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gdb-msvc/gdb/alpha-nbsd-tdep.c

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Import GDB 9.2
2020-06-18 10:11:10 +02:00
/* Target-dependent code for NetBSD/alpha.
Copyright (C) 2002-2020 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 (i, regs + (i - ALPHA_FP0_REGNUM) * 8);
}
if (regnum == ALPHA_FPCR_REGNUM || regnum == -1)
regcache->raw_supply (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 (i, regs + regmap[i] * 8);
}
if (regnum == ALPHA_PC_REGNUM || regnum == -1)
regcache->raw_supply (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 (i, regs + i * 8);
}
if (regnum == ALPHA_PC_REGNUM || regnum == -1)
regcache->raw_supply (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_SIZEOF_GREGS,
&alphanbsd_gregset, NULL, cb_data);
cb (".reg2", ALPHANBSD_SIZEOF_FPREGS, 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);
}
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);
}