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/* Target-dependent code for GNU/Linux running on the Fujitsu FR-V,

   for GDB.

   Copyright (C) 2004, 2006, 2007, 2008, 2009, 2010

   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 "gdbcore.h"

#include "target.h"

#include "frame.h"

#include "osabi.h"

#include "regcache.h"

#include "elf-bfd.h"

#include "elf/frv.h"

#include "frv-tdep.h"

#include "trad-frame.h"

#include "frame-unwind.h"

#include "regset.h"

#include "gdb_string.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 (struct gdbarch *gdbarch, CORE_ADDR pc, char *name)

{

  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);

  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, byte_order);

  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, byte_order);

  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, the "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/frv/kernel/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-frv/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-frv/signal.h:

      typedef struct sigaltstack {

              void *ss_sp;

              int ss_flags;

              size_t ss_size;

      } stack_t;

   From include/asm-frv/sigcontext.h:

      struct sigcontext {

              struct user_context       sc_context;

              unsigned long             sc_oldmask;

      } __attribute__((aligned(8)));

   From include/asm-frv/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 LONGEST

frv_linux_sigcontext_reg_addr (struct frame_info *this_frame, int regno,

                               CORE_ADDR *sc_addr_cache_ptr)

{

  struct gdbarch *gdbarch = get_frame_arch (this_frame);

  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);

  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 = get_frame_pc (this_frame);

      tramp_type = frv_linux_pc_in_sigtramp (gdbarch, pc, 0);

      get_frame_register (this_frame, sp_regnum, buf);

      sp = extract_unsigned_integer (buf, sizeof buf, byte_order);

      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 a ucontext struct.  The ucontext struct contains a

             sigcontext struct starting 24 bytes in.  (The offset of

             uc_mcontext within struct ucontext is derived as follows:

             stack_t is a 12-byte struct and struct sigcontext is

             8-byte aligned.  This gives an offset of 8 + 12 + 4 (for

             padding) = 24.) */

          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, byte_order);

          sc_addr += 24;

        }

      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. */

    }

}

/* Signal trampolines.  */

static struct trad_frame_cache *

frv_linux_sigtramp_frame_cache (struct frame_info *this_frame, void **this_cache)

{

  struct gdbarch *gdbarch = get_frame_arch (this_frame);

  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);

  struct trad_frame_cache *cache;

  CORE_ADDR addr;

  char buf[4];

  int regnum;

  CORE_ADDR sc_addr_cache_val = 0;

  struct frame_id this_id;

  if (*this_cache)

    return *this_cache;

  cache = trad_frame_cache_zalloc (this_frame);

  /* FIXME: cagney/2004-05-01: This is is long standing broken code.

     The frame ID's code address should be the start-address of the

     signal trampoline and not the current PC within that

     trampoline.  */

  get_frame_register (this_frame, sp_regnum, buf);

  addr = extract_unsigned_integer (buf, sizeof buf, byte_order);

  this_id = frame_id_build (addr, get_frame_pc (this_frame));

  trad_frame_set_id (cache, this_id);

  for (regnum = 0; regnum < frv_num_regs; regnum++)

    {

      LONGEST reg_addr = frv_linux_sigcontext_reg_addr (this_frame, regnum,

                                                        &sc_addr_cache_val);

      if (reg_addr != -1)

        trad_frame_set_reg_addr (cache, regnum, reg_addr);

    }

  *this_cache = cache;

  return cache;

}

static void

frv_linux_sigtramp_frame_this_id (struct frame_info *this_frame, void **this_cache,

                             struct frame_id *this_id)

{

  struct trad_frame_cache *cache =

    frv_linux_sigtramp_frame_cache (this_frame, this_cache);

  trad_frame_get_id (cache, this_id);

}

static struct value *

frv_linux_sigtramp_frame_prev_register (struct frame_info *this_frame,

                                        void **this_cache, int regnum)

{

  /* Make sure we've initialized the cache.  */

  struct trad_frame_cache *cache =

    frv_linux_sigtramp_frame_cache (this_frame, this_cache);

  return trad_frame_get_register (cache, this_frame, regnum);

}

static int

frv_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,

                                  struct frame_info *this_frame,

                                  void **this_cache)

{

  struct gdbarch *gdbarch = get_frame_arch (this_frame);

  CORE_ADDR pc = get_frame_pc (this_frame);

  char *name;

  find_pc_partial_function (pc, &name, NULL, NULL);

  if (frv_linux_pc_in_sigtramp (gdbarch, pc, name))

    return 1;

  return 0;

}

static const struct frame_unwind frv_linux_sigtramp_frame_unwind =

{

  SIGTRAMP_FRAME,

  frv_linux_sigtramp_frame_this_id,

  frv_linux_sigtramp_frame_prev_register,

  NULL,

  frv_linux_sigtramp_frame_sniffer

};

/* The FRV kernel defines ELF_NGREG as 46.  We add 2 in order to include

   the loadmap addresses in the register set.  (See below for more info.)  */

#define FRV_ELF_NGREG (46 + 2)

typedef unsigned char frv_elf_greg_t[4];

typedef struct { frv_elf_greg_t reg[FRV_ELF_NGREG]; } frv_elf_gregset_t;

typedef unsigned char frv_elf_fpreg_t[4];

typedef struct

{

  frv_elf_fpreg_t fr[64];

  frv_elf_fpreg_t fner[2];

  frv_elf_fpreg_t msr[2];

  frv_elf_fpreg_t acc[8];

  unsigned char accg[8];

  frv_elf_fpreg_t fsr[1];

} frv_elf_fpregset_t;

/* Constants for accessing elements of frv_elf_gregset_t.  */

#define FRV_PT_PSR 0

#define FRV_PT_ISR 1

#define FRV_PT_CCR 2

#define FRV_PT_CCCR 3

#define FRV_PT_LR 4

#define FRV_PT_LCR 5

#define FRV_PT_PC 6

#define FRV_PT_GNER0 10

#define FRV_PT_GNER1 11

#define FRV_PT_IACC0H 12

#define FRV_PT_IACC0L 13

/* Note: Only 32 of the GRs will be found in the corefile.  */

#define FRV_PT_GR(j)    ( 14 + (j))     /* GRj for 0<=j<=63. */

#define FRV_PT_TBR FRV_PT_GR(0)         /* gr0 is always 0, so TBR is stuffed

                                           there.  */

/* Technically, the loadmap addresses are not part of `pr_reg' as

   found in the elf_prstatus struct.  The fields which communicate the

   loadmap address appear (by design) immediately after `pr_reg'

   though, and the BFD function elf32_frv_grok_prstatus() has been

   implemented to include these fields in the register section that it

   extracts from the core file.  So, for our purposes, they may be

   viewed as registers.  */

#define FRV_PT_EXEC_FDPIC_LOADMAP 46

#define FRV_PT_INTERP_FDPIC_LOADMAP 47

/* Unpack an frv_elf_gregset_t into GDB's register cache.  */

static void

frv_linux_supply_gregset (const struct regset *regset,

                          struct regcache *regcache,

                          int regnum, const void *gregs, size_t len)

{

  int regi;

  char zerobuf[MAX_REGISTER_SIZE];

  const frv_elf_gregset_t *gregsetp = gregs;

  memset (zerobuf, 0, MAX_REGISTER_SIZE);

  /* gr0 always contains 0.  Also, the kernel passes the TBR value in

     this slot.  */

  regcache_raw_supply (regcache, first_gpr_regnum, zerobuf);

  for (regi = first_gpr_regnum + 1; regi <= last_gpr_regnum; regi++)

    {

      if (regi >= first_gpr_regnum + 32)

        regcache_raw_supply (regcache, regi, zerobuf);

      else

        regcache_raw_supply (regcache, regi,

                             gregsetp->reg[FRV_PT_GR (regi - first_gpr_regnum)]);

    }

  regcache_raw_supply (regcache, pc_regnum, gregsetp->reg[FRV_PT_PC]);

  regcache_raw_supply (regcache, psr_regnum, gregsetp->reg[FRV_PT_PSR]);

  regcache_raw_supply (regcache, ccr_regnum, gregsetp->reg[FRV_PT_CCR]);

  regcache_raw_supply (regcache, cccr_regnum, gregsetp->reg[FRV_PT_CCCR]);

  regcache_raw_supply (regcache, lr_regnum, gregsetp->reg[FRV_PT_LR]);

  regcache_raw_supply (regcache, lcr_regnum, gregsetp->reg[FRV_PT_LCR]);

  regcache_raw_supply (regcache, gner0_regnum, gregsetp->reg[FRV_PT_GNER0]);

  regcache_raw_supply (regcache, gner1_regnum, gregsetp->reg[FRV_PT_GNER1]);

  regcache_raw_supply (regcache, tbr_regnum, gregsetp->reg[FRV_PT_TBR]);

  regcache_raw_supply (regcache, fdpic_loadmap_exec_regnum,

                       gregsetp->reg[FRV_PT_EXEC_FDPIC_LOADMAP]);

  regcache_raw_supply (regcache, fdpic_loadmap_interp_regnum,

                       gregsetp->reg[FRV_PT_INTERP_FDPIC_LOADMAP]);

}

/* Unpack an frv_elf_fpregset_t into GDB's register cache.  */

static void

frv_linux_supply_fpregset (const struct regset *regset,

                           struct regcache *regcache,

                           int regnum, const void *gregs, size_t len)

{

  int regi;

  const frv_elf_fpregset_t *fpregsetp = gregs;

  for (regi = first_fpr_regnum; regi <= last_fpr_regnum; regi++)

    regcache_raw_supply (regcache, regi, fpregsetp->fr[regi - first_fpr_regnum]);

  regcache_raw_supply (regcache, fner0_regnum, fpregsetp->fner[0]);

  regcache_raw_supply (regcache, fner1_regnum, fpregsetp->fner[1]);

  regcache_raw_supply (regcache, msr0_regnum, fpregsetp->msr[0]);

  regcache_raw_supply (regcache, msr1_regnum, fpregsetp->msr[1]);

  for (regi = acc0_regnum; regi <= acc7_regnum; regi++)

    regcache_raw_supply (regcache, regi, fpregsetp->acc[regi - acc0_regnum]);

  regcache_raw_supply (regcache, accg0123_regnum, fpregsetp->accg);

  regcache_raw_supply (regcache, accg4567_regnum, fpregsetp->accg + 4);

  regcache_raw_supply (regcache, fsr0_regnum, fpregsetp->fsr[0]);

}

/* FRV Linux kernel register sets.  */

static struct regset frv_linux_gregset =

{

  NULL,

  frv_linux_supply_gregset

};

static struct regset frv_linux_fpregset =

{

  NULL,

  frv_linux_supply_fpregset

};

static const struct regset *

frv_linux_regset_from_core_section (struct gdbarch *gdbarch,

                                    const char *sect_name, size_t sect_size)

{

  if (strcmp (sect_name, ".reg") == 0

      && sect_size >= sizeof (frv_elf_gregset_t))

    return &frv_linux_gregset;

  if (strcmp (sect_name, ".reg2") == 0

      && sect_size >= sizeof (frv_elf_fpregset_t))

    return &frv_linux_fpregset;

  return NULL;

}

static void

frv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)

{

  /* Set the sigtramp frame sniffer.  */

  frame_unwind_append_unwinder (gdbarch, &frv_linux_sigtramp_frame_unwind);

  set_gdbarch_regset_from_core_section (gdbarch,

                                        frv_linux_regset_from_core_section);

}

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);

}