/* Target-dependent code for NetBSD/alpha.

Copyright (C) 2002-2016 Free Software Foundation, Inc.

Contributed by Wasabi Systems, 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 "frame.h"

#include "gdbcore.h"

#include "osabi.h"

#include "regcache.h"

#include "regset.h"

#include "value.h"

#include "alpha-tdep.h"

#include "alpha-bsd-tdep.h"

#include "nbsd-tdep.h"

#include "solib-svr4.h"

#include "target.h"

/* Core file support. */

/* Sizeof `struct reg' in <machine/reg.h>. */

#define ALPHANBSD_SIZEOF_GREGS (32 * 8)

/* Sizeof `struct fpreg' in <machine/reg.h. */

#define ALPHANBSD_SIZEOF_FPREGS ((32 * 8) + 8)

/* Supply register REGNUM from the buffer specified by FPREGS and LEN

in the floating-point register set REGSET to register cache

REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */

static void

alphanbsd_supply_fpregset (const struct regset *regset,

struct regcache *regcache,

int regnum, const void *fpregs, size_t len)

{

const gdb_byte *regs = (const gdb_byte *) fpregs;

int i;

gdb_assert (len >= ALPHANBSD_SIZEOF_FPREGS);

for (i = ALPHA_FP0_REGNUM; i < ALPHA_FP0_REGNUM + 31; i++)

{

if (regnum == i || regnum == -1)

regcache_raw_supply (regcache, i, regs + (i - ALPHA_FP0_REGNUM) * 8);

}

if (regnum == ALPHA_FPCR_REGNUM || regnum == -1)

regcache_raw_supply (regcache, ALPHA_FPCR_REGNUM, regs + 32 * 8);

}

/* Supply register REGNUM from the buffer specified by GREGS and LEN

in the general-purpose register set REGSET to register cache

REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */

static void

alphanbsd_aout_supply_gregset (const struct regset *regset,

struct regcache *regcache,

int regnum, const void *gregs, size_t len)

{

const gdb_byte *regs = (const gdb_byte *) gregs;

int i;

/* Table to map a GDB register number to a trapframe register index. */

static const int regmap[] =

{

0, 1, 2, 3,

4, 5, 6, 7,

8, 9, 10, 11,

12, 13, 14, 15,

30, 31, 32, 16,

17, 18, 19, 20,

21, 22, 23, 24,

25, 29, 26

};

gdb_assert (len >= ALPHANBSD_SIZEOF_GREGS);

for (i = 0; i < ARRAY_SIZE(regmap); i++)

{

if (regnum == i || regnum == -1)

regcache_raw_supply (regcache, i, regs + regmap[i] * 8);

}

if (regnum == ALPHA_PC_REGNUM || regnum == -1)

regcache_raw_supply (regcache, ALPHA_PC_REGNUM, regs + 31 * 8);

if (len >= ALPHANBSD_SIZEOF_GREGS + ALPHANBSD_SIZEOF_FPREGS)

{

regs += ALPHANBSD_SIZEOF_GREGS;

len -= ALPHANBSD_SIZEOF_GREGS;

alphanbsd_supply_fpregset (regset, regcache, regnum, regs, len);

}

}

/* Supply register REGNUM from the buffer specified by GREGS and LEN

in the general-purpose register set REGSET to register cache

REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */

static void

alphanbsd_supply_gregset (const struct regset *regset,

struct regcache *regcache,

int regnum, const void *gregs, size_t len)

{

const gdb_byte *regs = (const gdb_byte *) gregs;

int i;

if (len >= ALPHANBSD_SIZEOF_GREGS + ALPHANBSD_SIZEOF_FPREGS)

{

alphanbsd_aout_supply_gregset (regset, regcache, regnum, gregs, len);

return;

}

for (i = 0; i < ALPHA_ZERO_REGNUM; i++)

{

if (regnum == i || regnum == -1)

regcache_raw_supply (regcache, i, regs + i * 8);

}

if (regnum == ALPHA_PC_REGNUM || regnum == -1)

regcache_raw_supply (regcache, ALPHA_PC_REGNUM, regs + 31 * 8);

}

/* NetBSD/alpha register sets. */

static const struct regset alphanbsd_gregset =

{

NULL,

alphanbsd_supply_gregset,

NULL,

REGSET_VARIABLE_SIZE

};

static const struct regset alphanbsd_fpregset =

{

NULL,

alphanbsd_supply_fpregset

};

/* Iterate over supported core file register note sections. */

void

alphanbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,

iterate_over_regset_sections_cb *cb,

void *cb_data,

const struct regcache *regcache)

{

cb (".reg", ALPHANBSD_SIZEOF_GREGS, &alphanbsd_gregset, NULL, cb_data);

cb (".reg2", ALPHANBSD_SIZEOF_FPREGS, &alphanbsd_fpregset, NULL, cb_data);

}



/* Signal trampolines. */

/* Under NetBSD/alpha, signal handler invocations can be identified by the

designated code sequence that is used to return from a signal handler.

In particular, the return address of a signal handler points to the

following code sequence:

ldq a0, 0(sp)

lda sp, 16(sp)

lda v0, 295(zero) # __sigreturn14

call_pal callsys

Each instruction has a unique encoding, so we simply attempt to match

the instruction the PC is pointing to with any of the above instructions.

If there is a hit, we know the offset to the start of the designated

sequence and can then check whether we really are executing in the

signal trampoline. If not, -1 is returned, otherwise the offset from the

start of the return sequence is returned. */

static const gdb_byte sigtramp_retcode[] =

{

0x00, 0x00, 0x1e, 0xa6, /* ldq a0, 0(sp) */

0x10, 0x00, 0xde, 0x23, /* lda sp, 16(sp) */

0x27, 0x01, 0x1f, 0x20, /* lda v0, 295(zero) */

0x83, 0x00, 0x00, 0x00, /* call_pal callsys */

};

#define RETCODE_NWORDS 4

#define RETCODE_SIZE (RETCODE_NWORDS * 4)

static LONGEST

alphanbsd_sigtramp_offset (struct gdbarch *gdbarch, CORE_ADDR pc)

{

gdb_byte ret[RETCODE_SIZE], w[4];

LONGEST off;

int i;

if (target_read_memory (pc, w, 4) != 0)

return -1;

for (i = 0; i < RETCODE_NWORDS; i++)

{

if (memcmp (w, sigtramp_retcode + (i * 4), 4) == 0)

break;

}

if (i == RETCODE_NWORDS)

return (-1);

off = i * 4;

pc -= off;

if (target_read_memory (pc, ret, sizeof (ret)) != 0)

return -1;

if (memcmp (ret, sigtramp_retcode, RETCODE_SIZE) == 0)

return off;

return -1;

}

static int

alphanbsd_pc_in_sigtramp (struct gdbarch *gdbarch,

CORE_ADDR pc, const char *func_name)

{

return (nbsd_pc_in_sigtramp (pc, func_name)

|| alphanbsd_sigtramp_offset (gdbarch, pc) >= 0);

}

static CORE_ADDR

alphanbsd_sigcontext_addr (struct frame_info *frame)

{

/* FIXME: This is not correct for all versions of NetBSD/alpha.

We will probably need to disassemble the trampoline to figure

out which trampoline frame type we have. */

if (!get_next_frame (frame))

return 0;

return get_frame_base (get_next_frame (frame));

}



static void

alphanbsd_init_abi (struct gdbarch_info info,

struct gdbarch *gdbarch)

{

struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

/* Hook into the DWARF CFI frame unwinder. */

alpha_dwarf2_init_abi (info, gdbarch);

/* Hook into the MDEBUG frame unwinder. */

alpha_mdebug_init_abi (info, gdbarch);

/* NetBSD/alpha does not provide single step support via ptrace(2); we

must use software single-stepping. */

set_gdbarch_software_single_step (gdbarch, alpha_software_single_step);

/* NetBSD/alpha has SVR4-style shared libraries. */

set_solib_svr4_fetch_link_map_offsets

(gdbarch, svr4_lp64_fetch_link_map_offsets);

tdep->dynamic_sigtramp_offset = alphanbsd_sigtramp_offset;

tdep->pc_in_sigtramp = alphanbsd_pc_in_sigtramp;

tdep->sigcontext_addr = alphanbsd_sigcontext_addr;

tdep->jb_pc = 2;

tdep->jb_elt_size = 8;

set_gdbarch_iterate_over_regset_sections

(gdbarch, alphanbsd_iterate_over_regset_sections);

}



/* Provide a prototype to silence -Wmissing-prototypes. */

void _initialize_alphanbsd_tdep (void);

void

_initialize_alphanbsd_tdep (void)

{

/* Even though NetBSD/alpha used ELF since day one, it used the

traditional a.out-style core dump format before NetBSD 1.6, but

we don't support those. */

gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_NETBSD,

alphanbsd_init_abi);

}