/* GNU/Linux S/390 specific low level interface, for the in-process
   agent library for GDB.

   Copyright (C) 2016-2021 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 "server.h"
#include <sys/mman.h>
#include "tracepoint.h"
#include "linux-s390-tdesc.h"
#include <elf.h>
#ifdef HAVE_GETAUXVAL
#include <sys/auxv.h>
#endif

#define FT_FPR(x) (0x000 + (x) * 0x10)
#define FT_VR(x) (0x000 + (x) * 0x10)
#define FT_VR_L(x) (0x008 + (x) * 0x10)
#define FT_GPR(x) (0x200 + (x) * 8)
#define FT_GPR_U(x) (0x200 + (x) * 8)
#define FT_GPR_L(x) (0x204 + (x) * 8)
#define FT_GPR(x) (0x200 + (x) * 8)
#define FT_ACR(x) (0x280 + (x) * 4)
#define FT_PSWM 0x2c0
#define FT_PSWM_U 0x2c0
#define FT_PSWA 0x2c8
#define FT_PSWA_L 0x2cc
#define FT_FPC 0x2d0

/* Mappings between registers collected by the jump pad and GDB's register
   array layout used by regcache.

   See linux-s390-low.c (s390_install_fast_tracepoint_jump_pad) for more
   details.  */

#ifndef __s390x__

/* Used for s390-linux32, s390-linux32v1, s390-linux32v2.  */

static const int s390_linux32_ft_collect_regmap[] = {
  /* 32-bit PSWA and PSWM.  */
  FT_PSWM_U, FT_PSWA_L,
  /* 32-bit GPRs (mapped to lower halves of 64-bit slots).  */
  FT_GPR_L (0), FT_GPR_L (1), FT_GPR_L (2), FT_GPR_L (3),
  FT_GPR_L (4), FT_GPR_L (5), FT_GPR_L (6), FT_GPR_L (7),
  FT_GPR_L (8), FT_GPR_L (9), FT_GPR_L (10), FT_GPR_L (11),
  FT_GPR_L (12), FT_GPR_L (13), FT_GPR_L (14), FT_GPR_L (15),
  /* ACRs */
  FT_ACR (0), FT_ACR (1), FT_ACR (2), FT_ACR (3),
  FT_ACR (4), FT_ACR (5), FT_ACR (6), FT_ACR (7),
  FT_ACR (8), FT_ACR (9), FT_ACR (10), FT_ACR (11),
  FT_ACR (12), FT_ACR (13), FT_ACR (14), FT_ACR (15),
  /* FPRs (mapped to upper halves of 128-bit VR slots).  */
  FT_FPR (0), FT_FPR (1), FT_FPR (2), FT_FPR (3),
  FT_FPR (4), FT_FPR (5), FT_FPR (6), FT_FPR (7),
  FT_FPR (8), FT_FPR (9), FT_FPR (10), FT_FPR (11),
  FT_FPR (12), FT_FPR (13), FT_FPR (14), FT_FPR (15),
  /* orig_r2, last_break, system_call */
  -1, -1, -1,
};

/* Used for s390-linux64, s390-linux64v1, s390-linux64v2, s390-vx-linux64.  */

static const int s390_linux64_ft_collect_regmap[] = {
  /* 32-bit PSWA and PSWM.  */
  FT_PSWM_U, FT_PSWA_L,
  /* 32-bit halves of 64-bit GPRs.  */
  FT_GPR_U (0), FT_GPR_L (0),
  FT_GPR_U (1), FT_GPR_L (1),
  FT_GPR_U (2), FT_GPR_L (2),
  FT_GPR_U (3), FT_GPR_L (3),
  FT_GPR_U (4), FT_GPR_L (4),
  FT_GPR_U (5), FT_GPR_L (5),
  FT_GPR_U (6), FT_GPR_L (6),
  FT_GPR_U (7), FT_GPR_L (7),
  FT_GPR_U (8), FT_GPR_L (8),
  FT_GPR_U (9), FT_GPR_L (9),
  FT_GPR_U (10), FT_GPR_L (10),
  FT_GPR_U (11), FT_GPR_L (11),
  FT_GPR_U (12), FT_GPR_L (12),
  FT_GPR_U (13), FT_GPR_L (13),
  FT_GPR_U (14), FT_GPR_L (14),
  FT_GPR_U (15), FT_GPR_L (15),
  /* ACRs */
  FT_ACR (0), FT_ACR (1), FT_ACR (2), FT_ACR (3),
  FT_ACR (4), FT_ACR (5), FT_ACR (6), FT_ACR (7),
  FT_ACR (8), FT_ACR (9), FT_ACR (10), FT_ACR (11),
  FT_ACR (12), FT_ACR (13), FT_ACR (14), FT_ACR (15),
  /* FPRs (mapped to upper halves of 128-bit VR slots).  */
  FT_FPR (0), FT_FPR (1), FT_FPR (2), FT_FPR (3),
  FT_FPR (4), FT_FPR (5), FT_FPR (6), FT_FPR (7),
  FT_FPR (8), FT_FPR (9), FT_FPR (10), FT_FPR (11),
  FT_FPR (12), FT_FPR (13), FT_FPR (14), FT_FPR (15),
  /* orig_r2, last_break, system_call */
  -1, -1, -1,
  /* Lower halves of 128-bit VRs. */
  FT_VR_L (0), FT_VR_L (1), FT_VR_L (2), FT_VR_L (3),
  FT_VR_L (4), FT_VR_L (5), FT_VR_L (6), FT_VR_L (7),
  FT_VR_L (8), FT_VR_L (9), FT_VR_L (10), FT_VR_L (11),
  FT_VR_L (12), FT_VR_L (13), FT_VR_L (14), FT_VR_L (15),
  /* And the next 16 VRs.  */
  FT_VR (16), FT_VR (17), FT_VR (18), FT_VR (19),
  FT_VR (20), FT_VR (21), FT_VR (22), FT_VR (23),
  FT_VR (24), FT_VR (25), FT_VR (26), FT_VR (27),
  FT_VR (28), FT_VR (29), FT_VR (30), FT_VR (31),
};

/* Used for s390-te-linux64, s390-tevx-linux64, and s390-gs-linux64.  */

static const int s390_te_linux64_ft_collect_regmap[] = {
  /* 32-bit PSWA and PSWM.  */
  FT_PSWM_U, FT_PSWA_L,
  /* 32-bit halves of 64-bit GPRs.  */
  FT_GPR_U (0), FT_GPR_L (0),
  FT_GPR_U (1), FT_GPR_L (1),
  FT_GPR_U (2), FT_GPR_L (2),
  FT_GPR_U (3), FT_GPR_L (3),
  FT_GPR_U (4), FT_GPR_L (4),
  FT_GPR_U (5), FT_GPR_L (5),
  FT_GPR_U (6), FT_GPR_L (6),
  FT_GPR_U (7), FT_GPR_L (7),
  FT_GPR_U (8), FT_GPR_L (8),
  FT_GPR_U (9), FT_GPR_L (9),
  FT_GPR_U (10), FT_GPR_L (10),
  FT_GPR_U (11), FT_GPR_L (11),
  FT_GPR_U (12), FT_GPR_L (12),
  FT_GPR_U (13), FT_GPR_L (13),
  FT_GPR_U (14), FT_GPR_L (14),
  FT_GPR_U (15), FT_GPR_L (15),
  /* ACRs */
  FT_ACR (0), FT_ACR (1), FT_ACR (2), FT_ACR (3),
  FT_ACR (4), FT_ACR (5), FT_ACR (6), FT_ACR (7),
  FT_ACR (8), FT_ACR (9), FT_ACR (10), FT_ACR (11),
  FT_ACR (12), FT_ACR (13), FT_ACR (14), FT_ACR (15),
  /* FPRs (mapped to upper halves of 128-bit VR slots).  */
  FT_FPR (0), FT_FPR (1), FT_FPR (2), FT_FPR (3),
  FT_FPR (4), FT_FPR (5), FT_FPR (6), FT_FPR (7),
  FT_FPR (8), FT_FPR (9), FT_FPR (10), FT_FPR (11),
  FT_FPR (12), FT_FPR (13), FT_FPR (14), FT_FPR (15),
  /* orig_r2, last_break, system_call */
  -1, -1, -1,
  /* TDB */
  -1, -1, -1, -1,
  -1, -1, -1, -1,
  -1, -1, -1, -1,
  -1, -1, -1, -1,
  -1, -1, -1, -1,
  /* Lower halves of 128-bit VRs. */
  FT_VR_L (0), FT_VR_L (1), FT_VR_L (2), FT_VR_L (3),
  FT_VR_L (4), FT_VR_L (5), FT_VR_L (6), FT_VR_L (7),
  FT_VR_L (8), FT_VR_L (9), FT_VR_L (10), FT_VR_L (11),
  FT_VR_L (12), FT_VR_L (13), FT_VR_L (14), FT_VR_L (15),
  /* And the next 16 VRs.  */
  FT_VR (16), FT_VR (17), FT_VR (18), FT_VR (19),
  FT_VR (20), FT_VR (21), FT_VR (22), FT_VR (23),
  FT_VR (24), FT_VR (25), FT_VR (26), FT_VR (27),
  FT_VR (28), FT_VR (29), FT_VR (30), FT_VR (31),
};

#else /* __s390x__ */

/* Used for s390x-linux64, s390x-linux64v1, s390x-linux64v2, s390x-vx-linux64.  */

static const int s390x_ft_collect_regmap[] = {
  /* 64-bit PSWA and PSWM.  */
  FT_PSWM, FT_PSWA,
  /* 64-bit GPRs.  */
  FT_GPR (0), FT_GPR (1), FT_GPR (2), FT_GPR (3),
  FT_GPR (4), FT_GPR (5), FT_GPR (6), FT_GPR (7),
  FT_GPR (8), FT_GPR (9), FT_GPR (10), FT_GPR (11),
  FT_GPR (12), FT_GPR (13), FT_GPR (14), FT_GPR (15),
  /* ACRs */
  FT_ACR (0), FT_ACR (1), FT_ACR (2), FT_ACR (3),
  FT_ACR (4), FT_ACR (5), FT_ACR (6), FT_ACR (7),
  FT_ACR (8), FT_ACR (9), FT_ACR (10), FT_ACR (11),
  FT_ACR (12), FT_ACR (13), FT_ACR (14), FT_ACR (15),
  /* FPRs (mapped to upper halves of 128-bit VR slots).  */
  FT_FPR (0), FT_FPR (1), FT_FPR (2), FT_FPR (3),
  FT_FPR (4), FT_FPR (5), FT_FPR (6), FT_FPR (7),
  FT_FPR (8), FT_FPR (9), FT_FPR (10), FT_FPR (11),
  FT_FPR (12), FT_FPR (13), FT_FPR (14), FT_FPR (15),
  /* orig_r2, last_break, system_call */
  -1, -1, -1,
  /* Lower halves of 128-bit VRs. */
  FT_VR_L (0), FT_VR_L (1), FT_VR_L (2), FT_VR_L (3),
  FT_VR_L (4), FT_VR_L (5), FT_VR_L (6), FT_VR_L (7),
  FT_VR_L (8), FT_VR_L (9), FT_VR_L (10), FT_VR_L (11),
  FT_VR_L (12), FT_VR_L (13), FT_VR_L (14), FT_VR_L (15),
  /* And the next 16 VRs.  */
  FT_VR (16), FT_VR (17), FT_VR (18), FT_VR (19),
  FT_VR (20), FT_VR (21), FT_VR (22), FT_VR (23),
  FT_VR (24), FT_VR (25), FT_VR (26), FT_VR (27),
  FT_VR (28), FT_VR (29), FT_VR (30), FT_VR (31),
};

/* Used for s390x-te-linux64, s390x-tevx-linux64, and
   s390x-gs-linux64.  */

static const int s390x_te_ft_collect_regmap[] = {
  /* 64-bit PSWA and PSWM.  */
  FT_PSWM, FT_PSWA,
  /* 64-bit GPRs.  */
  FT_GPR (0), FT_GPR (1), FT_GPR (2), FT_GPR (3),
  FT_GPR (4), FT_GPR (5), FT_GPR (6), FT_GPR (7),
  FT_GPR (8), FT_GPR (9), FT_GPR (10), FT_GPR (11),
  FT_GPR (12), FT_GPR (13), FT_GPR (14), FT_GPR (15),
  /* ACRs */
  FT_ACR (0), FT_ACR (1), FT_ACR (2), FT_ACR (3),
  FT_ACR (4), FT_ACR (5), FT_ACR (6), FT_ACR (7),
  FT_ACR (8), FT_ACR (9), FT_ACR (10), FT_ACR (11),
  FT_ACR (12), FT_ACR (13), FT_ACR (14), FT_ACR (15),
  /* FPRs (mapped to upper halves of 128-bit VR slots).  */
  FT_FPR (0), FT_FPR (1), FT_FPR (2), FT_FPR (3),
  FT_FPR (4), FT_FPR (5), FT_FPR (6), FT_FPR (7),
  FT_FPR (8), FT_FPR (9), FT_FPR (10), FT_FPR (11),
  FT_FPR (12), FT_FPR (13), FT_FPR (14), FT_FPR (15),
  /* orig_r2, last_break, system_call */
  -1, -1, -1,
  /* TDB */
  -1, -1, -1, -1,
  -1, -1, -1, -1,
  -1, -1, -1, -1,
  -1, -1, -1, -1,
  -1, -1, -1, -1,
  /* Lower halves of 128-bit VRs. */
  FT_VR_L (0), FT_VR_L (1), FT_VR_L (2), FT_VR_L (3),
  FT_VR_L (4), FT_VR_L (5), FT_VR_L (6), FT_VR_L (7),
  FT_VR_L (8), FT_VR_L (9), FT_VR_L (10), FT_VR_L (11),
  FT_VR_L (12), FT_VR_L (13), FT_VR_L (14), FT_VR_L (15),
  /* And the next 16 VRs.  */
  FT_VR (16), FT_VR (17), FT_VR (18), FT_VR (19),
  FT_VR (20), FT_VR (21), FT_VR (22), FT_VR (23),
  FT_VR (24), FT_VR (25), FT_VR (26), FT_VR (27),
  FT_VR (28), FT_VR (29), FT_VR (30), FT_VR (31),
};

#endif

/* Initialized by get_ipa_tdesc according to the tdesc in use.  */

static const int *s390_regmap;
static int s390_regnum;

/* Fill in REGCACHE with registers saved by the jump pad in BUF.  */

void
supply_fast_tracepoint_registers (struct regcache *regcache,
				  const unsigned char *buf)
{
  int i;
  for (i = 0; i < s390_regnum; i++)
    if (s390_regmap[i] != -1)
      supply_register (regcache, i, ((char *) buf) + s390_regmap[i]);
}

ULONGEST
get_raw_reg (const unsigned char *raw_regs, int regnum)
{
  int offset;
  if (regnum >= s390_regnum)
    return 0;
  offset = s390_regmap[regnum];
  if (offset == -1)
    return 0;

  /* The regnums are variable, better to figure out size by FT offset.  */

  /* 64-bit ones.  */
  if (offset < FT_VR(16)
#ifdef __s390x__
      || (offset >= FT_GPR(0) && offset < FT_ACR(0))
      || offset == FT_PSWM
      || offset == FT_PSWA
#endif
     )
    return *(uint64_t *) (raw_regs + offset);

  if (offset >= FT_ACR(0 && offset < FT_PSWM)
      || offset == FT_FPC
#ifndef __s390x__
      || (offset >= FT_GPR(0) && offset < FT_ACR(0))
      || offset == FT_PSWM_U
      || offset == FT_PSWA_L
#endif
     )
    return *(uint32_t *) (raw_regs + offset);

  /* This leaves 128-bit VX.  No way to return them.  */
  return 0;
}

/* Return target_desc to use for IPA, given the tdesc index passed by
   gdbserver.  For s390, it also sets s390_regmap and s390_regnum.  */

const struct target_desc *
get_ipa_tdesc (int idx)
{
#define SET_REGMAP(regmap, skip_last) \
	do { \
	  s390_regmap = regmap; \
	  s390_regnum = (sizeof regmap / sizeof regmap[0]) - skip_last; \
	} while(0)
  switch (idx)
    {
#ifdef __s390x__
    case S390_TDESC_64:
      /* Subtract number of VX regs.  */
      SET_REGMAP(s390x_ft_collect_regmap, 32);
      return tdesc_s390x_linux64;
    case S390_TDESC_64V1:
      SET_REGMAP(s390x_ft_collect_regmap, 32);
      return tdesc_s390x_linux64v1;
    case S390_TDESC_64V2:
      SET_REGMAP(s390x_ft_collect_regmap, 32);
      return tdesc_s390x_linux64v2;
    case S390_TDESC_TE:
      SET_REGMAP(s390x_te_ft_collect_regmap, 32);
      return tdesc_s390x_te_linux64;
    case S390_TDESC_VX:
      SET_REGMAP(s390x_ft_collect_regmap, 0);
      return tdesc_s390x_vx_linux64;
    case S390_TDESC_TEVX:
      SET_REGMAP(s390x_te_ft_collect_regmap, 0);
      return tdesc_s390x_tevx_linux64;
    case S390_TDESC_GS:
      SET_REGMAP(s390x_te_ft_collect_regmap, 0);
      return tdesc_s390x_gs_linux64;
#else
    case S390_TDESC_32:
      SET_REGMAP(s390_linux32_ft_collect_regmap, 0);
      return tdesc_s390_linux32;
    case S390_TDESC_32V1:
      SET_REGMAP(s390_linux32_ft_collect_regmap, 0);
      return tdesc_s390_linux32v1;
    case S390_TDESC_32V2:
      SET_REGMAP(s390_linux32_ft_collect_regmap, 0);
      return tdesc_s390_linux32v2;
    case S390_TDESC_64:
      SET_REGMAP(s390_linux64_ft_collect_regmap, 32);
      return tdesc_s390_linux64;
    case S390_TDESC_64V1:
      SET_REGMAP(s390_linux64_ft_collect_regmap, 32);
      return tdesc_s390_linux64v1;
    case S390_TDESC_64V2:
      SET_REGMAP(s390_linux64_ft_collect_regmap, 32);
      return tdesc_s390_linux64v2;
    case S390_TDESC_TE:
      SET_REGMAP(s390_te_linux64_ft_collect_regmap, 32);
      return tdesc_s390_te_linux64;
    case S390_TDESC_VX:
      SET_REGMAP(s390_linux64_ft_collect_regmap, 0);
      return tdesc_s390_vx_linux64;
    case S390_TDESC_TEVX:
      SET_REGMAP(s390_te_linux64_ft_collect_regmap, 0);
      return tdesc_s390_tevx_linux64;
    case S390_TDESC_GS:
      SET_REGMAP(s390_te_linux64_ft_collect_regmap, 0);
      return tdesc_s390_gs_linux64;
#endif
    default:
      internal_error (__FILE__, __LINE__,
		      "unknown ipa tdesc index: %d", idx);
#ifdef __s390x__
      return tdesc_s390x_linux64;
#else
      return tdesc_s390_linux32;
#endif
    }
}

/* Allocate buffer for the jump pads.  On 31-bit, JG reaches everywhere,
   so just allocate normally.  On 64-bit, we have +/-4GiB of reach, and
   the executable is usually mapped at 0x80000000 - aim for somewhere
   below it.  */

void *
alloc_jump_pad_buffer (size_t size)
{
#ifdef __s390x__
  uintptr_t addr;
  uintptr_t exec_base = getauxval (AT_PHDR);
  int pagesize;
  void *res;

  if (exec_base == 0)
    exec_base = 0x80000000;

  pagesize = sysconf (_SC_PAGE_SIZE);
  if (pagesize == -1)
    perror_with_name ("sysconf");

  addr = exec_base - size;

  /* size should already be page-aligned, but this can't hurt.  */
  addr &= ~(pagesize - 1);

  /* Search for a free area.  If we hit 0, we're out of luck.  */
  for (; addr; addr -= pagesize)
    {
      /* No MAP_FIXED - we don't want to zap someone's mapping.  */
      res = mmap ((void *) addr, size,
		  PROT_READ | PROT_WRITE | PROT_EXEC,
		  MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);

      /* If we got what we wanted, return.  */
      if ((uintptr_t) res == addr)
	return res;

      /* If we got a mapping, but at a wrong address, undo it.  */
      if (res != MAP_FAILED)
	munmap (res, size);
    }

  return NULL;
#else
  void *res = mmap (NULL, size, PROT_READ | PROT_WRITE | PROT_EXEC,
		    MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);

  if (res == MAP_FAILED)
    return NULL;

  return res;
#endif
}

void
initialize_low_tracepoint (void)
{
#ifdef __s390x__
  init_registers_s390x_linux64 ();
  init_registers_s390x_linux64v1 ();
  init_registers_s390x_linux64v2 ();
  init_registers_s390x_te_linux64 ();
  init_registers_s390x_vx_linux64 ();
  init_registers_s390x_tevx_linux64 ();
  init_registers_s390x_gs_linux64 ();
#else
  init_registers_s390_linux32 ();
  init_registers_s390_linux32v1 ();
  init_registers_s390_linux32v2 ();
  init_registers_s390_linux64 ();
  init_registers_s390_linux64v1 ();
  init_registers_s390_linux64v2 ();
  init_registers_s390_te_linux64 ();
  init_registers_s390_vx_linux64 ();
  init_registers_s390_tevx_linux64 ();
  init_registers_s390_gs_linux64 ();
#endif
}