Based on kernel version 2.6.25. Page generated on 2008-04-18 21:22 EST.
1 Copyright 2004 Linus Torvalds 2 Copyright 2004 Pavel Machek <pavel[AT]suse[DOT]cz> 3 Copyright 2006 Bob Copeland <me[AT]bobcopeland[DOT]com> 4 5 Using sparse for typechecking 6 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 7 8 "__bitwise" is a type attribute, so you have to do something like this: 9 10 typedef int __bitwise pm_request_t; 11 12 enum pm_request { 13 PM_SUSPEND = (__force pm_request_t) 1, 14 PM_RESUME = (__force pm_request_t) 2 15 }; 16 17 which makes PM_SUSPEND and PM_RESUME "bitwise" integers (the "__force" is 18 there because sparse will complain about casting to/from a bitwise type, 19 but in this case we really _do_ want to force the conversion). And because 20 the enum values are all the same type, now "enum pm_request" will be that 21 type too. 22 23 And with gcc, all the __bitwise/__force stuff goes away, and it all ends 24 up looking just like integers to gcc. 25 26 Quite frankly, you don't need the enum there. The above all really just 27 boils down to one special "int __bitwise" type. 28 29 So the simpler way is to just do 30 31 typedef int __bitwise pm_request_t; 32 33 #define PM_SUSPEND ((__force pm_request_t) 1) 34 #define PM_RESUME ((__force pm_request_t) 2) 35 36 and you now have all the infrastructure needed for strict typechecking. 37 38 One small note: the constant integer "0" is special. You can use a 39 constant zero as a bitwise integer type without sparse ever complaining. 40 This is because "bitwise" (as the name implies) was designed for making 41 sure that bitwise types don't get mixed up (little-endian vs big-endian 42 vs cpu-endian vs whatever), and there the constant "0" really _is_ 43 special. 44 45 Getting sparse 46 ~~~~~~~~~~~~~~ 47 48 You can get latest released versions from the Sparse homepage at 49 http://www.kernel.org/pub/linux/kernel/people/josh/sparse/ 50 51 Alternatively, you can get snapshots of the latest development version 52 of sparse using git to clone.. 53 54 git://git.kernel.org/pub/scm/linux/kernel/git/josh/sparse.git 55 56 DaveJ has hourly generated tarballs of the git tree available at.. 57 58 http://www.codemonkey.org.uk/projects/git-snapshots/sparse/ 59 60 61 Once you have it, just do 62 63 make 64 make install 65 66 as a regular user, and it will install sparse in your ~/bin directory. 67 68 Using sparse 69 ~~~~~~~~~~~~ 70 71 Do a kernel make with "make C=1" to run sparse on all the C files that get 72 recompiled, or use "make C=2" to run sparse on the files whether they need to 73 be recompiled or not. The latter is a fast way to check the whole tree if you 74 have already built it. 75 76 The optional make variable CHECKFLAGS can be used to pass arguments to sparse. 77 The build system passes -Wbitwise to sparse automatically. To perform 78 endianness checks, you may define __CHECK_ENDIAN__: 79 80 make C=2 CHECKFLAGS="-D__CHECK_ENDIAN__" 81 82 These checks are disabled by default as they generate a host of warnings.
