While looking for something else I noticed that the symbol
hash function used by kconfig is quite poor. It doesn't
use any of the standard hash techniques but simply
adds up the string and then uses power of two masking,
which is both known to perform poorly.

The current x86 kconfig has over 7000 symbols.

When I instrumented it showed that the minimum hash chain
length was 16 and a significant number of them was over
30.

It didn't help that the hash table size was only 256 buckets.

This patch increases the hash table size to a larger prime
and switches to a FNV32 hash. I played around with a couple of hash
functions, but that one seemed to perform best with reasonable
hash table sizes.

Increasing the hash table size even further didn't
seem like a good idea, because there are a couple of global
walks which walk the complete hash table.

I also moved the unnamed bucket to 0. It's still the longest
of all the buckets (44 entries), but hopefully it's not
often hit except for the global walk which doesn't care.

The result is a much nicer distribution:
(first column bucket length, second number of buckets with that length)

1: 3505
2: 1236
3: 294
4: 52
5: 3
47: 1		<--- this is the unnamed symbols bucket

There are still some 5+ buckets, but increasing the hash table
even more would be likely not worth it.

This also cleans up the code slightly by removing hard coded
magic numbers.

I didn't notice a big performance difference either way
on my Nehalem system, but I presume it'll help somewhat
on slower systems.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

Warnings found via gcc -Wmissing-prototypes.
Signed-off-by: NTrevor Keith <tsrk@tsrk.net>
Acked-by: NWANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

As choice dependency are now fully checked, it's quite easy to add support
for named choices. This lifts the restriction that a choice value can only
appear once, although it still has to be within the same group,
but multiple choices can be joined by giving them a name.
While at it I cleaned up a little the choice type logic to simplify it a
bit.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Properly check the dependency of choices as a group.
Also fix that sym_check_deps() correctly terminates the dependency loop
error check (otherwise it would continue printing the dependency chain).
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

> The attached .config (with current -git) results in a compile
> error since it contains:
>
> CONFIG_X86=y
> # CONFIG_EMBEDDED is not set
> CONFIG_SERIO=m
> CONFIG_SERIO_I8042=y
>
> Looking at drivers/input/serio/Kconfig I simply don't get how this
> can happen.

You've hit the rather subtle rules of select vs default. What happened is
that SERIO is selected to m, but SERIO_I8042 isn't selected so the default
of y is used instead.
We already had the problem in the past that select and default don't work
well together, so this patch cleans this up and makes the rule hopefully
more straightforward. Basically now the value is calculated like this:

	(value && dependency) || select

where the value is the user choice (if available and the symbol is
visible) or default.

In this case it means SERIO and SERIO_I8042 are both set to y due to their
default and if SERIO didn't had the default, then the SERIO_I8042 value
would be limited to m due to the dependency.

I tested this patch with more 10000 random configs and above case is the
only the difference that showed up, so I hope there is nothing that
depended on the old more complex and subtle rules.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Tested-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Use the environment option to provide the ARCH symbol
and the KERNELVERSION symbol.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Add the possibility to import a value from the environment into kconfig
via the option syntax. Beside flexibility this has the advantage
providing proper dependencies.
Documented the options syntax.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Rename E_CHOICE to E_LIST to explicitly add support for expression
lists. Add a helper macro expr_list_for_each_sym to more easily iterate
over the list.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

We had macros named the same as a set of enumeration values.
It is legal code but very confusing to read - so rename
the macros from E_* to EXPR_*
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Cc: Roman Zippel <zippel@linux-m68k.org>

Sample:
config FOO
	bool "This is foo"
	depends on BAR

config BAR
	bool "This is bar"
	depends on FOO

This will result in following error message:
error: found recursive dependency: FOO -> BAR -> FOO

And will then exit with exit code equal 1 so make will stop.
Inspired by patch from: Adrian Bunk <bunk@stusta.de>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Cc: Adrian Bunk <bunk@stusta.de>
Cc: Roman Zippel <zippel@linux-m68k.org>

Those two functions are
	void sym_set_change_count(int count)
and
	void sym_add_change_count(int count)

All write accesses to sym_change_count are replaced by calls to above
functions.

Variable and changer-functions are moved to confdata.c.  IMO thats ok, as
sym_change_count is an attribute of the .config's change state.
Signed-off-by: NKarsten Wiese <fzu@wemgehoertderstaat.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Acked-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This makes it possible to change two options which were hardcoded sofar.
1. Any symbol can now take the role of CONFIG_MODULES
2. The more useful option is to change the list of default file names,
   which kconfig uses to load the base configuration if .config isn't
   available.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Extend conf_read_simple() so it can load multiple configurations.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Extend struct symbol to allow storing multiple default values, which can be
used to hold multiple configurations.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

The SYMBOL_{YES,MOD,NO} are not really used anymore (they were more used be
the cml1 converter), so just remove them.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

To enable 'make kernelrelease' earlier now create .kernelrelease when
one of the *config targets are used.
Also introduce KERNELVERSION - only user is kconfig.
KERNELVERSION was needed to display kernel version in menuconfig -
KERNELRELEASE is not valid until configuration has completed.
kconfig files modified to use KERNELVERSION.
Bug reported by: Rene Rebe <rene@exactcode.de>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

This allows variable arguments in the range option for int and hex config
symbols.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The restart check whether new symbols became visible, didn't always work for
choice symbols.  Even if a choice symbol itself isn't changable, the childs
are.  This also requires to update the new status of all choice values, once
one of them is set.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

When doing its recursive dependency check, scripts/kconfig/conf uses the flag
SYMBOL_CHECK_DONE to avoid rechecking a symbol it has already checked.
However, that flag is only set at the top level, so if a symbol is first
encountered as a dependency of another symbol it will be rechecked every time
it is encountered until it's encountered at the top level.

This patch adjusts the flag setting so that each symbol will only be checked
once, regardless of whether it is first encountered at the top level, or while
recursing down from another symbol.  On complex configurations, this vastly
speeds up scripts/kconfig/conf.  The config in the powerpc merge tree is
particularly bad: this patch reduces the time for 'scripts/kconfig/conf -o
arch/powerpc/Kconfig' by a factor of 40 on a G5.  That's even including the
time to print the config, so the speedup in the actual checking is more likely
2 or 3 orders of magnitude.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!