[PATCH v3 2/2] malloc: aarch64: Add ifuncs for malloc functions

Introduce ifuncs and resolvers for functions pertinent to the
malloc interface on the AArch64 target: malloc, calloc, free,
realloc, memalign, valloc, pvalloc, posix_memalign, aligned_alloc,
free_sized, free_aligned_sized, malloc_usable_size.

A target can define the USE_MULTIARCH_MALLOC macro. In this case
it must provide alternative aliases for the malloc functions that
point to the ifuncs.

This implementation respects the --disable-multi-arch configure
flag. If multi-arch support is disabled, the generic aliases
are used on aarch64.

This patch contains aarch64-specific resolvers. At this point they
return core implementations but in the future they can be changed
to support for features, e.g. to handle memory tagging.
---
 malloc/malloc-internal.h                  |  1 +
 malloc/malloc.c                           | 11 ++-
 sysdeps/aarch64/multiarch/Makefile        |  6 ++
 sysdeps/aarch64/multiarch/malloc-ifuncs.c | 82 +++++++++++++++++++++++
 sysdeps/aarch64/multiarch/malloc-ifuncs.h | 25 +++++++
 sysdeps/generic/malloc-ifuncs.h           | 36 ++++++++++
 6 files changed, 159 insertions(+), 2 deletions(-)
 create mode 100644 sysdeps/aarch64/multiarch/malloc-ifuncs.c
 create mode 100644 sysdeps/aarch64/multiarch/malloc-ifuncs.h
 create mode 100644 sysdeps/generic/malloc-ifuncs.h

diff --git a/malloc/malloc-internal.h b/malloc/malloc-internal.h
index 4b36a76cf8..29bc3734c6 100644
--- a/malloc/malloc-internal.h
+++ b/malloc/malloc-internal.h
@@ -25,6 +25,7 @@
 #include <hugepages.h>
 #include <calloc-clear-memory.h>
 #include <malloc-api.h>
+#include <malloc-ifuncs.h>
 
 /* Called in the parent process before a fork.  */
 void __malloc_fork_lock_parent (void) attribute_hidden;
diff --git a/malloc/malloc.c b/malloc/malloc.c
index 4866c59e65..5fc35a14f4 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -5168,6 +5168,9 @@ __malloc_info (int options, FILE *fp)
 }
 
 #if IS_IN (libc)
+
+/* See sysdeps/generic/malloc-ifuncs.h for details.  */
+# if !USE_MULTIARCH_MALLOC
 strong_alias (__libc_malloc, malloc)
 strong_alias (__libc_realloc, realloc)
 strong_alias (__libc_free, free)
@@ -5180,6 +5183,7 @@ weak_alias (__malloc_usable_size, malloc_usable_size)
 weak_alias (__aligned_alloc, aligned_alloc)
 weak_alias (__free_sized, free_sized)
 weak_alias (__free_aligned_sized, free_aligned_sized)
+#endif /* !USE_MULTIARCH_MALLOC */
 
 weak_alias (__malloc_info, malloc_info)
 weak_alias (__libc_mallinfo, mallinfo)
@@ -5187,11 +5191,14 @@ weak_alias (__libc_mallinfo2, mallinfo2)
 weak_alias (__libc_mallopt, mallopt)
 weak_alias (__malloc_stats, malloc_stats)
 weak_alias (__malloc_trim, malloc_trim)
+
 #endif /* IS_IN (libc) */
 
-#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_26)
+#if !USE_MULTIARCH_MALLOC
+# if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_26)
 compat_symbol (libc, __libc_free, cfree, GLIBC_2_0);
-#endif
+# endif
+#endif /* !USE_MULTIARCH_MALLOC */
 
 /* ------------------------------------------------------------
    History:
diff --git a/sysdeps/aarch64/multiarch/Makefile b/sysdeps/aarch64/multiarch/Makefile
index 6294a70c25..a8a03a0491 100644
--- a/sysdeps/aarch64/multiarch/Makefile
+++ b/sysdeps/aarch64/multiarch/Makefile
@@ -20,3 +20,9 @@ sysdep_routines += \
   strlen_generic \
   # sysdep_routines
 endif # ifeq ($(subdir),string)
+
+ifeq ($(subdir),malloc)
+sysdep_routines += \
+  malloc-ifuncs \
+  # sysdep_routines
+endif # ifeq ($(subdir),malloc)
diff --git a/sysdeps/aarch64/multiarch/malloc-ifuncs.c b/sysdeps/aarch64/multiarch/malloc-ifuncs.c
new file mode 100644
index 0000000000..4b5db036ff
--- /dev/null
+++ b/sysdeps/aarch64/multiarch/malloc-ifuncs.c
@@ -0,0 +1,82 @@
+/* Code for ifunc resolvers for malloc: aarch64 version.
+   Copyright (C) 2026 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/>.  */
+
+#include "malloc-ifuncs.h"
+
+#if USE_MULTIARCH_MALLOC
+# if IS_IN (libc)
+
+#include <init-arch.h>
+#include <malloc-api.h>
+#include <shlib-compat.h>
+
+libc_ifunc_hidden (__libc_malloc, __libc_malloc_redirect,
+		   __libc_malloc)
+strong_alias (__libc_malloc_redirect, malloc)
+
+libc_ifunc_hidden (__libc_calloc, __libc_calloc_redirect,
+		   __libc_calloc)
+weak_alias (__libc_calloc_redirect, calloc)
+
+libc_ifunc_hidden (__libc_memalign, __libc_memalign_redirect,
+		   __libc_memalign)
+weak_alias (__libc_memalign_redirect, memalign)
+
+libc_ifunc_hidden (__libc_valloc, __libc_valloc_redirect,
+		   __libc_valloc)
+weak_alias (__libc_valloc_redirect, valloc)
+
+libc_ifunc_hidden (__libc_pvalloc, __libc_pvalloc_redirect,
+		   __libc_pvalloc)
+weak_alias (__libc_pvalloc_redirect, pvalloc)
+
+libc_ifunc_hidden (__libc_realloc, __libc_realloc_redirect,
+		   __libc_realloc)
+strong_alias (__libc_realloc_redirect, realloc)
+
+libc_ifunc_hidden (__libc_free, __libc_free_redirect,
+		   __libc_free)
+strong_alias (__libc_free_redirect, free)
+
+libc_ifunc_hidden (__malloc_usable_size, __malloc_usable_size_redirect,
+		   __malloc_usable_size)
+weak_alias (__malloc_usable_size_redirect, malloc_usable_size)
+
+libc_ifunc_hidden (__posix_memalign, __posix_memalign_redirect,
+		   __posix_memalign)
+weak_alias (__posix_memalign_redirect, posix_memalign)
+
+libc_ifunc_hidden (__aligned_alloc, __aligned_alloc_redirect,
+		   __aligned_alloc)
+weak_alias (__aligned_alloc_redirect, aligned_alloc)
+
+libc_ifunc_hidden (__free_sized, __free_sized_redirect,
+		   __free_sized)
+weak_alias (__free_sized_redirect, free_sized)
+
+libc_ifunc_hidden (__free_aligned_sized, __free_aligned_sized_redirect,
+		   __free_aligned_sized)
+weak_alias (__free_aligned_sized_redirect, free_aligned_sized)
+
+# endif /* IS_IN (libc) */
+
+# if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_26)
+compat_symbol (libc, __libc_free_redirect, cfree, GLIBC_2_0);
+# endif
+
+#endif /* #if USE_MULTIARCH_MALLOC */
diff --git a/sysdeps/aarch64/multiarch/malloc-ifuncs.h b/sysdeps/aarch64/multiarch/malloc-ifuncs.h
new file mode 100644
index 0000000000..abd5d3ef19
--- /dev/null
+++ b/sysdeps/aarch64/multiarch/malloc-ifuncs.h
@@ -0,0 +1,25 @@
+/* Definitions for ifunc resolvers for malloc: aarch64 version.
+   Copyright (C) 2026 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 _AARCH64_MALLOC_IFUNCS_H
+#define _AARCH64_MALLOC_IFUNCS_H
+
+/* AArch64 target provides ifuncs for malloc functions.  */
+#define USE_MULTIARCH_MALLOC 1
+
+#endif /* _AARCH64_MALLOC_IFUNCS_H */
diff --git a/sysdeps/generic/malloc-ifuncs.h b/sysdeps/generic/malloc-ifuncs.h
new file mode 100644
index 0000000000..8fe88af95e
--- /dev/null
+++ b/sysdeps/generic/malloc-ifuncs.h
@@ -0,0 +1,36 @@
+/* Definitions for ifunc resolvers for malloc: generic version.
+   Copyright (C) 2026 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 _GENERIC_MALLOC_IFUNCS_H
+#define _GENERIC_MALLOC_IFUNCS_H
+
+/* Targets that support GNU ifuncs should define this macro
+   if they provide ifuncs for malloc functions.
+
+   When USE_MULTIARCH_MALLOC is defined as 1, the following
+   functions should be implemented via ifuncs:
+
+     malloc, calloc, free, realloc
+     memalign, valloc, pvalloc
+     posix_memalign
+     malloc_usable_size
+     aligned_alloc, free_sized, free_aligned_sized
+*/
+#define USE_MULTIARCH_MALLOC 0
+
+#endif /* _GENERIC_MALLOC_IFUNCS_H */
-- 
2.47.3