dynamic_debug: replace if (verbose) pr_info with macro vpr_info

Use vpr_info to declutter code, reduce indenting, and change one
additional pr_info call in ddebug_exec_queries.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
dynamic_debug: fix leading spaces in dynamic_debug.h

clean up some space-before-tabs problems.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
params: add 3rd arg to option handler callback signature

Add a 3rd arg, named "doing", to unknown-options callbacks invoked
from parse_args(). The arg is passed as:

  "Booting kernel" from start_kernel(),
  initcall_level_names[i] from do_initcall_level(),
  mod->name from load_module(), via parse_args(), parse_one()

parse_args() already has the "name" parameter, which is renamed to
"doing" to better reflect current uses 1,2 above.  parse_args() passes
it to an altered parse_one(), which now passes it down into the
unknown option handler callbacks.

The mod->name will be needed to handle dyndbg for loadable modules,
since params passed by modprobe are not qualified (they do not have a
"$modname." prefix), and by the time the unknown-param callback is
called, the module name is not otherwise available.

Minor tweaks:

Add param-name to parse_one's pr_debug(), current message doesnt
identify the param being handled, add it.

Add a pr_info to print current level and level_name of the initcall,
and number of registered initcalls at that level.  This adds 7 lines
to dmesg output, like:

   initlevel:6=device, 172 registered initcalls

Drop "parameters" from initcall_level_names[], its unhelpful in the
pr_info() added above.  This array is passed into parse_args() by
do_initcall_level().

CC: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
dynamic_debug: make dynamic-debug work for module initialization

This introduces a fake module param $module.dyndbg.  Its based upon
Thomas Renninger's $module.ddebug boot-time debugging patch from
https://lkml.org/lkml/2010/9/15/397

The 'fake' module parameter is provided for all modules, whether or
not they need it.  It is not explicitly added to each module, but is
implemented in callbacks invoked from parse_args.

For builtin modules, dynamic_debug_init() now directly calls
parse_args(..., &ddebug_dyndbg_boot_params_cb), to process the params
undeclared in the modules, just after the ddebug tables are processed.

While its slightly weird to reprocess the boot params, parse_args() is
already called repeatedly by do_initcall_levels().  More importantly,
the dyndbg queries (given in ddebug_query or dyndbg params) cannot be
activated until after the ddebug tables are ready, and reusing
parse_args is cleaner than doing an ad-hoc parse.  This reparse would
break options like inc_verbosity, but they probably should be params,
like verbosity=3.

ddebug_dyndbg_boot_params_cb() handles both bare dyndbg (aka:
ddebug_query) and module-prefixed dyndbg params, and ignores all other
parameters.  For example, the following will enable pr_debug()s in 4
builtin modules, in the order given:

  dyndbg="module params +p; module aio +p" module.dyndbg=+p pci.dyndbg

For loadable modules, parse_args() in load_module() calls
ddebug_dyndbg_module_params_cb().  This handles bare dyndbg params as
passed from modprobe, and errors on other unknown params.

Note that modprobe reads /proc/cmdline, so "modprobe foo" grabs all
foo.params, strips the "foo.", and passes these to the kernel.
ddebug_dyndbg_module_params_cb() is again called for the unknown
params; it handles dyndbg, and errors on others.  The "doing" arg
added previously contains the module name.

For non CONFIG_DYNAMIC_DEBUG builds, the stub function accepts
and ignores $module.dyndbg params, other unknowns get -ENOENT.

If no param value is given (as in pci.dyndbg example above), "+p" is
assumed, which enables all pr_debug callsites in the module.

The dyndbg fake parameter is not shown in /sys/module/*/parameters,
thus it does not use any resources.  Changes to it are made via the
control file.

Also change pr_info in ddebug_exec_queries to vpr_info,
no need to see it all the time.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
CC: Thomas Renninger <trenn@suse.de>
CC: Rusty Russell <rusty@rustcorp.com.au>
dynamic_debug: deprecate ddebug_query, suggest dyndbg instead

With ddebug_dyndbg_boot_params_cb() handling bare dyndbg params, we
dont need ddebug_query param anymore.  Add a warning when processing
ddebug_query= param that it is deprecated, and to change it to dyndbg=

Add a deprecation notice for v3.8 to feature-removal-schedule.txt, and
add a suggested deprecation period of 3 releases to the header.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
dynamic_debug: combine parse_args callbacks together

Refactor ddebug_dyndbg_boot_param_cb and ddebug_dyndbg_module_param_cb
into a common helper function, and call it from both.  The handling of
foo.dyndbg is unneeded by the latter, but harmless.

The 2 callers differ only by pr_info and the return code they pass to
the helper for when an unknown param is handled.  I could slightly
reduce dmesg clutter by putting the vpr_info in the common helper,
after the return on_err, but that loses __func__ context, is overly
silent on module_cb unknown param errors, and the clutter is only when
dynamic_debug.verbose=1 anyway.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
dynamic_debug: simplify dynamic_debug_init error exit

We dont want errors while parsing ddebug_query to unload ddebug
tables, so set success after tables are loaded, and return 0 after
query parsing is done.

Simplify error handling code since its no longer used for success,
and change goto label to out_err to clarify this.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
dynamic_debug: print ram usage by ddebug tables if verbose

Print ram usage of dynamic-debug tables and verbose section so user
knows cost of enabling CONFIG_DYNAMIC_DEBUG.  This only counts the
size of the _ddebug tables for builtins and the __verbose section that
they refer to, not those used in loadable modules.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
dynamic_debug: add modname arg to exec_query callchain

Pass module name into ddebug_exec_queries(), ddebug_exec_query(), and
ddebug_parse_query() as separate parameter.  In ddebug_parse_query(),
the module name is added into the query struct before the query-string
is parsed.  This allows the query-string to be shorter:

instead of:
   $modname.dyndbg="module $modname +fp"
do this:
   $modname.dyndbg="+fp"

Omitting "module $modname" from the query string is actually required
for $modname.dyndbg rules; the set-only-once check added in a previous
patch will throw an error if its added again.  ddebug_query="..." has
no $modname associated with it, so the query string may include it.

This also fixes redundant "module $modname" otherwise needed to handle
multiple queries per string:

   $modname.dyndbg="func foo +fp; func bar +fp"

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
dynamic_debug: update Documentation/*, Kconfig.debug

In dynamic-debug-howto.txt:

- add section: Debug Messages at Module Initialization Time
- update flags indicators in example outputs to include '='
- make flags descriptions tabular
- add item on '_' flag-char
- add dyndbg, boot-args examples
- rewrap some paragraphs with long lines

In Kconfig.debug, note that compiling with -DDEBUG enables all
pr_debug()s in that code.

In kernel-parameters.txt, add dyndbg and module.dyndbg items,
and deprecate ddebug_query.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
dynamic_debug: init with early_initcall, not arch_initcall

1- Call dynamic_debug_init() from early_initcall, not arch_initcall.
2- Call dynamic_debug_init_debugfs() from fs_initcall, not module_init.

RFC: This works for me on a 64 bit desktop and a i586 SBC, but is
untested on other arches.  I presume there is or was a reason
original code used arch_initcall, maybe the constraints have changed.

This makes facility available as soon as possible.

2nd change has a downside when dynamic_debug.verbose=1; all the
vpr_info()s called in the proc-fs code are activated, causing
voluminous output from dmesg.  TBD: Im unsure of this explanation, but
the output is there.  This could be fixed by changing those callsites
to v2pr_info(if verbose > 1).

1st change is still not early enough to enable pr_debugs in
kernel/params, so parsing of boot-args isnt logged.  The reparse of
those args is however visible after params.dyndbg="+p" is processed.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
kernel/params: use pr_<level>

Theres one case (in param_sysfs_init) where __FILE__, __LINE__ args
are used.  While these are similar to KBUILD_MODNAME.__func__
sometimes set via pr_fmt(), pr_fmt() may not be used, so preserve
them.
kernel/params: banish backtick in quoting
pnp: if CONFIG_DYNAMIC_DEBUG, use pnp.dyndbg instead of pnp.debug

based upon https://lkml.org/lkml/2010/9/15/398

This patch splits control of pnp debug messages for 2 configs:

CONFIG_DYNAMIC_DEBUG:
  use pnp.dyndbg, using pnp.debug will warn
!CONFIG_DYNAMIC_DEBUG:
  use pnp.debug, using pnp.dyndbg will warn

2 separate boot options is perhaps suboptimal, but dyndbg is a 'fake'
parameter, and is special enough that adapting one to another is both
more suboptimal and harder to explain succinctly.

Thomas' original comments, still pertinent:

I wonder whether CONFIG_PNP_DEBUG_MESSAGES can vanish totally with
this or at some time. Only advantage having it is: If you are
restricted and your kernel must not exceed X bytes, you cannot compile
in PNP debug messages only, but you have to compile in all debug
messages.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
CC: Thomas Renninger <trenn@suse.de>
CC: Bjorn Helgaas <bhelgaas@google.com>