linux/scripts/kconfig/expr.h, branch v2.6.36

kconfig: delay symbol direct dependency initialization

2010-10-04T13:13:13Z

This fixes the use-after-free and associated crash in kconfig introduced in commit 246cf9c26bf11f2bffbecea6e5bd222eee7b1df8. Signed-off-by: Arnaud Lacombe Acked-by: Catalin Marinas Signed-off-by: Michal Marek

kconfig: save location of config symbols

2010-08-03T11:49:31Z

When we add a new config symbol save the file/line so we later can refer to their location. The information is saved as a property to a config symbol because we may have multiple definitions of the same symbol. This has the side-effect that a symbol always has at least one property. Signed-off-by: Sam Ravnborg Cc: Roman Zippel Signed-off-by: Michal Marek

kbuild: Warn on selecting symbols with unmet direct dependencies

2010-07-02T12:53:09Z

The "select" statement in Kconfig files allows the enabling of options even if they have unmet direct dependencies (i.e. "depends on" expands to "no"). Currently, the "depends on" clauses are used in calculating the visibility but they do not affect the reverse dependencies in any way. The patch introduces additional tracking of the "depends on" statements and prints a warning on selecting an option if its direct dependencies are not met. Signed-off-by: Catalin Marinas Cc: Sam Ravnborg Cc: Arnd Bergmann Cc: Andrew Morton Cc: Linus Torvalds Signed-off-by: Michal Marek

Improve kconfig symbol hashing

2010-02-02T13:33:55Z

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: Andi Kleen Signed-off-by: Michal Marek

kconfig: struct property commented

2009-01-02T19:43:21Z

No functional changes Signed-off-by: Sam Ravnborg

kconfig: add comments to symbol flags

2009-01-02T19:43:21Z

No functional changes - only comments. Signed-off-by: Sam Ravnborg

kconfig: explain symbol value defaults

2009-01-02T19:43:20Z

Added a few comments - no functional change. Signed-off-by: Sam Ravnborg

kconfig: environment symbol support

2008-01-28T22:14:39Z

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: Roman Zippel Signed-off-by: Sam Ravnborg

kconfig: explicitly introduce expression list

2008-01-28T22:14:39Z

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: Roman Zippel Signed-off-by: Sam Ravnborg

kconfig: delete unused FILE_ and SYMBOL_ flags

2008-01-28T22:14:38Z

The *_PRINTED flags were never used - so delete them. Do we need them later then we can re-add them. Signed-off-by: Sam Ravnborg Cc: Roman Zippel