/*      $NetBSD: cdefs_elf.h,v 1.59 2024/05/29 02:06:46 riastradh Exp $ */

/*
 * Copyright (c) 1995, 1996 Carnegie-Mellon University.
 * All rights reserved.
 *
 * Author: Chris G. Demetriou
 *
 * Permission to use, copy, modify and distribute this software and
 * its documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 */

#ifndef _SYS_CDEFS_ELF_H_
#define _SYS_CDEFS_ELF_H_

#ifdef __LEADING_UNDERSCORE
#define _C_LABEL(x)             __CONCAT(_,x)
#define _C_LABEL_STRING(x)      "_"x
#else
#define _C_LABEL(x)             x
#define _C_LABEL_STRING(x)      x
#endif

#if __STDC__
#define ___RENAME(x)    __asm(___STRING(_C_LABEL(x)))
#else
#ifdef __LEADING_UNDERSCORE
#define ___RENAME(x)    ____RENAME(_/**/x)
#define ____RENAME(x)   __asm(___STRING(x))
#else
#define ___RENAME(x)    __asm(___STRING(x))
#endif
#endif

#define __indr_reference(sym,alias)     /* nada, since we do weak refs */

#if __STDC__
#define __strong_alias(alias,sym)                                       \
    __asm(".global " _C_LABEL_STRING(#alias) "\n"                       \
            _C_LABEL_STRING(#alias) " = " _C_LABEL_STRING(#sym));

#define __weak_alias(alias,sym)                                         \
    __asm(".weak " _C_LABEL_STRING(#alias) "\n"                         \
            _C_LABEL_STRING(#alias) " = " _C_LABEL_STRING(#sym));

/* Do not use __weak_extern, use __weak_reference instead */
#define __weak_extern(sym)                                              \
    __asm(".weak " _C_LABEL_STRING(#sym));

#if __GNUC_PREREQ__(4, 0)
#define __weak  __attribute__((__weak__))
#else
#define __weak
#endif

#if __GNUC_PREREQ__(4, 0)
#define __weak_reference(sym)   __attribute__((__weakref__(#sym)))
#else
#define __weak_reference(sym)   ; __asm(".weak " _C_LABEL_STRING(#sym))
#endif

#if __GNUC_PREREQ__(4, 2)
#define __weakref_visible       static
#else
#define __weakref_visible       extern
#endif

#define __warn_references(sym,msg)                                      \
    __asm(".pushsection .gnu.warning." #sym "\n"                        \
          ".ascii \"" msg "\"\n"                                        \
          ".popsection");

#else /* !__STDC__ */

#ifdef __LEADING_UNDERSCORE
#define __weak_alias(alias,sym) ___weak_alias(_/**/alias,_/**/sym)
#define ___weak_alias(alias,sym)                                        \
    __asm(".weak alias\nalias = sym");
#else
#define __weak_alias(alias,sym)                                         \
    __asm(".weak alias\nalias = sym");
#endif
#ifdef __LEADING_UNDERSCORE
#define __weak_extern(sym) ___weak_extern(_/**/sym)
#define ___weak_extern(sym)                                             \
    __asm(".weak sym");
#else
#define __weak_extern(sym)                                              \
    __asm(".weak sym");
#endif
#define __warn_references(sym,msg)                                      \
    __asm(".pushsection .gnu.warning.sym\n"                             \
          ".ascii \"" msg "\"\n"                                        \
          ".popsection");

#endif /* !__STDC__ */

#if __arm__
#define __ifunc(name, resolver) \
        __asm(".globl   " _C_LABEL_STRING(#name) "\n" \
              ".type    " _C_LABEL_STRING(#name) ", %gnu_indirect_function\n" \
               _C_LABEL_STRING(#name) " = " _C_LABEL_STRING(#resolver))
#define __hidden_ifunc(name, resolver) \
        __asm(".globl   " _C_LABEL_STRING(#name) "\n" \
              ".hidden  " _C_LABEL_STRING(#name) "\n" \
              ".type    " _C_LABEL_STRING(#name) ", %gnu_indirect_function\n" \
               _C_LABEL_STRING(#name) " = " _C_LABEL_STRING(#resolver))
#else
#define __ifunc(name, resolver) \
        __asm(".globl   " _C_LABEL_STRING(#name) "\n" \
              ".type    " _C_LABEL_STRING(#name) ", @gnu_indirect_function\n" \
              _C_LABEL_STRING(#name) " = " _C_LABEL_STRING(#resolver))
#define __hidden_ifunc(name, resolver) \
        __asm(".globl   " _C_LABEL_STRING(#name) "\n" \
              ".hidden  " _C_LABEL_STRING(#name) "\n" \
              ".type    " _C_LABEL_STRING(#name) ", @gnu_indirect_function\n" \
              _C_LABEL_STRING(#name) " = " _C_LABEL_STRING(#resolver))
#endif

#ifdef __arm__
#if __STDC__
#  define       __SECTIONSTRING(_sec, _str)                             \
        __asm(".pushsection " #_sec ",\"MS\",%progbits,1\n"             \
              ".asciz \"" _str "\"\n"                                   \
              ".popsection")
#else
#  define       __SECTIONSTRING(_sec, _str)                             \
        __asm(".pushsection " _sec ",\"MS\",%progbits,1\n"              \
              ".asciz \"" _str "\"\n"                                   \
              ".popsection")
#  endif
#else
#  if __STDC__
#  define       __SECTIONSTRING(_sec, _str)                                     \
        __asm(".pushsection " #_sec ",\"MS\",@progbits,1\n"             \
              ".asciz \"" _str "\"\n"                                   \
              ".popsection")
#  else
#  define       __SECTIONSTRING(_sec, _str)                                     \
        __asm(".pushsection " _sec ",\"MS\",@progbits,1\n"              \
              ".asciz \"" _str "\"\n"                                   \
              ".popsection")
#  endif
#endif

#define __IDSTRING(_n,_s)               __SECTIONSTRING(.ident,_s)

#ifdef _NETBSD_REVISIONID
#define __RCSID(_s)                                                           \
        __IDSTRING(rcsid,_s);                                                 \
        __IDSTRING(revisionid,                                                \
            "$" "NetBSD: " __FILE__ " " _NETBSD_REVISIONID " $")
#else
#define __RCSID(_s)     __IDSTRING(rcsid,_s)
#endif
#define __SCCSID(_s)
#define __SCCSID2(_s)
#define __COPYRIGHT(_s)                 __SECTIONSTRING(.copyright,_s)

#define __KERNEL_RCSID(_n, _s)          __RCSID(_s)
#define __KERNEL_SCCSID(_n, _s)
#define __KERNEL_COPYRIGHT(_n, _s)      __COPYRIGHT(_s)

#ifndef __lint__
#define __link_set_make_entry(set, sym)                                 \
        static void const * const __link_set_##set##_sym_##sym          \
            __section("link_set_" #set) __used = (const void *)&sym
#define __link_set_make_entry2(set, sym, n)                             \
        static void const * const __link_set_##set##_sym_##sym##_##n    \
            __section("link_set_" #set) __used = (const void *)&sym[n]
#else
#define __link_set_make_entry(set, sym)                                 \
        extern void const * const __link_set_##set##_sym_##sym
#define __link_set_make_entry2(set, sym, n)                             \
        extern void const * const __link_set_##set##_sym_##sym##_##n
#endif /* __lint__ */

#define __link_set_add_text(set, sym)   __link_set_make_entry(set, sym)
#define __link_set_add_rodata(set, sym) __link_set_make_entry(set, sym)
#define __link_set_add_data(set, sym)   __link_set_make_entry(set, sym)
#define __link_set_add_bss(set, sym)    __link_set_make_entry(set, sym)
#define __link_set_add_text2(set, sym, n)   __link_set_make_entry2(set, sym, n)
#define __link_set_add_rodata2(set, sym, n) __link_set_make_entry2(set, sym, n)
#define __link_set_add_data2(set, sym, n)   __link_set_make_entry2(set, sym, n)
#define __link_set_add_bss2(set, sym, n)    __link_set_make_entry2(set, sym, n)

#define __link_set_start(set)   (__start_link_set_##set)
#define __link_set_end(set)     (__stop_link_set_##set)

#define __link_set_decl(set, ptype)                                     \
        extern ptype * const __link_set_start(set)[] __dso_hidden;      \
        __asm__(".hidden " __STRING(__stop_link_set_##set)); \
        extern ptype * const __link_set_end(set)[] __weak __dso_hidden

#define __link_set_count(set)                                           \
        (__link_set_end(set) - __link_set_start(set))


#ifdef _KERNEL

/*
 * On multiprocessor systems we can gain an improvement in performance
 * by being mindful of which cachelines data is placed in.
 *
 * __read_mostly:
 *
 *      It makes sense to ensure that rarely modified data is not
 *      placed in the same cacheline as frequently modified data.
 *      To mitigate the phenomenon known as "false-sharing" we
 *      can annotate rarely modified variables with __read_mostly.
 *      All such variables are placed into the .data.read_mostly
 *      section in the kernel ELF.
 *
 *      Prime candidates for __read_mostly annotation are variables
 *      which are hardly ever modified and which are used in code
 *      hot-paths, e.g. pmap_initialized.
 *
 * __cacheline_aligned:
 *
 *      Some data structures (mainly locks) benefit from being aligned
 *      on a cacheline boundary, and having a cacheline to themselves.
 *      This way, the modification of other data items cannot adversely
 *      affect the lock and vice versa.
 *
 *      Any variables annotated with __cacheline_aligned will be
 *      placed into the .data.cacheline_aligned ELF section.
 */
#define __read_mostly                                           \
    __attribute__((__section__(".data.read_mostly")))

#define __cacheline_aligned                                     \
    __attribute__((__aligned__(COHERENCY_UNIT),                 \
                 __section__(".data.cacheline_aligned")))

#endif /* _KERNEL */

#endif /* !_SYS_CDEFS_ELF_H_ */