binutils-gdb/gdb/arm-fbsd-tdep.c
John Baldwin 7176dfd28d Add FreeBSD/arm architecture.
Support for collecting and supplying general purpose and floating
point registers is provided along with signal frame unwinding.  While
FreeBSD/arm kernels do populate NT_FPREGSET notes, they are always
zero-filled, so this implementation ignores them.  Recent FreeBSD/arm
kernels generate NT_ARM_VFP notes which are used to supply
floating-point registers.  As with Linux, the AT_HWCAP feature flags
are used to determine the correct target description.

gdb/ChangeLog:

	* Makefile.in (ALL_TARGET_OBS): Add arm-fbsd-tdep.o.
	(ALLDEPFILES): Add arm-fbsd-tdep.c.
	* NEWS: Mention new FreeBSD/arm target.
	* configure.tgt: Add arm*-*-freebsd*.
	* arm-fbsd-tdep.c: New file.
	* arm-fbsd-tdep.h: New file.
2017-10-11 11:16:34 -07:00

258 lines
6.7 KiB
C

/* Target-dependent code for FreeBSD/arm.
Copyright (C) 2017 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 "elf/common.h"
#include "arm-tdep.h"
#include "arm-fbsd-tdep.h"
#include "auxv.h"
#include "fbsd-tdep.h"
#include "gdbcore.h"
#include "osabi.h"
#include "solib-svr4.h"
#include "trad-frame.h"
#include "tramp-frame.h"
/* In a signal frame, sp points to a 'struct sigframe' which is
defined as:
struct sigframe {
siginfo_t sf_si;
ucontext_t sf_uc;
mcontext_vfp_t sf_vfp;
};
ucontext_t is defined as:
struct __ucontext {
sigset_t uc_sigmask;
mcontext_t uc_mcontext;
...
};
mcontext_t is defined as:
struct {
unsigned int __gregs[17];
size_t mc_vfp_size;
void *mc_vfp_ptr;
...
};
mcontext_vfp_t is defined as:
struct {
uint64_t mcv_reg[32];
uint32_t mcv_fpscr;
};
If the VFP state is valid, then mc_vfp_ptr will point to sf_vfp in
the sigframe, otherwise it is NULL. There is no non-VFP floating
point register state saved in the signal frame. */
#define ARM_MCONTEXT_REG_SIZE 4
#define ARM_MCONTEXT_VFP_REG_SIZE 8
#define ARM_SIGFRAME_UCONTEXT_OFFSET 64
#define ARM_UCONTEXT_MCONTEXT_OFFSET 16
#define ARM_MCONTEXT_VFP_PTR_OFFSET 72
/* Implement the "init" method of struct tramp_frame. */
static void
arm_fbsd_sigframe_init (const struct tramp_frame *self,
struct frame_info *this_frame,
struct trad_frame_cache *this_cache,
CORE_ADDR func)
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
CORE_ADDR mcontext_addr = (sp
+ ARM_SIGFRAME_UCONTEXT_OFFSET
+ ARM_UCONTEXT_MCONTEXT_OFFSET);
ULONGEST mcontext_vfp_addr;
for (int i = 0; i < 16; i++)
{
trad_frame_set_reg_addr (this_cache,
ARM_A1_REGNUM + i,
mcontext_addr + i * ARM_MCONTEXT_REG_SIZE);
}
trad_frame_set_reg_addr (this_cache, ARM_PS_REGNUM,
mcontext_addr + 16 * ARM_MCONTEXT_REG_SIZE);
if (safe_read_memory_unsigned_integer (mcontext_addr
+ ARM_MCONTEXT_VFP_PTR_OFFSET, 4,
byte_order,
&mcontext_vfp_addr)
&& mcontext_vfp_addr != 0)
{
for (int i = 0; i < 32; i++)
{
trad_frame_set_reg_addr (this_cache, ARM_D0_REGNUM + i,
mcontext_vfp_addr
+ i * ARM_MCONTEXT_VFP_REG_SIZE);
}
trad_frame_set_reg_addr (this_cache, ARM_FPSCR_REGNUM,
mcontext_vfp_addr
+ 32 * ARM_MCONTEXT_VFP_REG_SIZE);
}
trad_frame_set_id (this_cache, frame_id_build (sp, func));
}
static const struct tramp_frame arm_fbsd_sigframe =
{
SIGTRAMP_FRAME,
4,
{
{0xe1a0000d, -1}, /* mov r0, sp */
{0xe2800040, -1}, /* add r0, r0, #SIGF_UC */
{0xe59f700c, -1}, /* ldr r7, [pc, #12] */
{0xef0001a1, -1}, /* swi SYS_sigreturn */
{TRAMP_SENTINEL_INSN, -1}
},
arm_fbsd_sigframe_init
};
/* Register maps. */
static const struct regcache_map_entry arm_fbsd_gregmap[] =
{
{ 13, ARM_A1_REGNUM, 4 }, /* r0 ... r12 */
{ 1, ARM_SP_REGNUM, 4 },
{ 1, ARM_LR_REGNUM, 4 },
{ 1, ARM_PC_REGNUM, 4 },
{ 1, ARM_PS_REGNUM, 4 },
{ 0 }
};
static const struct regcache_map_entry arm_fbsd_vfpregmap[] =
{
{ 32, ARM_D0_REGNUM, 8 }, /* d0 ... d31 */
{ 1, ARM_FPSCR_REGNUM, 4 },
{ 0 }
};
/* Register set definitions. */
const struct regset arm_fbsd_gregset =
{
arm_fbsd_gregmap,
regcache_supply_regset, regcache_collect_regset
};
const struct regset arm_fbsd_vfpregset =
{
arm_fbsd_vfpregmap,
regcache_supply_regset, regcache_collect_regset
};
/* Implement the "regset_from_core_section" gdbarch method. */
static void
arm_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
iterate_over_regset_sections_cb *cb,
void *cb_data,
const struct regcache *regcache)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
cb (".reg", ARM_FBSD_SIZEOF_GREGSET, &arm_fbsd_gregset, NULL, cb_data);
/* While FreeBSD/arm cores do contain a NT_FPREGSET / ".reg2"
register set, it is not populated with register values by the
kernel but just contains all zeroes. */
if (tdep->vfp_register_count > 0)
cb (".reg-arm-vfp", ARM_FBSD_SIZEOF_VFPREGSET, &arm_fbsd_vfpregset,
"VFP floating-point", cb_data);
}
/* Lookup a target description from a target's AT_HWCAP auxiliary
vector. */
const struct target_desc *
arm_fbsd_read_description_auxv (struct target_ops *target)
{
CORE_ADDR arm_hwcap = 0;
if (target_auxv_search (target, AT_FREEBSD_HWCAP, &arm_hwcap) != 1)
return NULL;
if (arm_hwcap & HWCAP_VFP)
{
if (arm_hwcap & HWCAP_NEON)
return tdesc_arm_with_neon;
else if ((arm_hwcap & (HWCAP_VFPv3 | HWCAP_VFPD32))
== (HWCAP_VFPv3 | HWCAP_VFPD32))
return tdesc_arm_with_vfpv3;
else
return tdesc_arm_with_vfpv2;
}
return NULL;
}
/* Implement the "core_read_description" gdbarch method. */
static const struct target_desc *
arm_fbsd_core_read_description (struct gdbarch *gdbarch,
struct target_ops *target,
bfd *abfd)
{
return arm_fbsd_read_description_auxv (target);
}
/* Implement the 'init_osabi' method of struct gdb_osabi_handler. */
static void
arm_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
/* Generic FreeBSD support. */
fbsd_init_abi (info, gdbarch);
if (tdep->fp_model == ARM_FLOAT_AUTO)
tdep->fp_model = ARM_FLOAT_SOFT_VFP;
tramp_frame_prepend_unwinder (gdbarch, &arm_fbsd_sigframe);
set_solib_svr4_fetch_link_map_offsets
(gdbarch, svr4_ilp32_fetch_link_map_offsets);
tdep->jb_pc = 24;
tdep->jb_elt_size = 4;
set_gdbarch_iterate_over_regset_sections
(gdbarch, arm_fbsd_iterate_over_regset_sections);
set_gdbarch_core_read_description (gdbarch, arm_fbsd_core_read_description);
/* Single stepping. */
set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
}
void
_initialize_arm_fbsd_tdep (void)
{
gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_FREEBSD,
arm_fbsd_init_abi);
}