gdb/loongarch-linux-tdep.c - binutils-gdb - Git at Google

 /* Target-dependent code for GNU/Linux on LoongArch processors.

    Copyright (C) 2022-2023 Free Software Foundation, Inc.
    Contributed by Loongson Ltd.

    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 "glibc-tdep.h"
 #include "inferior.h"
 #include "linux-tdep.h"
 #include "loongarch-tdep.h"
 #include "solib-svr4.h"
 #include "target-descriptions.h"
 #include "trad-frame.h"
 #include "tramp-frame.h"

 /* Unpack an elf_gregset_t into GDB's register cache.  */

 static void
 loongarch_supply_gregset (const struct regset *regset,
 			  struct regcache *regcache, int regnum,
 			  const void *gprs, size_t len)
 {
   int regsize = register_size (regcache->arch (), 0);
   const gdb_byte *buf = nullptr;

   if (regnum == -1)
     {
       regcache->raw_supply_zeroed (0);

       for (int i = 1; i < 32; i++)
 	{
 	  buf = (const gdb_byte*) gprs + regsize * i;
 	  regcache->raw_supply (i, (const void *) buf);
 	}

       buf = (const gdb_byte*) gprs + regsize * LOONGARCH_ORIG_A0_REGNUM;
       regcache->raw_supply (LOONGARCH_ORIG_A0_REGNUM, (const void *) buf);

       buf = (const gdb_byte*) gprs + regsize * LOONGARCH_PC_REGNUM;
       regcache->raw_supply (LOONGARCH_PC_REGNUM, (const void *) buf);

       buf = (const gdb_byte*) gprs + regsize * LOONGARCH_BADV_REGNUM;
       regcache->raw_supply (LOONGARCH_BADV_REGNUM, (const void *) buf);
     }
   else if (regnum == 0)
     regcache->raw_supply_zeroed (0);
   else if ((regnum > 0 && regnum < 32)
 	   || regnum == LOONGARCH_ORIG_A0_REGNUM
 	   || regnum == LOONGARCH_PC_REGNUM
 	   || regnum == LOONGARCH_BADV_REGNUM)
     {
       buf = (const gdb_byte*) gprs + regsize * regnum;
       regcache->raw_supply (regnum, (const void *) buf);
     }
 }

 /* Pack the GDB's register cache value into an elf_gregset_t.  */

 static void
 loongarch_fill_gregset (const struct regset *regset,
 			const struct regcache *regcache, int regnum,
 			void *gprs, size_t len)
 {
   int regsize = register_size (regcache->arch (), 0);
   gdb_byte *buf = nullptr;

   if (regnum == -1)
     {
       for (int i = 0; i < 32; i++)
 	{
 	  buf = (gdb_byte *) gprs + regsize * i;
 	  regcache->raw_collect (i, (void *) buf);
 	}

       buf = (gdb_byte *) gprs + regsize * LOONGARCH_ORIG_A0_REGNUM;
       regcache->raw_collect (LOONGARCH_ORIG_A0_REGNUM, (void *) buf);

       buf = (gdb_byte *) gprs + regsize * LOONGARCH_PC_REGNUM;
       regcache->raw_collect (LOONGARCH_PC_REGNUM, (void *) buf);

       buf = (gdb_byte *) gprs + regsize * LOONGARCH_BADV_REGNUM;
       regcache->raw_collect (LOONGARCH_BADV_REGNUM, (void *) buf);
     }
   else if ((regnum >= 0 && regnum < 32)
 	   || regnum == LOONGARCH_ORIG_A0_REGNUM
 	   || regnum == LOONGARCH_PC_REGNUM
 	   || regnum == LOONGARCH_BADV_REGNUM)
     {
       buf = (gdb_byte *) gprs + regsize * regnum;
       regcache->raw_collect (regnum, (void *) buf);
     }
 }

 /* Define the general register regset.  */

 const struct regset loongarch_gregset =
 {
   nullptr,
   loongarch_supply_gregset,
   loongarch_fill_gregset,
 };

 /* Unpack an elf_fpregset_t into GDB's register cache.  */
 static void
 loongarch_supply_fpregset (const struct regset *r,
 			   struct regcache *regcache, int regnum,
 			   const void *fprs, size_t len)
 {
   const gdb_byte *buf = nullptr;
   int fprsize = register_size (regcache->arch (), LOONGARCH_FIRST_FP_REGNUM);
   int fccsize = register_size (regcache->arch (), LOONGARCH_FIRST_FCC_REGNUM);

   if (regnum == -1)
     {
       for (int i = 0; i < LOONGARCH_LINUX_NUM_FPREGSET; i++)
 	{
 	  buf = (const gdb_byte *)fprs + fprsize * i;
 	  regcache->raw_supply (LOONGARCH_FIRST_FP_REGNUM + i, (const void *)buf);
 	}
       for (int i = 0; i < LOONGARCH_LINUX_NUM_FCC; i++)
 	{
 	  buf = (const gdb_byte *)fprs + fprsize * LOONGARCH_LINUX_NUM_FPREGSET +
 	    fccsize * i;
 	  regcache->raw_supply (LOONGARCH_FIRST_FCC_REGNUM + i, (const void *)buf);
 	}
       buf = (const gdb_byte *)fprs + fprsize * LOONGARCH_LINUX_NUM_FPREGSET +
 	fccsize * LOONGARCH_LINUX_NUM_FCC;
       regcache->raw_supply (LOONGARCH_FCSR_REGNUM, (const void *)buf);
     }
   else if (regnum >= LOONGARCH_FIRST_FP_REGNUM && regnum < LOONGARCH_FIRST_FCC_REGNUM)
     {
       buf = (const gdb_byte *)fprs + fprsize * (regnum - LOONGARCH_FIRST_FP_REGNUM);
       regcache->raw_supply (regnum, (const void *)buf);
     }
   else if (regnum >= LOONGARCH_FIRST_FCC_REGNUM && regnum < LOONGARCH_FCSR_REGNUM)
     {
       buf = (const gdb_byte *)fprs + fprsize * LOONGARCH_LINUX_NUM_FPREGSET +
 	fccsize * (regnum - LOONGARCH_FIRST_FCC_REGNUM);
       regcache->raw_supply (regnum, (const void *)buf);
     }
   else if (regnum == LOONGARCH_FCSR_REGNUM)
     {
       buf = (const gdb_byte *)fprs + fprsize * LOONGARCH_LINUX_NUM_FPREGSET +
 	fccsize * LOONGARCH_LINUX_NUM_FCC;
       regcache->raw_supply (regnum, (const void *)buf);
     }
 }

 /* Pack the GDB's register cache value into an elf_fpregset_t.  */
 static void
 loongarch_fill_fpregset (const struct regset *r,
 			 const struct regcache *regcache, int regnum,
 			 void *fprs, size_t len)
 {
   gdb_byte *buf = nullptr;
   int fprsize = register_size (regcache->arch (), LOONGARCH_FIRST_FP_REGNUM);
   int fccsize = register_size (regcache->arch (), LOONGARCH_FIRST_FCC_REGNUM);

   if (regnum == -1)
     {
       for (int i = 0; i < LOONGARCH_LINUX_NUM_FPREGSET; i++)
 	{
 	  buf = (gdb_byte *)fprs + fprsize * i;
 	  regcache->raw_collect (LOONGARCH_FIRST_FP_REGNUM + i, (void *)buf);
 	}
       for (int i = 0; i < LOONGARCH_LINUX_NUM_FCC; i++)
 	{
 	  buf = (gdb_byte *)fprs + fprsize * LOONGARCH_LINUX_NUM_FPREGSET +
 	    fccsize * i;
 	  regcache->raw_collect (LOONGARCH_FIRST_FCC_REGNUM + i, (void *)buf);
 	}
       buf = (gdb_byte *)fprs + fprsize * LOONGARCH_LINUX_NUM_FPREGSET +
 	fccsize * LOONGARCH_LINUX_NUM_FCC;
       regcache->raw_collect (LOONGARCH_FCSR_REGNUM, (void *)buf);
     }
   else if (regnum >= LOONGARCH_FIRST_FP_REGNUM && regnum < LOONGARCH_FIRST_FCC_REGNUM)
     {
       buf = (gdb_byte *)fprs + fprsize * (regnum - LOONGARCH_FIRST_FP_REGNUM);
       regcache->raw_collect (regnum, (void *)buf);
     }
   else if (regnum >= LOONGARCH_FIRST_FCC_REGNUM && regnum < LOONGARCH_FCSR_REGNUM)
     {
       buf = (gdb_byte *)fprs + fprsize * LOONGARCH_LINUX_NUM_FPREGSET +
 	fccsize * (regnum - LOONGARCH_FIRST_FCC_REGNUM);
       regcache->raw_collect (regnum, (void *)buf);
     }
   else if (regnum == LOONGARCH_FCSR_REGNUM)
     {
       buf = (gdb_byte *)fprs + fprsize * LOONGARCH_LINUX_NUM_FPREGSET +
 	fccsize * LOONGARCH_LINUX_NUM_FCC;
       regcache->raw_collect (regnum, (void *)buf);
     }
 }

 /* Define the FP register regset.  */
 const struct regset loongarch_fpregset =
 {
   nullptr,
   loongarch_supply_fpregset,
   loongarch_fill_fpregset,
 };

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

 #define LOONGARCH_RT_SIGFRAME_UCONTEXT_OFFSET	128
 #define LOONGARCH_UCONTEXT_SIGCONTEXT_OFFSET	176

 static void
 loongarch_linux_rt_sigframe_init (const struct tramp_frame *self,
 				  frame_info_ptr this_frame,
 				  struct trad_frame_cache *this_cache,
 				  CORE_ADDR func)
 {
   CORE_ADDR frame_sp = get_frame_sp (this_frame);
   CORE_ADDR sigcontext_base = (frame_sp + LOONGARCH_RT_SIGFRAME_UCONTEXT_OFFSET
 			       + LOONGARCH_UCONTEXT_SIGCONTEXT_OFFSET);

   trad_frame_set_reg_addr (this_cache, LOONGARCH_PC_REGNUM, sigcontext_base);
   for (int i = 0; i < 32; i++)
     trad_frame_set_reg_addr (this_cache, i, sigcontext_base + 8 + i * 8);

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

 /* li.w    a7, __NR_rt_sigreturn  */
 #define LOONGARCH_INST_LIW_A7_RT_SIGRETURN	0x03822c0b
 /* syscall 0  */
 #define LOONGARCH_INST_SYSCALL			0x002b0000

 static const struct tramp_frame loongarch_linux_rt_sigframe =
 {
   SIGTRAMP_FRAME,
   4,
   {
     { LOONGARCH_INST_LIW_A7_RT_SIGRETURN, ULONGEST_MAX },
     { LOONGARCH_INST_SYSCALL, ULONGEST_MAX },
     { TRAMP_SENTINEL_INSN, ULONGEST_MAX }
   },
   loongarch_linux_rt_sigframe_init,
   nullptr
 };

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

 static void
 loongarch_iterate_over_regset_sections (struct gdbarch *gdbarch,
 					iterate_over_regset_sections_cb *cb,
 					void *cb_data,
 					const struct regcache *regcache)
 {
   int gprsize = register_size (gdbarch, 0);
   int fprsize = register_size (gdbarch, LOONGARCH_FIRST_FP_REGNUM);
   int fccsize = register_size (gdbarch, LOONGARCH_FIRST_FCC_REGNUM);
   int fcsrsize = register_size (gdbarch, LOONGARCH_FCSR_REGNUM);
   int fpsize = fprsize * LOONGARCH_LINUX_NUM_FPREGSET +
     fccsize * LOONGARCH_LINUX_NUM_FCC + fcsrsize;

   cb (".reg", LOONGARCH_LINUX_NUM_GREGSET * gprsize,
       LOONGARCH_LINUX_NUM_GREGSET * gprsize, &loongarch_gregset, nullptr, cb_data);
   cb (".reg2", fpsize, fpsize, &loongarch_fpregset, nullptr, cb_data);
 }

 /* The following value is derived from __NR_rt_sigreturn in
    <include/uapi/asm-generic/unistd.h> from the Linux source tree.  */

 #define LOONGARCH_NR_rt_sigreturn	139

 /* When FRAME is at a syscall instruction, return the PC of the next
    instruction to be executed.  */

 static CORE_ADDR
 loongarch_linux_syscall_next_pc (frame_info_ptr frame)
 {
   const CORE_ADDR pc = get_frame_pc (frame);
   ULONGEST a7 = get_frame_register_unsigned (frame, LOONGARCH_A7_REGNUM);

   /* If we are about to make a sigreturn syscall, use the unwinder to
      decode the signal frame.  */
   if (a7 == LOONGARCH_NR_rt_sigreturn)
     return frame_unwind_caller_pc (frame);

   return pc + 4;
 }

 /* Initialize LoongArch Linux ABI info.  */

 static void
 loongarch_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
   loongarch_gdbarch_tdep *tdep = gdbarch_tdep<loongarch_gdbarch_tdep> (gdbarch);

   linux_init_abi (info, gdbarch, 0);

   set_solib_svr4_fetch_link_map_offsets (gdbarch,
 					 info.bfd_arch_info->bits_per_address == 32
 					 ? linux_ilp32_fetch_link_map_offsets
 					 : linux_lp64_fetch_link_map_offsets);

   /* GNU/Linux uses SVR4-style shared libraries.  */
   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);

   /* GNU/Linux uses the dynamic linker included in the GNU C Library.  */
   set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);

   /* Enable TLS support.  */
   set_gdbarch_fetch_tls_load_module_address (gdbarch, svr4_fetch_objfile_link_map);

   /* Prepend tramp frame unwinder for signal.  */
   tramp_frame_prepend_unwinder (gdbarch, &loongarch_linux_rt_sigframe);

   /* Core file support.  */
   set_gdbarch_iterate_over_regset_sections (gdbarch, loongarch_iterate_over_regset_sections);

   tdep->syscall_next_pc = loongarch_linux_syscall_next_pc;
 }

 /* Initialize LoongArch Linux target support.  */

 void _initialize_loongarch_linux_tdep ();
 void
 _initialize_loongarch_linux_tdep ()
 {
   gdbarch_register_osabi (bfd_arch_loongarch, bfd_mach_loongarch32,
 			  GDB_OSABI_LINUX, loongarch_linux_init_abi);
   gdbarch_register_osabi (bfd_arch_loongarch, bfd_mach_loongarch64,
 			  GDB_OSABI_LINUX, loongarch_linux_init_abi);
 }
	/* Target-dependent code for GNU/Linux on LoongArch processors.

	Copyright (C) 2022-2023 Free Software Foundation, Inc.
	Contributed by Loongson Ltd.

	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 "glibc-tdep.h"
	#include "inferior.h"
	#include "linux-tdep.h"
	#include "loongarch-tdep.h"
	#include "solib-svr4.h"
	#include "target-descriptions.h"
	#include "trad-frame.h"
	#include "tramp-frame.h"

	/* Unpack an elf_gregset_t into GDB's register cache. */

	static void
	loongarch_supply_gregset (const struct regset *regset,
	struct regcache *regcache, int regnum,
	const void *gprs, size_t len)
	{
	int regsize = register_size (regcache->arch (), 0);
	const gdb_byte *buf = nullptr;

	if (regnum == -1)
	{
	regcache->raw_supply_zeroed (0);

	for (int i = 1; i < 32; i++)
	{
	buf = (const gdb_byte) gprs + regsize i;
	regcache->raw_supply (i, (const void *) buf);
	}

	buf = (const gdb_byte) gprs + regsize LOONGARCH_ORIG_A0_REGNUM;
	regcache->raw_supply (LOONGARCH_ORIG_A0_REGNUM, (const void *) buf);

	buf = (const gdb_byte) gprs + regsize LOONGARCH_PC_REGNUM;
	regcache->raw_supply (LOONGARCH_PC_REGNUM, (const void *) buf);

	buf = (const gdb_byte) gprs + regsize LOONGARCH_BADV_REGNUM;
	regcache->raw_supply (LOONGARCH_BADV_REGNUM, (const void *) buf);
	}
	else if (regnum == 0)
	regcache->raw_supply_zeroed (0);
	else if ((regnum > 0 && regnum < 32)
	\|\| regnum == LOONGARCH_ORIG_A0_REGNUM
	\|\| regnum == LOONGARCH_PC_REGNUM
	\|\| regnum == LOONGARCH_BADV_REGNUM)
	{
	buf = (const gdb_byte) gprs + regsize regnum;
	regcache->raw_supply (regnum, (const void *) buf);
	}
	}

	/* Pack the GDB's register cache value into an elf_gregset_t. */

	static void
	loongarch_fill_gregset (const struct regset *regset,
	const struct regcache *regcache, int regnum,
	void *gprs, size_t len)
	{
	int regsize = register_size (regcache->arch (), 0);
	gdb_byte *buf = nullptr;

	if (regnum == -1)
	{
	for (int i = 0; i < 32; i++)
	{
	buf = (gdb_byte ) gprs + regsize i;
	regcache->raw_collect (i, (void *) buf);
	}

	buf = (gdb_byte ) gprs + regsize LOONGARCH_ORIG_A0_REGNUM;
	regcache->raw_collect (LOONGARCH_ORIG_A0_REGNUM, (void *) buf);

	buf = (gdb_byte ) gprs + regsize LOONGARCH_PC_REGNUM;
	regcache->raw_collect (LOONGARCH_PC_REGNUM, (void *) buf);

	buf = (gdb_byte ) gprs + regsize LOONGARCH_BADV_REGNUM;
	regcache->raw_collect (LOONGARCH_BADV_REGNUM, (void *) buf);
	}
	else if ((regnum >= 0 && regnum < 32)
	\|\| regnum == LOONGARCH_ORIG_A0_REGNUM
	\|\| regnum == LOONGARCH_PC_REGNUM
	\|\| regnum == LOONGARCH_BADV_REGNUM)
	{
	buf = (gdb_byte ) gprs + regsize regnum;
	regcache->raw_collect (regnum, (void *) buf);
	}
	}

	/* Define the general register regset. */

	const struct regset loongarch_gregset =
	{
	nullptr,
	loongarch_supply_gregset,
	loongarch_fill_gregset,
	};

	/* Unpack an elf_fpregset_t into GDB's register cache. */
	static void
	loongarch_supply_fpregset (const struct regset *r,
	struct regcache *regcache, int regnum,
	const void *fprs, size_t len)
	{
	const gdb_byte *buf = nullptr;
	int fprsize = register_size (regcache->arch (), LOONGARCH_FIRST_FP_REGNUM);
	int fccsize = register_size (regcache->arch (), LOONGARCH_FIRST_FCC_REGNUM);

	if (regnum == -1)
	{
	for (int i = 0; i < LOONGARCH_LINUX_NUM_FPREGSET; i++)
	{
	buf = (const gdb_byte )fprs + fprsize i;
	regcache->raw_supply (LOONGARCH_FIRST_FP_REGNUM + i, (const void *)buf);
	}
	for (int i = 0; i < LOONGARCH_LINUX_NUM_FCC; i++)
	{
	buf = (const gdb_byte )fprs + fprsize LOONGARCH_LINUX_NUM_FPREGSET +
	fccsize * i;
	regcache->raw_supply (LOONGARCH_FIRST_FCC_REGNUM + i, (const void *)buf);
	}
	buf = (const gdb_byte )fprs + fprsize LOONGARCH_LINUX_NUM_FPREGSET +
	fccsize * LOONGARCH_LINUX_NUM_FCC;
	regcache->raw_supply (LOONGARCH_FCSR_REGNUM, (const void *)buf);
	}
	else if (regnum >= LOONGARCH_FIRST_FP_REGNUM && regnum < LOONGARCH_FIRST_FCC_REGNUM)
	{
	buf = (const gdb_byte )fprs + fprsize (regnum - LOONGARCH_FIRST_FP_REGNUM);
	regcache->raw_supply (regnum, (const void *)buf);
	}
	else if (regnum >= LOONGARCH_FIRST_FCC_REGNUM && regnum < LOONGARCH_FCSR_REGNUM)
	{
	buf = (const gdb_byte )fprs + fprsize LOONGARCH_LINUX_NUM_FPREGSET +
	fccsize * (regnum - LOONGARCH_FIRST_FCC_REGNUM);
	regcache->raw_supply (regnum, (const void *)buf);
	}
	else if (regnum == LOONGARCH_FCSR_REGNUM)
	{
	buf = (const gdb_byte )fprs + fprsize LOONGARCH_LINUX_NUM_FPREGSET +
	fccsize * LOONGARCH_LINUX_NUM_FCC;
	regcache->raw_supply (regnum, (const void *)buf);
	}
	}

	/* Pack the GDB's register cache value into an elf_fpregset_t. */
	static void
	loongarch_fill_fpregset (const struct regset *r,
	const struct regcache *regcache, int regnum,
	void *fprs, size_t len)
	{
	gdb_byte *buf = nullptr;
	int fprsize = register_size (regcache->arch (), LOONGARCH_FIRST_FP_REGNUM);
	int fccsize = register_size (regcache->arch (), LOONGARCH_FIRST_FCC_REGNUM);

	if (regnum == -1)
	{
	for (int i = 0; i < LOONGARCH_LINUX_NUM_FPREGSET; i++)
	{
	buf = (gdb_byte )fprs + fprsize i;
	regcache->raw_collect (LOONGARCH_FIRST_FP_REGNUM + i, (void *)buf);
	}
	for (int i = 0; i < LOONGARCH_LINUX_NUM_FCC; i++)
	{
	buf = (gdb_byte )fprs + fprsize LOONGARCH_LINUX_NUM_FPREGSET +
	fccsize * i;
	regcache->raw_collect (LOONGARCH_FIRST_FCC_REGNUM + i, (void *)buf);
	}
	buf = (gdb_byte )fprs + fprsize LOONGARCH_LINUX_NUM_FPREGSET +
	fccsize * LOONGARCH_LINUX_NUM_FCC;
	regcache->raw_collect (LOONGARCH_FCSR_REGNUM, (void *)buf);
	}
	else if (regnum >= LOONGARCH_FIRST_FP_REGNUM && regnum < LOONGARCH_FIRST_FCC_REGNUM)
	{
	buf = (gdb_byte )fprs + fprsize (regnum - LOONGARCH_FIRST_FP_REGNUM);
	regcache->raw_collect (regnum, (void *)buf);
	}
	else if (regnum >= LOONGARCH_FIRST_FCC_REGNUM && regnum < LOONGARCH_FCSR_REGNUM)
	{
	buf = (gdb_byte )fprs + fprsize LOONGARCH_LINUX_NUM_FPREGSET +
	fccsize * (regnum - LOONGARCH_FIRST_FCC_REGNUM);
	regcache->raw_collect (regnum, (void *)buf);
	}
	else if (regnum == LOONGARCH_FCSR_REGNUM)
	{
	buf = (gdb_byte )fprs + fprsize LOONGARCH_LINUX_NUM_FPREGSET +
	fccsize * LOONGARCH_LINUX_NUM_FCC;
	regcache->raw_collect (regnum, (void *)buf);
	}
	}

	/* Define the FP register regset. */
	const struct regset loongarch_fpregset =
	{
	nullptr,
	loongarch_supply_fpregset,
	loongarch_fill_fpregset,
	};

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

	#define LOONGARCH_RT_SIGFRAME_UCONTEXT_OFFSET 128
	#define LOONGARCH_UCONTEXT_SIGCONTEXT_OFFSET 176

	static void
	loongarch_linux_rt_sigframe_init (const struct tramp_frame *self,
	frame_info_ptr this_frame,
	struct trad_frame_cache *this_cache,
	CORE_ADDR func)
	{
	CORE_ADDR frame_sp = get_frame_sp (this_frame);
	CORE_ADDR sigcontext_base = (frame_sp + LOONGARCH_RT_SIGFRAME_UCONTEXT_OFFSET
	+ LOONGARCH_UCONTEXT_SIGCONTEXT_OFFSET);

	trad_frame_set_reg_addr (this_cache, LOONGARCH_PC_REGNUM, sigcontext_base);
	for (int i = 0; i < 32; i++)
	trad_frame_set_reg_addr (this_cache, i, sigcontext_base + 8 + i * 8);

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

	/* li.w a7, __NR_rt_sigreturn */
	#define LOONGARCH_INST_LIW_A7_RT_SIGRETURN 0x03822c0b
	/* syscall 0 */
	#define LOONGARCH_INST_SYSCALL 0x002b0000

	static const struct tramp_frame loongarch_linux_rt_sigframe =
	{
	SIGTRAMP_FRAME,
	4,
	{
	{ LOONGARCH_INST_LIW_A7_RT_SIGRETURN, ULONGEST_MAX },
	{ LOONGARCH_INST_SYSCALL, ULONGEST_MAX },
	{ TRAMP_SENTINEL_INSN, ULONGEST_MAX }
	},
	loongarch_linux_rt_sigframe_init,
	nullptr
	};

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

	static void
	loongarch_iterate_over_regset_sections (struct gdbarch *gdbarch,
	iterate_over_regset_sections_cb *cb,
	void *cb_data,
	const struct regcache *regcache)
	{
	int gprsize = register_size (gdbarch, 0);
	int fprsize = register_size (gdbarch, LOONGARCH_FIRST_FP_REGNUM);
	int fccsize = register_size (gdbarch, LOONGARCH_FIRST_FCC_REGNUM);
	int fcsrsize = register_size (gdbarch, LOONGARCH_FCSR_REGNUM);
	int fpsize = fprsize * LOONGARCH_LINUX_NUM_FPREGSET +
	fccsize * LOONGARCH_LINUX_NUM_FCC + fcsrsize;

	cb (".reg", LOONGARCH_LINUX_NUM_GREGSET * gprsize,
	LOONGARCH_LINUX_NUM_GREGSET * gprsize, &loongarch_gregset, nullptr, cb_data);
	cb (".reg2", fpsize, fpsize, &loongarch_fpregset, nullptr, cb_data);
	}

	/* The following value is derived from __NR_rt_sigreturn in
	<include/uapi/asm-generic/unistd.h> from the Linux source tree. */

	#define LOONGARCH_NR_rt_sigreturn 139

	/* When FRAME is at a syscall instruction, return the PC of the next
	instruction to be executed. */

	static CORE_ADDR
	loongarch_linux_syscall_next_pc (frame_info_ptr frame)
	{
	const CORE_ADDR pc = get_frame_pc (frame);
	ULONGEST a7 = get_frame_register_unsigned (frame, LOONGARCH_A7_REGNUM);

	/* If we are about to make a sigreturn syscall, use the unwinder to
	decode the signal frame. */
	if (a7 == LOONGARCH_NR_rt_sigreturn)
	return frame_unwind_caller_pc (frame);

	return pc + 4;
	}

	/* Initialize LoongArch Linux ABI info. */

	static void
	loongarch_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
	{
	loongarch_gdbarch_tdep *tdep = gdbarch_tdep<loongarch_gdbarch_tdep> (gdbarch);

	linux_init_abi (info, gdbarch, 0);

	set_solib_svr4_fetch_link_map_offsets (gdbarch,
	info.bfd_arch_info->bits_per_address == 32
	? linux_ilp32_fetch_link_map_offsets
	: linux_lp64_fetch_link_map_offsets);

	/* GNU/Linux uses SVR4-style shared libraries. */
	set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);

	/* GNU/Linux uses the dynamic linker included in the GNU C Library. */
	set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);

	/* Enable TLS support. */
	set_gdbarch_fetch_tls_load_module_address (gdbarch, svr4_fetch_objfile_link_map);

	/* Prepend tramp frame unwinder for signal. */
	tramp_frame_prepend_unwinder (gdbarch, &loongarch_linux_rt_sigframe);

	/* Core file support. */
	set_gdbarch_iterate_over_regset_sections (gdbarch, loongarch_iterate_over_regset_sections);

	tdep->syscall_next_pc = loongarch_linux_syscall_next_pc;
	}

	/* Initialize LoongArch Linux target support. */

	void _initialize_loongarch_linux_tdep ();
	void
	_initialize_loongarch_linux_tdep ()
	{
	gdbarch_register_osabi (bfd_arch_loongarch, bfd_mach_loongarch32,
	GDB_OSABI_LINUX, loongarch_linux_init_abi);
	gdbarch_register_osabi (bfd_arch_loongarch, bfd_mach_loongarch64,
	GDB_OSABI_LINUX, loongarch_linux_init_abi);
	}