Commit Graph

7 Commits

Author SHA1 Message Date
Michal Marek e37ddb8250 genksyms: Track changes to enum constants
Enum constants can be used as array sizes; if the enum itself does not
appear in the symbol expansion, a change in the enum constant will go
unnoticed. Example patch that changes the ABI but does not change the
checksum with current genksyms:

| enum e {
|	E1,
|	E2,
|+	E3,
|	E_MAX
| };
|
| struct s {
|	int a[E_MAX];
| }
|
| int f(struct s *s) { ... }
| EXPORT_SYMBOL(f)

Therefore, remember the value of each enum constant and
expand each occurence to <constant> <value>. The value is not actually
computed, but instead an expression in the form
(last explicitly assigned value) + N
is used. This avoids having to parse and semantically understand whole
of C.

Note: The changes won't take effect until the lexer and parser are
rebuilt by the next patch.

Signed-off-by: Michal Marek <mmarek@suse.cz>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
2011-03-17 15:13:56 +01:00
Michal Marek 01762c4ec5 genksyms: simplify usage of find_symbol()
Allow searching for symbols of an exact type. The lexer does this and a
subsequent patch will add one more usage.

Signed-off-by: Michal Marek <mmarek@suse.cz>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
2011-03-17 15:13:55 +01:00
Andreas Gruenbacher 5dae9a550a genksyms: allow to ignore symbol checksum changes
This adds an "override" keyword for use in *.symvers / *.symref files.
When a symbol is overridden, the symbol's old definition will be used for
computing checksums instead of the new one, preserving the previous
checksum.  (Genksyms will still warn about the change.)

This is meant to allow distributions to hide minor actual as well as fake
ABI changes.  (For example, when extra type information becomes available
because additional headers are included, this may change checksums even
though none of the types used have actully changed.)

This approach also allows to get rid of "#ifdef __GENKSYMS__" hacks in the
code, which are currently used in some vendor kernels to work around
checksum changes.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2008-12-03 22:33:12 +01:00
Andreas Gruenbacher 64e6c1e123 genksyms: track symbol checksum changes
Sometimes it is preferable to avoid changes of exported symbol checksums
(to avoid breaking externally provided modules).  When a checksum change
occurs, it can be hard to figure out what caused this change: underlying
types may have changed, or additional type information may simply have
become available at the point where a symbol is exported.

Add a new --reference option to genksyms which allows it to report why
checksums change, based on the type information dumps it creates with the
--dump-types flag.  Genksyms will read in such a dump from a previous run,
and report which symbols have changed (and why).

The behavior can be controlled for an entire build as follows: If
KBUILD_SYMTYPES is set, genksyms uses --dump-types to produce *.symtypes
dump files.  If any *.symref files exist, those will be used as the
reference to check against.  If KBUILD_PRESERVE is set, checksum changes
will fail the build.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2008-12-03 22:33:11 +01:00
Andreas Gruenbacher 15fde67518 kbuild: support for %.symtypes files
Here is a patch that adds a new -T option to genksyms for generating dumps of
the type definition that makes up the symbol version hashes. This allows to
trace modversion changes back to what caused them. The dump format is the
name of the type defined, followed by its definition (which is almost C):

  s#list_head struct list_head { s#list_head * next , * prev ; }

The s#, u#, e#, and t# prefixes stand for struct, union, enum, and typedef.
The exported symbols do not define types, and thus do not have an x# prefix:

  nfs4_acl_get_whotype int nfs4_acl_get_whotype ( char * , t#u32 )

The symbol type defintion of a single file can be generated with:

  make fs/jbd/journal.symtypes

If KBUILD_SYMTYPES is defined, all the *.symtypes of all object files that
export symbols are generated.

The single *.symtypes files can be combined into a single file after a kernel
build with a script like the following:

for f in $(find -name '*.symtypes' | sort); do
    f=${f#./}
    echo "/* ${f%.symtypes}.o */"
    cat $f
    echo
done \
| sed -e '\:UNKNOWN:d' \
      -e 's:[,;] }:}:g' \
      -e 's:\([[({]\) :\1:g' \
      -e 's: \([])},;]\):\1:g' \
      -e 's: $::' \
      $f \
| awk '
/^.#/   { if (defined[$1] == $0) {
            print $1
            next
          }
          defined[$1] = $0
        }
        { print }
'

When the kernel ABI changes, diffing individual *.symtype files, or the
combined files, against each other will show which symbol changes caused the
ABI changes. This can save a tremendous amount of time.

Dump the types that make up modversions

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2006-06-24 23:42:46 +02:00
Sam Ravnborg ce56068694 kbuild: clean-up genksyms
o remove all inlines
o declare everything static which is only used by genksyms.c
o delete unused functions
o delete unused variables
o delete unused stuff in genksyms.h
o properly ident genksyms.h

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2006-03-12 23:26:29 +01:00
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2
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!
2005-04-16 15:20:36 -07:00