1  /* libc-internal interface for tagged (colored) memory support.
       2     Copyright (C) 2020-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <http://www.gnu.org/licenses/>.  */
      18  
      19  #ifndef _GENERIC_LIBC_MTAG_H
      20  #define _GENERIC_LIBC_MTAG_H 1
      21  
      22  /* Generic bindings for systems that do not support memory tagging.  */
      23  
      24  /* Used to ensure additional alignment when objects need to have distinct
      25     tags.  */
      26  #define __MTAG_GRANULE_SIZE 1
      27  
      28  /* Non-zero if memory obtained via morecore (sbrk) is not tagged.  */
      29  #define __MTAG_SBRK_UNTAGGED 0
      30  
      31  /* Extra flags to pass to mmap() to request a tagged region of memory.  */
      32  #define __MTAG_MMAP_FLAGS 0
      33  
      34  /* Memory tagging target hooks are only called when memory tagging is
      35     enabled at runtime.  The generic definitions here must not be used.  */
      36  void __libc_mtag_link_error (void);
      37  
      38  /* Set the tags for a region of memory, which must have size and alignment
      39     that are multiples of __MTAG_GRANULE_SIZE.  Size cannot be zero.  */
      40  static inline void *
      41  __libc_mtag_tag_region (void *p, size_t n)
      42  {
      43    __libc_mtag_link_error ();
      44    return p;
      45  }
      46  
      47  /* Optimized equivalent to __libc_mtag_tag_region followed by memset to 0.  */
      48  static inline void *
      49  __libc_mtag_tag_zero_region (void *p, size_t n)
      50  {
      51    __libc_mtag_link_error ();
      52    return memset (p, 0, n);
      53  }
      54  
      55  /* Convert address P to a pointer that is tagged correctly for that
      56     location.  */
      57  static inline void *
      58  __libc_mtag_address_get_tag (void *p)
      59  {
      60    __libc_mtag_link_error ();
      61    return p;
      62  }
      63  
      64  /* Assign a new (random) tag to a pointer P (does not adjust the tag on
      65     the memory addressed).  */
      66  static inline void *
      67  __libc_mtag_new_tag (void *p)
      68  {
      69    __libc_mtag_link_error ();
      70    return p;
      71  }
      72  
      73  #endif /* _GENERIC_LIBC_MTAG_H */