Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Remove some unused fields from struct linker_file. They were added in
r172862 for use by the DTrace SDT framework but don't seem to have ever
been used.

MFC after: 2 weeks

Provide convenience function for obtaining MODINFO_ADDR and MODINFO_SIZE
attributes for preloaded modules/images. In particular, MODINFO_ADDR has
the added complexity of not always being relocated properly. Rather than
kluging this in the various components that are affected, we handle it
in a centralized place (preload_fetch_addr()). To that end, expose a new
variable, preload_addr_relocate, that MD initialization code can set and
that turns the address attribute into a valid kernel VA.

Architectures that need the relocation: arm & powerpc (at least).
Components that can utilize this: acpi(4), md(4), fb(4), pci(4), ZFS, geli.

Sponsored by: Juniper Networks

Implement a facility for dynamic per-cpu variables.
- Modules and kernel code alike may use DPCPU_DEFINE(),
DPCPU_GET(), DPCPU_SET(), etc. akin to the statically defined
PCPU_*. Requires only one extra instruction more than PCPU_* and is
virtually the same as __thread for builtin and much faster for shared
objects. DPCPU variables can be initialized when defined.
- Modules are supported by relocating the module's per-cpu linker set
over space reserved in the kernel. Modules may fail to load if there
is insufficient space available.
- Track space available for modules with a one-off extent allocator.
Free may block for memory to allocate space for an extent.

Reviewed by: jhb, rwatson, kan, sam, grehan, marius, marcel, stas

Add hooks for the Compact C Type Format (CTF) data to be attached to
the elf files. This is complicated by the fact that the actual CTF
parsing has to be done in CDDL'd code, so the BSD licensed code only
knows about the opaque data which it must be able to free.

The kernel linker includes a number of utility functions to look up symbol
information in support of DDB(4); these functions bypass normal linker
locking as they may run in contexts where locking is unsafe (such as the
kernel debugger).

Add a new interface linker_ddb_search_symbol_name(), which looks up a
symbol name and offset given an address, and also
linker_search_symbol_name() which does the same but *does* follow the
locking conventions of the linker.

Unlike existing functions, these functions place the name in a
caller-provided buffer, which is stable even after linker locks have been
released. These functions will be used in upcoming revisions to stack(9)
to support kernel stack trace generation in contexts as part of a live,
rather than suspended, kernel.

Fix comments.

Add a function to list symbols in a file and their values at the
same time rather than having to list the symbols and then go back
and look each one up by name.

Add the full module path name to the kld_file_stat structure
for kldstat(2).

This allows libdtrace to determine the exact file from which
a kernel module was loaded without having to guess.

The kldstat(2) API is versioned with the size of the
kld_file_stat structure, so this change creates version 2.

Add the pathname to the verbose output of kldstat(8) too.

MFC: 3 days

Add a new section in this file for functions that are only exported by the
linker for use in the linker class handlers. Move linker_add_class(),
linker_file_unload(), linker_load_dependencies(), and linker_make_file()
into this section.

- Push Giant down into linker_reference_module().
- Add a new function linker_release_module() as a more intuitive complement
to linker_reference_module() that wraps linker_file_unload().
linker_release_module() can either take the module name and version info
passed to linker_reference_module() or it can accept the linker file
object returned by linker_reference_module().

Make linker_find_file_by_name() and linker_find_file_by_id() static to
simplify linker locking. The only external consumers now use
linker_file_foreach().

- Add a new linker_file_foreach() function that walks the list of linker
file objects calling a user-specified predicate function on each object.
The iteration terminates either when the entire list has been iterated
over or the predicate function returns a non-zero value.
linker_file_foreach() returns the value returned by the last invocation
of the predicate function. It also accepts a void * context pointer that
is passed to the predicate function as well. Using an iterator function
avoids exposing linker internals to the rest of the kernel making locking
simpler.
- Use linker_file_foreach() instead of walking the list of linker files
manually to lookup ndis files in ndis(4).
- Use linker_file_foreach() to implement linker_hwpmc_list_objects().

Make linker_file_add_dependency() and linker_load_module() static since
only the linker uses them.

MFP4: Support for profiling dynamically loaded objects.

Kernel changes:

Inform hwpmc of executable objects brought into the system by
kldload() and mmap(), and of their removal by kldunload() and
munmap(). A helper function linker_hwpmc_list_objects() has been
added to "sys/kern/kern_linker.c" and is used by hwpmc to retrieve
the list of currently loaded kernel modules.

The unused `MAPPINGCHANGE' event has been deprecated in favour
of separate `MAP_IN' and `MAP_OUT' events; this change reduces
space wastage in the log.

Bump the hwpmc's ABI version to "2.0.00". Teach hwpmc(4) to
handle the map change callbacks.

Change the default per-cpu sample buffer size to hold
32 samples (up from 16).

Increment __FreeBSD_version.

libpmc(3) changes:

Update libpmc(3) to deal with the new events in the log file; bring
the pmclog(3) manual page in sync with the code.

pmcstat(8) changes:

Introduce new options to pmcstat(8): "-r" (root fs path), "-M"
(mapfile name), "-q"/"-v" (verbosity control). Option "-k" now
takes a kernel directory as its argument but will also work with
the older invocation syntax.

Rework string handling in pmcstat(8) to use an opaque type for
interned strings. Clean up ELF parsing code and add support for
tracking dynamic object mappings reported by a v2.0.00 hwpmc(4).

Report statistics at the end of a log conversion run depending
on the requested verbosity level.

Reviewed by: jhb, dds (kernel parts of an earlier patch)
Tested by: gallatin (earlier patch)

Make our ELF64 type definitions match standards. In particular this
means:
o Remove Elf64_Quarter,
o Redefine Elf64_Half to be 16-bit,
o Redefine Elf64_Word to be 32-bit,
o Add Elf64_Xword and Elf64_Sxword for 64-bit entities,
o Use Elf_Size in MI code to abstract the difference between
Elf32_Word and Elf64_Word.
o Add Elf_Ssize as the signed counterpart of Elf_Size.

MFC after: 2 weeks

Add a new module information type MODINFOMD_SHDR that will be used
by the loader to pass the section header table from preloaded ELF
relocatable modules into the kernel.

Give kldunload a -f(orce) argument.

Add a MOD_QUIESCE event for modules. This should return error (EBUSY)
of the module is in use.

MOD_UNLOAD should now only fail if it is impossible (as opposed to
inconvenient) to unload the module. Valid reasons are memory references
into the module which cannot be tracked down and eliminated.

When kldunloading, we abandon if MOD_UNLOAD fails, and if -force is
not given, MOD_QUIESCE failing will also prevent the unload.

For backwards compatibility, we treat EOPNOTSUPP from MOD_QUIESCE as
success.

Document that modules should return EOPNOTSUPP for unknown events.

Make a small revision to the api between the elf linker core and the
elf_reloc() backends for two reasons. First, to support the possibility
of there being two elf linkers in the kernel (eg: amd64), and second, to
pass the relocbase explicitly (for relocating .o format kld files).

Slight reorg and added AMD64 support. A couple of the MODINFOMD_* values
that were added to sparc64 and later powerpc, really should have been in
the MI area. But changing that now with insufficient preperation will
just cause too much pain.

Move MD_FETCH() to the MI sys/linker.h file to avoid another two copies
of it.

Resolve relative relocations in klds before trying to parse the module's
metadata. This fixes module dependency resolution by the kernel linker on
sparc64, where the relocations for the metadata are different than on other
architectures; the relative offset is in the addend of an Elf_Rela record
instead of the original value of the location being patched.
Also fix printf formats in debug code.

Submitted by: Hartmut Brandt <brandt@fokus.gmd.de>
PR: 46732
Tested on: alpha (obrien), i386, sparc64

Add two hooks to signal module load and module unload to MD code.
The primary reason for this is to allow MD code to process machine
specific attributes, segments or sections in the ELF file and
update machine specific state accordingly. An immediate use of this
is in the ia64 port where unwind information is updated to allow
debugging and tracing in/across modules. Note that this commit
does not add the functionality to the ia64 port. See revision 1.9
of ia64/ia64/elf_machdep.c.

Validated on: alpha, i386, ia64

Fix kernel module loading on ia64. Cross-module function calls
were improperly relocated due to faulty logic in lookup_fdesc()
in elf_machdep.c. The symbol index (symidx) was bogusly used for
load modules other than the one the relocation applied to. This
resulted in bogus bindings and consequently runtime failures.

The fix is to use the symbol index only for the module being
relocated and to use the symbol name for look-ups in the
modules in the dependent list. As such, we need a function to
return the symbol name given the linker file and symbol index.

Add a workaround for what seems to be confusion between binutils and the
sparc v9 ABI. The Elf_Rela records for local symbols appear to already
have the symbol's value added in to the addend field, even though the ABI
specifies we need to lookup the symbol and add its value too. This breaks
text relocations in klds because the symbol's value is added twice, and
the resulting address points off into nowhere land, so for now just use
the addend.

Tested by: rwatson

Make the consumers of the linker_load_file() function use
linker_load_module() instead.

This fixes a bug where the kernel was unable to properly locate and
load a kernel module in vfs_mount() (and probably in the netgraph
code as well since it was using the same function). This is because
the linker_load_file() does not properly search the module path.

Problem found by: peter
Reviewed by: peter
Thanks to: peter

Don't use the symbol name to lookup the symbol value when we can use
the symbol index defined by the relocation. The elf_lookup() support
function is to be used by elf_reloc() when symbol lookups need to be
done. The elf_lookup() function operates on the symbol index and
will do a symbol name based lookup when such is required, otherwise
it uses the symbol index directly. This solves the problem seen on
ia64 where the symbol hash table does not contain local symbols and
a symbol name based lookup would fail for those symbols.

Don't pass the symbol name to elf_reloc(), as it isn't used any more.

Change linker_reference_module() so that it's passed a struct
mod_depend * (which may be NULL). The only consumer of this
function at the moment is digi_loadmoduledata(), and that passes
a NULL mod_depend *.

In linker_reference_module(), check to see if we've already got
the required module loaded. If we have, bump the reference count
and return that, otherwise continue the module search as normal.

Fix a number of misspellings of "dependency" and "dependencies" in
comments and function names.

PR: kern/8589
Submitted by: Rajesh Vaidheeswarran <rv@fore.com>

Add the sysctl "kern.function_list", which currently exports all
function symbols in the kernel in a list of C strings, with an extra
nul-termination at the end.

This sysctl requires addition of a new linker operation. Now,
linker_file_t's need to respond to "each_function_name" to export
their function symbols.

Note that the sysctl doesn't currently allow distinguishing multiple
symbols with the same name from different modules, but could quite
easily without a change to the linker operation. This will be a nicety
to have when it can be used.

Obtained from: NAI Labs CBOSS project
Funded by: DARPA

Implement the long-awaited module->file cache database. A userland
tool (kldxref(8)) keeps a cache of what modules and versions are inside
what .ko files. I have tested this on both Alpha and i386.

Submitted by: bp

Add linker_reference_module().

This function loads a module if required, otherwise bumps the reference
count -- the opposite of linker_file_unload().

With this commit, I hereby pronounce gensetdefs past its use-by date.

Replace the a.out emulation of 'struct linker_set' with something
a little more flexible. <sys/linker_set.h> now provides macros for
accessing elements and completely hides the implementation.

The linker_set.h macros have been on the back burner in various
forms since 1998 and has ideas and code from Mike Smith (SET_FOREACH()),
John Polstra (ELF clue) and myself (cleaned up API and the conversion
of the rest of the kernel to use it).

The macros declare a strongly typed set. They return elements with the
type that you declare the set with, rather than a generic void *.

For ELF, we use the magic ld symbols (__start_<setname> and
__stop_<setname>). Thanks to Richard Henderson <rth@redhat.com> for the
trick about how to force ld to provide them for kld's.

For a.out, we use the old linker_set struct.

NOTE: the item lists are no longer null terminated. This is why
the code impact is high in certain areas.

The runtime linker has a new method to find the linker set
boundaries depending on which backend format is in use.

linker sets are still module/kld unfriendly and should never be used
for anything that may be modular one day.

Reviewed by: eivind

Correct a warning where the r_debug_state() dummy function used to trigger
a breakpoint in the kernel didn't use the proper argument list. To avoid
having to include the userland link.h header everyhwere that sys/linker.h
is used, make r_debug_state() a static function in link_elf.c as well.

style(9)'ify all the function prototypes by protecting all the parameter
names with a leading underscore. Notably, the 'stat' parameter in the
kld_stat() prototype conflicted with stat() and generated a BDE warning.

Approved by: peter

Back out the previous change to the queue(3) interface.
It was not discussed and should probably not happen.

Requested by: msmith and others

Change the way that the queue(3) structures are declared; don't assume that
the type argument to *_HEAD and *_ENTRY is a struct.

Suggested by: phk
Reviewed by: phk
Approved by: mdodd

First round implementation of a fine grain enhanced module to module
version dependency system. This isn't quite finished, but it is at a
useful stage to do a functional checkpoint.

Highlights:
- version and dependency metadata is gathered via linker sets, so things
are handled the same for static kernels and code built to live in a kld.
- The dependencies are at module level (versus at file level).
- Dependencies determine kld symbol search order - this means that you
cannot link against symbols in another file unless you depend on it. This
is so that you cannot accidently unload the target out from underneath
the ones referencing it.
- It is flexible enough that we can put tags in #include files and macros
so that we can get decent hooks for enforcing recompiles on incompatable
ABI changes. eg: if we change struct proc, we could force a recompile
for all kld's that reference the proc struct.
- Tangled dependency references at boot time are sorted. Files are
relocated once all their dependencies are already relocated.

Caveats:
- Loader support is incomplete, but has been worked on seperately.
- Actual enforcement of the version number tags is not active yet - just
the module dependencies are live. The actual structure of versioning
hasn't been agreed on yet. (eg: major.minor, or whatever)
- There is some backwards compatability for old modules without metadata
but I'm not sure how good it is.

This is based on work originally done by Boris Popov (bp@freebsd.org),
but I'm not sure he'd recognize much of it now. Don't blame him. :-)
Also, ideas have been borrowed from Mike Smith.

* Rewrite to use kobj(9) instead of hard-coded function tables.
* Report link errors to stdout with uprintf() so that the user can see
what went wrong (PR kern/9214).
* Add support code to allow module symbols to be loaded into GDB using
the debugger's "sharedlibrary" command.

Change #ifdef KERNEL to #ifdef _KERNEL in the public headers. "KERNEL"
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot). This is consistant with the other
BSD's who made this change quite some time ago. More commits to come.

$Id$ -> $FreeBSD$

Add MODINFO_ARGS, parameters passed to a module at load time.

VS: ----------------------------------------------------------------------

Fix warnings in preparation for adding -Wall -Wcast-qual to the
kernel compile.

This commit includes significant work to proper handle const arguments
for the DDB symbol routines.

Fix warnings in preparation for adding -Wall -Wcast-qual to the
kernel compile

Don't try to call SYSUNINIT functions if there was a link error.

Reviewed by: Peter Wemm <peter@netplex.com.au>

kldsym(2) prototype implementation

The handle for the kernel is common. With this fix, ELF kernels can load
a.out kld modules, and a.out kernels can load ELF kld modules.

*gulp*. Jordan specifically OK'ed this..

This is the bulk of the support for doing kld modules. Two linker_sets
were replaced by SYSINIT()'s. VFS's and exec handlers are self registered.
kld is now a superset of lkm. I have converted most of them, they will
follow as a seperate commit as samples.
This all still works as a static a.out kernel using LKM's.

Debug typo fixes.
Change symbol_values return type to int, on the chance that we've
been given the wrong symbol table. Symbols have a string index that
must be relative to the correct string table.
Add prototypes for better kld support for ddb.

MODINFO_NAME can't be 0, that's the end of the metadata area.

Missing defines for the kernel environment and module metadata lookup
functions

Add constants associated with preloaded kernel modules.

Modify the internal interfaces to the kernel linker to make it possible
for DDB to use its symbol tables.

Use a real malloc type for M_LINKER instead of #defining it as M_TEMP.

Fixed a sloppy common-style definitions.

This is the kernel linker. To use it, you will first need to apply
the patches in freefall:/home/dfr/ld.diffs to your ld sources and set
BINFORMAT to aoutkld when linking the kernel.

Library changes and userland utilities will appear in a later commit.