Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC r234840:
Split the symlook_obj1 into a loop iterating over the ELF object symbol
hash elements, and a helper matched_symbol() which match the given hash
entry and request, performing needed type and version checks.

MFC r234841:
Add GNU hash support for rtld.

MFC r235054:
Work around a situation where symlook_obj() could be called for the
object for which digest_dynamic1() was not done yet. Just return
EINVAL and do not try to dereference NULL buckets hash array.

MFC r233307:
Use xmalloc() instead of malloc() in the places where malloc() calls
are assumed to not fail.

Make the xcalloc() calling conventions follow the calloc(3) calling
conventions and replace unchecked calls to calloc() with calls to
xcalloc().

Remove redundand declarations from xmalloc.c, which are already
present in rtld.h.

MFC r233231:
Fix several problems with our ELF filters implementation.

Do not relocate twice an object which happens to be needed by loaded
binary (or dso) and some filtee opened due to symbol resolution when
relocating need objects. Record the state of the relocation
processing in Obj_Entry and short-circuit relocate_objects() if
current object already processed.

Do not call constructors for filtees loaded during the early
relocation processing before image is initialized enough to run
user-provided code. Filtees are loaded using dlopen_object(), which
normally performs relocation and initialization. If filtee is
lazy-loaded during the relocation of dso needed by the main object,
dlopen_object() runs too earlier, when most runtime services are not
yet ready.

Postpone the constructors call to the time when main binary and
depended libraries constructors are run, passing the new flag
RTLD_LO_EARLY to dlopen_object(). Symbol lookups callers inform
symlook_* functions about early stage of initialization with
SYMLOOK_EARLY. Pass flags through all functions participating in
object relocation.

Use the opportunity and fix flags argument to find_symdef() in
arch-specific reloc.c to use proper name SYMLOOK_IN_PLT instead of
true, which happen to have the same numeric value.

MFC r233777 (by kan):
Do not try to adjust stacks if dlopen_object is called too early.

MFC r233778 (by kan):
Remove extra blank line from revious commit.

MFC note: the ARM and MIPS TLS support is not merged back, so the chunks
from r233231 which fix misuse of flags in calls to find_symdef() in
the corresponding relocation type handlers were not applied. When TLS
support is merged, the rest of r233231 should be applied too.

MFC r232831:
Add support for preinit, init and fini arrays to rtld.
Only binaries marked with proper ABI note gets array ctr/dtrs called.

MFC r232856:
When iterating over the dso program headers, the object is not initialized
yet, and object segments are not yet mapped. Only parse the notes that
appear in the first page of the dso (as it should be anyway), and use
the preloaded page content.

MFC r232857 (by dim):
Fix a warning/error with clang.

MFC r232859 (by dim):
Amend r232857, now dropping the casts entirely, as they were not
necessary at all.

MFC r228435:
Add support for STT_GNU_IFUNC and R_MACHINE_IRELATIVE GNU extensions to
rtld on 386 and amd64.

MFC r228503:
Postpone the resolution for irelative/ifunc right before initializers
are called, and drop bind lock around calls to dispatcher. Use
initlist to iterate over the objects instead of the ->next, due to
drop of the bind lock in iteration.

For i386/reloc.c:reloc_iresolve(), fix calculation of the dispatch
function address for dso, by taking into account possible non-zero
relocbase.

MFC r228635 (by nwhitehorn):
Fix RTLD on PowerPC after r228435. Changing the order of init_pltgot()
caused the icache to be invalidated at the wrong time, resulting in
an icache full of nonsense in the PLT section.

MFC r228646:
Additional icache paranoia: non-PLT relocations can modify the text segment.
It is then important to make sure the icache is synchronized again to
prevent (rare) random seg faults and illegal instructions.

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Remove dead code that snuck in from the 32-bit PowerPC version of this
file. The error being checked for does not exist on 64-bit systems.

Turn off default generation of userland dot symbols on powerpc64 now that
we have a binutils that supports it. Kernel dot symbols remain on to assist
DDB.

When loading dso without PT_GNU_STACK phdr, only call
__pthread_map_stacks_exec() on architectures that allow executable
stacks.

Reported and tested by: marcel (ia64)

Mark rtld on PowerPC as not requiring executable stack.

Reviewed and tested by: nwhitehorn

Add support for R_PPC64_UADDR64 relocations.

Fix an error in the ABI in rtld_bind_start(). When passing arguments to a
C function, the caller's stack frame must have room to store all of the
arguments to that function. While here, fix stack frame alignment issues.

Without this change, the compiler will save r3 and r4 into the caller's
stack frame before calling setjmp() in _rtld_bind(). These would then
overwrite arguments to the newly-bound function, causing eventual failures.

Implement support for ELF filters in rtld. Both normal and auxillary
filters are implemented.

Filtees are loaded on demand, unless LD_LOADFLTR environment variable
is set or -z loadfltr was specified during the linking. This forces
rtld to upgrade read-locked rtld_bind_lock to write lock when it
encounters an object with filter during symbol lookup.

Consolidate common arguments of the symbol lookup functions in the
SymLook structure. Track the state of the rtld locks in the
RtldLockState structure. Pass local RtldLockState through the rtld
symbol lookup calls to allow lock upgrades.

Reviewed by: kan
Tested by: Mykola Dzham <i levsha me>, nwhitehorn (powerpc)

Check for undefined weak symbols during PLT binding on powerpc64, and do
not attempt to copy NULL function descriptors. This fixes LD_BIND_NOW on
powerpc64 after r211706.

Reviewed by: kib

RTLD support for powerpc64. A few small modifications to the Makefile
and symbol map are required to support various consequences of the dot
symbol scheme:

- Symbols beginning with a dot are reserved, so start private symbols with
an underscore.
- In order to set RTLD breakpoints, gdb must be able to locate the text
entry point, not the data section function descriptor, so add
.r_debug_state to the symbol map on powerpc64.

Obtained from: projects/ppc64

Only use the cache after the early stage of loading. This is
because calling mmap() etc. may use GOT which is not set up
yet. Use calloc() instead of mmap() in cases where this
was the case before (sparc64, powerpc, arm).

Submitted by: Dimitry Andric (dimitry andric com)
Reviewed by: kan
Approved by: ed (mentor)

Support the extended PLT format used when objects have more than 8192
PLT relocations on PPC32.

Now that the kernel defines CACHE_LINE_SIZE in machine/param.h, use
that definition in the custom locking code for the run-time linker
rather than local definitions.

Pointed out by: tinderbox
MFC after: 2 weeks

Include an extra header to get a function prototype.

Unbreak the dynamic linker by not creating a cache for rtld-elf
itself. It needs mmap(2), which now needs getosreldate(3) and
which in turn uses a global variable to cache the result. This
cannot be done before linking is done.

See also: ../sparc64/reloc.c:1.15
Approved by: re (kensmith)

o Fix the static TLS relocation. We were subtracting the size of
the TCB.
o Use NULL for null pointer argument.
o Replace magic 8 with TLS_TCB_SIZE.

Implement ELF symbol versioning using GNU semantics. This code aims
to be compatible with symbol versioning support as implemented by
GNU libc and documented by http://people.redhat.com/~drepper/symbol-versioning
and LSB 3.0.

Implement dlvsym() function to allow lookups for a specific version of
a given symbol.

Remove these unused files before any other archs include the same bogus
file.

Implement TLS relocations for powerpc.

Approved by: grehan (mentor)

Add stubs for powerpc TLS.

Submitted by: ssouhlal

Allow threading libraries to register their own locking
implementation in case default one provided by rtld is
not suitable.

Consolidate various identical MD lock implementation into
a single file using appropriate machine/atomic.h.

Approved by: re (scottl)

No need to zero fill memory, mmapped anonymously. Kernel will
return pre-zeroed pages itself.

Noticed by: jake

rtld support for PowerPC. Mostly obtained from NetBSD, with mods
for binutils 2.13

Reviewed by: benno

Approved by: re (blanket)