gdb/nat/x86-linux-tdesc.h

/* Target description related code for GNU/Linux x86 (i386 and x86-64).

   Copyright (C) 2024 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/>.  */

#ifndef NAT_X86_LINUX_TDESC_H
#define NAT_X86_LINUX_TDESC_H

#include "gdbsupport/function-view.h"

struct target_desc;

#ifndef IN_PROCESS_AGENT

/* Return the target description for Linux thread TID.

   When *HAVE_PTRACE_GETREGSET is TRIBOOL_UNKNOWN then the current value of
   xcr0 is read using ptrace calls and stored into *XCR0_STORAGE.  Then
   XCR0_INIT_CB is called with the value of *XCR0_STORAGE and
   *HAVE_PTRACE_GETREGSET is set to TRIBOOL_TRUE.

   If the attempt to read xcr0 using ptrace fails then *XCR0_STORAGE is set
   to zero and *HAVE_PTRACE_GETREGSET is set to TRIBOOL_FALSE.

   The storage pointed to by XCR0_STORAGE must exist until the program
   terminates, this storage is used to cache the xcr0 value.  As such
   XCR0_INIT_CB will only be called once if xcr0 is successfully read using
   ptrace, or not at all if the ptrace call fails.

   This function returns a target description based on the extracted xcr0
   value along with other characteristics of the thread identified by TID.

   This function can return nullptr if we encounter a machine configuration
   for which a target_desc cannot be created.  Ideally this would not be
   the case, we should be able to create a target description for every
   possible machine configuration.  See amd64_linux_read_description and
   i386_linux_read_description for cases when nullptr might be
   returned.

   ERROR_MSG is using in an error() call if we try to create a target
   description for a 64-bit process but this is a 32-bit build of GDB.  */

extern const target_desc *
x86_linux_tdesc_for_tid (int tid, enum tribool *have_ptrace_getregset,
			 gdb::function_view<void (uint64_t)> xcr0_init_cb,
			 const char *error_msg, uint64_t *xcr0_storage);

#endif /* !IN_PROCESS_AGENT */

#ifdef __x86_64__

/* Return the AMD64 target descriptions corresponding to XCR0 and IS_X32.  */

extern const target_desc *amd64_linux_read_description (uint64_t xcr0,
							bool is_x32);

#endif /* __x86_64__ */

/* Return the i386 target description corresponding to XCR0.  */

extern const struct target_desc *i386_linux_read_description (uint64_t xcr0);

/* This function is called from amd64_linux_read_description and
   i386_linux_read_description after a new target description has been
   created, TDESC is the new target description, IS_64BIT will be true
   when called from amd64_linux_read_description, otherwise IS_64BIT will
   be false.  If the *_linux_read_description functions found a cached
   target description then this function will not be called.

   Both GDB and gdbserver have their own implementations of this
   function.  */

extern void x86_linux_post_init_tdesc (target_desc *tdesc, bool is_64bit);

/* Convert an xcr0 value into an integer.  The integer will be passed to
   the in-process-agent where it will then be passed to
   x86_linux_tdesc_idx_to_xcr0 to get back the xcr0 value.  */

extern int x86_linux_xcr0_to_tdesc_idx (uint64_t xcr0);


#ifdef IN_PROCESS_AGENT

/* Convert an index number (as returned from x86_linux_xcr0_to_tdesc_idx)
   into an xcr0 value which can then be used to create a target
   description.  */

extern uint64_t x86_linux_tdesc_idx_to_xcr0 (int idx);

/* Within the in-process-agent we need to pre-initialise all of the target
   descriptions, to do this we need to know how many target descriptions
   there are for each different target type.  These functions return the
   target description count for the relevant target.  */

extern int x86_linux_amd64_ipa_tdesc_count ();
extern int x86_linux_x32_ipa_tdesc_count ();
extern int x86_linux_i386_ipa_tdesc_count ();

#endif /* IN_PROCESS_AGENT */

#endif /* NAT_X86_LINUX_TDESC_H */