[deliverable/binutils-gdb.git] / gdb / riscv-linux-nat.c

/* Native-dependent code for GNU/Linux RISC-V.
   Copyright (C) 2018-2019 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 "regcache.h"
#include "gregset.h"
#include "linux-nat.h"
#include "riscv-tdep.h"
#include "inferior.h"
#include "target-descriptions.h"

#include "elf/common.h"

#include <sys/ptrace.h>

/* RISC-V Linux native additions to the default linux support.  */

class riscv_linux_nat_target final : public linux_nat_target
{
public:
  /* Add our register access methods.  */
  void fetch_registers (struct regcache *regcache, int regnum) override;
  void store_registers (struct regcache *regcache, int regnum) override;

  /* Read suitable target description.  */
  const struct target_desc *read_description () override;
};

static riscv_linux_nat_target the_riscv_linux_nat_target;

/* Copy general purpose register REGNUM (or all gp regs if REGNUM == -1)
   from regset GREGS into REGCACHE.  */

static void
supply_gregset_regnum (struct regcache *regcache, const prgregset_t *gregs,
		       int regnum)
{
  int i;
  const elf_greg_t *regp = *gregs;

  if (regnum == -1)
    {
      /* We only support the integer registers and PC here.  */
      for (i = RISCV_ZERO_REGNUM + 1; i < RISCV_PC_REGNUM; i++)
	regcache->raw_supply (i, regp + i);

      /* GDB stores PC in reg 32.  Linux kernel stores it in reg 0.  */
      regcache->raw_supply (32, regp + 0);

      /* Fill the inaccessible zero register with zero.  */
      regcache->raw_supply_zeroed (0);
    }
  else if (regnum == RISCV_ZERO_REGNUM)
    regcache->raw_supply_zeroed (0);
  else if (regnum > RISCV_ZERO_REGNUM && regnum < RISCV_PC_REGNUM)
    regcache->raw_supply (regnum, regp + regnum);
  else if (regnum == RISCV_PC_REGNUM)
    regcache->raw_supply (32, regp + 0);
}

/* Copy all general purpose registers from regset GREGS into REGCACHE.  */

void
supply_gregset (struct regcache *regcache, const prgregset_t *gregs)
{
  supply_gregset_regnum (regcache, gregs, -1);
}

/* Copy floating point register REGNUM (or all fp regs if REGNUM == -1)
   from regset FPREGS into REGCACHE.  */

static void
supply_fpregset_regnum (struct regcache *regcache, const prfpregset_t *fpregs,
			int regnum)
{
  int i;

  if (regnum == -1)
    {
      /* We only support the FP registers and FCSR here.  */
      for (i = RISCV_FIRST_FP_REGNUM; i <= RISCV_LAST_FP_REGNUM; i++)
	regcache->raw_supply (i, &fpregs->__d.__f[i - RISCV_FIRST_FP_REGNUM]);

      regcache->raw_supply (RISCV_CSR_FCSR_REGNUM, &fpregs->__d.__fcsr);
    }
  else if (regnum >= RISCV_FIRST_FP_REGNUM && regnum <= RISCV_LAST_FP_REGNUM)
    regcache->raw_supply (regnum,
			  &fpregs->__d.__f[regnum - RISCV_FIRST_FP_REGNUM]);
  else if (regnum == RISCV_CSR_FCSR_REGNUM)
    regcache->raw_supply (RISCV_CSR_FCSR_REGNUM, &fpregs->__d.__fcsr);
}

/* Copy all floating point registers from regset FPREGS into REGCACHE.  */

void
supply_fpregset (struct regcache *regcache, const prfpregset_t *fpregs)
{
  supply_fpregset_regnum (regcache, fpregs, -1);
}

/* Copy general purpose register REGNUM (or all gp regs if REGNUM == -1)
   from REGCACHE into regset GREGS.  */

void
fill_gregset (const struct regcache *regcache, prgregset_t *gregs, int regnum)
{
  elf_greg_t *regp = *gregs;

  if (regnum == -1)
    {
      /* We only support the integer registers and PC here.  */
      for (int i = RISCV_ZERO_REGNUM + 1; i < RISCV_PC_REGNUM; i++)
	regcache->raw_collect (i, regp + i);

      regcache->raw_collect (32, regp + 0);
    }
  else if (regnum == RISCV_ZERO_REGNUM)
    /* Nothing to do here.  */
    ;
  else if (regnum > RISCV_ZERO_REGNUM && regnum < RISCV_PC_REGNUM)
    regcache->raw_collect (regnum, regp + regnum);
  else if (regnum == RISCV_PC_REGNUM)
    regcache->raw_collect (32, regp + 0);
}

/* Copy floating point register REGNUM (or all fp regs if REGNUM == -1)
   from REGCACHE into regset FPREGS.  */

void
fill_fpregset (const struct regcache *regcache, prfpregset_t *fpregs,
	       int regnum)
{
  if (regnum == -1)
    {
      /* We only support the FP registers and FCSR here.  */
      for (int i = RISCV_FIRST_FP_REGNUM; i <= RISCV_LAST_FP_REGNUM; i++)
	regcache->raw_collect (i, &fpregs->__d.__f[i - RISCV_FIRST_FP_REGNUM]);

      regcache->raw_collect (RISCV_CSR_FCSR_REGNUM, &fpregs->__d.__fcsr);
    }
  else if (regnum >= RISCV_FIRST_FP_REGNUM && regnum <= RISCV_LAST_FP_REGNUM)
    regcache->raw_collect (regnum,
			   &fpregs->__d.__f[regnum - RISCV_FIRST_FP_REGNUM]);
  else if (regnum == RISCV_CSR_FCSR_REGNUM)
    regcache->raw_collect (RISCV_CSR_FCSR_REGNUM, &fpregs->__d.__fcsr);
}

/* Return a target description for the current target.  */

const struct target_desc *
riscv_linux_nat_target::read_description ()
{
  struct riscv_gdbarch_features features;
  struct iovec iov;
  elf_fpregset_t regs;
  int tid;

  /* Figuring out xlen is easy.  */
  features.xlen = sizeof (elf_greg_t);

  tid = inferior_ptid.lwp ();

  iov.iov_base = &regs;
  iov.iov_len = sizeof (regs);

  /* Can we fetch the f-registers?  */
  if (ptrace (PTRACE_GETREGSET, tid, NT_FPREGSET,
	      (PTRACE_TYPE_ARG3) &iov) == -1)
    features.flen = 0;		/* No f-registers.  */
  else
    {
      /* TODO: We need a way to figure out the actual length of the
	 f-registers.  We could have 64-bit x-registers, with 32-bit
	 f-registers.  For now, just assumed xlen and flen match.  */
      features.flen = features.xlen;
    }

  return riscv_create_target_description (features);
}

/* Fetch REGNUM (or all registers if REGNUM == -1) from the target
   into REGCACHE using PTRACE_GETREGSET.  */

void
riscv_linux_nat_target::fetch_registers (struct regcache *regcache, int regnum)
{
  int tid;

  tid = get_ptrace_pid (regcache->ptid());

  if ((regnum >= RISCV_ZERO_REGNUM && regnum <= RISCV_PC_REGNUM)
      || (regnum == -1))
    {
      struct iovec iov;
      elf_gregset_t regs;

      iov.iov_base = &regs;
      iov.iov_len = sizeof (regs);

      if (ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS,
		  (PTRACE_TYPE_ARG3) &iov) == -1)
	perror_with_name (_("Couldn't get registers"));
      else
	supply_gregset_regnum (regcache, &regs, regnum);
    }

  if ((regnum >= RISCV_FIRST_FP_REGNUM
       && regnum <= RISCV_LAST_FP_REGNUM)
      || (regnum == RISCV_CSR_FCSR_REGNUM)
      || (regnum == -1))
    {
      struct iovec iov;
      elf_fpregset_t regs;

      iov.iov_base = &regs;
      iov.iov_len = sizeof (regs);

      if (ptrace (PTRACE_GETREGSET, tid, NT_FPREGSET,
		  (PTRACE_TYPE_ARG3) &iov) == -1)
	perror_with_name (_("Couldn't get registers"));
      else
	supply_fpregset_regnum (regcache, &regs, regnum);
    }

  if ((regnum == RISCV_CSR_MISA_REGNUM)
      || (regnum == -1))
    {
      /* TODO: Need to add a ptrace call for this.  */
      regcache->raw_supply_zeroed (RISCV_CSR_MISA_REGNUM);
    }

  /* Access to other CSRs has potential security issues, don't support them for
     now.  */
}

/* Store REGNUM (or all registers if REGNUM == -1) to the target
   from REGCACHE using PTRACE_SETREGSET.  */

void
riscv_linux_nat_target::store_registers (struct regcache *regcache, int regnum)
{
  int tid;

  tid = get_ptrace_pid (regcache->ptid ());

  if ((regnum >= RISCV_ZERO_REGNUM && regnum <= RISCV_PC_REGNUM)
      || (regnum == -1))
    {
      struct iovec iov;
      elf_gregset_t regs;

      iov.iov_base = &regs;
      iov.iov_len = sizeof (regs);

      if (ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS,
		  (PTRACE_TYPE_ARG3) &iov) == -1)
	perror_with_name (_("Couldn't get registers"));
      else
	{
	  fill_gregset (regcache, &regs, regnum);

	  if (ptrace (PTRACE_SETREGSET, tid, NT_PRSTATUS,
		      (PTRACE_TYPE_ARG3) &iov) == -1)
	    perror_with_name (_("Couldn't set registers"));
	}
    }

  if ((regnum >= RISCV_FIRST_FP_REGNUM
       && regnum <= RISCV_LAST_FP_REGNUM)
      || (regnum == RISCV_CSR_FCSR_REGNUM)
      || (regnum == -1))
    {
      struct iovec iov;
      elf_fpregset_t regs;

      iov.iov_base = &regs;
      iov.iov_len = sizeof (regs);

      if (ptrace (PTRACE_GETREGSET, tid, NT_FPREGSET,
		  (PTRACE_TYPE_ARG3) &iov) == -1)
	perror_with_name (_("Couldn't get registers"));
      else
	{
	  fill_fpregset (regcache, &regs, regnum);

	  if (ptrace (PTRACE_SETREGSET, tid, NT_FPREGSET,
		      (PTRACE_TYPE_ARG3) &iov) == -1)
	    perror_with_name (_("Couldn't set registers"));
	}
    }

  /* Access to CSRs has potential security issues, don't support them for
     now.  */
}

/* Initialize RISC-V Linux native support.  */

void
_initialize_riscv_linux_nat (void)
{
  /* Register the target.  */
  linux_target = &the_riscv_linux_nat_target;
  add_inf_child_target (&the_riscv_linux_nat_target);
}
Commit	Line	Data
3c77f97e	1	/* Native-dependent code for GNU/Linux RISC-V.
42a4f53d	2	Copyright (C) 2018-2019 Free Software Foundation, Inc.
3c77f97e JW	3
	4	This file is part of GDB.
	5
	6	This program is free software; you can redistribute it and/or modify
	7	it under the terms of the GNU General Public License as published by
	8	the Free Software Foundation; either version 3 of the License, or
	9	(at your option) any later version.
	10
	11	This program is distributed in the hope that it will be useful,
	12	but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	GNU General Public License for more details.
	15
	16	You should have received a copy of the GNU General Public License
	17	along with this program. If not, see <http://www.gnu.org/licenses/>. */
	18
	19	#include "defs.h"
	20	#include "regcache.h"
	21	#include "gregset.h"
	22	#include "linux-nat.h"
3c77f97e	23	#include "riscv-tdep.h"
92528b67 AB	24	#include "inferior.h"
92528b67 AB	25	#include "target-descriptions.h"
3c77f97e	26
4d3928d7 JW	27	#include "elf/common.h"
4d3928d7 JW	28
3c77f97e JW	29	#include <sys/ptrace.h>
	30
	31	/* RISC-V Linux native additions to the default linux support. */
	32
	33	class riscv_linux_nat_target final : public linux_nat_target
	34	{
	35	public:
	36	/* Add our register access methods. */
	37	void fetch_registers (struct regcache *regcache, int regnum) override;
	38	void store_registers (struct regcache *regcache, int regnum) override;
92528b67 AB	39
	40	/* Read suitable target description. */
	41	const struct target_desc *read_description () override;
3c77f97e JW	42	};
	43
	44	static riscv_linux_nat_target the_riscv_linux_nat_target;
	45
	46	/* Copy general purpose register REGNUM (or all gp regs if REGNUM == -1)
	47	from regset GREGS into REGCACHE. */
	48
	49	static void
	50	supply_gregset_regnum (struct regcache regcache, const prgregset_t gregs,
	51	int regnum)
	52	{
	53	int i;
	54	const elf_greg_t regp = gregs;
	55
	56	if (regnum == -1)
	57	{
	58	/* We only support the integer registers and PC here. */
	59	for (i = RISCV_ZERO_REGNUM + 1; i < RISCV_PC_REGNUM; i++)
	60	regcache->raw_supply (i, regp + i);
	61
	62	/* GDB stores PC in reg 32. Linux kernel stores it in reg 0. */
	63	regcache->raw_supply (32, regp + 0);
	64
	65	/* Fill the inaccessible zero register with zero. */
	66	regcache->raw_supply_zeroed (0);
	67	}
	68	else if (regnum == RISCV_ZERO_REGNUM)
	69	regcache->raw_supply_zeroed (0);
	70	else if (regnum > RISCV_ZERO_REGNUM && regnum < RISCV_PC_REGNUM)
	71	regcache->raw_supply (regnum, regp + regnum);
	72	else if (regnum == RISCV_PC_REGNUM)
	73	regcache->raw_supply (32, regp + 0);
	74	}
	75
	76	/* Copy all general purpose registers from regset GREGS into REGCACHE. */
	77
	78	void
	79	supply_gregset (struct regcache regcache, const prgregset_t gregs)
	80	{
	81	supply_gregset_regnum (regcache, gregs, -1);
	82	}
	83
	84	/* Copy floating point register REGNUM (or all fp regs if REGNUM == -1)
	85	from regset FPREGS into REGCACHE. */
	86
	87	static void
	88	supply_fpregset_regnum (struct regcache regcache, const prfpregset_t fpregs,
	89	int regnum)
	90	{
	91	int i;
	92
	93	if (regnum == -1)
	94	{
	95	/* We only support the FP registers and FCSR here. */
	96	for (i = RISCV_FIRST_FP_REGNUM; i <= RISCV_LAST_FP_REGNUM; i++)
	97	regcache->raw_supply (i, &fpregs->__d.__f[i - RISCV_FIRST_FP_REGNUM]);
	98
	99	regcache->raw_supply (RISCV_CSR_FCSR_REGNUM, &fpregs->__d.__fcsr);
	100	}
	101	else if (regnum >= RISCV_FIRST_FP_REGNUM && regnum <= RISCV_LAST_FP_REGNUM)
	102	regcache->raw_supply (regnum,
	103	&fpregs->__d.__f[regnum - RISCV_FIRST_FP_REGNUM]);
	104	else if (regnum == RISCV_CSR_FCSR_REGNUM)
	105	regcache->raw_supply (RISCV_CSR_FCSR_REGNUM, &fpregs->__d.__fcsr);
106	}
107
108	/* Copy all floating point registers from regset FPREGS into REGCACHE. */
109
110	void
111	supply_fpregset (struct regcache regcache, const prfpregset_t fpregs)
112	{
113	supply_fpregset_regnum (regcache, fpregs, -1);
114	}
115
116	/* Copy general purpose register REGNUM (or all gp regs if REGNUM == -1)
117	from REGCACHE into regset GREGS. */
118
119	void
120	fill_gregset (const struct regcache regcache, prgregset_t gregs, int regnum)
121	{
122	elf_greg_t regp = gregs;
123
124	if (regnum == -1)
125	{
126	/* We only support the integer registers and PC here. */
127	for (int i = RISCV_ZERO_REGNUM + 1; i < RISCV_PC_REGNUM; i++)
128	regcache->raw_collect (i, regp + i);
129
130	regcache->raw_collect (32, regp + 0);
131	}
132	else if (regnum == RISCV_ZERO_REGNUM)
133	/* Nothing to do here. */
134	;
135	else if (regnum > RISCV_ZERO_REGNUM && regnum < RISCV_PC_REGNUM)
136	regcache->raw_collect (regnum, regp + regnum);
137	else if (regnum == RISCV_PC_REGNUM)
138	regcache->raw_collect (32, regp + 0);
139	}
140
141	/* Copy floating point register REGNUM (or all fp regs if REGNUM == -1)
142	from REGCACHE into regset FPREGS. */
143
144	void
145	fill_fpregset (const struct regcache regcache, prfpregset_t fpregs,
146	int regnum)
147	{
148	if (regnum == -1)
149	{
150	/* We only support the FP registers and FCSR here. */
151	for (int i = RISCV_FIRST_FP_REGNUM; i <= RISCV_LAST_FP_REGNUM; i++)
152	regcache->raw_collect (i, &fpregs->__d.__f[i - RISCV_FIRST_FP_REGNUM]);
153
154	regcache->raw_collect (RISCV_CSR_FCSR_REGNUM, &fpregs->__d.__fcsr);
155	}
156	else if (regnum >= RISCV_FIRST_FP_REGNUM && regnum <= RISCV_LAST_FP_REGNUM)
157	regcache->raw_collect (regnum,
158	&fpregs->__d.__f[regnum - RISCV_FIRST_FP_REGNUM]);
159	else if (regnum == RISCV_CSR_FCSR_REGNUM)
160	regcache->raw_collect (RISCV_CSR_FCSR_REGNUM, &fpregs->__d.__fcsr);
161	}
162
92528b67 AB	163	/* Return a target description for the current target. */
	164
	165	const struct target_desc *
	166	riscv_linux_nat_target::read_description ()
	167	{
	168	struct riscv_gdbarch_features features;
	169	struct iovec iov;
	170	elf_fpregset_t regs;
	171	int tid;
	172
	173	/* Figuring out xlen is easy. */
	174	features.xlen = sizeof (elf_greg_t);
	175
	176	tid = inferior_ptid.lwp ();
	177
	178	iov.iov_base = &regs;
	179	iov.iov_len = sizeof (regs);
	180
	181	/* Can we fetch the f-registers? */
	182	if (ptrace (PTRACE_GETREGSET, tid, NT_FPREGSET,
	183	(PTRACE_TYPE_ARG3) &iov) == -1)
	184	features.flen = 0; /* No f-registers. */
	185	else
	186	{
	187	/* TODO: We need a way to figure out the actual length of the
	188	f-registers. We could have 64-bit x-registers, with 32-bit
	189	f-registers. For now, just assumed xlen and flen match. */
	190	features.flen = features.xlen;
	191	}
	192
	193	return riscv_create_target_description (features);
	194	}
	195
3c77f97e JW	196	/* Fetch REGNUM (or all registers if REGNUM == -1) from the target
	197	into REGCACHE using PTRACE_GETREGSET. */
	198
	199	void
	200	riscv_linux_nat_target::fetch_registers (struct regcache *regcache, int regnum)
	201	{
	202	int tid;
	203
	204	tid = get_ptrace_pid (regcache->ptid());
	205
	206	if ((regnum >= RISCV_ZERO_REGNUM && regnum <= RISCV_PC_REGNUM)
	207	\|\| (regnum == -1))
	208	{
	209	struct iovec iov;
	210	elf_gregset_t regs;
	211
	212	iov.iov_base = &regs;
	213	iov.iov_len = sizeof (regs);
	214
	215	if (ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS,
	216	(PTRACE_TYPE_ARG3) &iov) == -1)
	217	perror_with_name (_("Couldn't get registers"));
	218	else
	219	supply_gregset_regnum (regcache, &regs, regnum);
	220	}
	221
	222	if ((regnum >= RISCV_FIRST_FP_REGNUM
	223	&& regnum <= RISCV_LAST_FP_REGNUM)
	224	\|\| (regnum == RISCV_CSR_FCSR_REGNUM)
	225	\|\| (regnum == -1))
	226	{
	227	struct iovec iov;
	228	elf_fpregset_t regs;
	229
	230	iov.iov_base = &regs;
	231	iov.iov_len = sizeof (regs);
	232
4d3928d7	233	if (ptrace (PTRACE_GETREGSET, tid, NT_FPREGSET,
3c77f97e JW	234	(PTRACE_TYPE_ARG3) &iov) == -1)
	235	perror_with_name (_("Couldn't get registers"));
	236	else
	237	supply_fpregset_regnum (regcache, &regs, regnum);
	238	}
	239
	240	if ((regnum == RISCV_CSR_MISA_REGNUM)
	241	\|\| (regnum == -1))
a3d72268 AB	242	{
	243	/* TODO: Need to add a ptrace call for this. */
	244	regcache->raw_supply_zeroed (RISCV_CSR_MISA_REGNUM);
	245	}
3c77f97e JW	246
	247	/* Access to other CSRs has potential security issues, don't support them for
	248	now. */
	249	}
	250
	251	/* Store REGNUM (or all registers if REGNUM == -1) to the target
	252	from REGCACHE using PTRACE_SETREGSET. */
	253
	254	void
	255	riscv_linux_nat_target::store_registers (struct regcache *regcache, int regnum)
	256	{
	257	int tid;
	258
	259	tid = get_ptrace_pid (regcache->ptid ());
	260
	261	if ((regnum >= RISCV_ZERO_REGNUM && regnum <= RISCV_PC_REGNUM)
	262	\|\| (regnum == -1))
	263	{
	264	struct iovec iov;
	265	elf_gregset_t regs;
	266
	267	iov.iov_base = &regs;
	268	iov.iov_len = sizeof (regs);
	269
	270	if (ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS,
	271	(PTRACE_TYPE_ARG3) &iov) == -1)
	272	perror_with_name (_("Couldn't get registers"));
	273	else
	274	{
	275	fill_gregset (regcache, &regs, regnum);
	276
	277	if (ptrace (PTRACE_SETREGSET, tid, NT_PRSTATUS,
	278	(PTRACE_TYPE_ARG3) &iov) == -1)
	279	perror_with_name (_("Couldn't set registers"));
	280	}
	281	}
	282
	283	if ((regnum >= RISCV_FIRST_FP_REGNUM
	284	&& regnum <= RISCV_LAST_FP_REGNUM)
	285	\|\| (regnum == RISCV_CSR_FCSR_REGNUM)
	286	\|\| (regnum == -1))
	287	{
	288	struct iovec iov;
	289	elf_fpregset_t regs;
	290
	291	iov.iov_base = &regs;
	292	iov.iov_len = sizeof (regs);
	293
4d3928d7	294	if (ptrace (PTRACE_GETREGSET, tid, NT_FPREGSET,
3c77f97e JW	295	(PTRACE_TYPE_ARG3) &iov) == -1)
	296	perror_with_name (_("Couldn't get registers"));
	297	else
	298	{
	299	fill_fpregset (regcache, &regs, regnum);
	300
4d3928d7	301	if (ptrace (PTRACE_SETREGSET, tid, NT_FPREGSET,
3c77f97e JW	302	(PTRACE_TYPE_ARG3) &iov) == -1)
	303	perror_with_name (_("Couldn't set registers"));
	304	}
	305	}
	306
	307	/* Access to CSRs has potential security issues, don't support them for
	308	now. */
	309	}
	310
	311	/* Initialize RISC-V Linux native support. */
	312
	313	void
	314	_initialize_riscv_linux_nat (void)
	315	{
	316	/* Register the target. */
	317	linux_target = &the_riscv_linux_nat_target;
	318	add_inf_child_target (&the_riscv_linux_nat_target);
	319	}