lkml.org 
[lkml]   [2004]   [Dec]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: swsusp bigdiff [was Re: [PATCH] Software Suspend split to two stage V2.]
    Pavel Machek wrote:
    > [...]
    > --- clean/Documentation/sparse.txt 2004-10-16 23:48:08.000000000 +0200
    > +++ linux/Documentation/sparse.txt 2004-10-24 22:44:47.000000000 +0200
    > @@ -0,0 +1,72 @@
    > +Copyright 2004 Linus Torvalds
    > +Copyright 2004 Pavel Machek <pavel@suse.cz>
    > +
    > +Using sparse for typechecking
    > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    > +
    > +"__bitwise" is a type attribute, so you have to do something like this:
    > +
    > + typedef int __bitwise pm_request_t;
    > +
    > + enum pm_request {
    > + PM_SUSPEND = (__force pm_request_t) 1,
    > + PM_RESUME = (__force pm_request_t) 2
    > + };
    > +
    > +which makes PM_SUSPEND and PM_RESUME "bitwise" integers (the "__force" is
    > +there because sparse will complain about casting to/from a bitwise type,
    > +but in this case we really _do_ want to force the conversion). And because
    > +the enum values are all the same type, now "enum pm_request" will be that
    > +type too.
    > +
    > +And with gcc, all the __bitwise/__force stuff goes away, and it all ends
    > +up looking just like integers to gcc.
    > +
    > +Quite frankly, you don't need the enum there. The above all really just
    > +boils down to one special "int __bitwise" type.
    > +
    > +So the simpler way is to just do
    > +
    > + typedef int __bitwise pm_request_t;
    > +
    > + #define PM_SUSPEND ((__force pm_request_t) 1)
    > + #define PM_RESUME ((__force pm_request_t) 2)
    > +
    > +and you now have all the infrastructure needed for strict typechecking.
    > +
    > +One small note: the constant integer "0" is special. You can use a
    > +constant zero as a bitwise integer type without sparse ever complaining.
    > +This is because "bitwise" (as the name implies) was designed for making
    > +sure that bitwise types don't get mixed up (little-endian vs big-endian
    > +vs cpu-endian vs whatever), and there the constant "0" really _is_
    > +special.
    > +
    > +Modify top-level Makefile to say
    > +
    > +CHECK = sparse -Wbitwise
    > +
    > +or you don't get any checking at all.
    > +
    > +
    > +Where to get sparse
    > +~~~~~~~~~~~~~~~~~~~
    > +
    > +With BK, you can just get it from
    > +
    > + bk://sparse.bkbits.net/sparse
    > +
    > +and DaveJ has tar-balls at
    > +
    > + http://www.codemonkey.org.uk/projects/bitkeeper/sparse/
    > +
    > +
    > +Once you have it, just do
    > +
    > + make
    > + make install
    > +
    > +as your regular user, and it will install sparse in your ~/bin directory.
    > +After that, doing a kernel make with "make C=1" will run sparse on all the
    > +C files that get recompiled, or with "make C=2" will run sparse on the
    > +files whether they need to be recompiled or not (ie the latter is fast way
    > +to check the whole tree if you have already built it).
    > --- clean/Makefile 2004-10-19 14:16:26.000000000 +0200
    > +++ linux/Makefile 2004-10-29 11:56:48.000000000 +0200
    > @@ -325,7 +325,7 @@
    > DEPMOD = /sbin/depmod
    > KALLSYMS = scripts/kallsyms
    > PERL = perl
    > -CHECK = sparse
    > +CHECK = sparse -Wbitwise

    I know this is a "big diff" patch, but it seems that these sparse
    changes are completely unrelated to software suspend.

    --
    Paulo Marques - www.grupopie.com

    "A journey of a thousand miles begins with a single step."
    Lao-tzu, The Way of Lao-tzu

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 14:08    [W:0.028 / U:61.668 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site