Updated copyright notices for most files.

[deliverable/binutils-gdb.git] / gdb / ppc-linux-tdep.c

diff --git a/gdb/ppc-linux-tdep.c b/gdb/ppc-linux-tdep.c
index c9a6812b879531c3252870b8d94267a1a9a78dc8..4b35f7f109e923989da811fc6d662395bb6c3c2d 100644 (file)
--- a/gdb/ppc-linux-tdep.c
+++ b/gdb/ppc-linux-tdep.c
@@ -1,12 +1,14 @@
 /* Target-dependent code for GDB, the GNU debugger.
 /* Target-dependent code for GDB, the GNU debugger.

-   Copyright 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000
+
+   Copyright (C) 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
+   2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008

    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
    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
+   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,
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,


@@ -15,9 +17,7 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    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.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

 
 #include "defs.h"
 #include "frame.h"
 
 #include "defs.h"
 #include "frame.h"


@@ -28,176 +28,20 @@
 #include "gdbcmd.h"
 #include "symfile.h"
 #include "objfiles.h"
 #include "gdbcmd.h"
 #include "symfile.h"
 #include "objfiles.h"

-
-/* The following two instructions are used in the signal trampoline
-   code on linux/ppc */
-#define INSTR_LI_R0_0x7777     0x38007777
-#define INSTR_SC               0x44000002
-
-/* Since the *-tdep.c files are platform independent (i.e, they may be
-   used to build cross platform debuggers), we can't include system
-   headers.  Therefore, details concerning the sigcontext structure
-   must be painstakingly rerecorded.  What's worse, if these details
-   ever change in the header files, they'll have to be changed here
-   as well. */
-
-/* __SIGNAL_FRAMESIZE from <asm/ptrace.h> */
-#define PPC_LINUX_SIGNAL_FRAMESIZE 64
-
-/* From <asm/sigcontext.h>, offsetof(struct sigcontext_struct, regs) == 0x1c */
-#define PPC_LINUX_REGS_PTR_OFFSET (PPC_LINUX_SIGNAL_FRAMESIZE + 0x1c)
-
-/* From <asm/sigcontext.h>, 
-   offsetof(struct sigcontext_struct, handler) == 0x14 */
-#define PPC_LINUX_HANDLER_PTR_OFFSET (PPC_LINUX_SIGNAL_FRAMESIZE + 0x14)
-
-/* From <asm/ptrace.h>, values for PT_NIP, PT_R1, and PT_LNK */
-#define PPC_LINUX_PT_R0                0
-#define PPC_LINUX_PT_R1                1
-#define PPC_LINUX_PT_R2                2
-#define PPC_LINUX_PT_R3                3
-#define PPC_LINUX_PT_R4                4
-#define PPC_LINUX_PT_R5                5
-#define PPC_LINUX_PT_R6                6
-#define PPC_LINUX_PT_R7                7
-#define PPC_LINUX_PT_R8                8
-#define PPC_LINUX_PT_R9                9
-#define PPC_LINUX_PT_R10       10
-#define PPC_LINUX_PT_R11       11
-#define PPC_LINUX_PT_R12       12
-#define PPC_LINUX_PT_R13       13
-#define PPC_LINUX_PT_R14       14
-#define PPC_LINUX_PT_R15       15
-#define PPC_LINUX_PT_R16       16
-#define PPC_LINUX_PT_R17       17
-#define PPC_LINUX_PT_R18       18
-#define PPC_LINUX_PT_R19       19
-#define PPC_LINUX_PT_R20       20
-#define PPC_LINUX_PT_R21       21
-#define PPC_LINUX_PT_R22       22
-#define PPC_LINUX_PT_R23       23
-#define PPC_LINUX_PT_R24       24
-#define PPC_LINUX_PT_R25       25
-#define PPC_LINUX_PT_R26       26
-#define PPC_LINUX_PT_R27       27
-#define PPC_LINUX_PT_R28       28
-#define PPC_LINUX_PT_R29       29
-#define PPC_LINUX_PT_R30       30
-#define PPC_LINUX_PT_R31       31
-#define PPC_LINUX_PT_NIP       32
-#define PPC_LINUX_PT_MSR       33
-#define PPC_LINUX_PT_CTR       35
-#define PPC_LINUX_PT_LNK       36
-#define PPC_LINUX_PT_XER       37
-#define PPC_LINUX_PT_CCR       38
-#define PPC_LINUX_PT_MQ                39
-#define PPC_LINUX_PT_FPR0      48      /* each FP reg occupies 2 slots in this space */
-#define PPC_LINUX_PT_FPR31 (PPC_LINUX_PT_FPR0 + 2*31)
-#define PPC_LINUX_PT_FPSCR (PPC_LINUX_PT_FPR0 + 2*32 + 1)
-
-/* Determine if pc is in a signal trampoline...
-
-   Ha!  That's not what this does at all.  wait_for_inferior in infrun.c
-   calls IN_SIGTRAMP in order to detect entry into a signal trampoline
-   just after delivery of a signal.  But on linux, signal trampolines
-   are used for the return path only.  The kernel sets things up so that
-   the signal handler is called directly.
-
-   If we use in_sigtramp2() in place of in_sigtramp() (see below)
-   we'll (often) end up with stop_pc in the trampoline and prev_pc in
-   the (now exited) handler.  The code there will cause a temporary
-   breakpoint to be set on prev_pc which is not very likely to get hit
-   again.
-
-   If this is confusing, think of it this way...  the code in
-   wait_for_inferior() needs to be able to detect entry into a signal
-   trampoline just after a signal is delivered, not after the handler
-   has been run.
-
-   So, we define in_sigtramp() below to return 1 if the following is
-   true:
-
-   1) The previous frame is a real signal trampoline.
-
-   - and -
-
-   2) pc is at the first or second instruction of the corresponding
-   handler.
-
-   Why the second instruction?  It seems that wait_for_inferior()
-   never sees the first instruction when single stepping.  When a
-   signal is delivered while stepping, the next instruction that
-   would've been stepped over isn't, instead a signal is delivered and
-   the first instruction of the handler is stepped over instead.  That
-   puts us on the second instruction.  (I added the test for the
-   first instruction long after the fact, just in case the observed
-   behavior is ever fixed.)
-
-   IN_SIGTRAMP is called from blockframe.c as well in order to set
-   the signal_handler_caller flag.  Because of our strange definition
-   of in_sigtramp below, we can't rely on signal_handler_caller getting
-   set correctly from within blockframe.c.  This is why we take pains
-   to set it in init_extra_frame_info().  */
-
-int
-ppc_linux_in_sigtramp (CORE_ADDR pc, char *func_name)
+#include "regcache.h"
+#include "value.h"
+#include "osabi.h"
+#include "regset.h"
+#include "solib-svr4.h"
+#include "ppc-tdep.h"
+#include "trad-frame.h"
+#include "frame-unwind.h"
+#include "tramp-frame.h"
+
+static CORE_ADDR
+ppc_linux_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)

 {
 {

-  CORE_ADDR lr;
-  CORE_ADDR sp;
-  CORE_ADDR tramp_sp;
-  char buf[4];
-  CORE_ADDR handler;
-
-  lr = read_register (LR_REGNUM);
-  if (!ppc_linux_at_sigtramp_return_path (lr))
-    return 0;
-
-  sp = read_register (SP_REGNUM);
-
-  if (target_read_memory (sp, buf, sizeof (buf)) != 0)
-    return 0;
-
-  tramp_sp = extract_unsigned_integer (buf, 4);
-
-  if (target_read_memory (tramp_sp + PPC_LINUX_HANDLER_PTR_OFFSET, buf,
-                         sizeof (buf)) != 0)
-    return 0;
-
-  handler = extract_unsigned_integer (buf, 4);
-
-  return (pc == handler || pc == handler + 4);
-}
-
-/*
- * The signal handler trampoline is on the stack and consists of exactly
- * two instructions.  The easiest and most accurate way of determining
- * whether the pc is in one of these trampolines is by inspecting the
- * instructions.  It'd be faster though if we could find a way to do this
- * via some simple address comparisons.
- */
-int
-ppc_linux_at_sigtramp_return_path (CORE_ADDR pc)
-{
-  char buf[12];
-  unsigned long pcinsn;
-  if (target_read_memory (pc - 4, buf, sizeof (buf)) != 0)
-    return 0;
-
-  /* extract the instruction at the pc */
-  pcinsn = extract_unsigned_integer (buf + 4, 4);
-
-  return (
-          (pcinsn == INSTR_LI_R0_0x7777
-           && extract_unsigned_integer (buf + 8, 4) == INSTR_SC)
-          ||
-          (pcinsn == INSTR_SC
-           && extract_unsigned_integer (buf, 4) == INSTR_LI_R0_0x7777));
-}
-
-CORE_ADDR
-ppc_linux_skip_trampoline_code (CORE_ADDR pc)
-{
-  char buf[4];
+  gdb_byte buf[4];

   struct obj_section *sect;
   struct objfile *objfile;
   unsigned long insn;
   struct obj_section *sect;
   struct objfile *objfile;
   unsigned long insn;


@@ -213,10 +57,10 @@ ppc_linux_skip_trampoline_code (CORE_ADDR pc)
   char symname[1024];
   struct minimal_symbol *msymbol;
 
   char symname[1024];
   struct minimal_symbol *msymbol;
 

-  /* Find the section pc is in; return if not in .plt */
+  /* Find the section pc is in; if not in .plt, try the default method.  */

   sect = find_pc_section (pc);
   if (!sect || strcmp (sect->the_bfd_section->name, ".plt") != 0)
   sect = find_pc_section (pc);
   if (!sect || strcmp (sect->the_bfd_section->name, ".plt") != 0)

-    return 0;
+    return find_solib_trampoline_target (frame, pc);

 
   objfile = sect->objfile;
 
 
   objfile = sect->objfile;
 


@@ -260,7 +104,7 @@ ppc_linux_skip_trampoline_code (CORE_ADDR pc)
   /* Get address of the relocation entry (Elf32_Rela) */
   if (target_read_memory (plt_table + reloc_index, buf, 4) != 0)
     return 0;
   /* Get address of the relocation entry (Elf32_Rela) */
   if (target_read_memory (plt_table + reloc_index, buf, 4) != 0)
     return 0;

-  reloc = extract_address (buf, 4);
+  reloc = extract_unsigned_integer (buf, 4);

 
   sect = find_pc_section (reloc);
   if (!sect)
 
   sect = find_pc_section (reloc);
   if (!sect)


@@ -290,310 +134,833 @@ ppc_linux_skip_trampoline_code (CORE_ADDR pc)
   /* Fetch the string; we don't know how long it is.  Is it possible
      that the following will fail because we're trying to fetch too
      much? */
   /* Fetch the string; we don't know how long it is.  Is it possible
      that the following will fail because we're trying to fetch too
      much? */

-  if (target_read_memory (strtab + symidx, symname, sizeof (symname)) != 0)
+  if (target_read_memory (strtab + symidx, (gdb_byte *) symname,
+                         sizeof (symname)) != 0)

     return 0;
 
   /* This might not work right if we have multiple symbols with the
      same name; the only way to really get it right is to perform
      the same sort of lookup as the dynamic linker. */
     return 0;
 
   /* This might not work right if we have multiple symbols with the
      same name; the only way to really get it right is to perform
      the same sort of lookup as the dynamic linker. */

-  msymbol = lookup_minimal_symbol_text (symname, NULL, NULL);
+  msymbol = lookup_minimal_symbol_text (symname, NULL);

   if (!msymbol)
     return 0;
 
   return SYMBOL_VALUE_ADDRESS (msymbol);
 }
 
   if (!msymbol)
     return 0;
 
   return SYMBOL_VALUE_ADDRESS (msymbol);
 }
 

-/* The rs6000 version of FRAME_SAVED_PC will almost work for us.  The
-   signal handler details are different, so we'll handle those here
-   and call the rs6000 version to do the rest. */
-unsigned long
-ppc_linux_frame_saved_pc (struct frame_info *fi)
+/* ppc_linux_memory_remove_breakpoints attempts to remove a breakpoint
+   in much the same fashion as memory_remove_breakpoint in mem-break.c,
+   but is careful not to write back the previous contents if the code
+   in question has changed in between inserting the breakpoint and
+   removing it.
+
+   Here is the problem that we're trying to solve...
+
+   Once upon a time, before introducing this function to remove
+   breakpoints from the inferior, setting a breakpoint on a shared
+   library function prior to running the program would not work
+   properly.  In order to understand the problem, it is first
+   necessary to understand a little bit about dynamic linking on
+   this platform.
+
+   A call to a shared library function is accomplished via a bl
+   (branch-and-link) instruction whose branch target is an entry
+   in the procedure linkage table (PLT).  The PLT in the object
+   file is uninitialized.  To gdb, prior to running the program, the
+   entries in the PLT are all zeros.
+
+   Once the program starts running, the shared libraries are loaded
+   and the procedure linkage table is initialized, but the entries in
+   the table are not (necessarily) resolved.  Once a function is
+   actually called, the code in the PLT is hit and the function is
+   resolved.  In order to better illustrate this, an example is in
+   order; the following example is from the gdb testsuite.
+           
+       We start the program shmain.
+
+           [kev@arroyo testsuite]$ ../gdb gdb.base/shmain
+           [...]
+
+       We place two breakpoints, one on shr1 and the other on main.
+
+           (gdb) b shr1
+           Breakpoint 1 at 0x100409d4
+           (gdb) b main
+           Breakpoint 2 at 0x100006a0: file gdb.base/shmain.c, line 44.
+
+       Examine the instruction (and the immediatly following instruction)
+       upon which the breakpoint was placed.  Note that the PLT entry
+       for shr1 contains zeros.
+
+           (gdb) x/2i 0x100409d4
+           0x100409d4 <shr1>:      .long 0x0
+           0x100409d8 <shr1+4>:    .long 0x0
+
+       Now run 'til main.
+
+           (gdb) r
+           Starting program: gdb.base/shmain 
+           Breakpoint 1 at 0xffaf790: file gdb.base/shr1.c, line 19.
+
+           Breakpoint 2, main ()
+               at gdb.base/shmain.c:44
+           44        g = 1;
+
+       Examine the PLT again.  Note that the loading of the shared
+       library has initialized the PLT to code which loads a constant
+       (which I think is an index into the GOT) into r11 and then
+       branchs a short distance to the code which actually does the
+       resolving.
+
+           (gdb) x/2i 0x100409d4
+           0x100409d4 <shr1>:      li      r11,4
+           0x100409d8 <shr1+4>:    b       0x10040984 <sg+4>
+           (gdb) c
+           Continuing.
+
+           Breakpoint 1, shr1 (x=1)
+               at gdb.base/shr1.c:19
+           19        l = 1;
+
+       Now we've hit the breakpoint at shr1.  (The breakpoint was
+       reset from the PLT entry to the actual shr1 function after the
+       shared library was loaded.) Note that the PLT entry has been
+       resolved to contain a branch that takes us directly to shr1. 
+       (The real one, not the PLT entry.)
+
+           (gdb) x/2i 0x100409d4
+           0x100409d4 <shr1>:      b       0xffaf76c <shr1>
+           0x100409d8 <shr1+4>:    b       0x10040984 <sg+4>
+
+   The thing to note here is that the PLT entry for shr1 has been
+   changed twice.
+
+   Now the problem should be obvious.  GDB places a breakpoint (a
+   trap instruction) on the zero value of the PLT entry for shr1. 
+   Later on, after the shared library had been loaded and the PLT
+   initialized, GDB gets a signal indicating this fact and attempts
+   (as it always does when it stops) to remove all the breakpoints.
+
+   The breakpoint removal was causing the former contents (a zero
+   word) to be written back to the now initialized PLT entry thus
+   destroying a portion of the initialization that had occurred only a
+   short time ago.  When execution continued, the zero word would be
+   executed as an instruction an an illegal instruction trap was
+   generated instead.  (0 is not a legal instruction.)
+
+   The fix for this problem was fairly straightforward.  The function
+   memory_remove_breakpoint from mem-break.c was copied to this file,
+   modified slightly, and renamed to ppc_linux_memory_remove_breakpoint.
+   In tm-linux.h, MEMORY_REMOVE_BREAKPOINT is defined to call this new
+   function.
+
+   The differences between ppc_linux_memory_remove_breakpoint () and
+   memory_remove_breakpoint () are minor.  All that the former does
+   that the latter does not is check to make sure that the breakpoint
+   location actually contains a breakpoint (trap instruction) prior
+   to attempting to write back the old contents.  If it does contain
+   a trap instruction, we allow the old contents to be written back. 
+   Otherwise, we silently do nothing.
+
+   The big question is whether memory_remove_breakpoint () should be
+   changed to have the same functionality.  The downside is that more
+   traffic is generated for remote targets since we'll have an extra
+   fetch of a memory word each time a breakpoint is removed.
+
+   For the time being, we'll leave this self-modifying-code-friendly
+   version in ppc-linux-tdep.c, but it ought to be migrated somewhere
+   else in the event that some other platform has similar needs with
+   regard to removing breakpoints in some potentially self modifying
+   code.  */
+int
+ppc_linux_memory_remove_breakpoint (struct bp_target_info *bp_tgt)

 {
 {

-  if (fi->signal_handler_caller)
-    {
-      CORE_ADDR regs_addr =
-      read_memory_integer (fi->frame + PPC_LINUX_REGS_PTR_OFFSET, 4);
-      /* return the NIP in the regs array */
-      return read_memory_integer (regs_addr + 4 * PPC_LINUX_PT_NIP, 4);
-    }
+  CORE_ADDR addr = bp_tgt->placed_address;
+  const unsigned char *bp;
+  int val;
+  int bplen;
+  gdb_byte old_contents[BREAKPOINT_MAX];
+
+  /* Determine appropriate breakpoint contents and size for this address.  */
+  bp = gdbarch_breakpoint_from_pc (current_gdbarch, &addr, &bplen);
+  if (bp == NULL)
+    error (_("Software breakpoints not implemented for this target."));
+
+  val = target_read_memory (addr, old_contents, bplen);
+
+  /* If our breakpoint is no longer at the address, this means that the
+     program modified the code on us, so it is wrong to put back the
+     old value */
+  if (val == 0 && memcmp (bp, old_contents, bplen) == 0)
+    val = target_write_memory (addr, bp_tgt->shadow_contents, bplen);
+
+  return val;
+}
+
+/* For historic reasons, PPC 32 GNU/Linux follows PowerOpen rather
+   than the 32 bit SYSV R4 ABI structure return convention - all
+   structures, no matter their size, are put in memory.  Vectors,
+   which were added later, do get returned in a register though.  */
+
+static enum return_value_convention
+ppc_linux_return_value (struct gdbarch *gdbarch, struct type *valtype,
+                       struct regcache *regcache, gdb_byte *readbuf,
+                       const gdb_byte *writebuf)
+{  
+  if ((TYPE_CODE (valtype) == TYPE_CODE_STRUCT
+       || TYPE_CODE (valtype) == TYPE_CODE_UNION)
+      && !((TYPE_LENGTH (valtype) == 16 || TYPE_LENGTH (valtype) == 8)
+          && TYPE_VECTOR (valtype)))
+    return RETURN_VALUE_STRUCT_CONVENTION;
+  else
+    return ppc_sysv_abi_return_value (gdbarch, valtype, regcache, readbuf,
+                                     writebuf);
+}
+
+/* Macros for matching instructions.  Note that, since all the
+   operands are masked off before they're or-ed into the instruction,
+   you can use -1 to make masks.  */
+
+#define insn_d(opcd, rts, ra, d)                \
+  ((((opcd) & 0x3f) << 26)                      \
+   | (((rts) & 0x1f) << 21)                     \
+   | (((ra) & 0x1f) << 16)                      \
+   | ((d) & 0xffff))
+
+#define insn_ds(opcd, rts, ra, d, xo)           \
+  ((((opcd) & 0x3f) << 26)                      \
+   | (((rts) & 0x1f) << 21)                     \
+   | (((ra) & 0x1f) << 16)                      \
+   | ((d) & 0xfffc)                             \
+   | ((xo) & 0x3))
+
+#define insn_xfx(opcd, rts, spr, xo)            \
+  ((((opcd) & 0x3f) << 26)                      \
+   | (((rts) & 0x1f) << 21)                     \
+   | (((spr) & 0x1f) << 16)                     \
+   | (((spr) & 0x3e0) << 6)                     \
+   | (((xo) & 0x3ff) << 1))
+
+/* Read a PPC instruction from memory.  PPC instructions are always
+   big-endian, no matter what endianness the program is running in, so
+   we can't use read_memory_integer or one of its friends here.  */
+static unsigned int
+read_insn (CORE_ADDR pc)
+{
+  unsigned char buf[4];

 
 

-  return rs6000_frame_saved_pc (fi);
+  read_memory (pc, buf, 4);
+  return (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];

 }
 
 }
 

-void
-ppc_linux_init_extra_frame_info (int fromleaf, struct frame_info *fi)
+
+/* An instruction to match.  */
+struct insn_pattern

 {
 {

-  rs6000_init_extra_frame_info (fromleaf, fi);
+  unsigned int mask;            /* mask the insn with this... */
+  unsigned int data;            /* ...and see if it matches this. */
+  int optional;                 /* If non-zero, this insn may be absent.  */
+};
+
+/* Return non-zero if the instructions at PC match the series
+   described in PATTERN, or zero otherwise.  PATTERN is an array of
+   'struct insn_pattern' objects, terminated by an entry whose mask is
+   zero.
+
+   When the match is successful, fill INSN[i] with what PATTERN[i]
+   matched.  If PATTERN[i] is optional, and the instruction wasn't
+   present, set INSN[i] to 0 (which is not a valid PPC instruction).
+   INSN should have as many elements as PATTERN.  Note that, if
+   PATTERN contains optional instructions which aren't present in
+   memory, then INSN will have holes, so INSN[i] isn't necessarily the
+   i'th instruction in memory.  */
+static int
+insns_match_pattern (CORE_ADDR pc,
+                     struct insn_pattern *pattern,
+                     unsigned int *insn)
+{
+  int i;

 
 

-  if (fi->next != 0)
+  for (i = 0; pattern[i].mask; i++)

     {
     {

-      /* We're called from get_prev_frame_info; check to see if
-         this is a signal frame by looking to see if the pc points
-         at trampoline code */
-      if (ppc_linux_at_sigtramp_return_path (fi->pc))
-       fi->signal_handler_caller = 1;
+      insn[i] = read_insn (pc);
+      if ((insn[i] & pattern[i].mask) == pattern[i].data)
+        pc += 4;
+      else if (pattern[i].optional)
+        insn[i] = 0;

       else
       else

-       fi->signal_handler_caller = 0;
+        return 0;

     }
     }

+
+  return 1;

 }
 
 }
 

-int
-ppc_linux_frameless_function_invocation (struct frame_info *fi)
+
+/* Return the 'd' field of the d-form instruction INSN, properly
+   sign-extended.  */
+static CORE_ADDR
+insn_d_field (unsigned int insn)

 {
 {

-  /* We'll find the wrong thing if we let 
-     rs6000_frameless_function_invocation () search for a signal trampoline */
-  if (ppc_linux_at_sigtramp_return_path (fi->pc))
-    return 0;
-  else
-    return rs6000_frameless_function_invocation (fi);
+  return ((((CORE_ADDR) insn & 0xffff) ^ 0x8000) - 0x8000);

 }
 
 }
 

-void
-ppc_linux_frame_init_saved_regs (struct frame_info *fi)
+
+/* Return the 'ds' field of the ds-form instruction INSN, with the two
+   zero bits concatenated at the right, and properly
+   sign-extended.  */
+static CORE_ADDR
+insn_ds_field (unsigned int insn)

 {
 {

-  if (fi->signal_handler_caller)
-    {
-      CORE_ADDR regs_addr;
-      int i;
-      if (fi->saved_regs)
-       return;
-
-      frame_saved_regs_zalloc (fi);
-
-      regs_addr =
-       read_memory_integer (fi->frame + PPC_LINUX_REGS_PTR_OFFSET, 4);
-      fi->saved_regs[PC_REGNUM] = regs_addr + 4 * PPC_LINUX_PT_NIP;
-      fi->saved_regs[PS_REGNUM] = regs_addr + 4 * PPC_LINUX_PT_MSR;
-      fi->saved_regs[CR_REGNUM] = regs_addr + 4 * PPC_LINUX_PT_CCR;
-      fi->saved_regs[LR_REGNUM] = regs_addr + 4 * PPC_LINUX_PT_LNK;
-      fi->saved_regs[CTR_REGNUM] = regs_addr + 4 * PPC_LINUX_PT_CTR;
-      fi->saved_regs[XER_REGNUM] = regs_addr + 4 * PPC_LINUX_PT_XER;
-      fi->saved_regs[MQ_REGNUM] = regs_addr + 4 * PPC_LINUX_PT_MQ;
-      for (i = 0; i < 32; i++)
-       fi->saved_regs[GP0_REGNUM + i] = regs_addr + 4 * PPC_LINUX_PT_R0 + 4 * i;
-      for (i = 0; i < 32; i++)
-       fi->saved_regs[FP0_REGNUM + i] = regs_addr + 4 * PPC_LINUX_PT_FPR0 + 8 * i;
-    }
-  else
-    rs6000_frame_init_saved_regs (fi);
+  return ((((CORE_ADDR) insn & 0xfffc) ^ 0x8000) - 0x8000);
+}
+
+
+/* If DESC is the address of a 64-bit PowerPC GNU/Linux function
+   descriptor, return the descriptor's entry point.  */
+static CORE_ADDR
+ppc64_desc_entry_point (CORE_ADDR desc)
+{
+  /* The first word of the descriptor is the entry point.  */
+  return (CORE_ADDR) read_memory_unsigned_integer (desc, 8);

 }
 
 }
 

-CORE_ADDR
-ppc_linux_frame_chain (struct frame_info *thisframe)
+
+/* Pattern for the standard linkage function.  These are built by
+   build_plt_stub in elf64-ppc.c, whose GLINK argument is always
+   zero.  */
+static struct insn_pattern ppc64_standard_linkage[] =
+  {
+    /* addis r12, r2, <any> */
+    { insn_d (-1, -1, -1, 0), insn_d (15, 12, 2, 0), 0 },
+
+    /* std r2, 40(r1) */
+    { -1, insn_ds (62, 2, 1, 40, 0), 0 },
+
+    /* ld r11, <any>(r12) */
+    { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 0 },
+
+    /* addis r12, r12, 1 <optional> */
+    { insn_d (-1, -1, -1, -1), insn_d (15, 12, 2, 1), 1 },
+
+    /* ld r2, <any>(r12) */
+    { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 12, 0, 0), 0 },
+
+    /* addis r12, r12, 1 <optional> */
+    { insn_d (-1, -1, -1, -1), insn_d (15, 12, 2, 1), 1 },
+
+    /* mtctr r11 */
+    { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 11, 9, 467),
+      0 },
+
+    /* ld r11, <any>(r12) */
+    { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 0 },
+      
+    /* bctr */
+    { -1, 0x4e800420, 0 },
+
+    { 0, 0, 0 }
+  };
+#define PPC64_STANDARD_LINKAGE_LEN \
+  (sizeof (ppc64_standard_linkage) / sizeof (ppc64_standard_linkage[0]))
+
+/* When the dynamic linker is doing lazy symbol resolution, the first
+   call to a function in another object will go like this:
+
+   - The user's function calls the linkage function:
+
+     100007c4: 4b ff fc d5     bl      10000498
+     100007c8: e8 41 00 28     ld      r2,40(r1)
+
+   - The linkage function loads the entry point (and other stuff) from
+     the function descriptor in the PLT, and jumps to it:
+
+     10000498: 3d 82 00 00     addis   r12,r2,0
+     1000049c: f8 41 00 28     std     r2,40(r1)
+     100004a0: e9 6c 80 98     ld      r11,-32616(r12)
+     100004a4: e8 4c 80 a0     ld      r2,-32608(r12)
+     100004a8: 7d 69 03 a6     mtctr   r11
+     100004ac: e9 6c 80 a8     ld      r11,-32600(r12)
+     100004b0: 4e 80 04 20     bctr
+
+   - But since this is the first time that PLT entry has been used, it
+     sends control to its glink entry.  That loads the number of the
+     PLT entry and jumps to the common glink0 code:
+
+     10000c98: 38 00 00 00     li      r0,0
+     10000c9c: 4b ff ff dc     b       10000c78
+
+   - The common glink0 code then transfers control to the dynamic
+     linker's fixup code:
+
+     10000c78: e8 41 00 28     ld      r2,40(r1)
+     10000c7c: 3d 82 00 00     addis   r12,r2,0
+     10000c80: e9 6c 80 80     ld      r11,-32640(r12)
+     10000c84: e8 4c 80 88     ld      r2,-32632(r12)
+     10000c88: 7d 69 03 a6     mtctr   r11
+     10000c8c: e9 6c 80 90     ld      r11,-32624(r12)
+     10000c90: 4e 80 04 20     bctr
+
+   Eventually, this code will figure out how to skip all of this,
+   including the dynamic linker.  At the moment, we just get through
+   the linkage function.  */
+
+/* If the current thread is about to execute a series of instructions
+   at PC matching the ppc64_standard_linkage pattern, and INSN is the result
+   from that pattern match, return the code address to which the
+   standard linkage function will send them.  (This doesn't deal with
+   dynamic linker lazy symbol resolution stubs.)  */
+static CORE_ADDR
+ppc64_standard_linkage_target (struct frame_info *frame,
+                              CORE_ADDR pc, unsigned int *insn)

 {
 {

-  /* Kernel properly constructs the frame chain for the handler */
-  if (thisframe->signal_handler_caller)
-    return read_memory_integer ((thisframe)->frame, 4);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (frame));
+
+  /* The address of the function descriptor this linkage function
+     references.  */
+  CORE_ADDR desc
+    = ((CORE_ADDR) get_frame_register_unsigned (frame,
+                                               tdep->ppc_gp0_regnum + 2)
+       + (insn_d_field (insn[0]) << 16)
+       + insn_ds_field (insn[2]));
+
+  /* The first word of the descriptor is the entry point.  Return that.  */
+  return ppc64_desc_entry_point (desc);
+}
+
+
+/* Given that we've begun executing a call trampoline at PC, return
+   the entry point of the function the trampoline will go to.  */
+static CORE_ADDR
+ppc64_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
+{
+  unsigned int ppc64_standard_linkage_insn[PPC64_STANDARD_LINKAGE_LEN];
+
+  if (insns_match_pattern (pc, ppc64_standard_linkage,
+                           ppc64_standard_linkage_insn))
+    return ppc64_standard_linkage_target (frame, pc,
+                                         ppc64_standard_linkage_insn);

   else
   else

-    return rs6000_frame_chain (thisframe);
+    return 0;

 }
 
 }
 

-/* FIXME: Move the following to rs6000-tdep.c (or some other file where
-   it may be used generically by ports which use either the SysV ABI or
-   the EABI */
-
-/* round2 rounds x up to the nearest multiple of s assuming that s is a
-   power of 2 */
-
-#undef round2
-#define round2(x,s) ((((long) (x) - 1) & ~(long)((s)-1)) + (s))
-
-/* Pass the arguments in either registers, or in the stack. Using the
-   ppc sysv ABI, the first eight words of the argument list (that might
-   be less than eight parameters if some parameters occupy more than one
-   word) are passed in r3..r10 registers.  float and double parameters are
-   passed in fpr's, in addition to that. Rest of the parameters if any
-   are passed in user stack. 
-
-   If the function is returning a structure, then the return address is passed
-   in r3, then the first 7 words of the parametes can be passed in registers,
-   starting from r4. */
-
-CORE_ADDR
-ppc_sysv_abi_push_arguments (nargs, args, sp, struct_return, struct_addr)
-     int nargs;
-     value_ptr *args;
-     CORE_ADDR sp;
-     int struct_return;
-     CORE_ADDR struct_addr;
+
+/* Support for convert_from_func_ptr_addr (ARCH, ADDR, TARG) on PPC
+   GNU/Linux.
+
+   Usually a function pointer's representation is simply the address
+   of the function.  On GNU/Linux on the PowerPC however, a function
+   pointer may be a pointer to a function descriptor.
+
+   For PPC64, a function descriptor is a TOC entry, in a data section,
+   which contains three words: the first word is the address of the
+   function, the second word is the TOC pointer (r2), and the third word
+   is the static chain value.
+
+   For PPC32, there are two kinds of function pointers: non-secure and
+   secure.  Non-secure function pointers point directly to the
+   function in a code section and thus need no translation.  Secure
+   ones (from GCC's -msecure-plt option) are in a data section and
+   contain one word: the address of the function.
+
+   Throughout GDB it is currently assumed that a function pointer contains
+   the address of the function, which is not easy to fix.  In addition, the
+   conversion of a function address to a function pointer would
+   require allocation of a TOC entry in the inferior's memory space,
+   with all its drawbacks.  To be able to call C++ virtual methods in
+   the inferior (which are called via function pointers),
+   find_function_addr uses this function to get the function address
+   from a function pointer.
+
+   If ADDR points at what is clearly a function descriptor, transform
+   it into the address of the corresponding function, if needed.  Be
+   conservative, otherwise GDB will do the transformation on any
+   random addresses such as occur when there is no symbol table.  */
+
+static CORE_ADDR
+ppc_linux_convert_from_func_ptr_addr (struct gdbarch *gdbarch,
+                                     CORE_ADDR addr,
+                                     struct target_ops *targ)

 {
 {

-  int argno;
-  int greg, freg;
-  int argstkspace;
-  int structstkspace;
-  int argoffset;
-  int structoffset;
-  value_ptr arg;
-  struct type *type;
-  int len;
-  char old_sp_buf[4];
-  CORE_ADDR saved_sp;
-
-  greg = struct_return ? 4 : 3;
-  freg = 1;
-  argstkspace = 0;
-  structstkspace = 0;
-
-  /* Figure out how much new stack space is required for arguments
-     which don't fit in registers.  Unlike the PowerOpen ABI, the
-     SysV ABI doesn't reserve any extra space for parameters which
-     are put in registers. */
-  for (argno = 0; argno < nargs; argno++)
-    {
-      arg = args[argno];
-      type = check_typedef (VALUE_TYPE (arg));
-      len = TYPE_LENGTH (type);
+  struct gdbarch_tdep *tdep;
+  struct section_table *s = target_section_by_addr (targ, addr);
+  char *sect_name = NULL;

 
 

-      if (TYPE_CODE (type) == TYPE_CODE_FLT)
-       {
-         if (freg <= 8)
-           freg++;
-         else
-           {
-             /* SysV ABI converts floats to doubles when placed in
-                memory and requires 8 byte alignment */
-             if (argstkspace & 0x4)
-               argstkspace += 4;
-             argstkspace += 8;
-           }
-       }
-      else if (TYPE_CODE (type) == TYPE_CODE_INT && len == 8)  /* long long */
-       {
-         if (greg > 9)
-           {
-             greg = 11;
-             if (argstkspace & 0x4)
-               argstkspace += 4;
-             argstkspace += 8;
-           }
-         else
-           {
-             if ((greg & 1) == 0)
-               greg++;
-             greg += 2;
-           }
-       }
-      else
-       {
-         if (len > 4
-             || TYPE_CODE (type) == TYPE_CODE_STRUCT
-             || TYPE_CODE (type) == TYPE_CODE_UNION)
-           {
-             /* Rounding to the nearest multiple of 8 may not be necessary,
-                but it is safe.  Particularly since we don't know the
-                field types of the structure */
-             structstkspace += round2 (len, 8);
-           }
-         if (greg <= 10)
-           greg++;
-         else
-           argstkspace += 4;
-       }
+  if (!s)
+    return addr;
+
+  tdep = gdbarch_tdep (gdbarch);
+
+  switch (tdep->wordsize)
+    {
+      case 4:
+       sect_name = ".plt";
+       break;
+      case 8:
+       sect_name = ".opd";
+       break;
+      default:
+       internal_error (__FILE__, __LINE__,
+                       _("failed internal consistency check"));

     }
 
     }
 

-  /* Get current SP location */
-  saved_sp = read_sp ();
+  /* Check if ADDR points to a function descriptor.  */

 
 

-  sp -= argstkspace + structstkspace;
+  /* NOTE: this depends on the coincidence that the address of a functions
+     entry point is contained in the first word of its function descriptor
+     for both PPC-64 and for PPC-32 with secure PLTs.  */
+  if ((strcmp (s->the_bfd_section->name, sect_name) == 0)
+      && s->the_bfd_section->flags & SEC_DATA)
+    return get_target_memory_unsigned (targ, addr, tdep->wordsize);

 
 

-  /* Allocate space for backchain and callee's saved lr */
-  sp -= 8;
+  return addr;
+}

 
 

-  /* Make sure that we maintain 16 byte alignment */
-  sp &= ~0x0f;
+/* This wrapper clears areas in the linux gregset not written by
+   ppc_collect_gregset.  */

 
 

-  /* Update %sp before proceeding any further */
-  write_register (SP_REGNUM, sp);
+static void
+ppc_linux_collect_gregset (const struct regset *regset,
+                          const struct regcache *regcache,
+                          int regnum, void *gregs, size_t len)
+{
+  if (regnum == -1)
+    memset (gregs, 0, len);
+  ppc_collect_gregset (regset, regcache, regnum, gregs, len);
+}

 
 

-  /* write the backchain */
-  store_address (old_sp_buf, 4, saved_sp);
-  write_memory (sp, old_sp_buf, 4);
+/* Regset descriptions.  */
+static const struct ppc_reg_offsets ppc32_linux_reg_offsets =
+  {
+    /* General-purpose registers.  */
+    /* .r0_offset = */ 0,
+    /* .gpr_size = */ 4,
+    /* .xr_size = */ 4,
+    /* .pc_offset = */ 128,
+    /* .ps_offset = */ 132,
+    /* .cr_offset = */ 152,
+    /* .lr_offset = */ 144,
+    /* .ctr_offset = */ 140,
+    /* .xer_offset = */ 148,
+    /* .mq_offset = */ 156,
+
+    /* Floating-point registers.  */
+    /* .f0_offset = */ 0,
+    /* .fpscr_offset = */ 256,
+    /* .fpscr_size = */ 8,
+
+    /* AltiVec registers.  */
+    /* .vr0_offset = */ 0,
+    /* .vscr_offset = */ 512 + 12,
+    /* .vrsave_offset = */ 528
+  };
+
+static const struct ppc_reg_offsets ppc64_linux_reg_offsets =
+  {
+    /* General-purpose registers.  */
+    /* .r0_offset = */ 0,
+    /* .gpr_size = */ 8,
+    /* .xr_size = */ 8,
+    /* .pc_offset = */ 256,
+    /* .ps_offset = */ 264,
+    /* .cr_offset = */ 304,
+    /* .lr_offset = */ 288,
+    /* .ctr_offset = */ 280,
+    /* .xer_offset = */ 296,
+    /* .mq_offset = */ 312,
+
+    /* Floating-point registers.  */
+    /* .f0_offset = */ 0,
+    /* .fpscr_offset = */ 256,
+    /* .fpscr_size = */ 8,
+
+    /* AltiVec registers.  */
+    /* .vr0_offset = */ 0,
+    /* .vscr_offset = */ 512 + 12,
+    /* .vrsave_offset = */ 528
+  };
+
+static const struct regset ppc32_linux_gregset = {
+  &ppc32_linux_reg_offsets,
+  ppc_supply_gregset,
+  ppc_linux_collect_gregset,
+  NULL
+};
+
+static const struct regset ppc64_linux_gregset = {
+  &ppc64_linux_reg_offsets,
+  ppc_supply_gregset,
+  ppc_linux_collect_gregset,
+  NULL
+};
+
+static const struct regset ppc32_linux_fpregset = {
+  &ppc32_linux_reg_offsets,
+  ppc_supply_fpregset,
+  ppc_collect_fpregset,
+  NULL
+};
+
+static const struct regset ppc32_linux_vrregset = {
+  &ppc32_linux_reg_offsets,
+  ppc_supply_vrregset,
+  ppc_collect_vrregset,
+  NULL
+};
+
+const struct regset *
+ppc_linux_gregset (int wordsize)
+{
+  return wordsize == 8 ? &ppc64_linux_gregset : &ppc32_linux_gregset;
+}

 
 

-  argoffset = 8;
-  structoffset = argoffset + argstkspace;
-  freg = 1;
-  greg = 3;
-  /* Now fill in the registers and stack... */
-  for (argno = 0; argno < nargs; argno++)
-    {
-      arg = args[argno];
-      type = check_typedef (VALUE_TYPE (arg));
-      len = TYPE_LENGTH (type);
+const struct regset *
+ppc_linux_fpregset (void)
+{
+  return &ppc32_linux_fpregset;
+}

 
 

-      if (TYPE_CODE (type) == TYPE_CODE_FLT)
-       {
-         if (freg <= 8)
-           {
-             if (len > 8)
-               printf_unfiltered (
-                                   "Fatal Error: a floating point parameter #%d with a size > 8 is found!\n", argno);
-             memcpy (&registers[REGISTER_BYTE (FP0_REGNUM + freg)],
-                     VALUE_CONTENTS (arg), len);
-             freg++;
-           }
-         else
-           {
-             /* SysV ABI converts floats to doubles when placed in
-                memory and requires 8 byte alignment */
-             /* FIXME: Convert floats to doubles */
-             if (argoffset & 0x4)
-               argoffset += 4;
-             write_memory (sp + argoffset, (char *) VALUE_CONTENTS (arg), len);
-             argoffset += 8;
-           }
-       }
-      else if (TYPE_CODE (type) == TYPE_CODE_INT && len == 8)  /* long long */
-       {
-         if (greg > 9)
-           {
-             greg = 11;
-             if (argoffset & 0x4)
-               argoffset += 4;
-             write_memory (sp + argoffset, (char *) VALUE_CONTENTS (arg), len);
-             argoffset += 8;
-           }
-         else
-           {
-             if ((greg & 1) == 0)
-               greg++;
-
-             memcpy (&registers[REGISTER_BYTE (greg)],
-                     VALUE_CONTENTS (arg), 4);
-             memcpy (&registers[REGISTER_BYTE (greg + 1)],
-                     VALUE_CONTENTS (arg) + 4, 4);
-             greg += 2;
-           }
-       }
+static const struct regset *
+ppc_linux_regset_from_core_section (struct gdbarch *core_arch,
+                                   const char *sect_name, size_t sect_size)
+{
+  struct gdbarch_tdep *tdep = gdbarch_tdep (core_arch);
+  if (strcmp (sect_name, ".reg") == 0)
+    {
+      if (tdep->wordsize == 4)
+       return &ppc32_linux_gregset;

       else
       else

+       return &ppc64_linux_gregset;
+    }
+  if (strcmp (sect_name, ".reg2") == 0)
+    return &ppc32_linux_fpregset;
+  if (strcmp (sect_name, ".reg-ppc-vmx") == 0)
+    return &ppc32_linux_vrregset;
+  return NULL;
+}
+
+static void
+ppc_linux_sigtramp_cache (struct frame_info *next_frame,
+                         struct trad_frame_cache *this_cache,
+                         CORE_ADDR func, LONGEST offset,
+                         int bias)
+{
+  CORE_ADDR base;
+  CORE_ADDR regs;
+  CORE_ADDR gpregs;
+  CORE_ADDR fpregs;
+  int i;
+  struct gdbarch *gdbarch = get_frame_arch (next_frame);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  base = frame_unwind_register_unsigned (next_frame,
+                                        gdbarch_sp_regnum (gdbarch));
+  if (bias > 0 && frame_pc_unwind (next_frame) != func)
+    /* See below, some signal trampolines increment the stack as their
+       first instruction, need to compensate for that.  */
+    base -= bias;
+
+  /* Find the address of the register buffer pointer.  */
+  regs = base + offset;
+  /* Use that to find the address of the corresponding register
+     buffers.  */
+  gpregs = read_memory_unsigned_integer (regs, tdep->wordsize);
+  fpregs = gpregs + 48 * tdep->wordsize;
+
+  /* General purpose.  */
+  for (i = 0; i < 32; i++)
+    {
+      int regnum = i + tdep->ppc_gp0_regnum;
+      trad_frame_set_reg_addr (this_cache, regnum, gpregs + i * tdep->wordsize);
+    }
+  trad_frame_set_reg_addr (this_cache,
+                          gdbarch_pc_regnum (gdbarch),
+                          gpregs + 32 * tdep->wordsize);
+  trad_frame_set_reg_addr (this_cache, tdep->ppc_ctr_regnum,
+                          gpregs + 35 * tdep->wordsize);
+  trad_frame_set_reg_addr (this_cache, tdep->ppc_lr_regnum,
+                          gpregs + 36 * tdep->wordsize);
+  trad_frame_set_reg_addr (this_cache, tdep->ppc_xer_regnum,
+                          gpregs + 37 * tdep->wordsize);
+  trad_frame_set_reg_addr (this_cache, tdep->ppc_cr_regnum,
+                          gpregs + 38 * tdep->wordsize);
+
+  if (ppc_floating_point_unit_p (gdbarch))
+    {
+      /* Floating point registers.  */
+      for (i = 0; i < 32; i++)

        {
        {

-         char val_buf[4];
-         if (len > 4
-             || TYPE_CODE (type) == TYPE_CODE_STRUCT
-             || TYPE_CODE (type) == TYPE_CODE_UNION)
-           {
-             write_memory (sp + structoffset, VALUE_CONTENTS (arg), len);
-             store_address (val_buf, 4, sp + structoffset);
-             structoffset += round2 (len, 8);
-           }
-         else
-           {
-             memset (val_buf, 0, 4);
-             memcpy (val_buf, VALUE_CONTENTS (arg), len);
-           }
-         if (greg <= 10)
-           {
-             *(int *) &registers[REGISTER_BYTE (greg)] = 0;
-             memcpy (&registers[REGISTER_BYTE (greg)], val_buf, 4);
-             greg++;
-           }
-         else
-           {
-             write_memory (sp + argoffset, val_buf, 4);
-             argoffset += 4;
-           }
+         int regnum = i + gdbarch_fp0_regnum (gdbarch);
+         trad_frame_set_reg_addr (this_cache, regnum,
+                                  fpregs + i * tdep->wordsize);

        }
        }

+      trad_frame_set_reg_addr (this_cache, tdep->ppc_fpscr_regnum,
+                         fpregs + 32 * tdep->wordsize);

     }
     }

+  trad_frame_set_id (this_cache, frame_id_build (base, func));
+}

 
 

-  target_store_registers (-1);
-  return sp;
+static void
+ppc32_linux_sigaction_cache_init (const struct tramp_frame *self,
+                                 struct frame_info *next_frame,
+                                 struct trad_frame_cache *this_cache,
+                                 CORE_ADDR func)
+{
+  ppc_linux_sigtramp_cache (next_frame, this_cache, func,
+                           0xd0 /* Offset to ucontext_t.  */
+                           + 0x30 /* Offset to .reg.  */,
+                           0);
+}
+
+static void
+ppc64_linux_sigaction_cache_init (const struct tramp_frame *self,
+                                 struct frame_info *next_frame,
+                                 struct trad_frame_cache *this_cache,
+                                 CORE_ADDR func)
+{
+  ppc_linux_sigtramp_cache (next_frame, this_cache, func,
+                           0x80 /* Offset to ucontext_t.  */
+                           + 0xe0 /* Offset to .reg.  */,
+                           128);
+}
+
+static void
+ppc32_linux_sighandler_cache_init (const struct tramp_frame *self,
+                                  struct frame_info *next_frame,
+                                  struct trad_frame_cache *this_cache,
+                                  CORE_ADDR func)
+{
+  ppc_linux_sigtramp_cache (next_frame, this_cache, func,
+                           0x40 /* Offset to ucontext_t.  */
+                           + 0x1c /* Offset to .reg.  */,
+                           0);
+}
+
+static void
+ppc64_linux_sighandler_cache_init (const struct tramp_frame *self,
+                                  struct frame_info *next_frame,
+                                  struct trad_frame_cache *this_cache,
+                                  CORE_ADDR func)
+{
+  ppc_linux_sigtramp_cache (next_frame, this_cache, func,
+                           0x80 /* Offset to struct sigcontext.  */
+                           + 0x38 /* Offset to .reg.  */,
+                           128);
+}
+
+static struct tramp_frame ppc32_linux_sigaction_tramp_frame = {
+  SIGTRAMP_FRAME,
+  4,
+  { 
+    { 0x380000ac, -1 }, /* li r0, 172 */
+    { 0x44000002, -1 }, /* sc */
+    { TRAMP_SENTINEL_INSN },
+  },
+  ppc32_linux_sigaction_cache_init
+};
+static struct tramp_frame ppc64_linux_sigaction_tramp_frame = {
+  SIGTRAMP_FRAME,
+  4,
+  {
+    { 0x38210080, -1 }, /* addi r1,r1,128 */
+    { 0x380000ac, -1 }, /* li r0, 172 */
+    { 0x44000002, -1 }, /* sc */
+    { TRAMP_SENTINEL_INSN },
+  },
+  ppc64_linux_sigaction_cache_init
+};
+static struct tramp_frame ppc32_linux_sighandler_tramp_frame = {
+  SIGTRAMP_FRAME,
+  4,
+  { 
+    { 0x38000077, -1 }, /* li r0,119 */
+    { 0x44000002, -1 }, /* sc */
+    { TRAMP_SENTINEL_INSN },
+  },
+  ppc32_linux_sighandler_cache_init
+};
+static struct tramp_frame ppc64_linux_sighandler_tramp_frame = {
+  SIGTRAMP_FRAME,
+  4,
+  { 
+    { 0x38210080, -1 }, /* addi r1,r1,128 */
+    { 0x38000077, -1 }, /* li r0,119 */
+    { 0x44000002, -1 }, /* sc */
+    { TRAMP_SENTINEL_INSN },
+  },
+  ppc64_linux_sighandler_cache_init
+};
+
+static void
+ppc_linux_init_abi (struct gdbarch_info info,
+                    struct gdbarch *gdbarch)
+{
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  /* PPC GNU/Linux uses either 64-bit or 128-bit long doubles; where
+     128-bit, they are IBM long double, not IEEE quad long double as
+     in the System V ABI PowerPC Processor Supplement.  We can safely
+     let them default to 128-bit, since the debug info will give the
+     size of type actually used in each case.  */
+  set_gdbarch_long_double_bit (gdbarch, 16 * TARGET_CHAR_BIT);
+  set_gdbarch_long_double_format (gdbarch, floatformats_ibm_long_double);
+
+  /* Handle PPC GNU/Linux 64-bit function pointers (which are really
+     function descriptors) and 32-bit secure PLT entries.  */
+  set_gdbarch_convert_from_func_ptr_addr
+    (gdbarch, ppc_linux_convert_from_func_ptr_addr);
+
+  if (tdep->wordsize == 4)
+    {
+      /* Until November 2001, gcc did not comply with the 32 bit SysV
+        R4 ABI requirement that structures less than or equal to 8
+        bytes should be returned in registers.  Instead GCC was using
+        the the AIX/PowerOpen ABI - everything returned in memory
+        (well ignoring vectors that is).  When this was corrected, it
+        wasn't fixed for GNU/Linux native platform.  Use the
+        PowerOpen struct convention.  */
+      set_gdbarch_return_value (gdbarch, ppc_linux_return_value);
+
+      set_gdbarch_memory_remove_breakpoint (gdbarch,
+                                            ppc_linux_memory_remove_breakpoint);
+
+      /* Shared library handling.  */
+      set_gdbarch_skip_trampoline_code (gdbarch,
+                                        ppc_linux_skip_trampoline_code);
+      set_solib_svr4_fetch_link_map_offsets
+        (gdbarch, svr4_ilp32_fetch_link_map_offsets);
+
+      /* Trampolines.  */
+      tramp_frame_prepend_unwinder (gdbarch, &ppc32_linux_sigaction_tramp_frame);
+      tramp_frame_prepend_unwinder (gdbarch, &ppc32_linux_sighandler_tramp_frame);
+    }
+  
+  if (tdep->wordsize == 8)
+    {
+      /* Shared library handling.  */
+      set_gdbarch_skip_trampoline_code (gdbarch, ppc64_skip_trampoline_code);
+      set_solib_svr4_fetch_link_map_offsets
+        (gdbarch, svr4_lp64_fetch_link_map_offsets);
+
+      /* Trampolines.  */
+      tramp_frame_prepend_unwinder (gdbarch, &ppc64_linux_sigaction_tramp_frame);
+      tramp_frame_prepend_unwinder (gdbarch, &ppc64_linux_sighandler_tramp_frame);
+    }
+  set_gdbarch_regset_from_core_section (gdbarch, ppc_linux_regset_from_core_section);
+
+  /* Enable TLS support.  */
+  set_gdbarch_fetch_tls_load_module_address (gdbarch,
+                                             svr4_fetch_objfile_link_map);
+}
+
+void
+_initialize_ppc_linux_tdep (void)
+{
+  /* Register for all sub-familes of the POWER/PowerPC: 32-bit and
+     64-bit PowerPC, and the older rs6k.  */
+  gdbarch_register_osabi (bfd_arch_powerpc, bfd_mach_ppc, GDB_OSABI_LINUX,
+                         ppc_linux_init_abi);
+  gdbarch_register_osabi (bfd_arch_powerpc, bfd_mach_ppc64, GDB_OSABI_LINUX,
+                         ppc_linux_init_abi);
+  gdbarch_register_osabi (bfd_arch_rs6000, bfd_mach_rs6k, GDB_OSABI_LINUX,
+                         ppc_linux_init_abi);

 }
 }