sysdeps/generic/libc-mtag.h

   1 /* libc-internal interface for tagged (colored) memory support.
   2    Copyright (C) 2020-2024 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 */