linux/arch/x86/include/asm/user_64.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_USER_64_H
#define _ASM_X86_USER_64_H

#include <asm/types.h>
#include <asm/page.h>
/* Core file format: The core file is written in such a way that gdb
   can understand it and provide useful information to the user.
   There are quite a number of obstacles to being able to view the
   contents of the floating point registers, and until these are
   solved you will not be able to view the contents of them.
   Actually, you can read in the core file and look at the contents of
   the user struct to find out what the floating point registers
   contain.

   The actual file contents are as follows:
   UPAGE: 1 page consisting of a user struct that tells gdb what is present
   in the file.  Directly after this is a copy of the task_struct, which
   is currently not used by gdb, but it may come in useful at some point.
   All of the registers are stored as part of the upage.  The upage should
   always be only one page.
   DATA: The data area is stored.  We use current->end_text to
   current->brk to pick up all of the user variables, plus any memory
   that may have been malloced.  No attempt is made to determine if a page
   is demand-zero or if a page is totally unused, we just cover the entire
   range.  All of the addresses are rounded in such a way that an integral
   number of pages is written.
   STACK: We need the stack information in order to get a meaningful
   backtrace.  We need to write the data from (esp) to
   current->start_stack, so we round each of these off in order to be able
   to write an integer number of pages.
   The minimum core file size is 3 pages, or 12288 bytes.  */

/*
 * Pentium III FXSR, SSE support
 *	Gareth Hughes <[email protected]>, May 2000
 *
 * Provide support for the GDB 5.0+ PTRACE_{GET|SET}FPXREGS requests for
 * interacting with the FXSR-format floating point environment.  Floating
 * point data can be accessed in the regular format in the usual manner,
 * and both the standard and SIMD floating point data can be accessed via
 * the new ptrace requests.  In either case, changes to the FPU environment
 * will be reflected in the task's state as expected.
 *
 * x86-64 support by Andi Kleen.
 */

/* This matches the 64bit FXSAVE format as defined by AMD. It is the same
   as the 32bit format defined by Intel, except that the selector:offset pairs
   for data and eip are replaced with flat 64bit pointers. */
struct user_i387_struct { … };

/*
 * Segment register layout in coredumps.
 */
struct user_regs_struct { … };

/* When the kernel dumps core, it starts by dumping the user struct -
   this will be used by gdb to figure out where the data and stack segments
   are within the file, and what virtual addresses to use. */

struct user { … };

#endif /* _ASM_X86_USER_64_H */