glibc/sysdeps/x86/sysdep.h

/* Assembler macros for x86.
   Copyright (C) 2017-2023 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#ifndef _X86_SYSDEP_H
#define _X86_SYSDEP_H 1

#include <sysdeps/generic/sysdep.h>

/* __CET__ is defined by GCC with Control-Flow Protection values:

enum cf_protection_level
{
  CF_NONE = 0,
  CF_BRANCH = 1 << 0,
  CF_RETURN = 1 << 1,
  CF_FULL = CF_BRANCH | CF_RETURN,
  CF_SET = 1 << 2
};
*/

/* Set if CF_BRANCH (IBT) is enabled.  */
#define X86_FEATURE_1_IBT	(1U << 0)
/* Set if CF_RETURN (SHSTK) is enabled.  */
#define X86_FEATURE_1_SHSTK	(1U << 1)

#ifdef __CET__
# define CET_ENABLED	1
# define IBT_ENABLED	(__CET__ & X86_FEATURE_1_IBT)
# define SHSTK_ENABLED	(__CET__ & X86_FEATURE_1_SHSTK)
#else
# define CET_ENABLED	0
# define IBT_ENABLED	0
# define SHSTK_ENABLED	0
#endif

/* Offset for fxsave/xsave area used by _dl_runtime_resolve.  Also need
   space to preserve RCX, RDX, RSI, RDI, R8, R9 and RAX.  It must be
   aligned to 16 bytes for fxsave and 64 bytes for xsave.  */
#define STATE_SAVE_OFFSET (8 * 7 + 8)

/* Save SSE, AVX, AVX512, mask and bound registers.  */
#define STATE_SAVE_MASK \
  ((1 << 1) | (1 << 2) | (1 << 3) | (1 << 5) | (1 << 6) | (1 << 7))

/* Constants for bits in __x86_string_control:  */

/* Avoid short distance REP MOVSB.  */
#define X86_STRING_CONTROL_AVOID_SHORT_DISTANCE_REP_MOVSB	(1 << 0)

#ifdef	__ASSEMBLER__

/* Syntactic details of assembler.  */

#ifdef _CET_ENDBR
# define _CET_NOTRACK notrack
#else
# define _CET_ENDBR
# define _CET_NOTRACK
#endif

/* ELF uses byte-counts for .align, most others use log2 of count of bytes.  */
#define ALIGNARG(log2) 1<<log2
#define ASM_SIZE_DIRECTIVE(name) .size name,.-name;

/* Define an entry point visible from C.  */
#define	ENTRY_P2ALIGN(name, alignment)					      \
  .globl C_SYMBOL_NAME(name);						      \
  .type C_SYMBOL_NAME(name),@function;					      \
  .align ALIGNARG(alignment);						      \
  C_LABEL(name)								      \
  cfi_startproc;							      \
  _CET_ENDBR;								      \
  CALL_MCOUNT

/* Common entry 16 byte aligns.  */
#define ENTRY(name) ENTRY_P2ALIGN (name, 4)

#undef	END
#define END(name)							      \
  cfi_endproc;								      \
  ASM_SIZE_DIRECTIVE(name)

#define ENTRY_CHK(name) ENTRY (name)
#define END_CHK(name) END (name)

/* Since C identifiers are not normally prefixed with an underscore
   on this system, the asm identifier `syscall_error' intrudes on the
   C name space.  Make sure we use an innocuous name.  */
#define	syscall_error	__syscall_error
#define mcount		_mcount

#undef	PSEUDO_END
#define	PSEUDO_END(name)						      \
  END (name)

/* Local label name for asm code. */
#ifndef L
/* ELF-like local names start with `.L'.  */
# define LOCAL_LABEL(name) .L##name
# define L(name)	LOCAL_LABEL(name)
#endif

#define atom_text_section .section ".text.atom", "ax"

#endif	/* __ASSEMBLER__ */

#endif	/* _X86_SYSDEP_H */