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arm64 LSE support in userland: introduce elf_aux_info?
> Date: Fri, 12 Jul 2024 18:23:25 +0200
> From: Jeremie Courreges-Anglas <jca@wxcvbn.org>
>
> On Fri, Jul 12, 2024 at 01:18:41PM +0200, Mark Kettenis wrote:
> > > Date: Wed, 10 Jul 2024 18:41:57 +0200
> > > From: Jeremie Courreges-Anglas <jca@wxcvbn.org>
> > >
> > > On Mon, Jul 08, 2024 at 09:17:23AM +0200, Mark Kettenis wrote:
> > > > > Date: Sun, 7 Jul 2024 17:44:39 +0200
> > > > > From: Jeremie Courreges-Anglas <jca@wxcvbn.org>
> > > > >
> > > > > On Sun, Jul 07, 2024 at 03:00:55PM +0200, Mark Kettenis wrote:
> > > > > > > Date: Sat, 6 Jul 2024 14:47:28 +0200
> > > > > > > From: Jeremie Courreges-Anglas <jca@wxcvbn.org>
> > > > > > >
> > > > > > > On Thu, Jul 04, 2024 at 08:14:15AM -0600, Theo de Raadt wrote:
> > > > > > > > In glibc, getauxval(3) is a monster API that keeps growing additional
> > > > > > > > heads and tentacles. Exporting a tiny version of it to userland is
> > > > > > > > worrying.
> > > > > > >
> > > > > > > Agreed about getauxval.
> > > > > >
> > > > > > Not sure what you folks mean with that. Is the problem that there are
> > > > > > too many AT_xxx constants for which we would not want to add support?
> > > > > > That I do agree with.
> > > > >
> > > > > Yep.
> > > > >
> > > > > > So do yout think that adding just the few AT_xxx constants that we
> > > > > > care about would cause too many problems in ports?
> > > > >
> > > > > (One common pattern visible in ports is to #define some AT_xxx
> > > > > constants (with a hardcoded value copied from Linux headers) if
> > > > > they're not already #defined.)
> > > > >
> > > > > I fear that detection of the getauxval() symbol may trigger the use of
> > > > > Linux-specific code paths, possibly with no useful/usable fallback in
> > > > > case of an error. Also, some ports may start to include <linux/*.h>
> > > > > headers along with their use of getauxval(). It would be a shame to
> > > > > implement getauxval() and yet need non-trivial patches in ports.
> > > > >
> > > > > > > > When the real problem here is a tiny little check to use done only
> > > > > > > > internal to only our libc, and therefore why not use an OpenBSD private
> > > > > > > > interface.
> > > > > > >
> > > > > > > Indeed we could use a private API for this specific need. But the
> > > > > > > problem is not just about our libc, ports also want a way to query
> > > > > > > hardware capabilities. We usually have to patch them to use a
> > > > > > > sysctl(2) or just drop the code that detects such capabilities.
> > > > > > > I feel like implementing elf_aux_info(3) should be considered. Has
> > > > > > > someone already tried that? If people don't object, that could be a
> > > > > > > todo entry for c2k24.
> > > > > >
> > > > > > So elf_aux_info(3) is just getauxval(3) with a somewhat different API.
> > > > > > It is a bit better in the sense that it unambiguously tells you if an
> > > > > > AT_xxx value isn't supported.
> > > > > >
> > > > > > Are you less worried about us not implementing all the AT_xxx defines
> > > > > > that FreeBSD has?
> > > > >
> > > > > Yes. Dumb comparison:
> > > > >
> > > > > https://www.man7.org/linux/man-pages/man3/getauxval.3.html 34 defines
> > > > > https://man.freebsd.org/cgi/man.cgi?elf_aux_info(3) 11 defines
> > > > >
> > > > > Compare that to the 8 AUX_xxx values handled in our kern/exec_elf.c...
> > > >
> > > > And perhaps more importantly, FreeBSD doesn't have bad ones like
> > > > AT_SECURE.
> > > >
> > > > > BTW, we currently always export 0 for AUX_flags. The comment in
> > > > > exec_elf.h says "processor flags". Have you considered reusing this
> > > > > for a quick compiler-rt hack?
> > > >
> > > > AUX_flags would be AT_FLAGS, which is related to e_flags in the ELF
> > > > header. Solaris used this to mark binaries that (unconditionally) use
> > > > certain instruction set extensions. I suppose we could use it on
> > > > arm64 but AT_HWCAP and AT_HWCAP2 on Linux and FreeBSD provide more
> > > > flags than we could fit in AT_FLAGS.
> > >
> > > Ack, forget my question. I introduced new AUX_hwcap* requests, that
> > > map to the AT_HWCAP* defines.
> > >
> > > > If we go this route we do want the features to align with what Linux
> > > > and FreeBSD use. I don't think we want to burden porters with
> > > > figuring out what OpenBSD feature bit maps onto what Linux uses.
> > >
> > > For the diff below I just used the bits from FreeBSD. Hopefully they
> > > should be the same as Linux, but I haven't checked yet.
> > >
> > > > > > I suspect that there is a much smaller number of ports that support
> > > > > > elf_aux_info(3).
> > > > >
> > > > > Well, maybe it's a good thing? ;)
> > > > >
> > > > > More seriously, I've started an amd64 bulk build on a system with a
> > > > > dumb elf_aux_info() that always returns ENOENT. I should have numbers
> > > > > in 2 days for ports that may automatically pick it up.
> > >
> > > That bulk build completed with no fallout, but I doubt that
> > > elf_aux_info() is used much on amd64.
> > >
> > > > > There would also be a bunch of other ports where we'd have to add an
> > > > > ugly "|| defined(__OpenBSD__)" chunk to the FreeBSD code path, but at
> > > > > least that's something that could be upstreamed.
> > > > >
> > > > > Feedback from other porters would be welcome.
> > >
> > > The diff below introduces elf_aux_info(3). Manpage and
> > > <machine/elf.h> bits taken from FreeBSD. I have only tested this
> > > (successfully) on amd64. I have no arm64 machine at hand, and the
> > > riscv64 ports machines are currently busy with a bulk build.
> > >
> > > Mark, as discussed, I'm only setting the Atomics/LSE bit on arm64.
> > > If I didn't mess something up, the regress test should show it.
> > >
> > > The main TODO entries:
> > > - arm
> > > - remaining arm64 bits (cpu_sysctl/hwcap refactoring?)
> > > - powerpc
> > >
> > > Thoughts? ok?
> >
> > A few thoughts here.
> >
> > * Reading the auxv stuff during libc init and storing it in local
> > variables is a good thing as it avoids issues from messing around
> > with envp and such.
> >
> > * I have no objection to also supporting AT_PAGESZ.
>
> Rationale was: it's harmless and it gives the regress test something
> to test on architectures with no hwcap support.
>
> > * We should probably properly prune the man page instead of commenting
> > out AT_xxx entries (unless we intend to support them at a later stage).
>
> I looked and decided to just drop them for now. There may be
> candidates but I'd rather have them discussed later if at all.
>
> > * I think we should prune the list of AT_xxx defines. Maybe we should
> > only provide the ones that we actually implement? Or at least we
> > should prune some of the non-standard ones that FreeBSD added. Or
> > are you afraid this may break ports code?
>
> That was my concern, indeed. Looking at the FreeBSD code, they're
> also not supporting all the defines they provide, they even document
> this in BUGS (which I trimmed and renamed to CAVEATS). Code using
> that function should check for ENOENT to know whether a feature is not
> supported.
>
> However, doing a quick audit using https://codesearch.debian.net/ it
> seems only very few of them are used; actually I could find only one,
> used in FreeBSD-specific code. So I trimmed the list, but keeping the
> same AT_* values (they are supposed to match our AUX_* values).
> I guess we could re-add some in case we find actual consumers.
>
> > * There are some tab vs. spaces inconsistencies, especially in the
> > multiple-include protection stuff.
>
> They were present in the original files, I just didn't bother to fix
> them. Done in the updated diff.
>
> > A few more comments below...
>
> Also adressed, thanks, see new diff. Christian and Stuart confirmed
> they liked the idea.
>
> ok?
I think this looks good. We can tweak the arm64 hwcap bits once this
has landed in the tree.
ok kettenis@ unless some show-stopper in your ports build shows up
> diff --git a/lib/libc/Symbols.list b/lib/libc/Symbols.list
> index eb4d78cc947..48c4965a6d9 100644
> --- a/lib/libc/Symbols.list
> +++ b/lib/libc/Symbols.list
> @@ -608,6 +608,7 @@ daemon
> devname
> dirfd
> dirname
> +elf_aux_info
> endfsent
> endgrent
> endnetgrent
> diff --git a/lib/libc/dlfcn/init.c b/lib/libc/dlfcn/init.c
> index 9fc63c97f98..0cf4347631c 100644
> --- a/lib/libc/dlfcn/init.c
> +++ b/lib/libc/dlfcn/init.c
> @@ -49,6 +49,8 @@ char ***_csu_finish(char **_argv, char **_envp, void (*_cleanup)(void));
> /* provide definitions for these */
> int _pagesize = 0;
> struct timekeep *_timekeep;
> +unsigned long _hwcap, _hwcap2;
> +int _hwcap_avail, _hwcap2_avail;
>
> /*
> * In dynamically linked binaries environ and __progname are overridden by
> @@ -96,6 +98,14 @@ _libc_preinit(int argc, char **argv, char **envp, dl_cb_cb *cb)
> ;
> for (aux = (void *)envp; aux->au_id != AUX_null; aux++) {
> switch (aux->au_id) {
> + case AUX_hwcap:
> + _hwcap = aux->au_v;
> + _hwcap_avail = 1;
> + break;
> + case AUX_hwcap2:
> + _hwcap2 = aux->au_v;
> + _hwcap2_avail = 1;
> + break;
> case AUX_pagesz:
> _pagesize = aux->au_v;
> break;
> diff --git a/lib/libc/gen/Makefile.inc b/lib/libc/gen/Makefile.inc
> index cf36ead40e9..1f1c25a9af5 100644
> --- a/lib/libc/gen/Makefile.inc
> +++ b/lib/libc/gen/Makefile.inc
> @@ -6,8 +6,8 @@
> SRCS+= alarm.c assert.c auth_subr.c authenticate.c \
> basename.c clock.c clock_getcpuclockid.c \
> closedir.c confstr.c ctermid.c ctype_.c \
> - daemon.c devname.c dirfd.c dirname.c disklabel.c err.c \
> - errc.c errx.c errlist.c errno.c exec.c \
> + daemon.c devname.c dirfd.c dirname.c disklabel.c elf_aux_info.c \
> + err.c errc.c errx.c errlist.c errno.c exec.c \
> fdatasync.c fnmatch.c fpclassify.c frexp.c \
> fstab.c ftok.c fts.c ftw.c getbsize.c getcap.c getcwd.c \
> getdomainname.c getgrent.c getgrouplist.c gethostname.c \
> @@ -36,7 +36,7 @@ SRCS+= alarm.c assert.c auth_subr.c authenticate.c \
>
> MAN+= __tfork_thread.3 alarm.3 auth_subr.3 authenticate.3 basename.3 clock.3 \
> clock_getcpuclockid.3 confstr.3 \
> - ctermid.3 daemon.3 devname.3 opendir.3 dirname.3 err.3 \
> + ctermid.3 daemon.3 devname.3 opendir.3 dirname.3 elf_aux_info.3 err.3 \
> execv.3 fabs.3 fnmatch.3 fpclassify.3 fpgetmask.3 frexp.3 ftok.3 fts_open.3 \
> ftw.3 getbsize.3 cgetent.3 getcwd.3 getdomainname.3 getdiskbyname.3 \
> getfsent.3 getgrent.3 getgrouplist.3 gethostname.3 getloadavg.3 \
> diff --git a/lib/libc/gen/elf_aux_info.3 b/lib/libc/gen/elf_aux_info.3
> new file mode 100644
> index 00000000000..c2a63c87e74
> --- /dev/null
> +++ b/lib/libc/gen/elf_aux_info.3
> @@ -0,0 +1,74 @@
> +.\" $OpenBSD$
> +.\"
> +.\" Origin: FreeBSD auxv.3
> +.\"
> +.\" Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
> +.\"
> +.\" Redistribution and use in source and binary forms, with or without
> +.\" modification, are permitted provided that the following conditions
> +.\" are met:
> +.\"
> +.\" 1. Redistributions of source code must retain the above copyright
> +.\" notice, this list of conditions and the following disclaimer.
> +.\" 2. Redistributions in binary form must reproduce the above copyright
> +.\" notice, this list of conditions and the following disclaimer in the
> +.\" documentation and/or other materials provided with the distribution.
> +.\"
> +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
> +.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
> +.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
> +.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
> +.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
> +.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
> +.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
> +.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> +.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
> +.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> +.\"
> +.Dd $Mdocdate$
> +.Dt ELF_AUX_INFO 3
> +.Os
> +.Sh NAME
> +.Nm elf_aux_info
> +.Nd extract data from the elf auxiliary vector of the current process
> +.Sh SYNOPSIS
> +.In sys/auxv.h
> +.Ft int
> +.Fn elf_aux_info "int aux" "void *buf" "int buflen"
> +.Sh DESCRIPTION
> +The
> +.Fn elf_aux_info
> +function retrieves the auxiliary info vector requested in
> +.Va aux .
> +The information is stored into the provided buffer if it will fit.
> +The following values can be requested (corresponding buffer sizes are
> +specified in parenthesis):
> +.Bl -tag -width AT_HWCAP2
> +.It AT_HWCAP
> +CPU / hardware feature flags
> +.Dv (sizeof(unsigned long)) .
> +.It AT_HWCAP2
> +CPU / hardware feature flags
> +.Dv (sizeof(unsigned long)) .
> +.It AT_PAGESZ
> +Page size in bytes
> +.Dv (sizeof(int)) .
> +.El
> +.Sh RETURN VALUES
> +Returns zero on success, or an error number on failure.
> +.Sh ERRORS
> +.Bl -tag -width Er
> +.It Bq Er EINVAL
> +An unknown item was requested.
> +.It Bq Er EINVAL
> +The provided buffer was not the right size for the requested item.
> +.It Bq Er ENOENT
> +The requested item is not available.
> +.El
> +.Sh HISTORY
> +The
> +.Fn elf_aux_info
> +function appeared in
> +.Fx 12.0
> +and was first available in
> +.Ox 7.6 .
> diff --git a/lib/libc/gen/elf_aux_info.c b/lib/libc/gen/elf_aux_info.c
> new file mode 100644
> index 00000000000..eef979a89e7
> --- /dev/null
> +++ b/lib/libc/gen/elf_aux_info.c
> @@ -0,0 +1,70 @@
> +/* $OpenBSD$ */
> +
> +/*
> + * Copyright (c) 2024 Jeremie Courreges-Anglas <jca@wxcvbn.org>
> + *
> + * Permission to use, copy, modify, and distribute this software for any
> + * purpose with or without fee is hereby granted, provided that the above
> + * copyright notice and this permission notice appear in all copies.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
> + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
> + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
> + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
> + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
> + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
> + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
> + */
> +
> +#include <sys/types.h>
> +#include <sys/auxv.h>
> +
> +#include <errno.h>
> +
> +extern int _pagesize;
> +extern unsigned long _hwcap, _hwcap2;
> +extern int _hwcap_avail, _hwcap2_avail;
> +
> +int
> +elf_aux_info(int request, void *buf, int buflen)
> +{
> + int ret = 0;
> +
> + if (buflen < 0)
> + return EINVAL;
> +
> + switch (request) {
> + case AT_HWCAP:
> + if (buflen != sizeof(unsigned long))
> + ret = EINVAL;
> + else if (!_hwcap_avail)
> + ret = ENOENT;
> + else
> + *(unsigned long *)buf = _hwcap;
> + break;
> + case AT_HWCAP2:
> + if (buflen != sizeof(unsigned long))
> + ret = EINVAL;
> + else if (!_hwcap2_avail)
> + ret = ENOENT;
> + else
> + *(unsigned long *)buf = _hwcap2;
> + break;
> + case AT_PAGESZ:
> + if (buflen != sizeof(int))
> + ret = EINVAL;
> + else if (!_pagesize)
> + ret = ENOENT;
> + else
> + *(int *)buf = _pagesize;
> + break;
> + default:
> + if (request < 0 || request >= AT_COUNT)
> + ret = EINVAL;
> + else
> + ret = ENOENT;
> + break;
> + }
> +
> + return ret;
> +}
> diff --git a/lib/libc/hidden/sys/auxv.h b/lib/libc/hidden/sys/auxv.h
> new file mode 100644
> index 00000000000..8d25aaaa826
> --- /dev/null
> +++ b/lib/libc/hidden/sys/auxv.h
> @@ -0,0 +1,26 @@
> +/* $OpenBSD$ */
> +
> +/*
> + * Copyright (c) 2024 Jeremie Courreges-Anglas <jca@wxcvbn.org>
> + *
> + * Permission to use, copy, modify, and distribute this software for any
> + * purpose with or without fee is hereby granted, provided that the above
> + * copyright notice and this permission notice appear in all copies.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
> + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
> + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
> + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
> + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
> + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
> + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
> + */
> +
> +#ifndef _LIBC_SYS_AUXV_H_
> +#define _LIBC_SYS_AUXV_H_
> +
> +#include_next <sys/auxv.h>
> +
> +PROTO_DEPRECATED(elf_aux_info);
> +
> +#endif /* !_LIBC_SYS_AUXV_H_ */
> diff --git a/regress/lib/libc/Makefile b/regress/lib/libc/Makefile
> index 8b5e4d45034..f27137d3f64 100644
> --- a/regress/lib/libc/Makefile
> +++ b/regress/lib/libc/Makefile
> @@ -5,6 +5,7 @@ SUBDIR+= alloca arc4random-fork atexit
> SUBDIR+= basename
> SUBDIR+= cephes cxa-atexit
> SUBDIR+= db dirname
> +SUBDIR+= elf_aux_info
> SUBDIR+= env explicit_bzero
> SUBDIR+= ffs fmemopen fnmatch fpclassify fread
> SUBDIR+= gcvt getaddrinfo getcap getopt getopt_long glob
> diff --git a/regress/lib/libc/elf_aux_info/Makefile b/regress/lib/libc/elf_aux_info/Makefile
> new file mode 100644
> index 00000000000..2885fb18512
> --- /dev/null
> +++ b/regress/lib/libc/elf_aux_info/Makefile
> @@ -0,0 +1,3 @@
> +PROG=elf_aux_info
> +
> +.include <bsd.regress.mk>
> diff --git a/regress/lib/libc/elf_aux_info/elf_aux_info.c b/regress/lib/libc/elf_aux_info/elf_aux_info.c
> new file mode 100644
> index 00000000000..481085d6d97
> --- /dev/null
> +++ b/regress/lib/libc/elf_aux_info/elf_aux_info.c
> @@ -0,0 +1,54 @@
> +#include <sys/auxv.h>
> +
> +#include <errno.h>
> +#include <stdio.h>
> +
> +int
> +main(void)
> +{
> + int ret = 0;
> + int a;
> + unsigned long b;
> +
> +
> + /* Should always succeed */
> + if (elf_aux_info(AT_PAGESZ, &a, sizeof(a)))
> + ret |= 1;
> + else
> + fprintf(stderr, "AT_PAGESZ %d\n", a);
> +
> + /* Wrong size */
> + if (elf_aux_info(AT_PAGESZ, &b, sizeof(b)) != EINVAL)
> + ret |= 2;
> +
> + /* Invalid request */
> + if (elf_aux_info(-1, &a, sizeof(a)) != EINVAL)
> + ret |= 4;
> +
> + /* Should either succeed or fail with ENOENT if not supported */
> + switch (elf_aux_info(AT_HWCAP, &b, sizeof(b))) {
> + case 0:
> + fprintf(stderr, "AT_HWCAP %lx\n", b);
> + break;
> + case ENOENT:
> + break;
> + default:
> + ret |= 8;
> + }
> +
> + /* Should either succeed or fail with ENOENT if not supported */
> + switch (elf_aux_info(AT_HWCAP2, &b, sizeof(b))) {
> + case 0:
> + fprintf(stderr, "AT_HWCAP2 %lx\n", b);
> + break;
> + case ENOENT:
> + break;
> + default:
> + ret |= 16;
> + }
> +
> + if (ret)
> + fprintf(stderr, "FAILED (status %x)\n", ret);
> +
> + return ret;
> +}
> diff --git a/sys/arch/alpha/include/elf.h b/sys/arch/alpha/include/elf.h
> new file mode 100644
> index 00000000000..5864bc487f4
> --- /dev/null
> +++ b/sys/arch/alpha/include/elf.h
> @@ -0,0 +1,7 @@
> +/* $OpenBSD$ */
> +
> +/*
> + * This file is in the public domain.
> + */
> +
> +/* Nothing for now */
> diff --git a/sys/arch/amd64/include/elf.h b/sys/arch/amd64/include/elf.h
> new file mode 100644
> index 00000000000..5864bc487f4
> --- /dev/null
> +++ b/sys/arch/amd64/include/elf.h
> @@ -0,0 +1,7 @@
> +/* $OpenBSD$ */
> +
> +/*
> + * This file is in the public domain.
> + */
> +
> +/* Nothing for now */
> diff --git a/sys/arch/arm/include/elf.h b/sys/arch/arm/include/elf.h
> new file mode 100644
> index 00000000000..a17ba1ae396
> --- /dev/null
> +++ b/sys/arch/arm/include/elf.h
> @@ -0,0 +1,77 @@
> +/* $OpenBSD$ */
> +
> +/*-
> + * SPDX-License-Identifier: BSD-2-Clause
> + *
> + * Copyright (c) 2001 David E. O'Brien
> + * Copyright (c) 1996-1997 John D. Polstra.
> + * All rights reserved.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + * 1. Redistributions of source code must retain the above copyright
> + * notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + * notice, this list of conditions and the following disclaimer in the
> + * documentation and/or other materials provided with the distribution.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
> + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
> + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
> + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
> + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> + * SUCH DAMAGE.
> + */
> +
> +#ifndef _MACHINE_ELF_H_
> +#define _MACHINE_ELF_H_
> +
> +/*
> + * ELF definitions for the ARM architecture.
> + */
> +
> +#ifdef _KERNEL
> +# define __HAVE_CPU_HWCAP
> +# define __HAVE_CPU_HWCAP2
> +extern unsigned long hwcap, hwcap2;
> +#endif /* _KERNEL */
> +
> +/* Flags passed in AT_HWCAP. */
> +#define HWCAP_SWP 0x00000001 /* Unsupported, never set. */
> +#define HWCAP_HALF 0x00000002 /* Always set. */
> +#define HWCAP_THUMB 0x00000004
> +#define HWCAP_26BIT 0x00000008 /* Unsupported, never set. */
> +#define HWCAP_FAST_MULT 0x00000010 /* Always set. */
> +#define HWCAP_FPA 0x00000020 /* Unsupported, never set. */
> +#define HWCAP_VFP 0x00000040
> +#define HWCAP_EDSP 0x00000080 /* Always set for ARMv6+. */
> +#define HWCAP_JAVA 0x00000100 /* Unsupported, never set. */
> +#define HWCAP_IWMMXT 0x00000200 /* Unsupported, never set. */
> +#define HWCAP_CRUNCH 0x00000400 /* Unsupported, never set. */
> +#define HWCAP_THUMBEE 0x00000800
> +#define HWCAP_NEON 0x00001000
> +#define HWCAP_VFPv3 0x00002000
> +#define HWCAP_VFPv3D16 0x00004000
> +#define HWCAP_TLS 0x00008000 /* Always set for ARMv6+. */
> +#define HWCAP_VFPv4 0x00010000
> +#define HWCAP_IDIVA 0x00020000
> +#define HWCAP_IDIVT 0x00040000
> +#define HWCAP_VFPD32 0x00080000
> +#define HWCAP_IDIV (HWCAP_IDIVA | HWCAP_IDIVT)
> +#define HWCAP_LPAE 0x00100000
> +#define HWCAP_EVTSTRM 0x00200000 /* Not implemented yet. */
> +
> +/* Flags passed in AT_HWCAP2. */
> +#define HWCAP2_AES 0x00000001
> +#define HWCAP2_PMULL 0x00000002
> +#define HWCAP2_SHA1 0x00000004
> +#define HWCAP2_SHA2 0x00000008
> +#define HWCAP2_CRC32 0x00000010
> +
> +#endif /* !_MACHINE_ELF_H_ */
> diff --git a/sys/arch/arm64/arm64/cpu.c b/sys/arch/arm64/arm64/cpu.c
> index ae17940fbc8..01db0046cb4 100644
> --- a/sys/arch/arm64/arm64/cpu.c
> +++ b/sys/arch/arm64/arm64/cpu.c
> @@ -32,6 +32,7 @@
> #include <uvm/uvm.h>
>
> #include <machine/fdt.h>
> +#include <machine/elf.h>
>
> #include <dev/ofw/openfirm.h>
> #include <dev/ofw/ofw_clock.h>
> @@ -716,6 +717,10 @@ cpu_identify(struct cpu_info *ci)
> printf("%sAtomic", sep);
> sep = ",";
> arm64_has_lse = 1;
> + /*
> + * XXX should be populated and sanitized like cpu_sysctl() does
> + */
> + hwcap |= HWCAP_ATOMICS;
> }
>
> if (ID_AA64ISAR0_CRC32(id) >= ID_AA64ISAR0_CRC32_BASE) {
> diff --git a/sys/arch/arm64/include/elf.h b/sys/arch/arm64/include/elf.h
> new file mode 100644
> index 00000000000..53be0b910c2
> --- /dev/null
> +++ b/sys/arch/arm64/include/elf.h
> @@ -0,0 +1,121 @@
> +/*-
> + * Copyright (c) 1996-1997 John D. Polstra.
> + * All rights reserved.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + * 1. Redistributions of source code must retain the above copyright
> + * notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + * notice, this list of conditions and the following disclaimer in the
> + * documentation and/or other materials provided with the distribution.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
> + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
> + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
> + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
> + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> + * SUCH DAMAGE.
> + */
> +
> +#ifndef _MACHINE_ELF_H_
> +#define _MACHINE_ELF_H_
> +
> +/*
> + * ELF definitions for the AArch64 architecture.
> + */
> +
> +#ifdef _KERNEL
> +# define __HAVE_CPU_HWCAP
> +# define __HAVE_CPU_HWCAP2
> +extern unsigned long hwcap, hwcap2;
> +#endif /* _KERNEL */
> +
> +/* HWCAP */
> +#define HWCAP_FP 0x00000001
> +#define HWCAP_ASIMD 0x00000002
> +#define HWCAP_EVTSTRM 0x00000004
> +#define HWCAP_AES 0x00000008
> +#define HWCAP_PMULL 0x00000010
> +#define HWCAP_SHA1 0x00000020
> +#define HWCAP_SHA2 0x00000040
> +#define HWCAP_CRC32 0x00000080
> +#define HWCAP_ATOMICS 0x00000100
> +#define HWCAP_FPHP 0x00000200
> +#define HWCAP_ASIMDHP 0x00000400
> +#define HWCAP_CPUID 0x00000800
> +#define HWCAP_ASIMDRDM 0x00001000
> +#define HWCAP_JSCVT 0x00002000
> +#define HWCAP_FCMA 0x00004000
> +#define HWCAP_LRCPC 0x00008000
> +#define HWCAP_DCPOP 0x00010000
> +#define HWCAP_SHA3 0x00020000
> +#define HWCAP_SM3 0x00040000
> +#define HWCAP_SM4 0x00080000
> +#define HWCAP_ASIMDDP 0x00100000
> +#define HWCAP_SHA512 0x00200000
> +#define HWCAP_SVE 0x00400000
> +#define HWCAP_ASIMDFHM 0x00800000
> +#define HWCAP_DIT 0x01000000
> +#define HWCAP_USCAT 0x02000000
> +#define HWCAP_ILRCPC 0x04000000
> +#define HWCAP_FLAGM 0x08000000
> +#define HWCAP_SSBS 0x10000000
> +#define HWCAP_SB 0x20000000
> +#define HWCAP_PACA 0x40000000
> +#define HWCAP_PACG 0x80000000
> +
> +/* HWCAP2 */
> +#define HWCAP2_DCPODP 0x0000000000000001ul
> +#define HWCAP2_SVE2 0x0000000000000002ul
> +#define HWCAP2_SVEAES 0x0000000000000004ul
> +#define HWCAP2_SVEPMULL 0x0000000000000008ul
> +#define HWCAP2_SVEBITPERM 0x0000000000000010ul
> +#define HWCAP2_SVESHA3 0x0000000000000020ul
> +#define HWCAP2_SVESM4 0x0000000000000040ul
> +#define HWCAP2_FLAGM2 0x0000000000000080ul
> +#define HWCAP2_FRINT 0x0000000000000100ul
> +#define HWCAP2_SVEI8MM 0x0000000000000200ul
> +#define HWCAP2_SVEF32MM 0x0000000000000400ul
> +#define HWCAP2_SVEF64MM 0x0000000000000800ul
> +#define HWCAP2_SVEBF16 0x0000000000001000ul
> +#define HWCAP2_I8MM 0x0000000000002000ul
> +#define HWCAP2_BF16 0x0000000000004000ul
> +#define HWCAP2_DGH 0x0000000000008000ul
> +#define HWCAP2_RNG 0x0000000000010000ul
> +#define HWCAP2_BTI 0x0000000000020000ul
> +#define HWCAP2_MTE 0x0000000000040000ul
> +#define HWCAP2_ECV 0x0000000000080000ul
> +#define HWCAP2_AFP 0x0000000000100000ul
> +#define HWCAP2_RPRES 0x0000000000200000ul
> +#define HWCAP2_MTE3 0x0000000000400000ul
> +#define HWCAP2_SME 0x0000000000800000ul
> +#define HWCAP2_SME_I16I64 0x0000000001000000ul
> +#define HWCAP2_SME_F64F64 0x0000000002000000ul
> +#define HWCAP2_SME_I8I32 0x0000000004000000ul
> +#define HWCAP2_SME_F16F32 0x0000000008000000ul
> +#define HWCAP2_SME_B16F32 0x0000000010000000ul
> +#define HWCAP2_SME_F32F32 0x0000000020000000ul
> +#define HWCAP2_SME_FA64 0x0000000040000000ul
> +#define HWCAP2_WFXT 0x0000000080000000ul
> +#define HWCAP2_EBF16 0x0000000100000000ul
> +#define HWCAP2_SVE_EBF16 0x0000000200000000ul
> +#define HWCAP2_CSSC 0x0000000400000000ul
> +#define HWCAP2_RPRFM 0x0000000800000000ul
> +#define HWCAP2_SVE2P1 0x0000001000000000ul
> +#define HWCAP2_SME2 0x0000002000000000ul
> +#define HWCAP2_SME2P1 0x0000004000000000ul
> +#define HWCAP2_SME_I16I32 0x0000008000000000ul
> +#define HWCAP2_SME_BI32I32 0x0000010000000000ul
> +#define HWCAP2_SME_B16B16 0x0000020000000000ul
> +#define HWCAP2_SME_F16F16 0x0000040000000000ul
> +#define HWCAP2_MOPS 0x0000080000000000ul
> +#define HWCAP2_HBC 0x0000100000000000ul
> +
> +#endif /* !_MACHINE_ELF_H_ */
> diff --git a/sys/arch/hppa/include/elf.h b/sys/arch/hppa/include/elf.h
> new file mode 100644
> index 00000000000..5864bc487f4
> --- /dev/null
> +++ b/sys/arch/hppa/include/elf.h
> @@ -0,0 +1,7 @@
> +/* $OpenBSD$ */
> +
> +/*
> + * This file is in the public domain.
> + */
> +
> +/* Nothing for now */
> diff --git a/sys/arch/i386/include/elf.h b/sys/arch/i386/include/elf.h
> new file mode 100644
> index 00000000000..5864bc487f4
> --- /dev/null
> +++ b/sys/arch/i386/include/elf.h
> @@ -0,0 +1,7 @@
> +/* $OpenBSD$ */
> +
> +/*
> + * This file is in the public domain.
> + */
> +
> +/* Nothing for now */
> diff --git a/sys/arch/m88k/include/elf.h b/sys/arch/m88k/include/elf.h
> new file mode 100644
> index 00000000000..5864bc487f4
> --- /dev/null
> +++ b/sys/arch/m88k/include/elf.h
> @@ -0,0 +1,7 @@
> +/* $OpenBSD$ */
> +
> +/*
> + * This file is in the public domain.
> + */
> +
> +/* Nothing for now */
> diff --git a/sys/arch/mips64/include/elf.h b/sys/arch/mips64/include/elf.h
> new file mode 100644
> index 00000000000..5864bc487f4
> --- /dev/null
> +++ b/sys/arch/mips64/include/elf.h
> @@ -0,0 +1,7 @@
> +/* $OpenBSD$ */
> +
> +/*
> + * This file is in the public domain.
> + */
> +
> +/* Nothing for now */
> diff --git a/sys/arch/powerpc/include/elf.h b/sys/arch/powerpc/include/elf.h
> new file mode 100644
> index 00000000000..821ba5ae3cb
> --- /dev/null
> +++ b/sys/arch/powerpc/include/elf.h
> @@ -0,0 +1,14 @@
> +/* $OpenBSD$ */
> +
> +/*
> + * This file is in the public domain.
> + */
> +
> +#ifndef _MACHINE_ELF_H_
> +#define _MACHINE_ELF_H_
> +
> +/*
> + * TODO FreeBSD puts PPC_FEATURE* in cpu.h
> + */
> +
> +#endif /* !_MACHINE_ELF_H_ */
> diff --git a/sys/arch/powerpc64/include/elf.h b/sys/arch/powerpc64/include/elf.h
> new file mode 100644
> index 00000000000..821ba5ae3cb
> --- /dev/null
> +++ b/sys/arch/powerpc64/include/elf.h
> @@ -0,0 +1,14 @@
> +/* $OpenBSD$ */
> +
> +/*
> + * This file is in the public domain.
> + */
> +
> +#ifndef _MACHINE_ELF_H_
> +#define _MACHINE_ELF_H_
> +
> +/*
> + * TODO FreeBSD puts PPC_FEATURE* in cpu.h
> + */
> +
> +#endif /* !_MACHINE_ELF_H_ */
> diff --git a/sys/arch/riscv64/include/elf.h b/sys/arch/riscv64/include/elf.h
> new file mode 100644
> index 00000000000..de902743da5
> --- /dev/null
> +++ b/sys/arch/riscv64/include/elf.h
> @@ -0,0 +1,52 @@
> +/* $OpenBSD$ */
> +
> +/*-
> + * Copyright (c) 1996-1997 John D. Polstra.
> + * All rights reserved.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + * 1. Redistributions of source code must retain the above copyright
> + * notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + * notice, this list of conditions and the following disclaimer in the
> + * documentation and/or other materials provided with the distribution.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
> + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
> + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
> + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
> + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> + * SUCH DAMAGE.
> + */
> +
> +#ifndef _MACHINE_ELF_H_
> +#define _MACHINE_ELF_H_
> +
> +/*
> + * ELF definitions for the RISC-V architecture.
> + */
> +
> +#ifdef _KERNEL
> +# define __HAVE_CPU_HWCAP
> +extern unsigned long hwcap;
> +#endif /* _KERNEL */
> +
> +/* Flags passed in AT_HWCAP */
> +#define HWCAP_ISA_BIT(c) (1 << ((c) - 'a'))
> +#define HWCAP_ISA_I HWCAP_ISA_BIT('i')
> +#define HWCAP_ISA_M HWCAP_ISA_BIT('m')
> +#define HWCAP_ISA_A HWCAP_ISA_BIT('a')
> +#define HWCAP_ISA_F HWCAP_ISA_BIT('f')
> +#define HWCAP_ISA_D HWCAP_ISA_BIT('d')
> +#define HWCAP_ISA_C HWCAP_ISA_BIT('c')
> +#define HWCAP_ISA_G \
> + (HWCAP_ISA_I | HWCAP_ISA_M | HWCAP_ISA_A | HWCAP_ISA_F | HWCAP_ISA_D)
> +
> +#endif /* !_MACHINE_ELF_H_ */
> diff --git a/sys/arch/riscv64/riscv64/cpu.c b/sys/arch/riscv64/riscv64/cpu.c
> index 0d40b236569..4e6c08adacf 100644
> --- a/sys/arch/riscv64/riscv64/cpu.c
> +++ b/sys/arch/riscv64/riscv64/cpu.c
> @@ -28,6 +28,7 @@
> #include <uvm/uvm.h>
>
> #include <machine/cpufunc.h>
> +#include <machine/elf.h>
> #include <machine/fdt.h>
> #include <machine/sbi.h>
>
> @@ -236,6 +237,8 @@ cpu_attach(struct device *parent, struct device *dev, void *aux)
> #endif
> cpu_identify(ci);
>
> + hwcap |= HWCAP_ISA_G | HWCAP_ISA_C;
> +
> if (OF_getproplen(ci->ci_node, "clocks") > 0) {
> cpu_node = ci->ci_node;
> cpu_cpuspeed = cpu_clockspeed;
> diff --git a/sys/arch/sh/include/elf.h b/sys/arch/sh/include/elf.h
> new file mode 100644
> index 00000000000..5864bc487f4
> --- /dev/null
> +++ b/sys/arch/sh/include/elf.h
> @@ -0,0 +1,7 @@
> +/* $OpenBSD$ */
> +
> +/*
> + * This file is in the public domain.
> + */
> +
> +/* Nothing for now */
> diff --git a/sys/arch/sparc64/include/elf.h b/sys/arch/sparc64/include/elf.h
> new file mode 100644
> index 00000000000..5864bc487f4
> --- /dev/null
> +++ b/sys/arch/sparc64/include/elf.h
> @@ -0,0 +1,7 @@
> +/* $OpenBSD$ */
> +
> +/*
> + * This file is in the public domain.
> + */
> +
> +/* Nothing for now */
> diff --git a/sys/sys/auxv.h b/sys/sys/auxv.h
> new file mode 100644
> index 00000000000..26de550fdc6
> --- /dev/null
> +++ b/sys/sys/auxv.h
> @@ -0,0 +1,50 @@
> +/* $OpenBSD$ */
> +
> +/*-
> + * SPDX-License-Identifier: BSD-2-Clause
> + *
> + * Copyright (c) 2017 Michal Meloun
> + * All rights reserved.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + * 1. Redistributions of source code must retain the above copyright
> + * notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + * notice, this list of conditions and the following disclaimer in the
> + * documentation and/or other materials provided with the distribution.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
> + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
> + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
> + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
> + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> + * SUCH DAMAGE.
> + */
> +
> +#ifndef _SYS_AUXV_H_
> +#define _SYS_AUXV_H_
> +
> +#include <sys/types.h>
> +#include <machine/elf.h>
> +
> +/* Values for a_type. */
> +#define AT_NULL 0 /* Terminates the vector. */
> +#define AT_IGNORE 1 /* Ignored entry. */
> +#define AT_PAGESZ 6 /* Page size in bytes. */
> +#define AT_HWCAP 25 /* CPU feature flags. */
> +#define AT_HWCAP2 26 /* CPU feature flags 2. */
> +
> +#define AT_COUNT 27 /* Count of defined aux entry types. */
> +
> +__BEGIN_DECLS
> +int elf_aux_info(int aux, void *buf, int buflen);
> +__END_DECLS
> +
> +#endif /* !_SYS_AUXV_H_ */
> diff --git a/sys/sys/exec_elf.h b/sys/sys/exec_elf.h
> index 7825dff418b..1b45c3ebb70 100644
> --- a/sys/sys/exec_elf.h
> +++ b/sys/sys/exec_elf.h
> @@ -727,6 +727,8 @@ enum AuxID {
> AUX_base = 7, /* base addr for ld.so or static PIE */
> AUX_flags = 8, /* processor flags */
> AUX_entry = 9, /* a.out entry */
> + AUX_hwcap = 25, /* processor flags */
> + AUX_hwcap2 = 26, /* processor flags (continued) */
> AUX_sun_uid = 2000, /* euid */
> AUX_sun_ruid = 2001, /* ruid */
> AUX_sun_gid = 2002, /* egid */
> @@ -820,7 +822,7 @@ extern Elf_Dyn _DYNAMIC[];
> /*
> * How many entries are in the AuxInfo array we pass to the process?
> */
> -#define ELF_AUX_ENTRIES 9
> +#define ELF_AUX_ENTRIES 11
> #define ELF_AUX_WORDS (sizeof(AuxInfo) * ELF_AUX_ENTRIES / sizeof(char *))
>
> struct exec_package;
>
>
> --
> jca
>
arm64 LSE support in userland: introduce elf_aux_info?