);
+
+  /* If we couldn't find the frame's function, we're probably dealing
+     with an on-stack signal trampoline.  */
+  if (cache->pc == 0)
+    {
+      cache->pc = sparc32nbsd_sigtramp_start;
+
+      /* Since we couldn't find the frame's function, the cache was
+         initialized under the assumption that we're frameless.  */
+      cache->frameless_p = 0;
+      addr = frame_unwind_register_unsigned (next_frame, SPARC_FP_REGNUM);
+      cache->base = addr;
+    }
+
+  cache->saved_regs = sparc32nbsd_sigcontext_saved_regs (next_frame);
+
   return cache;
 }
 
@@ -324,7 +336,5 @@ _initialize_sparnbsd_tdep (void)
   gdbarch_register_osabi (bfd_arch_sparc, 0, GDB_OSABI_NETBSD_AOUT,
 			  sparc32nbsd_aout_init_abi);
   gdbarch_register_osabi (bfd_arch_sparc, 0, GDB_OSABI_NETBSD_ELF,
-			  sparc32nbsd_elf_init_abi);
-  gdbarch_register_osabi (bfd_arch_sparc, 0, GDB_OSABI_OPENBSD_ELF,
 			  sparc32nbsd_elf_init_abi);
 }
Index: sparcobsd-tdep.c
===================================================================
RCS file: sparcobsd-tdep.c
diff -N sparcobsd-tdep.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ sparcobsd-tdep.c 25 Jan 2004 11:43:55 -0000
@@ -0,0 +1,171 @@
+/* Target-dependent code for OpenBSD/sparc.
+
+   Copyright 2004 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 2 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, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+#include "floatformat.h"
+#include "frame.h"
+#include "frame-unwind.h"
+#include "osabi.h"
+#include "solib-svr4.h"
+#include "symtab.h"
+#include "trad-frame.h"
+
+#include "gdb_assert.h"
+
+#include "sparc-tdep.h"
+#include "nbsd-tdep.h"
+
+/* Signal trampolines.  */
+
+/* The OpenBSD kernel maps the signal trampoline at some random
+   location in user space, which means that the traditional BSD way of
+   detecting it won't work.
+
+   The signal trampoline will be mapped at an address that is page
+   aligned.  We recognize the signal trampoline by the looking for the
+   sigreturn system call.  */
+
+static const int sparc32obsd_page_size = 4096;
+
+static int
+sparc32obsd_pc_in_sigtramp (CORE_ADDR pc, char *name)
+{
+  CORE_ADDR start_pc = (pc & ~(sparc32obsd_page_size - 1));
+  unsigned long insn;
+
+  if (name)
+    return 0;
+
+  /* Check for "restore %g0, SYS_sigreturn, %g1".  */
+  insn = sparc_fetch_instruction (start_pc + 0xec);
+  if (insn != 0x83e82067)
+    return 0;
+
+  /* Check for "t ST_SYSCALL".  */
+  insn = sparc_fetch_instruction (start_pc + 0xf4);
+  if (insn != 0x91d02000)
+    return 0;
+
+  return 1;
+}
+
+static struct sparc_frame_cache *
+sparc32obsd_frame_cache (struct frame_info *next_frame, void **this_cache)
+{
+  struct sparc_frame_cache *cache;
+  CORE_ADDR addr;
+
+  if (*this_cache)
+    return *this_cache;
+
+  cache = sparc_frame_cache (next_frame, this_cache);
+  gdb_assert (cache == *this_cache);
+
+  /* If we couldn't find the frame's function, we're probably dealing
+     with an on-stack signal trampoline.  */
+  if (cache->pc == 0)
+    {
+      cache->pc = frame_pc_unwind (next_frame);
+      cache->pc &= ~(sparc32obsd_page_size - 1);
+
+      /* Since we couldn't find the frame's function, the cache was
+         initialized under the assumption that we're frameless.  */
+      cache->frameless_p = 0;
+      addr = frame_unwind_register_unsigned (next_frame, SPARC_FP_REGNUM);
+      cache->base = addr;
+    }
+
+  cache->saved_regs = sparc32nbsd_sigcontext_saved_regs (next_frame);
+
+  return cache;
+}
+
+static void
+sparc32obsd_frame_this_id (struct frame_info *next_frame, void **this_cache,
+			   struct frame_id *this_id)
+{
+  struct sparc_frame_cache *cache =
+    sparc32obsd_frame_cache (next_frame, this_cache);
+
+  (*this_id) = frame_id_build (cache->base, cache->pc);
+}
+
+static void
+sparc32obsd_frame_prev_register (struct frame_info *next_frame,
+				 void **this_cache,
+				 int regnum, int *optimizedp,
+				 enum lval_type *lvalp, CORE_ADDR *addrp,
+				 int *realnump, void *valuep)
+{
+  struct sparc_frame_cache *cache =
+    sparc32obsd_frame_cache (next_frame, this_cache);
+
+  trad_frame_prev_register (next_frame, cache->saved_regs, regnum,
+			    optimizedp, lvalp, addrp, realnump, valuep);
+}
+
+static const struct frame_unwind sparc32obsd_frame_unwind =
+{
+  SIGTRAMP_FRAME,
+  sparc32obsd_frame_this_id,
+  sparc32obsd_frame_prev_register
+};
+
+static const struct frame_unwind *
+sparc32obsd_sigtramp_frame_sniffer (struct frame_info *next_frame)
+{
+  CORE_ADDR pc = frame_pc_unwind (next_frame);
+  char *name;
+
+  find_pc_partial_function (pc, &name, NULL, NULL);
+  if (sparc32obsd_pc_in_sigtramp (pc, name))
+    return &sparc32obsd_frame_unwind;
+
+  return NULL;
+}
+
+
+static void
+sparc32obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
+{
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  /* OpenBSD doesn't support the 128-bit `long double' from the psABI.  */
+  set_gdbarch_long_double_bit (gdbarch, 64);
+  set_gdbarch_long_double_format (gdbarch, &floatformat_ieee_double_big);
+
+  set_gdbarch_pc_in_sigtramp (gdbarch, sparc32obsd_pc_in_sigtramp);
+  frame_unwind_append_sniffer (gdbarch, sparc32obsd_sigtramp_frame_sniffer);
+
+  set_solib_svr4_fetch_link_map_offsets
+    (gdbarch, nbsd_ilp32_solib_svr4_fetch_link_map_offsets);
+}
+
+
+/* Provide a prototype to silence -Wmissing-prototypes.  */
+void _initialize_sparc32obsd_tdep (void);
+
+void
+_initialize_sparc32obsd_tdep (void)
+{
+  gdbarch_register_osabi (bfd_arch_sparc, 0, GDB_OSABI_OPENBSD_ELF,
+			  sparc32obsd_init_abi);
+}
Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/Makefile.in,v
retrieving revision 1.481
diff -u -p -r1.481 Makefile.in
--- Makefile.in 24 Jan 2004 22:18:21 -0000 1.481
+++ Makefile.in 25 Jan 2004 11:43:57 -0000
@@ -1328,7 +1328,7 @@ ALLDEPFILES = \
 	sparc64-linux-tdep.c sparc64-nat.c sparc64-sol2-tdep.c \
 	sparc64-tdep.c sparc64fbsd-nat.c sparc64fbsd-tdep.c \
 	sparc64nbsd-nat.c sparc64nbsd-tdep.c sparc64obsd-tdep.c \
-	sparcnbsd-nat.c sparcnbsd-tdep.c \
+	sparcnbsd-nat.c sparcnbsd-tdep.c sparcobsd-tdep.c \
 	sun3-nat.c \
 	symm-tdep.c symm-nat.c \
 	vax-tdep.c \
@@ -2386,6 +2386,9 @@ sparcnbsd-tdep.o: sparcnbsd-tdep.c $(def
 	$(frame_unwind_h) $(gdbcore_h) $(osabi_h) $(regcache_h) $(regset_h) \
 	$(solib_svr4_h) $(symtab_h) $(trad_frame_h) $(gdb_assert_h) \
 	$(gdb_string_h) $(sparc_tdep_h) $(nbsd_tdep_h)
+sparcobsd-tdep.o: sparcobsd-tdep.c $(defs_h) $(floatformat_h) $(frame_h) \
+	$(frame_unwind_h) $(osabi_h) $(solib_svr4_h) $(symtab_h) \
+	$(trad_frame_h) $(gdb_assert_h) $(sparc_tdep_h) $(nbsd_tdep_h)
 sparc-sol2-nat.o: sparc-sol2-nat.c $(defs_h) $(regcache_h) $(gregset_h) \
 	$(sparc_tdep_h) $(sparc64_tdep_h)
 sparc-sol2-tdep.o: sparc-sol2-tdep.c $(defs_h) $(frame_h) $(frame_unwind_h) \
Index: configure.tgt
===================================================================
RCS file: /cvs/src/src/gdb/configure.tgt,v
retrieving revision 1.127
diff -u -p -r1.127 configure.tgt
--- configure.tgt 24 Jan 2004 22:18:21 -0000 1.127
+++ configure.tgt 25 Jan 2004 11:43:57 -0000
@@ -38,8 +38,7 @@ esac
 case "${target}" in
 
 x86_64-*-freebsd*)	gdb_target=fbsd64 ;;
-*-*-freebsd*)		gdb_target=fbsd
-			;;
+*-*-freebsd*)		gdb_target=fbsd	;;
 
 alpha*-*-osf*)		gdb_target=alpha-osf1 ;;
 alpha*-*-linux*)	gdb_target=alpha-linux ;;
@@ -190,7 +189,7 @@ sparc-*-linux*)		gdb_target=linux ;;
 sparc64-*-linux*)	gdb_target=linux64 ;;
 sparc-*-netbsd*)	gdb_target=nbsd ;;
 sparc64-*-netbsd*)	gdb_target=nbsd64 ;;
-sparc-*-openbsd*)	gdb_target=nbsd ;;
+sparc-*-openbsd*)	gdb_target=obsd ;;
 sparc64-*-openbsd*)	gdb_target=obsd64
 			gdb_osabi=GDB_OSABI_OPENBSD_ELF
 			;;
Index: config/sparc/obsd.mt
===================================================================
RCS file: config/sparc/obsd.mt
diff -N config/sparc/obsd.mt
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ config/sparc/obsd.mt 25 Jan 2004 11:43:57 -0000
@@ -0,0 +1,4 @@
+# Target: OpenBSD/sparc
+TDEPFILES= sparc-tdep.o sparcnbsd-tdep.o sparcobsd-tdep.o nbsd-tdep.o \
+	corelow.o solib.o solib-svr4.o
+TM_FILE= tm-nbsd.h