[v4,6/6] aarch64: Add aarch64-specific files for memory tagging support

  This final patch provides the architecture-specific implementation of
the memory-tagging support hooks for aarch64.
---
 sysdeps/aarch64/Makefile                 |  5 +++
 sysdeps/aarch64/__mtag_address_get_tag.S | 32 +++++++++++++
 sysdeps/aarch64/__mtag_memset_tag.S      | 53 ++++++++++++++++++++++
 sysdeps/aarch64/__mtag_new_tag.S         | 37 +++++++++++++++
 sysdeps/aarch64/__mtag_tag_region.S      | 51 +++++++++++++++++++++
 sysdeps/aarch64/libc-mtag.h              | 57 ++++++++++++++++++++++++
 6 files changed, 235 insertions(+)
 create mode 100644 sysdeps/aarch64/__mtag_address_get_tag.S
 create mode 100644 sysdeps/aarch64/__mtag_memset_tag.S
 create mode 100644 sysdeps/aarch64/__mtag_new_tag.S
 create mode 100644 sysdeps/aarch64/__mtag_tag_region.S
 create mode 100644 sysdeps/aarch64/libc-mtag.h
  

The 12/18/2020 19:29, Richard Earnshaw wrote:
> This final patch provides the architecture-specific implementation of
> the memory-tagging support hooks for aarch64.

i see some gnu style issues in libc-mtag.h otherwise it looks ok.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>

> ---
>  sysdeps/aarch64/Makefile                 |  5 +++
>  sysdeps/aarch64/__mtag_address_get_tag.S | 32 +++++++++++++
>  sysdeps/aarch64/__mtag_memset_tag.S      | 53 ++++++++++++++++++++++
>  sysdeps/aarch64/__mtag_new_tag.S         | 37 +++++++++++++++
>  sysdeps/aarch64/__mtag_tag_region.S      | 51 +++++++++++++++++++++
>  sysdeps/aarch64/libc-mtag.h              | 57 ++++++++++++++++++++++++
>  6 files changed, 235 insertions(+)
>  create mode 100644 sysdeps/aarch64/__mtag_address_get_tag.S
>  create mode 100644 sysdeps/aarch64/__mtag_memset_tag.S
>  create mode 100644 sysdeps/aarch64/__mtag_new_tag.S
>  create mode 100644 sysdeps/aarch64/__mtag_tag_region.S
>  create mode 100644 sysdeps/aarch64/libc-mtag.h
> 

> diff --git a/sysdeps/aarch64/Makefile b/sysdeps/aarch64/Makefile
> index d8e06d27b2..d3ab37a40a 100644
> --- a/sysdeps/aarch64/Makefile
> +++ b/sysdeps/aarch64/Makefile
> @@ -40,4 +40,9 @@ endif
>  
>  ifeq ($(subdir),misc)
>  sysdep_headers += sys/ifunc.h
> +sysdep_routines += __mtag_address_get_tag \
> +		   __mtag_memset_tag \
> +		   __mtag_new_tag \
> +		   __mtag_tag_region
> +
>  endif
> diff --git a/sysdeps/aarch64/__mtag_address_get_tag.S b/sysdeps/aarch64/__mtag_address_get_tag.S
> new file mode 100644
> index 0000000000..4ffe884c95
> --- /dev/null
> +++ b/sysdeps/aarch64/__mtag_address_get_tag.S
> @@ -0,0 +1,32 @@
> +/* Copyright (C) 2020 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
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <sysdep.h>
> +
> +#ifdef USE_MTAG
> +#define ptr x0
> +
> +	.arch armv8.5-a
> +	.arch_extension memtag
> +
> +ENTRY (__libc_mtag_address_get_tag)
> +
> +	ldg	ptr, [ptr]
> +	ret
> +END (__libc_mtag_address_get_tag)
> +#endif /* USE_MTAG */
> diff --git a/sysdeps/aarch64/__mtag_memset_tag.S b/sysdeps/aarch64/__mtag_memset_tag.S
> new file mode 100644
> index 0000000000..6f78d91b79
> --- /dev/null
> +++ b/sysdeps/aarch64/__mtag_memset_tag.S
> @@ -0,0 +1,53 @@
> +/* Copyright (C) 2020 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
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <sysdep.h>
> +
> +#ifdef USE_MTAG
> +
> +/* Use the same register names and assignments as memset.  */
> +#include "memset-reg.h"
> +
> +	.arch armv8.5-a
> +	.arch_extension memtag
> +
> +/* NB, only supported on variants with 64-bit pointers.  */
> +
> +/* FIXME: This is a minimal implementation.  We could do much better than
> +   this for large values of COUNT.  */
> +
> +ENTRY(__libc_mtag_memset_with_tag)
> +
> +	and	valw, valw, 255
> +	orr	valw, valw, valw, lsl 8
> +	orr	valw, valw, valw, lsl 16
> +	orr	val, val, val, lsl 32
> +	mov	dst, dstin
> +
> +L(loop):
> +	stgp	val, val, [dst], #16
> +	subs	count, count, 16
> +	bne	L(loop)
> +#if 0
> +	/* This is not currently needed, since for now we are only called
> +	   to tag memory that is taggable.  */
> +	ldg	dstin, [dstin] // Recover the tag created (might be untagged).
> +#endif
> +	ret
> +END (__libc_mtag_memset_with_tag)
> +#endif /* USE_MTAG */
> diff --git a/sysdeps/aarch64/__mtag_new_tag.S b/sysdeps/aarch64/__mtag_new_tag.S
> new file mode 100644
> index 0000000000..663e3a484f
> --- /dev/null
> +++ b/sysdeps/aarch64/__mtag_new_tag.S
> @@ -0,0 +1,37 @@
> +/* Copyright (C) 2020 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
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <sysdep.h>
> +
> +#ifdef USE_MTAG
> +
> +	.arch armv8.5-a
> +	.arch_extension memtag
> +
> +/* NB, only supported on variants with 64-bit pointers.  */
> +
> +#define ptr x0
> +#define xset x1
> +
> +ENTRY(__libc_mtag_new_tag)
> +	// Guarantee that the new tag is not the same as now.
> +	gmi	xset, ptr, xzr
> +	irg	ptr, ptr, xset
> +	ret
> +END (__libc_mtag_new_tag)
> +#endif /* USE_MTAG */
> diff --git a/sysdeps/aarch64/__mtag_tag_region.S b/sysdeps/aarch64/__mtag_tag_region.S
> new file mode 100644
> index 0000000000..7af4f0fa0a
> --- /dev/null
> +++ b/sysdeps/aarch64/__mtag_tag_region.S
> @@ -0,0 +1,51 @@
> +/* Copyright (C) 2020 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
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <sysdep.h>
> +
> +#ifdef USE_MTAG
> +
> +/* Use the same register names and assignments as memset.  */
> +
> +	.arch armv8.5-a
> +	.arch_extension memtag
> +
> +/* NB, only supported on variants with 64-bit pointers.  */
> +
> +/* FIXME: This is a minimal implementation.  We could do better than
> +   this for larger values of COUNT.  */
> +
> +#define dstin x0
> +#define count x1
> +#define dst   x2
> +
> +ENTRY_ALIGN(__libc_mtag_tag_region, 6)
> +
> +	mov	dst, dstin
> +L(loop):
> +	stg	dst, [dst], #16
> +	subs	count, count, 16
> +	bne	L(loop)
> +#if 0
> +	/* This is not currently needed, since for now we are only called
> +	   to tag memory that is taggable.  */
> +	ldg	dstin, [dstin] // Recover the tag created (might be untagged).
> +#endif
> +	ret
> +END (__libc_mtag_tag_region)
> +#endif /* USE_MTAG */
> diff --git a/sysdeps/aarch64/libc-mtag.h b/sysdeps/aarch64/libc-mtag.h
> new file mode 100644
> index 0000000000..0e9b63e95b
> --- /dev/null
> +++ b/sysdeps/aarch64/libc-mtag.h
> @@ -0,0 +1,57 @@
> +/* libc-internal interface for tagged (colored) memory support.
> +   Copyright (C) 2020 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
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#ifndef _AARCH64_LIBC_MTAG_H
> +#define _AARCH64_LIBC_MTAG_H 1
> +
> +#ifndef USE_MTAG
> +/* Generic bindings for systems that do not support memory tagging.  */
> +#include_next "libc-mtag.h"
> +#else
> +
> +/* Used to ensure additional alignment when objects need to have distinct
> +   tags.  */
> +#define __MTAG_GRANULE_SIZE 16
> +
> +/* Non-zero if memory obtained via morecore (sbrk) is not tagged.  */
> +#define __MTAG_SBRK_UNTAGGED 1
> +
> +/* Extra flags to pass to mmap to get tagged pages.  */
> +#define __MTAG_MMAP_FLAGS PROT_MTE
> +
> +/* Set the tags for a region of memory, which must have size and alignment
> +   that are multiples of __MTAG_GRANULE_SIZE.  Size cannot be zero.
> +   void *__libc_mtag_tag_region (const void *, size_t)  */
> +void *__libc_mtag_tag_region (void *, size_t);
> +
> +/* Optimized equivalent to __libc_mtag_tag_region followed by memset.  */
> +void *__libc_mtag_memset_with_tag(void *, int, size_t);
> +
> +/* Convert address P to a pointer that is tagged correctly for that
> +   location.
> +   void *__libc_mtag_address_get_tag (void*)  */
> +void *__libc_mtag_address_get_tag(void *);
> +
> +/* Assign a new (random) tag to a pointer P (does not adjust the tag on
> +   the memory addressed).
> +   void *__libc_mtag_new_tag (void*)  */
> +void *__libc_mtag_new_tag(void *);

missing spaces before (

> +
> +#endif /* USE_MTAG */
> +
> +#endif /* _AARCH64_LIBC_MTAG_H */
  

On 21/12/2020 12:44, Szabolcs Nagy via Libc-alpha wrote:
> The 12/18/2020 19:29, Richard Earnshaw wrote:
>> This final patch provides the architecture-specific implementation of
>> the memory-tagging support hooks for aarch64.
> 
> i see some gnu style issues in libc-mtag.h otherwise it looks ok.
> 
> Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
> 
>> ---
>>  sysdeps/aarch64/Makefile                 |  5 +++
>>  sysdeps/aarch64/__mtag_address_get_tag.S | 32 +++++++++++++
>>  sysdeps/aarch64/__mtag_memset_tag.S      | 53 ++++++++++++++++++++++
>>  sysdeps/aarch64/__mtag_new_tag.S         | 37 +++++++++++++++
>>  sysdeps/aarch64/__mtag_tag_region.S      | 51 +++++++++++++++++++++
>>  sysdeps/aarch64/libc-mtag.h              | 57 ++++++++++++++++++++++++
>>  6 files changed, 235 insertions(+)
>>  create mode 100644 sysdeps/aarch64/__mtag_address_get_tag.S
>>  create mode 100644 sysdeps/aarch64/__mtag_memset_tag.S
>>  create mode 100644 sysdeps/aarch64/__mtag_new_tag.S
>>  create mode 100644 sysdeps/aarch64/__mtag_tag_region.S
>>  create mode 100644 sysdeps/aarch64/libc-mtag.h
>>
> 
>> diff --git a/sysdeps/aarch64/Makefile b/sysdeps/aarch64/Makefile
>> index d8e06d27b2..d3ab37a40a 100644
>> --- a/sysdeps/aarch64/Makefile
>> +++ b/sysdeps/aarch64/Makefile
>> @@ -40,4 +40,9 @@ endif
>>  
>>  ifeq ($(subdir),misc)
>>  sysdep_headers += sys/ifunc.h
>> +sysdep_routines += __mtag_address_get_tag \
>> +		   __mtag_memset_tag \
>> +		   __mtag_new_tag \
>> +		   __mtag_tag_region
>> +
>>  endif
>> diff --git a/sysdeps/aarch64/__mtag_address_get_tag.S b/sysdeps/aarch64/__mtag_address_get_tag.S
>> new file mode 100644
>> index 0000000000..4ffe884c95
>> --- /dev/null
>> +++ b/sysdeps/aarch64/__mtag_address_get_tag.S
>> @@ -0,0 +1,32 @@
>> +/* Copyright (C) 2020 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
>> +   <http://www.gnu.org/licenses/>.  */
>> +
>> +#include <sysdep.h>
>> +
>> +#ifdef USE_MTAG
>> +#define ptr x0
>> +
>> +	.arch armv8.5-a
>> +	.arch_extension memtag
>> +
>> +ENTRY (__libc_mtag_address_get_tag)
>> +
>> +	ldg	ptr, [ptr]
>> +	ret
>> +END (__libc_mtag_address_get_tag)
>> +#endif /* USE_MTAG */
>> diff --git a/sysdeps/aarch64/__mtag_memset_tag.S b/sysdeps/aarch64/__mtag_memset_tag.S
>> new file mode 100644
>> index 0000000000..6f78d91b79
>> --- /dev/null
>> +++ b/sysdeps/aarch64/__mtag_memset_tag.S
>> @@ -0,0 +1,53 @@
>> +/* Copyright (C) 2020 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
>> +   <http://www.gnu.org/licenses/>.  */
>> +
>> +#include <sysdep.h>
>> +
>> +#ifdef USE_MTAG
>> +
>> +/* Use the same register names and assignments as memset.  */
>> +#include "memset-reg.h"
>> +
>> +	.arch armv8.5-a
>> +	.arch_extension memtag
>> +
>> +/* NB, only supported on variants with 64-bit pointers.  */
>> +
>> +/* FIXME: This is a minimal implementation.  We could do much better than
>> +   this for large values of COUNT.  */
>> +
>> +ENTRY(__libc_mtag_memset_with_tag)
>> +
>> +	and	valw, valw, 255
>> +	orr	valw, valw, valw, lsl 8
>> +	orr	valw, valw, valw, lsl 16
>> +	orr	val, val, val, lsl 32
>> +	mov	dst, dstin
>> +
>> +L(loop):
>> +	stgp	val, val, [dst], #16
>> +	subs	count, count, 16
>> +	bne	L(loop)
>> +#if 0
>> +	/* This is not currently needed, since for now we are only called
>> +	   to tag memory that is taggable.  */
>> +	ldg	dstin, [dstin] // Recover the tag created (might be untagged).
>> +#endif
>> +	ret
>> +END (__libc_mtag_memset_with_tag)
>> +#endif /* USE_MTAG */
>> diff --git a/sysdeps/aarch64/__mtag_new_tag.S b/sysdeps/aarch64/__mtag_new_tag.S
>> new file mode 100644
>> index 0000000000..663e3a484f
>> --- /dev/null
>> +++ b/sysdeps/aarch64/__mtag_new_tag.S
>> @@ -0,0 +1,37 @@
>> +/* Copyright (C) 2020 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
>> +   <http://www.gnu.org/licenses/>.  */
>> +
>> +#include <sysdep.h>
>> +
>> +#ifdef USE_MTAG
>> +
>> +	.arch armv8.5-a
>> +	.arch_extension memtag
>> +
>> +/* NB, only supported on variants with 64-bit pointers.  */
>> +
>> +#define ptr x0
>> +#define xset x1
>> +
>> +ENTRY(__libc_mtag_new_tag)
>> +	// Guarantee that the new tag is not the same as now.
>> +	gmi	xset, ptr, xzr
>> +	irg	ptr, ptr, xset
>> +	ret
>> +END (__libc_mtag_new_tag)
>> +#endif /* USE_MTAG */
>> diff --git a/sysdeps/aarch64/__mtag_tag_region.S b/sysdeps/aarch64/__mtag_tag_region.S
>> new file mode 100644
>> index 0000000000..7af4f0fa0a
>> --- /dev/null
>> +++ b/sysdeps/aarch64/__mtag_tag_region.S
>> @@ -0,0 +1,51 @@
>> +/* Copyright (C) 2020 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
>> +   <http://www.gnu.org/licenses/>.  */
>> +
>> +#include <sysdep.h>
>> +
>> +#ifdef USE_MTAG
>> +
>> +/* Use the same register names and assignments as memset.  */
>> +
>> +	.arch armv8.5-a
>> +	.arch_extension memtag
>> +
>> +/* NB, only supported on variants with 64-bit pointers.  */
>> +
>> +/* FIXME: This is a minimal implementation.  We could do better than
>> +   this for larger values of COUNT.  */
>> +
>> +#define dstin x0
>> +#define count x1
>> +#define dst   x2
>> +
>> +ENTRY_ALIGN(__libc_mtag_tag_region, 6)
>> +
>> +	mov	dst, dstin
>> +L(loop):
>> +	stg	dst, [dst], #16
>> +	subs	count, count, 16
>> +	bne	L(loop)
>> +#if 0
>> +	/* This is not currently needed, since for now we are only called
>> +	   to tag memory that is taggable.  */
>> +	ldg	dstin, [dstin] // Recover the tag created (might be untagged).
>> +#endif
>> +	ret
>> +END (__libc_mtag_tag_region)
>> +#endif /* USE_MTAG */
>> diff --git a/sysdeps/aarch64/libc-mtag.h b/sysdeps/aarch64/libc-mtag.h
>> new file mode 100644
>> index 0000000000..0e9b63e95b
>> --- /dev/null
>> +++ b/sysdeps/aarch64/libc-mtag.h
>> @@ -0,0 +1,57 @@
>> +/* libc-internal interface for tagged (colored) memory support.
>> +   Copyright (C) 2020 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
>> +   <http://www.gnu.org/licenses/>.  */
>> +
>> +#ifndef _AARCH64_LIBC_MTAG_H
>> +#define _AARCH64_LIBC_MTAG_H 1
>> +
>> +#ifndef USE_MTAG
>> +/* Generic bindings for systems that do not support memory tagging.  */
>> +#include_next "libc-mtag.h"
>> +#else
>> +
>> +/* Used to ensure additional alignment when objects need to have distinct
>> +   tags.  */
>> +#define __MTAG_GRANULE_SIZE 16
>> +
>> +/* Non-zero if memory obtained via morecore (sbrk) is not tagged.  */
>> +#define __MTAG_SBRK_UNTAGGED 1
>> +
>> +/* Extra flags to pass to mmap to get tagged pages.  */
>> +#define __MTAG_MMAP_FLAGS PROT_MTE
>> +
>> +/* Set the tags for a region of memory, which must have size and alignment
>> +   that are multiples of __MTAG_GRANULE_SIZE.  Size cannot be zero.
>> +   void *__libc_mtag_tag_region (const void *, size_t)  */
>> +void *__libc_mtag_tag_region (void *, size_t);
>> +
>> +/* Optimized equivalent to __libc_mtag_tag_region followed by memset.  */
>> +void *__libc_mtag_memset_with_tag(void *, int, size_t);
>> +
>> +/* Convert address P to a pointer that is tagged correctly for that
>> +   location.
>> +   void *__libc_mtag_address_get_tag (void*)  */
>> +void *__libc_mtag_address_get_tag(void *);
>> +
>> +/* Assign a new (random) tag to a pointer P (does not adjust the tag on
>> +   the memory addressed).
>> +   void *__libc_mtag_new_tag (void*)  */
>> +void *__libc_mtag_new_tag(void *);
> 
> missing spaces before (

Oops, fixed.

> 
>> +
>> +#endif /* USE_MTAG */
>> +
>> +#endif /* _AARCH64_LIBC_MTAG_H */

R.