MFC r340136:
Move the fixed base for PIE loading on arm.

Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

MFC 323580,323933,323934,324814,324817: Enable AT_HWCAP on arm.

I reused the SV_HWCAP stub to cover the sv_hwcap2 field as well.

323580:
Add AT_HWCAP flags for VFP settings for FreeBSD/arm.

These flags match the meaning and value of flags in Linux, though
Linux has many more flags.

323933:
Correct HWCAP_VFP3* values to match Linux.

323934:
Detect NEON and set HWCAP_NEON if present.

324814:
Add AT_HWCAP2 ELF auxiliary vector.
- allocate value for new AT_HWCAP2 auxiliary vector on all platforms.
- expand 'struct sysentvec' by new 'u_long *sv_hwcap2', in exactly
same way as for AT_HWCAP.

324817:
Fullify implementation of AT_HWCAP and AT_HWCAP2 for ARMv6,7.
This makes elf_aux_info(3) useable for ARM ports.

Tested by: mmel

MFC 323579,323585: Add AT_HWCAP and AT_EHDRFLAGS on all platforms.

To preserve KBI on stable/11, a new SV_HWCAP flag is added which
indicates if the sv_hwcap field is present and valid to avoid examining
the field in old modules. Only sysentvec's which wish to use sv_hwcap
need to set the flag in stable/11.

323579:
Add AT_HWCAP and AT_EHDRFLAGS on all platforms.

A new 'u_long *sv_hwcap' field is added to 'struct sysentvec'. A
process ABI can set this field to point to a value holding a mask of
architecture-specific CPU feature flags. If an ABI does not wish to
supply AT_HWCAP to processes the field can be left as NULL.

The support code for AT_EHDRFLAGS was already present on all systems,
just the #define was not present. This is a step towards unifying the
AT_* constants across platforms.

323585:
Add AT_EHDRFLAGS and AT_HWCAP on amd64.

x86 has two separate (but identical) list of AT_* constants and the
earlier commit to add AT_HWCAP only updated the i386 list.

MFC r303677: Move/add ARM ELF PHDR types to elf_common.h

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Export the eflags field from the elf header. This allows better
discrimination between different subarch binaries, at least for mips
and arm. Arm is implemented, mips is still tbd, so not currently
exported. aarch64 does not export this because aarch64 binaries use
different tags and flags than arm.

Differential Revision: https://reviews.freebsd.org/D2611

Update ELF headers to include additional defines

The elftoolchain project includes these additional defines for various
userland programs. Given that arch-specific defines are still interesting
in the context of userland programs reading or writing ELF metadata, they
should be included in top-level ELF headers.

Remove duplicate defines from ARM and MIPS elf headers.

Submitted by: will (initial version)
Reviewed by: imp, will
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D844

Expand the elf brandelf infrastructure to give access to the whole ELF
header (Elf_Ehdr) to determine if a particular interpretor wants to
accept it or not. Use this mechanism to filter EABI arm on OABI arm
kernels, and vice versa. This method could also be used to implement
OABI on EABI arm kernels, if desired, or to allow a single mips kernel
to run o32, n32 and n64 binaries.

Differential Revision: https://reviews.freebsd.org/D609

Add dl_unwind_find_exidx() for ARM EABI, required for C++ exception
handling. For statically linked apps this uses the __exidx_start/end
symbols set up by the linker. For dynamically linked apps it finds the
shared object that contains the given address and returns the location and
size of the exidx section in that shared object.

The dl_unwind_find_exidx() name is used by other BSD projects and Android,
and is mentioned in clang 3.5 comments as "the BSD interface" for finding
exidx data. GCC (in libgcc_s) expects the exact same API and functionality
to be provided by a function named __gnu_Unwind_Find_exidx(), so we provide
that with an alias ("strong reference").

Reviewed by: kib@
MFC after: 1 week

Reserve AT_TIMEKEEP auxv entry for providing usermode the pointer to
timekeeping information.

MFC after: 1 week

trim trailing whitespace

Add AT_STACKPROT elf aux vector. Will be used to inform rtld about the
initial stack protection set by the kernel image activator.

Supply some useful information to the started image using ELF aux vectors.
In particular, provide pagesize and pagesizes array, the canary value
for SSP use, number of host CPUs and osreldate.

Tested by: marius (sparc64)
MFC after: 1 month

Define architectural load bases for PIE binaries. Addresses were selected
by looking at the bases used for non-relocatable executables by gnu ld(1),
and adjusting it slightly.

Discussed with: bz
Reviewed by: kan
Tested by: bz (i386, amd64), bsam (linux)
MFC after: some time

Add AT_EXECPATH ELF auxinfo entry type. The value's a_ptr is a pointer
to the full path of the image that is being executed.
Increase AT_COUNT.

Remove no longer true comment about types used in Linux ELF binaries,
listed types contain FreeBSD-specific entries.

Reviewed by: kan

AT_DEBUG and AT_BRK were OBE like 10 years ago, so retire them.

Reviewed by: peter

PR:
Submitted by:
Reviewed by:
Approved by:
Obtained from:
MFC after:
Security:
Move the relocation definitions to the common elf header so that DTrace
can use them on one architecture targeted to a different one.

Add the additional ELF types defines in Sun's "Linker and Libraries"
manual.

Use ELFDATA2MSB if we're building big endian.

Noticed by: Oleksandr Tymoshenko <gonzo freebsd org>

Use a magic number to know we were started from the elf wrapper.
Add a dummy _start function to make the non-elf version of the wrapper work.

Add the Elf32_Auxinfo declaretion.
Define AT_*.
(Maybe some of this could go in a MI header ?)

Add sysentvec->sv_fixlimits() hook so that we can catch cases on 64 bit
systems where the data/stack/etc limits are too big for a 32 bit process.

Move the 5 or so identical instances of ELF_RTLD_ADDR() into imgact_elf.c.

Supply an ia32_fixlimits function. Export the clip/default values to
sysctl under the compat.ia32 heirarchy.

Have mmap(0, ...) respect the current p->p_limits[RLIMIT_DATA].rlim_max
value rather than the sysctl tweakable variable. This allows mmap to
place mappings at sensible locations when limits have been reduced.

Have the imgact_elf.c ld-elf.so.1 placement algorithm use the same
method as mmap(0, ...) now does.

Note that we cannot remove all references to the sysctl tweakable
maxdsiz etc variables because /etc/login.conf specifies a datasize
of 'unlimited'. And that causes exec etc to fail since it can no
longer find space to mmap things.

Make MAXTSIZ, DFLDSIZ, MAXDSIZ, DFLSSIZ, MAXSSIZ, SGROWSIZ loader
tunable.

Reviewed by: peter
MFC after: 2 weeks

Fix style of defines.

StrongARM platform-specific definitions.