[thirdparty/binutils-gdb.git] / gdb / bpf-tdep.c

/* Target-dependent code for BPF.

   Copyright (C) 2020-2021 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 "arch-utils.h"
#include "dis-asm.h"
#include "frame.h"
#include "frame-unwind.h"
#include "trad-frame.h"
#include "symtab.h"
#include "value.h"
#include "gdbcmd.h"
#include "breakpoint.h"
#include "inferior.h"
#include "regcache.h"
#include "target.h"
#include "dwarf2/frame.h"
#include "osabi.h"
#include "target-descriptions.h"
#include "remote.h"

\f
/* eBPF registers.  */

enum bpf_regnum
{
  BPF_R0_REGNUM,		/* return value */
  BPF_R1_REGNUM,
  BPF_R2_REGNUM,
  BPF_R3_REGNUM,
  BPF_R4_REGNUM,
  BPF_R5_REGNUM,
  BPF_R6_REGNUM,
  BPF_R7_REGNUM,
  BPF_R8_REGNUM,
  BPF_R9_REGNUM,
  BPF_R10_REGNUM,		/* sp */
  BPF_PC_REGNUM,
};

#define BPF_NUM_REGS	(BPF_PC_REGNUM + 1)

/* Target-dependent structure in gdbarch.  */
struct gdbarch_tdep
{
};

\f
/* Internal debugging facilities.  */

/* When this is set to non-zero debugging information will be
   printed.  */

static unsigned int bpf_debug_flag = 0;

/* The show callback for 'show debug bpf'.  */

static void
show_bpf_debug (struct ui_file *file, int from_tty,
		struct cmd_list_element *c, const char *value)
{
  fprintf_filtered (file, _("Debugging of BPF is %s.\n"), value);
}

\f
/* BPF registers.  */

static const char *bpf_register_names[] =
{
  "r0",   "r1",  "r2",    "r3",   "r4",   "r5",   "r6",   "r7",
  "r8",   "r9",  "r10",   "pc"
};

/* Return the name of register REGNUM.  */

static const char *
bpf_register_name (struct gdbarch *gdbarch, int reg)
{
  if (reg >= 0 && reg < BPF_NUM_REGS)
    return bpf_register_names[reg];
  return NULL;
}

/* Return the GDB type of register REGNUM.  */

static struct type *
bpf_register_type (struct gdbarch *gdbarch, int reg)
{
  if (reg == BPF_R10_REGNUM)
    return builtin_type (gdbarch)->builtin_data_ptr;
  else if (reg == BPF_PC_REGNUM)
    return builtin_type (gdbarch)->builtin_func_ptr;
  return builtin_type (gdbarch)->builtin_int64;
}

/* Return the GDB register number corresponding to DWARF's REG.  */

static int
bpf_dwarf2_reg_to_regnum (struct gdbarch *gdbarch, int reg)
{
  if (reg >= 0 && reg < BPF_NUM_REGS)
    return reg;
  return -1;
}

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

static int
bpf_gdb_print_insn (bfd_vma memaddr, disassemble_info *info)
{
  info->symbols = NULL;
  return default_print_insn (memaddr, info);
}

\f
/* Return PC of first real instruction of the function starting at
   START_PC.  */

static CORE_ADDR
bpf_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR start_pc)
{
  fprintf_unfiltered (gdb_stdlog,
		      "Skipping prologue: start_pc=%s\n",
		      paddress (gdbarch, start_pc));
  /* XXX: to be completed.  */
  return start_pc + 0;
}

\f
/* Frame unwinder.

   XXX it is not clear how to unwind in eBPF, since the stack is not
   guaranteed to be contiguous, and therefore no relative stack
   addressing can be done in the callee in order to access the
   caller's stack frame.  To explore with xBPF, which will relax this
   restriction.  */

/* Given THIS_FRAME, return its ID.  */

static void
bpf_frame_this_id (struct frame_info *this_frame,
		   void **this_prologue_cache,
		   struct frame_id *this_id)
{
  /* Note that THIS_ID defaults to the outermost frame if we don't set
     anything here.  See frame.c:compute_frame_id.  */
}

/* Return the reason why we can't unwind past THIS_FRAME.  */

static enum unwind_stop_reason
bpf_frame_unwind_stop_reason (struct frame_info *this_frame,
			      void **this_cache)
{
  return UNWIND_OUTERMOST;
}

/* Ask THIS_FRAME to unwind its register.  */

static struct value *
bpf_frame_prev_register (struct frame_info *this_frame,
			 void **this_prologue_cache, int regnum)
{
  return frame_unwind_got_register (this_frame, regnum, regnum);
}

/* Frame unwinder machinery for BPF.  */

static const struct frame_unwind bpf_frame_unwind =
{
  NORMAL_FRAME,
  bpf_frame_unwind_stop_reason,
  bpf_frame_this_id,
  bpf_frame_prev_register,
  NULL,
  default_frame_sniffer
};

\f
/* Breakpoints.  */

/* Enum describing the different kinds of breakpoints.  We currently
   just support one, implemented by the brkpt xbpf instruction.   */

enum bpf_breakpoint_kinds
{
  BPF_BP_KIND_BRKPT = 0,
};

/* Implement the breakpoint_kind_from_pc gdbarch method.  */

static int
bpf_breakpoint_kind_from_pc (struct gdbarch *gdbarch, CORE_ADDR *start_pc)
{
  /* We support just one kind of breakpoint.  */
  return BPF_BP_KIND_BRKPT;
}

/* Implement the sw_breakpoint_from_kind gdbarch method.  */

static const gdb_byte *
bpf_sw_breakpoint_from_kind (struct gdbarch *gdbarch, int kind, int *size)
{
  static unsigned char brkpt_insn[]
    = {0x8c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

  switch (kind)
    {
    case BPF_BP_KIND_BRKPT:
      *size = 8;
      return brkpt_insn;
    default:
      gdb_assert_not_reached ("unexpected BPF breakpoint kind");
    }
}

\f
/* Assuming THIS_FRAME is a dummy frame, return its frame ID.  */

static struct frame_id
bpf_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
{
  CORE_ADDR sp = get_frame_register_unsigned (this_frame,
					      gdbarch_sp_regnum (gdbarch));
  return frame_id_build (sp, get_frame_pc (this_frame));
}

/* Implement the push dummy call gdbarch callback.  */

static CORE_ADDR
bpf_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
		     struct regcache *regcache, CORE_ADDR bp_addr,
		     int nargs, struct value **args, CORE_ADDR sp,
		     function_call_return_method return_method,
		     CORE_ADDR struct_addr)
{
  fprintf_unfiltered (gdb_stdlog, "Pushing dummy call: sp=%s\n",
		      paddress (gdbarch, sp));
  /* XXX writeme  */
  return sp;
}

/* Extract a function return value of TYPE from REGCACHE,
   and copy it into VALBUF.  */

static void
bpf_extract_return_value (struct type *type, struct regcache *regcache,
			  gdb_byte *valbuf)
{
  int len = TYPE_LENGTH (type);
  gdb_byte vbuf[8];

  gdb_assert (len <= 8);
  regcache->cooked_read (BPF_R0_REGNUM, vbuf);
  memcpy (valbuf, vbuf + 8 - len, len);
}

/* Store the function return value of type TYPE from VALBUF into REGNAME.  */

static void
bpf_store_return_value (struct type *type, struct regcache *regcache,
			const gdb_byte *valbuf)
{
  int len = TYPE_LENGTH (type);
  gdb_byte vbuf[8];

  gdb_assert (len <= 8);
  memset (vbuf, 0, sizeof (vbuf));
  memcpy (vbuf + 8 - len, valbuf, len);
  regcache->cooked_write (BPF_R0_REGNUM, vbuf);
}

/* Handle function's return value.  */

static enum return_value_convention
bpf_return_value (struct gdbarch *gdbarch, struct value *function,
		  struct type *type, struct regcache *regcache,
		  gdb_byte *readbuf, const gdb_byte *writebuf)
{
  int len = TYPE_LENGTH (type);

  if (len > 8)
    return RETURN_VALUE_STRUCT_CONVENTION;

  if (readbuf != NULL)
    bpf_extract_return_value (type, regcache, readbuf);
  if (writebuf != NULL)
    bpf_store_return_value (type, regcache, writebuf);

  return RETURN_VALUE_REGISTER_CONVENTION;
}

\f
/* Initialize the current architecture based on INFO.  If possible, re-use an
   architecture from ARCHES, which is a list of architectures already created
   during this debugging session.  */

static struct gdbarch *
bpf_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
{
  /* If there is already a candidate, use it.  */
  arches = gdbarch_list_lookup_by_info (arches, &info);
  if (arches != NULL)
    return arches->gdbarch;

  /* Allocate space for the new architecture.  */
  struct gdbarch_tdep *tdep = XCNEW (struct gdbarch_tdep);
  struct gdbarch *gdbarch = gdbarch_alloc (&info, tdep);

  /* Information about registers, etc.  */
  set_gdbarch_num_regs (gdbarch, BPF_NUM_REGS);
  set_gdbarch_register_name (gdbarch, bpf_register_name);
  set_gdbarch_register_type (gdbarch, bpf_register_type);

  /* Register numbers of various important registers.  */
  set_gdbarch_sp_regnum (gdbarch, BPF_R10_REGNUM);
  set_gdbarch_pc_regnum (gdbarch, BPF_PC_REGNUM);

  /* Map DWARF2 registers to GDB registers.  */
  set_gdbarch_dwarf2_reg_to_regnum (gdbarch, bpf_dwarf2_reg_to_regnum);

  /* Call dummy code.  */
  set_gdbarch_call_dummy_location (gdbarch, ON_STACK);
  set_gdbarch_dummy_id (gdbarch, bpf_dummy_id);
  set_gdbarch_push_dummy_call (gdbarch, bpf_push_dummy_call);

  /* Returning results.  */
  set_gdbarch_return_value (gdbarch, bpf_return_value);

  /* Advance PC across function entry code.  */
  set_gdbarch_skip_prologue (gdbarch, bpf_skip_prologue);

  /* Stack grows downward.  */
  set_gdbarch_inner_than (gdbarch, core_addr_lessthan);

  /* Breakpoint manipulation.  */
  set_gdbarch_breakpoint_kind_from_pc (gdbarch, bpf_breakpoint_kind_from_pc);
  set_gdbarch_sw_breakpoint_from_kind (gdbarch, bpf_sw_breakpoint_from_kind);

  /* Frame handling.  */
  set_gdbarch_frame_args_skip (gdbarch, 8);

  /* Disassembly.  */
  set_gdbarch_print_insn (gdbarch, bpf_gdb_print_insn);

  /* Hook in ABI-specific overrides, if they have been registered.  */
  gdbarch_init_osabi (info, gdbarch);

  /* Install unwinders.  */
  frame_unwind_append_unwinder (gdbarch, &bpf_frame_unwind);

  return gdbarch;
}

void _initialize_bpf_tdep ();
void
_initialize_bpf_tdep ()
{
  register_gdbarch_init (bfd_arch_bpf, bpf_gdbarch_init);

  /* Add commands 'set/show debug bpf'.  */
  add_setshow_zuinteger_cmd ("bpf", class_maintenance,
			     &bpf_debug_flag,
			     _("Set BPF debugging."),
			     _("Show BPF debugging."),
			     _("Enables BPF specific debugging output."),
			     NULL,
			     &show_bpf_debug,
			     &setdebuglist, &showdebuglist);
}
Commit	Line	Data
39791af2 JM	1	/* Target-dependent code for BPF.
39791af2 JM	2
3666a048	3	Copyright (C) 2020-2021 Free Software Foundation, Inc.
39791af2 JM	4
	5	This file is part of GDB.
	6
	7	This program is free software; you can redistribute it and/or modify
	8	it under the terms of the GNU General Public License as published by
	9	the Free Software Foundation; either version 3 of the License, or
	10	(at your option) any later version.
	11
	12	This program is distributed in the hope that it will be useful,
	13	but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	GNU General Public License for more details.
	16
	17	You should have received a copy of the GNU General Public License
	18	along with this program. If not, see <http://www.gnu.org/licenses/>. */
	19
	20	#include "defs.h"
	21	#include "arch-utils.h"
	22	#include "dis-asm.h"
	23	#include "frame.h"
	24	#include "frame-unwind.h"
	25	#include "trad-frame.h"
	26	#include "symtab.h"
	27	#include "value.h"
	28	#include "gdbcmd.h"
	29	#include "breakpoint.h"
	30	#include "inferior.h"
	31	#include "regcache.h"
	32	#include "target.h"
	33	#include "dwarf2/frame.h"
	34	#include "osabi.h"
	35	#include "target-descriptions.h"
	36	#include "remote.h"
	37
	38	\f
	39	/* eBPF registers. */
	40
	41	enum bpf_regnum
	42	{
	43	BPF_R0_REGNUM, /* return value */
	44	BPF_R1_REGNUM,
	45	BPF_R2_REGNUM,
	46	BPF_R3_REGNUM,
	47	BPF_R4_REGNUM,
	48	BPF_R5_REGNUM,
	49	BPF_R6_REGNUM,
	50	BPF_R7_REGNUM,
	51	BPF_R8_REGNUM,
	52	BPF_R9_REGNUM,
	53	BPF_R10_REGNUM, /* sp */
	54	BPF_PC_REGNUM,
	55	};
	56
	57	#define BPF_NUM_REGS (BPF_PC_REGNUM + 1)
	58
	59	/* Target-dependent structure in gdbarch. */
	60	struct gdbarch_tdep
	61	{
	62	};
	63
	64	\f
	65	/* Internal debugging facilities. */
	66
	67	/* When this is set to non-zero debugging information will be
68	printed. */
69
70	static unsigned int bpf_debug_flag = 0;
71
72	/* The show callback for 'show debug bpf'. */
73
74	static void
75	show_bpf_debug (struct ui_file *file, int from_tty,
dda83cd7	76	struct cmd_list_element c, const char value)
39791af2 JM	77	{
	78	fprintf_filtered (file, _("Debugging of BPF is %s.\n"), value);
	79	}
	80
	81	\f
	82	/* BPF registers. */
	83
	84	static const char *bpf_register_names[] =
	85	{
	86	"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
	87	"r8", "r9", "r10", "pc"
	88	};
	89
	90	/* Return the name of register REGNUM. */
	91
	92	static const char *
	93	bpf_register_name (struct gdbarch *gdbarch, int reg)
	94	{
	95	if (reg >= 0 && reg < BPF_NUM_REGS)
	96	return bpf_register_names[reg];
	97	return NULL;
	98	}
	99
	100	/* Return the GDB type of register REGNUM. */
	101
	102	static struct type *
	103	bpf_register_type (struct gdbarch *gdbarch, int reg)
	104	{
	105	if (reg == BPF_R10_REGNUM)
	106	return builtin_type (gdbarch)->builtin_data_ptr;
	107	else if (reg == BPF_PC_REGNUM)
	108	return builtin_type (gdbarch)->builtin_func_ptr;
	109	return builtin_type (gdbarch)->builtin_int64;
	110	}
	111
	112	/* Return the GDB register number corresponding to DWARF's REG. */
	113
	114	static int
	115	bpf_dwarf2_reg_to_regnum (struct gdbarch *gdbarch, int reg)
	116	{
	117	if (reg >= 0 && reg < BPF_NUM_REGS)
	118	return reg;
	119	return -1;
	120	}
	121
	122	/* Implement the "print_insn" gdbarch method. */
	123
	124	static int
	125	bpf_gdb_print_insn (bfd_vma memaddr, disassemble_info *info)
	126	{
	127	info->symbols = NULL;
	128	return default_print_insn (memaddr, info);
	129	}
	130
	131	\f
	132	/* Return PC of first real instruction of the function starting at
	133	START_PC. */
	134
	135	static CORE_ADDR
	136	bpf_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR start_pc)
	137	{
	138	fprintf_unfiltered (gdb_stdlog,
	139	"Skipping prologue: start_pc=%s\n",
	140	paddress (gdbarch, start_pc));
141	/* XXX: to be completed. */
142	return start_pc + 0;
143	}
144
145	\f
146	/* Frame unwinder.
147
148	XXX it is not clear how to unwind in eBPF, since the stack is not
149	guaranteed to be contiguous, and therefore no relative stack
150	addressing can be done in the callee in order to access the
151	caller's stack frame. To explore with xBPF, which will relax this
152	restriction. */
153
154	/* Given THIS_FRAME, return its ID. */
155
156	static void
157	bpf_frame_this_id (struct frame_info *this_frame,
158	void **this_prologue_cache,
159	struct frame_id *this_id)
160	{
161	/* Note that THIS_ID defaults to the outermost frame if we don't set
162	anything here. See frame.c:compute_frame_id. */
163	}
164
165	/* Return the reason why we can't unwind past THIS_FRAME. */
166
167	static enum unwind_stop_reason
168	bpf_frame_unwind_stop_reason (struct frame_info *this_frame,
169	void **this_cache)
170	{
171	return UNWIND_OUTERMOST;
172	}
173
174	/* Ask THIS_FRAME to unwind its register. */
175
176	static struct value *
177	bpf_frame_prev_register (struct frame_info *this_frame,
178	void **this_prologue_cache, int regnum)
179	{
180	return frame_unwind_got_register (this_frame, regnum, regnum);
181	}
182
183	/* Frame unwinder machinery for BPF. */
184
185	static const struct frame_unwind bpf_frame_unwind =
186	{
187	NORMAL_FRAME,
188	bpf_frame_unwind_stop_reason,
189	bpf_frame_this_id,
190	bpf_frame_prev_register,
191	NULL,
192	default_frame_sniffer
193	};
194
195	\f
196	/* Breakpoints. */
197
198	/* Enum describing the different kinds of breakpoints. We currently
199	just support one, implemented by the brkpt xbpf instruction. */
200
201	enum bpf_breakpoint_kinds
202	{
203	BPF_BP_KIND_BRKPT = 0,
204	};
205
206	/* Implement the breakpoint_kind_from_pc gdbarch method. */
207
208	static int
209	bpf_breakpoint_kind_from_pc (struct gdbarch gdbarch, CORE_ADDR start_pc)
210	{
211	/* We support just one kind of breakpoint. */
212	return BPF_BP_KIND_BRKPT;
213	}
214
215	/* Implement the sw_breakpoint_from_kind gdbarch method. */
216
217	static const gdb_byte *
218	bpf_sw_breakpoint_from_kind (struct gdbarch gdbarch, int kind, int size)
219	{
220	static unsigned char brkpt_insn[]
221	= {0x8c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
222
223	switch (kind)
224	{
225	case BPF_BP_KIND_BRKPT:
226	*size = 8;
227	return brkpt_insn;
228	default:
229	gdb_assert_not_reached ("unexpected BPF breakpoint kind");
230	}
231	}
232
233	\f
234	/* Assuming THIS_FRAME is a dummy frame, return its frame ID. */
235
236	static struct frame_id
237	bpf_dummy_id (struct gdbarch gdbarch, struct frame_info this_frame)
238	{
239	CORE_ADDR sp = get_frame_register_unsigned (this_frame,
240	gdbarch_sp_regnum (gdbarch));
241	return frame_id_build (sp, get_frame_pc (this_frame));
242	}
243
244	/* Implement the push dummy call gdbarch callback. */
245
246	static CORE_ADDR
247	bpf_push_dummy_call (struct gdbarch gdbarch, struct value function,
248	struct regcache *regcache, CORE_ADDR bp_addr,
249	int nargs, struct value **args, CORE_ADDR sp,
250	function_call_return_method return_method,
251	CORE_ADDR struct_addr)
252	{
253	fprintf_unfiltered (gdb_stdlog, "Pushing dummy call: sp=%s\n",
254	paddress (gdbarch, sp));
255	/* XXX writeme */
256	return sp;
257	}
258
259	/* Extract a function return value of TYPE from REGCACHE,
260	and copy it into VALBUF. */
261
262	static void
263	bpf_extract_return_value (struct type type, struct regcache regcache,
264	gdb_byte *valbuf)
265	{
266	int len = TYPE_LENGTH (type);
267	gdb_byte vbuf[8];
268
269	gdb_assert (len <= 8);
270	regcache->cooked_read (BPF_R0_REGNUM, vbuf);
271	memcpy (valbuf, vbuf + 8 - len, len);
272	}
273
274	/* Store the function return value of type TYPE from VALBUF into REGNAME. */
275
276	static void
277	bpf_store_return_value (struct type type, struct regcache regcache,
278	const gdb_byte *valbuf)
279	{
280	int len = TYPE_LENGTH (type);
281	gdb_byte vbuf[8];
282
283	gdb_assert (len <= 8);
284	memset (vbuf, 0, sizeof (vbuf));
285	memcpy (vbuf + 8 - len, valbuf, len);
286	regcache->cooked_write (BPF_R0_REGNUM, vbuf);
287	}
288
289	/* Handle function's return value. */
290
291	static enum return_value_convention
292	bpf_return_value (struct gdbarch gdbarch, struct value function,
293	struct type type, struct regcache regcache,
294	gdb_byte readbuf, const gdb_byte writebuf)
295	{
296	int len = TYPE_LENGTH (type);
297
298	if (len > 8)
299	return RETURN_VALUE_STRUCT_CONVENTION;
300
301	if (readbuf != NULL)
302	bpf_extract_return_value (type, regcache, readbuf);
303	if (writebuf != NULL)
304	bpf_store_return_value (type, regcache, writebuf);
305
306	return RETURN_VALUE_REGISTER_CONVENTION;
307	}
308
309	\f
310	/* Initialize the current architecture based on INFO. If possible, re-use an
311	architecture from ARCHES, which is a list of architectures already created
312	during this debugging session. */
313
314	static struct gdbarch *
315	bpf_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
316	{
317	/* If there is already a candidate, use it. */
318	arches = gdbarch_list_lookup_by_info (arches, &info);
319	if (arches != NULL)
320	return arches->gdbarch;
321
322	/* Allocate space for the new architecture. */
323	struct gdbarch_tdep *tdep = XCNEW (struct gdbarch_tdep);
324	struct gdbarch *gdbarch = gdbarch_alloc (&info, tdep);
325
326	/* Information about registers, etc. */
327	set_gdbarch_num_regs (gdbarch, BPF_NUM_REGS);
328	set_gdbarch_register_name (gdbarch, bpf_register_name);
329	set_gdbarch_register_type (gdbarch, bpf_register_type);
330
331	/* Register numbers of various important registers. */
332	set_gdbarch_sp_regnum (gdbarch, BPF_R10_REGNUM);
333	set_gdbarch_pc_regnum (gdbarch, BPF_PC_REGNUM);
334
335	/* Map DWARF2 registers to GDB registers. */
336	set_gdbarch_dwarf2_reg_to_regnum (gdbarch, bpf_dwarf2_reg_to_regnum);
337
338	/* Call dummy code. */
339	set_gdbarch_call_dummy_location (gdbarch, ON_STACK);
340	set_gdbarch_dummy_id (gdbarch, bpf_dummy_id);
341	set_gdbarch_push_dummy_call (gdbarch, bpf_push_dummy_call);
342
343	/* Returning results. */
344	set_gdbarch_return_value (gdbarch, bpf_return_value);
345
346	/* Advance PC across function entry code. */
347	set_gdbarch_skip_prologue (gdbarch, bpf_skip_prologue);
348
349	/* Stack grows downward. */
350	set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
351
352	/* Breakpoint manipulation. */
353	set_gdbarch_breakpoint_kind_from_pc (gdbarch, bpf_breakpoint_kind_from_pc);
354	set_gdbarch_sw_breakpoint_from_kind (gdbarch, bpf_sw_breakpoint_from_kind);
355
356	/* Frame handling. */
357	set_gdbarch_frame_args_skip (gdbarch, 8);
358
359	/* Disassembly. */
360	set_gdbarch_print_insn (gdbarch, bpf_gdb_print_insn);
361
362	/* Hook in ABI-specific overrides, if they have been registered. */
363	gdbarch_init_osabi (info, gdbarch);
364
365	/* Install unwinders. */
366	frame_unwind_append_unwinder (gdbarch, &bpf_frame_unwind);
367
368	return gdbarch;
369	}
370
371	void _initialize_bpf_tdep ();
372	void
f39632d9	373	_initialize_bpf_tdep ()
39791af2 JM	374	{
	375	register_gdbarch_init (bfd_arch_bpf, bpf_gdbarch_init);
	376
	377	/* Add commands 'set/show debug bpf'. */
	378	add_setshow_zuinteger_cmd ("bpf", class_maintenance,
	379	&bpf_debug_flag,
	380	_("Set BPF debugging."),
	381	_("Show BPF debugging."),
	382	_("Enables BPF specific debugging output."),
	383	NULL,
	384	&show_bpf_debug,
	385	&setdebuglist, &showdebuglist);
	386	}