gdbserver/linux-aarch32-low.cc - binutils-gdb - Git at Google

 /* Copyright (C) 1995-2023 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 "arch/arm.h"
 #include "arch/arm-linux.h"
 #include "linux-low.h"
 #include "linux-aarch32-low.h"

 #include <sys/ptrace.h>
 /* Don't include elf.h if linux/elf.h got included by gdb_proc_service.h.
    On Bionic elf.h and linux/elf.h have conflicting definitions.  */
 #ifndef ELFMAG0
 #include <elf.h>
 #endif

 /* Correct in either endianness.  */
 #define arm_abi_breakpoint 0xef9f0001UL

 /* For new EABI binaries.  We recognize it regardless of which ABI
    is used for gdbserver, so single threaded debugging should work
    OK, but for multi-threaded debugging we only insert the current
    ABI's breakpoint instruction.  For now at least.  */
 #define arm_eabi_breakpoint 0xe7f001f0UL

 #if (defined __ARM_EABI__ || defined __aarch64__)
 static const unsigned long arm_breakpoint = arm_eabi_breakpoint;
 #else
 static const unsigned long arm_breakpoint = arm_abi_breakpoint;
 #endif

 #define arm_breakpoint_len 4
 static const unsigned short thumb_breakpoint = 0xde01;
 #define thumb_breakpoint_len 2
 static const unsigned short thumb2_breakpoint[] = { 0xf7f0, 0xa000 };
 #define thumb2_breakpoint_len 4

 /* Some older versions of GNU/Linux and Android do not define
    the following macros.  */
 #ifndef NT_ARM_VFP
 #define NT_ARM_VFP 0x400
 #endif

 /* Collect GP registers from REGCACHE to buffer BUF.  */

 void
 arm_fill_gregset (struct regcache *regcache, void *buf)
 {
   int i;
   uint32_t *regs = (uint32_t *) buf;
   uint32_t cpsr = regs[ARM_CPSR_GREGNUM];

   for (i = ARM_A1_REGNUM; i <= ARM_PC_REGNUM; i++)
     collect_register (regcache, i, &regs[i]);

   collect_register (regcache, ARM_PS_REGNUM, &regs[ARM_CPSR_GREGNUM]);
   /* Keep reserved bits bit 20 to bit 23.  */
   regs[ARM_CPSR_GREGNUM] = ((regs[ARM_CPSR_GREGNUM] & 0xff0fffff)
 			    | (cpsr & 0x00f00000));
 }

 /* Supply GP registers contents, stored in BUF, to REGCACHE.  */

 void
 arm_store_gregset (struct regcache *regcache, const void *buf)
 {
   int i;
   char zerobuf[8];
   const uint32_t *regs = (const uint32_t *) buf;
   uint32_t cpsr = regs[ARM_CPSR_GREGNUM];

   memset (zerobuf, 0, 8);
   for (i = ARM_A1_REGNUM; i <= ARM_PC_REGNUM; i++)
     supply_register (regcache, i, &regs[i]);

   for (; i < ARM_PS_REGNUM; i++)
     supply_register (regcache, i, zerobuf);

   /* Clear reserved bits bit 20 to bit 23.  */
   cpsr &= 0xff0fffff;
   supply_register (regcache, ARM_PS_REGNUM, &cpsr);
 }

 /* Collect NUM number of VFP registers from REGCACHE to buffer BUF.  */

 void
 arm_fill_vfpregset_num (struct regcache *regcache, void *buf, int num)
 {
   int i, base;

   gdb_assert (num == 16 || num == 32);

   base = find_regno (regcache->tdesc, "d0");
   for (i = 0; i < num; i++)
     collect_register (regcache, base + i, (char *) buf + i * 8);

   collect_register_by_name (regcache, "fpscr", (char *) buf + 32 * 8);
 }

 /* Supply NUM number of VFP registers contents, stored in BUF, to
    REGCACHE.  */

 void
 arm_store_vfpregset_num (struct regcache *regcache, const void *buf, int num)
 {
   int i, base;

   gdb_assert (num == 16 || num == 32);

   base = find_regno (regcache->tdesc, "d0");
   for (i = 0; i < num; i++)
     supply_register (regcache, base + i, (char *) buf + i * 8);

   supply_register_by_name (regcache, "fpscr", (char *) buf + 32 * 8);
 }

 static void
 arm_fill_vfpregset (struct regcache *regcache, void *buf)
 {
   arm_fill_vfpregset_num (regcache, buf, 32);
 }

 static void
 arm_store_vfpregset (struct regcache *regcache, const void *buf)
 {
   arm_store_vfpregset_num (regcache, buf, 32);
 }

 /* Register sets with using PTRACE_GETREGSET.  */

 static struct regset_info aarch32_regsets[] = {
   { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS,
     ARM_CORE_REGS_SIZE + ARM_INT_REGISTER_SIZE, GENERAL_REGS,
     arm_fill_gregset, arm_store_gregset },
   { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_ARM_VFP, ARM_VFP3_REGS_SIZE,
     EXTENDED_REGS,
     arm_fill_vfpregset, arm_store_vfpregset },
   NULL_REGSET
 };

 static struct regsets_info aarch32_regsets_info =
   {
     aarch32_regsets, /* regsets */
     0, /* num_regsets */
     NULL, /* disabled_regsets */
   };

 struct regs_info regs_info_aarch32 =
   {
     NULL, /* regset_bitmap */
     NULL, /* usrregs */
     &aarch32_regsets_info
   };

 /* Returns 1 if the current instruction set is thumb, 0 otherwise.  */

 int
 arm_is_thumb_mode (void)
 {
   struct regcache *regcache = get_thread_regcache (current_thread, 1);
   unsigned long cpsr;

   collect_register_by_name (regcache, "cpsr", &cpsr);

   if (cpsr & 0x20)
     return 1;
   else
     return 0;
 }

 /* Returns 1 if there is a software breakpoint at location.  */

 int
 arm_breakpoint_at (CORE_ADDR where)
 {
   if (arm_is_thumb_mode ())
     {
       /* Thumb mode.  */
       unsigned short insn;

       the_target->read_memory (where, (unsigned char *) &insn, 2);
       if (insn == thumb_breakpoint)
 	return 1;

       if (insn == thumb2_breakpoint[0])
 	{
 	  the_target->read_memory (where + 2, (unsigned char *) &insn, 2);
 	  if (insn == thumb2_breakpoint[1])
 	    return 1;
 	}
     }
   else
     {
       /* ARM mode.  */
       unsigned long insn;

       the_target->read_memory (where, (unsigned char *) &insn, 4);
       if (insn == arm_abi_breakpoint)
 	return 1;

       if (insn == arm_eabi_breakpoint)
 	return 1;
     }

   return 0;
 }

 /* Implementation of linux_target_ops method "breakpoint_kind_from_pc".

    Determine the type and size of breakpoint to insert at PCPTR.  Uses the
    program counter value to determine whether a 16-bit or 32-bit breakpoint
    should be used.  It returns the breakpoint's kind, and adjusts the program
    counter (if necessary) to point to the actual memory location where the
    breakpoint should be inserted.  */

 int
 arm_breakpoint_kind_from_pc (CORE_ADDR *pcptr)
 {
   if (IS_THUMB_ADDR (*pcptr))
     {
       gdb_byte buf[2];

       *pcptr = UNMAKE_THUMB_ADDR (*pcptr);

       /* Check whether we are replacing a thumb2 32-bit instruction.  */
       if (target_read_memory (*pcptr, buf, 2) == 0)
 	{
 	  unsigned short inst1 = 0;

 	  target_read_memory (*pcptr, (gdb_byte *) &inst1, 2);
 	  if (thumb_insn_size (inst1) == 4)
 	    return ARM_BP_KIND_THUMB2;
 	}
       return ARM_BP_KIND_THUMB;
     }
   else
     return ARM_BP_KIND_ARM;
 }

 /*  Implementation of the linux_target_ops method "sw_breakpoint_from_kind".  */

 const gdb_byte *
 arm_sw_breakpoint_from_kind (int kind , int *size)
 {
   *size = arm_breakpoint_len;
   /* Define an ARM-mode breakpoint; we only set breakpoints in the C
      library, which is most likely to be ARM.  If the kernel supports
      clone events, we will never insert a breakpoint, so even a Thumb
      C library will work; so will mixing EABI/non-EABI gdbserver and
      application.  */
   switch (kind)
     {
       case ARM_BP_KIND_THUMB:
 	*size = thumb_breakpoint_len;
 	return (gdb_byte *) &thumb_breakpoint;
       case ARM_BP_KIND_THUMB2:
 	*size = thumb2_breakpoint_len;
 	return (gdb_byte *) &thumb2_breakpoint;
       case ARM_BP_KIND_ARM:
 	*size = arm_breakpoint_len;
 	return (const gdb_byte *) &arm_breakpoint;
       default:
        return NULL;
     }
   return NULL;
 }

 /* Implementation of the linux_target_ops method
    "breakpoint_kind_from_current_state".  */

 int
 arm_breakpoint_kind_from_current_state (CORE_ADDR *pcptr)
 {
   if (arm_is_thumb_mode ())
     {
       *pcptr = MAKE_THUMB_ADDR (*pcptr);
       return arm_breakpoint_kind_from_pc (pcptr);
     }
   else
     {
       return arm_breakpoint_kind_from_pc (pcptr);
     }
 }

 void
 initialize_low_arch_aarch32 (void)
 {
   initialize_regsets_info (&aarch32_regsets_info);
 }
	/* Copyright (C) 1995-2023 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 "arch/arm.h"
	#include "arch/arm-linux.h"
	#include "linux-low.h"
	#include "linux-aarch32-low.h"

	#include <sys/ptrace.h>
	/* Don't include elf.h if linux/elf.h got included by gdb_proc_service.h.
	On Bionic elf.h and linux/elf.h have conflicting definitions. */
	#ifndef ELFMAG0
	#include <elf.h>
	#endif

	/* Correct in either endianness. */
	#define arm_abi_breakpoint 0xef9f0001UL

	/* For new EABI binaries. We recognize it regardless of which ABI
	is used for gdbserver, so single threaded debugging should work
	OK, but for multi-threaded debugging we only insert the current
	ABI's breakpoint instruction. For now at least. */
	#define arm_eabi_breakpoint 0xe7f001f0UL

	#if (defined __ARM_EABI__ \|\| defined __aarch64__)
	static const unsigned long arm_breakpoint = arm_eabi_breakpoint;
	#else
	static const unsigned long arm_breakpoint = arm_abi_breakpoint;
	#endif

	#define arm_breakpoint_len 4
	static const unsigned short thumb_breakpoint = 0xde01;
	#define thumb_breakpoint_len 2
	static const unsigned short thumb2_breakpoint[] = { 0xf7f0, 0xa000 };
	#define thumb2_breakpoint_len 4

	/* Some older versions of GNU/Linux and Android do not define
	the following macros. */
	#ifndef NT_ARM_VFP
	#define NT_ARM_VFP 0x400
	#endif

	/* Collect GP registers from REGCACHE to buffer BUF. */

	void
	arm_fill_gregset (struct regcache regcache, void buf)
	{
	int i;
	uint32_t regs = (uint32_t ) buf;
	uint32_t cpsr = regs[ARM_CPSR_GREGNUM];

	for (i = ARM_A1_REGNUM; i <= ARM_PC_REGNUM; i++)
	collect_register (regcache, i, &regs[i]);

	collect_register (regcache, ARM_PS_REGNUM, &regs[ARM_CPSR_GREGNUM]);
	/* Keep reserved bits bit 20 to bit 23. */
	regs[ARM_CPSR_GREGNUM] = ((regs[ARM_CPSR_GREGNUM] & 0xff0fffff)
	\| (cpsr & 0x00f00000));
	}

	/* Supply GP registers contents, stored in BUF, to REGCACHE. */

	void
	arm_store_gregset (struct regcache regcache, const void buf)
	{
	int i;
	char zerobuf[8];
	const uint32_t regs = (const uint32_t ) buf;
	uint32_t cpsr = regs[ARM_CPSR_GREGNUM];

	memset (zerobuf, 0, 8);
	for (i = ARM_A1_REGNUM; i <= ARM_PC_REGNUM; i++)
	supply_register (regcache, i, &regs[i]);

	for (; i < ARM_PS_REGNUM; i++)
	supply_register (regcache, i, zerobuf);

	/* Clear reserved bits bit 20 to bit 23. */
	cpsr &= 0xff0fffff;
	supply_register (regcache, ARM_PS_REGNUM, &cpsr);
	}

	/* Collect NUM number of VFP registers from REGCACHE to buffer BUF. */

	void
	arm_fill_vfpregset_num (struct regcache regcache, void buf, int num)
	{
	int i, base;

	gdb_assert (num == 16 \|\| num == 32);

	base = find_regno (regcache->tdesc, "d0");
	for (i = 0; i < num; i++)
	collect_register (regcache, base + i, (char ) buf + i 8);

	collect_register_by_name (regcache, "fpscr", (char ) buf + 32 8);
	}

	/* Supply NUM number of VFP registers contents, stored in BUF, to
	REGCACHE. */

	void
	arm_store_vfpregset_num (struct regcache regcache, const void buf, int num)
	{
	int i, base;

	gdb_assert (num == 16 \|\| num == 32);

	base = find_regno (regcache->tdesc, "d0");
	for (i = 0; i < num; i++)
	supply_register (regcache, base + i, (char ) buf + i 8);

	supply_register_by_name (regcache, "fpscr", (char ) buf + 32 8);
	}

	static void
	arm_fill_vfpregset (struct regcache regcache, void buf)
	{
	arm_fill_vfpregset_num (regcache, buf, 32);
	}

	static void
	arm_store_vfpregset (struct regcache regcache, const void buf)
	{
	arm_store_vfpregset_num (regcache, buf, 32);
	}

	/* Register sets with using PTRACE_GETREGSET. */

	static struct regset_info aarch32_regsets[] = {
	{ PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS,
	ARM_CORE_REGS_SIZE + ARM_INT_REGISTER_SIZE, GENERAL_REGS,
	arm_fill_gregset, arm_store_gregset },
	{ PTRACE_GETREGSET, PTRACE_SETREGSET, NT_ARM_VFP, ARM_VFP3_REGS_SIZE,
	EXTENDED_REGS,
	arm_fill_vfpregset, arm_store_vfpregset },
	NULL_REGSET
	};

	static struct regsets_info aarch32_regsets_info =
	{
	aarch32_regsets, /* regsets */
	0, /* num_regsets */
	NULL, /* disabled_regsets */
	};

	struct regs_info regs_info_aarch32 =
	{
	NULL, /* regset_bitmap */
	NULL, /* usrregs */
	&aarch32_regsets_info
	};

	/* Returns 1 if the current instruction set is thumb, 0 otherwise. */

	int
	arm_is_thumb_mode (void)
	{
	struct regcache *regcache = get_thread_regcache (current_thread, 1);
	unsigned long cpsr;

	collect_register_by_name (regcache, "cpsr", &cpsr);

	if (cpsr & 0x20)
	return 1;
	else
	return 0;
	}

	/* Returns 1 if there is a software breakpoint at location. */

	int
	arm_breakpoint_at (CORE_ADDR where)
	{
	if (arm_is_thumb_mode ())
	{
	/* Thumb mode. */
	unsigned short insn;

	the_target->read_memory (where, (unsigned char *) &insn, 2);
	if (insn == thumb_breakpoint)
	return 1;

	if (insn == thumb2_breakpoint[0])
	{
	the_target->read_memory (where + 2, (unsigned char *) &insn, 2);
	if (insn == thumb2_breakpoint[1])
	return 1;
	}
	}
	else
	{
	/* ARM mode. */
	unsigned long insn;

	the_target->read_memory (where, (unsigned char *) &insn, 4);
	if (insn == arm_abi_breakpoint)
	return 1;

	if (insn == arm_eabi_breakpoint)
	return 1;
	}

	return 0;
	}

	/* Implementation of linux_target_ops method "breakpoint_kind_from_pc".

	Determine the type and size of breakpoint to insert at PCPTR. Uses the
	program counter value to determine whether a 16-bit or 32-bit breakpoint
	should be used. It returns the breakpoint's kind, and adjusts the program
	counter (if necessary) to point to the actual memory location where the
	breakpoint should be inserted. */

	int
	arm_breakpoint_kind_from_pc (CORE_ADDR *pcptr)
	{
	if (IS_THUMB_ADDR (*pcptr))
	{
	gdb_byte buf[2];

	pcptr = UNMAKE_THUMB_ADDR (pcptr);

	/* Check whether we are replacing a thumb2 32-bit instruction. */
	if (target_read_memory (*pcptr, buf, 2) == 0)
	{
	unsigned short inst1 = 0;

	target_read_memory (pcptr, (gdb_byte ) &inst1, 2);
	if (thumb_insn_size (inst1) == 4)
	return ARM_BP_KIND_THUMB2;
	}
	return ARM_BP_KIND_THUMB;
	}
	else
	return ARM_BP_KIND_ARM;
	}

	/* Implementation of the linux_target_ops method "sw_breakpoint_from_kind". */

	const gdb_byte *
	arm_sw_breakpoint_from_kind (int kind , int *size)
	{
	*size = arm_breakpoint_len;
	/* Define an ARM-mode breakpoint; we only set breakpoints in the C
	library, which is most likely to be ARM. If the kernel supports
	clone events, we will never insert a breakpoint, so even a Thumb
	C library will work; so will mixing EABI/non-EABI gdbserver and
	application. */
	switch (kind)
	{
	case ARM_BP_KIND_THUMB:
	*size = thumb_breakpoint_len;
	return (gdb_byte *) &thumb_breakpoint;
	case ARM_BP_KIND_THUMB2:
	*size = thumb2_breakpoint_len;
	return (gdb_byte *) &thumb2_breakpoint;
	case ARM_BP_KIND_ARM:
	*size = arm_breakpoint_len;
	return (const gdb_byte *) &arm_breakpoint;
	default:
	return NULL;
	}
	return NULL;
	}

	/* Implementation of the linux_target_ops method
	"breakpoint_kind_from_current_state". */

	int
	arm_breakpoint_kind_from_current_state (CORE_ADDR *pcptr)
	{
	if (arm_is_thumb_mode ())
	{
	pcptr = MAKE_THUMB_ADDR (pcptr);
	return arm_breakpoint_kind_from_pc (pcptr);
	}
	else
	{
	return arm_breakpoint_kind_from_pc (pcptr);
	}
	}

	void
	initialize_low_arch_aarch32 (void)
	{
	initialize_regsets_info (&aarch32_regsets_info);
	}