path: root/gdb/aarch64-fbsd-tdep.c

/* Target-dependent code for FreeBSD/aarch64.

   Copyright (C) 2017-2022 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 "gdbarch.h"
#include "fbsd-tdep.h"
#include "aarch64-tdep.h"
#include "aarch64-fbsd-tdep.h"
#include "inferior.h"
#include "osabi.h"
#include "solib-svr4.h"
#include "target.h"
#include "tramp-frame.h"
#include "trad-frame.h"

/* Register maps.  */

static const struct regcache_map_entry aarch64_fbsd_gregmap[] =
  {
    { 30, AARCH64_X0_REGNUM, 8 }, /* x0 ... x29 */
    { 1, AARCH64_LR_REGNUM, 8 },
    { 1, AARCH64_SP_REGNUM, 8 },
    { 1, AARCH64_PC_REGNUM, 8 },
    { 1, AARCH64_CPSR_REGNUM, 4 },
    { 0 }
  };

static const struct regcache_map_entry aarch64_fbsd_fpregmap[] =
  {
    { 32, AARCH64_V0_REGNUM, 16 }, /* v0 ... v31 */
    { 1, AARCH64_FPSR_REGNUM, 4 },
    { 1, AARCH64_FPCR_REGNUM, 4 },
    { 0 }
  };

static const struct regcache_map_entry aarch64_fbsd_capregmap[] =
  {
    { 30, AARCH64_C0_REGNUM(0), 16 }, /* c0 ... c29 */
    { 1, AARCH64_CLR_REGNUM(0), 16 },
    { 1, AARCH64_CSP_REGNUM(0), 16 },
    { 1, AARCH64_PCC_REGNUM(0), 16 },
    { 1, AARCH64_DDC_REGNUM(0), 16 },
    { 1, AARCH64_CTPIDR_REGNUM(0), 16 },
    { 1, REGCACHE_MAP_SKIP, 16 }, /* ctpidrro */
    { 1, AARCH64_CID_REGNUM(0), 16 },
    { 1, AARCH64_RCSP_REGNUM(0), 16 },
    { 1, AARCH64_RDDC_REGNUM(0), 16 },
    { 1, AARCH64_RCTPIDR_REGNUM(0), 16 },
    { 2, REGCACHE_MAP_SKIP, 8 },  /* tagmask and pad */
    { 0 }
  };

#define	TAGMASK_OFFSET		(16 * 40)

static const struct regcache_map_entry aarch64_fbsd_tls_regmap[] =
  {
    { 1, 0, 8 },
    { 0 }
  };

/* In a signal frame, sp points to a 'struct sigframe' which is
   defined as:

   struct sigframe {
	   siginfo_t	sf_si;
	   ucontext_t	sf_uc;
   };

   ucontext_t is defined as:

   struct __ucontext {
	   sigset_t	uc_sigmask;
	   mcontext_t	uc_mcontext;
	   ...
   };

   The mcontext_t contains the general purpose register set followed
   by the floating point register set.  The floating point register
   set is only valid if the _MC_FP_VALID flag is set in mc_flags.  */

#define AARCH64_SIGFRAME_UCONTEXT_OFFSET	80
#define AARCH64_UCONTEXT_MCONTEXT_OFFSET	16
#define	AARCH64_MCONTEXT_FPREGS_OFFSET		272
#define	AARCH64_MCONTEXT_FLAGS_OFFSET		800
#define AARCH64_MCONTEXT_FLAG_FP_VALID		0x1

/* Implement the "init" method of struct tramp_frame.  */

static void
aarch64_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, AARCH64_SP_REGNUM);
  CORE_ADDR mcontext_addr
    = (sp
       + AARCH64_SIGFRAME_UCONTEXT_OFFSET
       + AARCH64_UCONTEXT_MCONTEXT_OFFSET);
  gdb_byte buf[4];

  trad_frame_set_reg_regmap (this_cache, aarch64_fbsd_gregmap, mcontext_addr,
			     regcache_map_entry_size (aarch64_fbsd_gregmap));

  if (target_read_memory (mcontext_addr + AARCH64_MCONTEXT_FLAGS_OFFSET, buf,
			  4) == 0
      && (extract_unsigned_integer (buf, 4, byte_order)
	  & AARCH64_MCONTEXT_FLAG_FP_VALID))
    trad_frame_set_reg_regmap (this_cache, aarch64_fbsd_fpregmap,
			       mcontext_addr + AARCH64_MCONTEXT_FPREGS_OFFSET,
			       regcache_map_entry_size (aarch64_fbsd_fpregmap));

  trad_frame_set_id (this_cache, frame_id_build (sp, func));
}

static const struct tramp_frame aarch64_fbsd_sigframe =
{
  SIGTRAMP_FRAME,
  4,
  {
    {0x910003e0, ULONGEST_MAX},		/* mov  x0, sp  */
    {0x91014000, ULONGEST_MAX},		/* add  x0, x0, #SF_UC  */
    {0xd2803428, ULONGEST_MAX},		/* mov  x8, #SYS_sigreturn  */
    {0xd4000001, ULONGEST_MAX},		/* svc  0x0  */
    {TRAMP_SENTINEL_INSN, ULONGEST_MAX}
  },
  aarch64_fbsd_sigframe_init
};

/* The CheriABI sigframe replaces struct gpregs at offset 0 of
   mcontext_t with a struct capregs.  This holds capability-sized
   registers for all GPRs.  To aid with this, two extra register maps
   are defined below.  The first one populates the X registers from
   mc_capregs.  The second populates the C registers.  */

#define AARCH64C_SIGFRAME_UCONTEXT_OFFSET	112
#define AARCH64C_UCONTEXT_MCONTEXT_OFFSET	16
#define	AARCH64C_MCONTEXT_CAPREGS_OFFSET	0
#define	AARCH64C_MCONTEXT_FPREGS_OFFSET		544
#define	AARCH64C_MCONTEXT_FLAGS_OFFSET		1072
#define AARCH64C_MCONTEXT_FLAG_FP_VALID		0x1
#define	AARCH64C_MCONTEXT_SPSR_OFFSET		1076

static const struct regcache_map_entry aarch64_fbsd_cheriabi_gregmap[] =
  {
    { 30, AARCH64_X0_REGNUM, 16 }, /* x0 ... x29 */
    { 1, AARCH64_LR_REGNUM, 16 },
    { 1, AARCH64_SP_REGNUM, 16 },
    { 1, AARCH64_PC_REGNUM, 16 },
    { 0 }
  };

const struct regcache_map_entry aarch64_fbsd_cheriabi_capregmap[] =
  {
    { 30, AARCH64_C0_REGNUM(0), 16 }, /* c0 ... c29 */
    { 1, AARCH64_CLR_REGNUM(0), 16 },
    { 1, AARCH64_CSP_REGNUM(0), 16 },
    { 1, AARCH64_PCC_REGNUM(0), 16 },
    { 1, AARCH64_DDC_REGNUM(0), 16 },
    { 0 }
  };

/* Implement the "init" method of struct tramp_frame.  */

static void
aarch64_fbsd_cheriabi_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);
  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  CORE_ADDR sp = get_frame_sp (this_frame);
  CORE_ADDR mcontext_addr
    = (sp
       + AARCH64C_SIGFRAME_UCONTEXT_OFFSET
       + AARCH64C_UCONTEXT_MCONTEXT_OFFSET);
  gdb_byte buf[4];

  /* SPSR.  */
  trad_frame_set_reg_addr (this_cache, AARCH64_CPSR_REGNUM,
			   mcontext_addr + AARCH64C_MCONTEXT_SPSR_OFFSET);

  /* X registers.  */
  trad_frame_set_reg_regmap (this_cache, aarch64_fbsd_cheriabi_gregmap,
			     mcontext_addr + AARCH64C_MCONTEXT_CAPREGS_OFFSET,
			     regcache_map_entry_size
			     (aarch64_fbsd_cheriabi_gregmap));

  /* C registers.  */
  trad_frame_set_reg_regmap (this_cache, aarch64_fbsd_cheriabi_capregmap,
			     mcontext_addr + AARCH64C_MCONTEXT_CAPREGS_OFFSET,
			     regcache_map_entry_size
			     (aarch64_fbsd_cheriabi_capregmap),
			     tdep->cap_reg_base);

  if (target_read_memory (mcontext_addr + AARCH64C_MCONTEXT_FLAGS_OFFSET, buf,
			  4) == 0
      && (extract_unsigned_integer (buf, 4, byte_order)
	  & AARCH64C_MCONTEXT_FLAG_FP_VALID))
    trad_frame_set_reg_regmap (this_cache, aarch64_fbsd_fpregmap,
			       mcontext_addr + AARCH64C_MCONTEXT_FPREGS_OFFSET,
			       regcache_map_entry_size (aarch64_fbsd_fpregmap));

  trad_frame_set_id (this_cache, frame_id_build (sp, func));
}

static const struct tramp_frame aarch64_fbsd_cheriabi_sigframe =
{
  SIGTRAMP_FRAME,
  4,
  {
    {0x0201c3e0, ULONGEST_MAX},		/* add  c0, csp, #SF_UC  */
    {0xd2803428, ULONGEST_MAX},		/* mov  x8, #SYS_sigreturn  */
    {0xd4000001, ULONGEST_MAX},		/* svc  0x0  */
    {TRAMP_SENTINEL_INSN, ULONGEST_MAX}
  },
  aarch64_fbsd_cheriabi_sigframe_init
};

/* Register set definitions.  */

const struct regset aarch64_fbsd_gregset =
  {
    aarch64_fbsd_gregmap,
    regcache_supply_regset, regcache_collect_regset
  };

const struct regset aarch64_fbsd_fpregset =
  {
    aarch64_fbsd_fpregmap,
    regcache_supply_regset, regcache_collect_regset
  };

static int
tag_map_regno(aarch64_gdbarch_tdep *tdep, int idx)
{
  switch (idx)
    {
    default:
      return AARCH64_C0_REGNUM(tdep->cap_reg_base) + idx;
    case 35:
      return -1;	/* ctpidrro */
    case 36:
      return AARCH64_CID_REGNUM(tdep->cap_reg_base);
    case 37:
      return AARCH64_RCSP_REGNUM(tdep->cap_reg_base);
    case 38:
      return AARCH64_RDDC_REGNUM(tdep->cap_reg_base);
    case 39:
      return AARCH64_RCTPIDR_REGNUM(tdep->cap_reg_base);
    }
}

static void
aarch64_fbsd_supply_capregset (const struct regset *regset,
			       struct regcache *regcache,
			       int regnum, const void *buf, size_t size)
{
  struct gdbarch *gdbarch = regcache->arch ();
  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);

  regcache->supply_regset (regset, tdep->cap_reg_base, regnum, buf, size);

  uint64_t tag_map = extract_unsigned_integer ((const gdb_byte *)buf
					       + TAGMASK_OFFSET, 8,
					       gdbarch_byte_order (gdbarch));
  for (unsigned i = 0; i < 40; i++)
    {
      int regno;

      regno = tag_map_regno(tdep, i);
      if (regno == -1)
	continue;
      if (regnum == -1 || regno == regnum)
	regcache->raw_supply_tag (regno, tag_map & 1);
      tag_map >>= 1;
    }
}

static void
aarch64_fbsd_collect_capregset (const struct regset *regset,
				const struct regcache *regcache,
				int regnum, void *buf, size_t size)
{
  struct gdbarch *gdbarch = regcache->arch ();
  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);

  regcache->collect_regset (regset, tdep->cap_reg_base, regnum, buf, size);

  uint64_t tag_map = extract_unsigned_integer ((const gdb_byte *)buf
					       + TAGMASK_OFFSET, 8,
					       gdbarch_byte_order (gdbarch));
  for (unsigned i = 0; i < 40; i++)
    {
      uint64_t mask;
      int regno;

      regno = tag_map_regno(tdep, i);
      if (regno == -1)
	continue;
      if (regnum == -1 || regno == regnum)
	{
	  mask = (uint64_t)1 << i;
	  if (regcache->raw_collect_tag (regno))
	    tag_map |= mask;
	  else
	    tag_map &= ~mask;
	}
    }
  store_unsigned_integer ((gdb_byte *)buf + TAGMASK_OFFSET, 8,
			  gdbarch_byte_order (gdbarch), tag_map);
}

const struct regset aarch64_fbsd_capregset =
  {
    aarch64_fbsd_capregmap,
    aarch64_fbsd_supply_capregset, aarch64_fbsd_collect_capregset
  };

static void
aarch64_fbsd_supply_tls_regset (const struct regset *regset,
				struct regcache *regcache,
				int regnum, const void *buf, size_t size)
{
  struct gdbarch *gdbarch = regcache->arch ();
  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);

  regcache->supply_regset (regset, tdep->tls_regnum, regnum, buf, size);
}

static void
aarch64_fbsd_collect_tls_regset (const struct regset *regset,
				 const struct regcache *regcache,
				 int regnum, void *buf, size_t size)
{
  struct gdbarch *gdbarch = regcache->arch ();
  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);

  regcache->collect_regset (regset, tdep->tls_regnum, regnum, buf, size);
}

const struct regset aarch64_fbsd_tls_regset =
  {
    aarch64_fbsd_tls_regmap,
    aarch64_fbsd_supply_tls_regset, aarch64_fbsd_collect_tls_regset
  };

/* Implement the "iterate_over_regset_sections" gdbarch method.  */

static void
aarch64_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
					   iterate_over_regset_sections_cb *cb,
					   void *cb_data,
					   const struct regcache *regcache)
{
  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);

  cb (".reg", AARCH64_FBSD_SIZEOF_GREGSET, AARCH64_FBSD_SIZEOF_GREGSET,
      &aarch64_fbsd_gregset, NULL, cb_data);
  cb (".reg2", AARCH64_FBSD_SIZEOF_FPREGSET, AARCH64_FBSD_SIZEOF_FPREGSET,
      &aarch64_fbsd_fpregset, NULL, cb_data);

  if (tdep->has_tls ())
    cb (".reg-aarch-tls", AARCH64_FBSD_SIZEOF_TLSREGSET,
	AARCH64_FBSD_SIZEOF_TLSREGSET, &aarch64_fbsd_tls_regset,
	"TLS register", cb_data);

  if (tdep->has_capability ())
    cb (".reg-cap", AARCH64_FBSD_SIZEOF_CAPREGSET,
	AARCH64_FBSD_SIZEOF_CAPREGSET, &aarch64_fbsd_capregset, NULL,
	cb_data);
}

/* Implement the "core_read_description" gdbarch method.  */

static const struct target_desc *
aarch64_fbsd_core_read_description (struct gdbarch *gdbarch,
				    struct target_ops *target, bfd *abfd)
{
  asection *tls = bfd_get_section_by_name (abfd, ".reg-aarch-tls");
  asection *cap = bfd_get_section_by_name (abfd, ".reg-cap");

  aarch64_features features;
  features.tls = tls != nullptr;
  features.capability = cap != nullptr;

  return aarch64_read_description (features);
}

/* Implement the get_thread_local_address gdbarch method.  */

static CORE_ADDR
aarch64_fbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
				       CORE_ADDR lm_addr, CORE_ADDR offset)
{
  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
  struct regcache *regcache;
  int regnum;

  regcache = get_thread_arch_regcache (current_inferior ()->process_target (),
				       ptid, gdbarch);

  if (tdep->has_capability () && tdep->abi == AARCH64_ABI_AAPCS64_CAP)
    regnum = AARCH64_CTPIDR_REGNUM(tdep->cap_reg_base);
  else
    regnum = tdep->tls_regnum;
  target_fetch_registers (regcache, regnum);

  ULONGEST tpidr;
  if (regcache->cooked_read (regnum, &tpidr) != REG_VALID)
    error (_("Unable to fetch %%tpidr"));

  /* %tpidr points to the TCB whose first member is the dtv
      pointer.  */
  CORE_ADDR dtv_addr = tpidr;
  return fbsd_get_thread_local_address (gdbarch, dtv_addr, lm_addr, offset);
}

/* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */

static void
aarch64_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);

  /* Generic FreeBSD support.  */
  fbsd_init_abi (info, gdbarch);

  if (tdep->abi == AARCH64_ABI_AAPCS64_CAP)
    {
      set_solib_svr4_fetch_link_map_offsets
	(gdbarch, svr4_lp64_cheri_fetch_link_map_offsets);

      tramp_frame_prepend_unwinder (gdbarch, &aarch64_fbsd_cheriabi_sigframe);
    }
  else
    {
      set_solib_svr4_fetch_link_map_offsets (gdbarch,
					     svr4_lp64_fetch_link_map_offsets);

      tramp_frame_prepend_unwinder (gdbarch, &aarch64_fbsd_sigframe);
    }

  /* Enable longjmp.  */
  tdep->jb_pc = 13;

  set_gdbarch_iterate_over_regset_sections
    (gdbarch, aarch64_fbsd_iterate_over_regset_sections);
  set_gdbarch_core_read_description (gdbarch,
				     aarch64_fbsd_core_read_description);

  if (tdep->has_tls ())
    {
      set_gdbarch_fetch_tls_load_module_address (gdbarch,
						 svr4_fetch_objfile_link_map);
      set_gdbarch_get_thread_local_address
	(gdbarch, aarch64_fbsd_get_thread_local_address);
    }
}

void _initialize_aarch64_fbsd_tdep ();
void
_initialize_aarch64_fbsd_tdep ()
{
  gdbarch_register_osabi (bfd_arch_aarch64, 0, GDB_OSABI_FREEBSD,
			  aarch64_fbsd_init_abi);
}