* Makefile.in (frv-linux-tdep.o): Add dependencies.

	* frv-linux-tdep.c: New file.
	* frv-tdep.c (struct gdbarch_tdep): Add new field
	``sigcontext_reg_addr''.
	(frv_set_sigcontext_reg_addr, frv_sigtramp,frame_cache)
	(frv_sigtramp_frame_this_id, frv_sigtramp_frame_prev_register)
	(frv_sigramp_frame_sniffer): New functions.
	(frv_sigtramp_frame_unwind): New static global.
	(frv_gdbarch_init): Hook in ABI-specific overrides.  Hook up frame
	sniffers.
	* frv-tdep.h (frv_set_sigcontext_reg_addr): New function.
	* config/frv/frv.mt (TDEPFILES): Add frv-linux-tdep.o.

6 files changed, 416 insertions, 2 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 4561d2f..4235154 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,20 @@
 2004-03-15  Kevin Buettner  <kevinb@redhat.com>
 
+	* Makefile.in (frv-linux-tdep.o): Add dependencies.
+	* frv-linux-tdep.c: New file.
+	* frv-tdep.c (struct gdbarch_tdep): Add new field
+	``sigcontext_reg_addr''.
+	(frv_set_sigcontext_reg_addr, frv_sigtramp,frame_cache)
+	(frv_sigtramp_frame_this_id, frv_sigtramp_frame_prev_register)
+	(frv_sigramp_frame_sniffer): New functions.
+	(frv_sigtramp_frame_unwind): New static global.
+	(frv_gdbarch_init): Hook in ABI-specific overrides.  Hook up frame
+	sniffers.
+	* frv-tdep.h (frv_set_sigcontext_reg_addr): New function.
+	* config/frv/frv.mt (TDEPFILES): Add frv-linux-tdep.o.
+
+2004-03-15  Kevin Buettner  <kevinb@redhat.com>
+
 	* frv-tdep.c (frv_analyze_prologue): Terminate prologue scan,
 	but not via a call to error(), when unable to read memory.
 
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 143ecd0..ab571af 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -1766,6 +1766,8 @@ frame.o: frame.c $(defs_h) $(frame_h) $(target_h) $(value_h) $(inferior_h) \
 	$(command_h) $(gdbcmd_h)
 frame-unwind.o: frame-unwind.c $(defs_h) $(frame_h) $(frame_unwind_h) \
 	$(gdb_assert_h) $(dummy_frame_h)
+frv-linux-tdep.o: frv-linux-tdep.c $(defs_h) $(target_h) $(osabi_h) \
+	$(elf_bfd_h) $(elf_frv_h) $(frv_tdep_h)
 frv-tdep.o: frv-tdep.c $(defs_h) $(gdb_string_h) $(inferior_h) $(gdbcore_h) \
 	$(arch_utils_h) $(regcache_h) $(frame_h) $(frame_unwind_h) \
 	$(frame_base_h) $(trad_frame_h) $(dis_asm_h) $(gdb_assert_h) \
diff --git a/gdb/config/frv/frv.mt b/gdb/config/frv/frv.mt
index d782915..5849f04 100644
--- a/gdb/config/frv/frv.mt
+++ b/gdb/config/frv/frv.mt
@@ -1,5 +1,5 @@
 # Target: Fujitsu FRV processor
-TDEPFILES= frv-tdep.o solib.o solib-frv.o
+TDEPFILES= frv-tdep.o frv-linux-tdep.o solib.o solib-frv.o
 TM_FILE= tm-frv.h
 SIM_OBS = remote-sim.o
 SIM = ../sim/frv/libsim.a
diff --git a/gdb/frv-linux-tdep.c b/gdb/frv-linux-tdep.c
new file mode 100644
index 0000000..8588cb1
--- /dev/null
+++ b/gdb/frv-linux-tdep.c
@@ -0,0 +1,273 @@
+/* Target-dependent code for GNU/Linux running on the Fujitsu FR-V,
+   for GDB.
+   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 "target.h"
+#include "frame.h"
+#include "osabi.h"
+#include "elf-bfd.h"
+#include "elf/frv.h"
+#include "frv-tdep.h"
+
+/* Define the size (in bytes) of an FR-V instruction.  */
+static const int frv_instr_size = 4;
+
+enum {
+  NORMAL_SIGTRAMP = 1,
+  RT_SIGTRAMP = 2
+};
+
+static int
+frv_linux_pc_in_sigtramp (CORE_ADDR pc, char *name)
+{
+  char buf[frv_instr_size];
+  LONGEST instr;
+  int retval = 0;
+
+  if (target_read_memory (pc, buf, sizeof buf) != 0)
+    return 0;
+
+  instr = extract_unsigned_integer (buf, sizeof buf);
+
+  if (instr == 0x8efc0077)	/* setlos #__NR_sigreturn, gr7 */
+    retval = NORMAL_SIGTRAMP;
+  else if (instr -= 0x8efc00ad)	/* setlos #__NR_rt_sigreturn, gr7 */
+    retval = RT_SIGTRAMP;
+  else
+    return 0;
+
+  if (target_read_memory (pc + frv_instr_size, buf, sizeof buf) != 0)
+    return 0;
+  instr = extract_unsigned_integer (buf, sizeof buf);
+  if (instr != 0xc0700000)	/* tira	gr0, 0 */
+    return 0;
+
+  /* If we get this far, we'll return a non-zero value, either
+     NORMAL_SIGTRAMP (1) or RT_SIGTRAMP (2).  */
+  return retval;
+}
+
+/* Given NEXT_FRAME, "callee" frame of the sigtramp frame that we
+   wish to decode, and REGNO, one of the frv register numbers defined
+   in frv-tdep.h, return the address of the saved register (corresponding
+   to REGNO) in the sigtramp frame.  Return -1 if the register is not
+   found in the sigtramp frame.  The magic numbers in the code below
+   were computed by examining the following kernel structs:
+
+   From arch/frvnommu/signal.c:
+
+      struct sigframe
+      {
+	      void (*pretcode)(void);
+	      int sig;
+	      struct sigcontext sc;
+	      unsigned long extramask[_NSIG_WORDS-1];
+	      uint32_t retcode[2];
+      };
+
+      struct rt_sigframe
+      {
+	      void (*pretcode)(void);
+	      int sig;
+	      struct siginfo *pinfo;
+	      void *puc;
+	      struct siginfo info;
+	      struct ucontext uc;
+	      uint32_t retcode[2];
+      };
+
+   From include/asm-frvnommu/ucontext.h:
+
+      struct ucontext {
+	      unsigned long		uc_flags;
+	      struct ucontext		*uc_link;
+	      stack_t			uc_stack;
+	      struct sigcontext	uc_mcontext;
+	      sigset_t		uc_sigmask;
+      };
+
+   From include/asm-frvnommu/sigcontext.h:
+
+      struct sigcontext {
+	      struct user_context	sc_context;
+	      unsigned long		sc_oldmask;
+      } __attribute__((aligned(8)));
+
+   From include/asm-frvnommu/registers.h:
+      struct user_int_regs
+      {
+	      unsigned long		psr;
+	      unsigned long		isr;
+	      unsigned long		ccr;
+	      unsigned long		cccr;
+	      unsigned long		lr;
+	      unsigned long		lcr;
+	      unsigned long		pc;
+	      unsigned long		__status;
+	      unsigned long		syscallno;
+	      unsigned long		orig_gr8;
+	      unsigned long		gner[2];
+	      unsigned long long	iacc[1];
+
+	      union {
+		      unsigned long	tbr;
+		      unsigned long	gr[64];
+	      };
+      };
+
+      struct user_fpmedia_regs
+      {
+	      unsigned long	fr[64];
+	      unsigned long	fner[2];
+	      unsigned long	msr[2];
+	      unsigned long	acc[8];
+	      unsigned char	accg[8];
+	      unsigned long	fsr[1];
+      };
+
+      struct user_context
+      {
+	      struct user_int_regs		i;
+	      struct user_fpmedia_regs	f;
+
+	      void *extension;
+      } __attribute__((aligned(8)));  */
+
+static CORE_ADDR
+frv_linux_sigcontext_reg_addr (struct frame_info *next_frame, int regno,
+                               CORE_ADDR *sc_addr_cache_ptr)
+{
+  CORE_ADDR sc_addr;
+
+  if (sc_addr_cache_ptr && *sc_addr_cache_ptr)
+    {
+      sc_addr = *sc_addr_cache_ptr;
+    }
+  else
+    {
+      CORE_ADDR pc, sp;
+      char buf[4];
+      int tramp_type;
+
+      pc = frame_pc_unwind (next_frame);
+      tramp_type = frv_linux_pc_in_sigtramp (pc, 0);
+
+      frame_unwind_register (next_frame, sp_regnum, buf);
+      sp = extract_unsigned_integer (buf, sizeof buf);
+
+      if (tramp_type == NORMAL_SIGTRAMP)
+	{
+	  /* For a normal sigtramp frame, the sigcontext struct starts
+	     at SP + 8.  */
+	  sc_addr = sp + 8;
+	}
+      else if (tramp_type == RT_SIGTRAMP)
+	{
+	  /* For a realtime sigtramp frame, SP + 12 contains a pointer
+	     to the a ucontext struct.  The ucontext struct contains
+	     a sigcontext struct starting 12 bytes in.  */
+	  if (target_read_memory (sp + 12, buf, sizeof buf) != 0)
+	    {
+	      warning ("Can't read realtime sigtramp frame.");
+	      return 0;
+	    }
+	  sc_addr = extract_unsigned_integer (buf, sizeof buf);
+	  sc_addr += 12;
+	}
+      else
+	internal_error (__FILE__, __LINE__, "not a signal trampoline");
+
+      if (sc_addr_cache_ptr)
+	*sc_addr_cache_ptr = sc_addr;
+    }
+
+  switch (regno)
+    {
+    case psr_regnum :
+      return sc_addr + 0;
+    /* sc_addr + 4 has "isr", the Integer Status Register.  */
+    case ccr_regnum :
+      return sc_addr + 8;
+    case cccr_regnum :
+      return sc_addr + 12;
+    case lr_regnum :
+      return sc_addr + 16;
+    case lcr_regnum :
+      return sc_addr + 20;
+    case pc_regnum :
+      return sc_addr + 24;
+    /* sc_addr + 28 is __status, the exception status.
+       sc_addr + 32 is syscallno, the syscall number or -1.
+       sc_addr + 36 is orig_gr8, the original syscall arg #1.
+       sc_addr + 40 is gner[0].
+       sc_addr + 44 is gner[1]. */
+    case iacc0h_regnum :
+      return sc_addr + 48;
+    case iacc0l_regnum :
+      return sc_addr + 52;
+    default : 
+      if (first_gpr_regnum <= regno && regno <= last_gpr_regnum)
+	return sc_addr + 56 + 4 * (regno - first_gpr_regnum);
+      else if (first_fpr_regnum <= regno && regno <= last_fpr_regnum)
+	return sc_addr + 312 + 4 * (regno - first_fpr_regnum);
+      else
+	return -1;  /* not saved. */
+    }
+}
+
+static void
+frv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
+{
+  /* When the FR-V Linux kernel calls a signal handler, the return
+     address points to a bit of code on the stack.  This function is
+     used to identify this bit of code as a signal trampoline in order
+     to support backtracing through calls to signal handlers.  */
+  set_gdbarch_pc_in_sigtramp (gdbarch, frv_linux_pc_in_sigtramp);
+  frv_set_sigcontext_reg_addr (gdbarch, frv_linux_sigcontext_reg_addr);
+}
+
+static enum gdb_osabi
+frv_linux_elf_osabi_sniffer (bfd *abfd)
+{
+  int elf_flags;
+
+  elf_flags = elf_elfheader (abfd)->e_flags;
+
+  /* Assume GNU/Linux if using the FDPIC ABI.  If/when another OS shows
+     up that uses this ABI, we'll need to start using .note sections
+     or some such.  */
+  if (elf_flags & EF_FRV_FDPIC)
+    return GDB_OSABI_LINUX;
+  else
+    return GDB_OSABI_UNKNOWN;
+}
+
+/* Provide a prototype to silence -Wmissing-prototypes.  */
+void _initialize_frv_linux_tdep (void);
+
+void
+_initialize_frv_linux_tdep (void)
+{
+  gdbarch_register_osabi (bfd_arch_frv, 0, GDB_OSABI_LINUX, frv_linux_init_abi);
+  gdbarch_register_osabi_sniffer (bfd_arch_frv,
+				  bfd_target_elf_flavour,
+				  frv_linux_elf_osabi_sniffer);
+}
diff --git a/gdb/frv-tdep.c b/gdb/frv-tdep.c
index ffd911e..48d241c 100644
--- a/gdb/frv-tdep.c
+++ b/gdb/frv-tdep.c
@@ -96,6 +96,11 @@ struct gdbarch_tdep
 
   /* Register names.  */
   char **register_names;
+
+  /* Given NEXT_FRAME, determine the address of register REGNO saved in
+     the calling sigtramp frame.  */
+  CORE_ADDR (*sigcontext_reg_addr) (struct frame_info *next_frame, int regno,
+                                    CORE_ADDR *);
 };
 
 #define CURRENT_VARIANT (gdbarch_tdep (current_gdbarch))
@@ -107,6 +112,15 @@ frv_abi (struct gdbarch *gdbarch)
   return gdbarch_tdep (gdbarch)->frv_abi;
 }
 
+/* Set sigcontext_reg_addr.  */
+void
+frv_set_sigcontext_reg_addr (struct gdbarch *gdbarch,
+                             CORE_ADDR (*sigcontext_reg_addr)
+			       (struct frame_info *, int, CORE_ADDR *))
+{
+  gdbarch_tdep (gdbarch)->sigcontext_reg_addr = sigcontext_reg_addr;
+}
+
 /* Fetch the interpreter and executable loadmap addresses (for shared
    library support) for the FDPIC ABI.  Return 0 if successful, -1 if
    not.  (E.g, -1 will be returned if the ABI isn't the FDPIC ABI.)  */
@@ -1344,6 +1358,101 @@ frv_unwind_dummy_id (struct gdbarch *gdbarch, struct frame_info *next_frame)
 			 frame_pc_unwind (next_frame));
 }
 
+/* Signal trampolines.  */
+
+static struct frv_unwind_cache *
+frv_sigtramp_frame_cache (struct frame_info *next_frame, void **this_cache)
+{
+  struct frv_unwind_cache *cache;
+  struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
+  CORE_ADDR addr;
+  char buf[4];
+  int regno;
+  CORE_ADDR sc_addr_cache_val = 0;
+
+  if (*this_cache)
+    return *this_cache;
+
+  cache = FRAME_OBSTACK_ZALLOC (struct frv_unwind_cache);
+  cache->saved_regs = trad_frame_alloc_saved_regs (next_frame);
+
+  frame_unwind_register (next_frame, sp_regnum, buf);
+  cache->base = extract_unsigned_integer (buf, sizeof buf);
+
+  for (regno = 0; regno < frv_num_regs; regno++)
+    {
+      cache->saved_regs[regno].addr 
+	= tdep->sigcontext_reg_addr (next_frame, regno, &sc_addr_cache_val);
+    }
+
+
+  if (cache->saved_regs[sp_regnum].addr != -1
+      && target_read_memory (cache->saved_regs[sp_regnum].addr,
+                              buf, sizeof buf) == 0)
+    {
+      cache->prev_sp = extract_unsigned_integer (buf, sizeof buf);
+
+      /* Now that we've bothered to read it out of memory, save the
+         prev frame's SP value in the cache.  */
+      trad_frame_set_value (cache->saved_regs, sp_regnum, cache->prev_sp);
+    }
+  else
+    {
+      warning ("Can't read SP value from sigtramp frame");
+    }
+
+  *this_cache = cache;
+  return cache;
+}
+
+static void
+frv_sigtramp_frame_this_id (struct frame_info *next_frame, void **this_cache,
+			     struct frame_id *this_id)
+{
+  struct frv_unwind_cache *cache =
+    frv_sigtramp_frame_cache (next_frame, this_cache);
+
+  (*this_id) = frame_id_build (cache->base, frame_pc_unwind (next_frame));
+}
+
+static void
+frv_sigtramp_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)
+{
+  /* Make sure we've initialized the cache.  */
+  frv_sigtramp_frame_cache (next_frame, this_cache);
+
+  frv_frame_prev_register (next_frame, this_cache, regnum,
+			    optimizedp, lvalp, addrp, realnump, valuep);
+}
+
+static const struct frame_unwind frv_sigtramp_frame_unwind =
+{
+  SIGTRAMP_FRAME,
+  frv_sigtramp_frame_this_id,
+  frv_sigtramp_frame_prev_register
+};
+
+static const struct frame_unwind *
+frv_sigtramp_frame_sniffer (struct frame_info *next_frame)
+{
+  CORE_ADDR pc = frame_pc_unwind (next_frame);
+  char *name;
+
+  /* We shouldn't even bother to try if the OSABI didn't register
+     a sigcontext_reg_addr handler.  */
+  if (!gdbarch_tdep (current_gdbarch)->sigcontext_reg_addr)
+    return NULL;
+
+  find_pc_partial_function (pc, &name, NULL, NULL);
+  if (PC_IN_SIGTRAMP (pc, name))
+    return &frv_sigtramp_frame_unwind;
+
+  return NULL;
+}
 
 static struct gdbarch *
 frv_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
@@ -1434,8 +1543,9 @@ frv_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   set_gdbarch_unwind_pc (gdbarch, frv_unwind_pc);
   set_gdbarch_unwind_sp (gdbarch, frv_unwind_sp);
   set_gdbarch_frame_align (gdbarch, frv_frame_align);
-  frame_unwind_append_sniffer (gdbarch, frv_frame_sniffer);
   frame_base_set_default (gdbarch, &frv_frame_base);
+  /* We set the sniffer lower down after the OSABI hooks have been
+     established.  */
 
   /* Settings for calling functions in the inferior.  */
   set_gdbarch_push_dummy_call (gdbarch, frv_push_dummy_call);
@@ -1480,6 +1590,15 @@ frv_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
     set_gdbarch_convert_from_func_ptr_addr (gdbarch,
 					    frv_convert_from_func_ptr_addr);
 
+  /* Hook in ABI-specific overrides, if they have been registered.  */
+  gdbarch_init_osabi (info, gdbarch);
+
+  /* Set the sigtramp frame sniffer.  */
+  frame_unwind_append_sniffer (gdbarch, frv_sigtramp_frame_sniffer); 
+
+  /* Set the fallback (prologue based) frame sniffer.  */
+  frame_unwind_append_sniffer (gdbarch, frv_frame_sniffer);
+
   return gdbarch;
 }
 
diff --git a/gdb/frv-tdep.h b/gdb/frv-tdep.h
index e33fb11..5b9b88b 100644
--- a/gdb/frv-tdep.h
+++ b/gdb/frv-tdep.h
@@ -84,6 +84,11 @@ enum {
 /* Return the FR-V ABI associated with GDBARCH.  */
 enum frv_abi frv_abi (struct gdbarch *gdbarch);
 
+/* Associate a sigcontext address fetcher with GDBARCH.  */
+void frv_set_sigcontext_reg_addr (struct gdbarch *gdbarch,
+                                  CORE_ADDR (*sigcontext_reg_addr)
+			            (struct frame_info *, int, CORE_ADDR *));
+
 /* Fetch the interpreter and executable loadmap addresses (for shared
    library support) for the FDPIC ABI.  Return 0 if successful, -1 if
    not.  (E.g, -1 will be returned if the ABI isn't the FDPIC ABI.)  */