Do you think kernel build is 100% dominated by gcc? You are wrong!
One small utility called "fixdep" consistently manages to sneak into
profile's first page (unless you have small monitor of course).
The choke point is this clever code:
for (; m < end; m++) {
if (*m == INT_CONF) { p = (char *) m ; goto conf; }
if (*m == INT_ONFI) { p = (char *) m-1; goto conf; }
if (*m == INT_NFIG) { p = (char *) m-2; goto conf; }
if (*m == INT_FIG_) { p = (char *) m-3; goto conf; }
4 branches per 4 characters is not fast.
Use strstr(3), so that SSE2 etc can be used.
With this patch, fixdep is so deep at the bottom, it is hard to find it.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
bin2c is used to create a valid C file out of a binary file where two
symbols will be globally defined: <name> and <name>_size. <name> is
passed as the first parameter of the host binary.
Building using goto-cc reported that the purgatory binary code (the only
current user of this utility) declares kexec_purgatory_size as 'size_t'
where bin2c generate <name>_size to be 'int' so in a 64-bit host where
sizeof(size_t) > sizeof(int) this type mismatch will always yield the
wrong value for big-endian architectures while for little-endian it will
be wrong if the object laid in memory directly after
kexec_purgatory_size contains non-zero value at the time of reading.
This commit changes <name>_size to be size_t instead.
Note:
Another way to fix the problem is to change the type of
kexec_purgatory_size to be 'int' as there's this check in code:
(kexec_purgatory_size <= 0)
Signed-off-by: Michael Tautschnig <tautschn@amazon.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
Like with kconfig options, we now have the ability to compile in and
out individual EXPORT_SYMBOL() declarations based on the content of
include/generated/autoksyms.h. However we don't want the entire
world to be rebuilt whenever that file is touched.
Let's apply the same build dependency trick used for CONFIG_* symbols
where the time stamp of empty files whose paths matching those symbols
is used to trigger fine grained rebuilds. In our case the key is the
symbol name passed to EXPORT_SYMBOL().
However, unlike config options, we cannot just use fixdep to parse
the source code for EXPORT_SYMBOL(ksym) because several variants exist
and parsing them all in a separate tool, and keeping it in synch, is
not trivially maintainable. Furthermore, there are variants such as
EXPORT_SYMBOL_GPL(pci_user_read_config_##size);
that are instanciated via a macro for which we can't easily determine
the actual exported symbol name(s) short of actually running the
preprocessor on them.
Storing the symbol name string in a special ELF section doesn't work
for targets that output assembly or preprocessed source.
So the best way is really to leverage the preprocessor by having it
output actual symbol names anchored by a special sequence that can be
easily filtered out. Then the list of symbols is simply fed to fixdep
to be merged with the other dependencies.
That implies the preprocessor is executed twice for each source file.
A previous attempt relied on a warning pragma for each EXPORT_SYMBOL()
instance that was filtered apart from stderr by the build system with
a sed script during the actual compilation pass. Unfortunately the
preprocessor/compiler diagnostic output isn't stable between versions
and this solution, although more efficient, was deemed too fragile.
Because of the lowercasing performed by fixdep, there might be name
collisions triggering spurious rebuilds for similar symbols. But this
shouldn't be a big issue in practice. (This is the case for CONFIG_*
symbols and I didn't want to be different here, whatever the original
reason for doing so.)
To avoid needless build overhead, the exported symbol name gathering is
performed only when CONFIG_TRIM_UNUSED_KSYMS is selected.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Coverity has recently added a check that will find when we don't check
the return code from fstat(2). Copy/paste the checking logic that
print_deps() has with an appropriate re-wording of the perror() message.
Signed-off-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
strrcmp only performs read access to the memory addressed by its
arguments so make them const pointers.
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
The clear_config() is called just once at the beginning of this
program, but the global variable hashtab[] is already zero-filled
at the start-up.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
If the target string matches "CONFIG_", move the pointer p
forward. This saves several 7-chars adjustments.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
This patch series does not do kernel signature verification yet. I plan
to post another patch series for that. Now distributions are already
signing PE/COFF bzImage with PKCS7 signature I plan to parse and verify
those signatures.
Primary goal of this patchset is to prepare groundwork so that kernel
image can be signed and signatures be verified during kexec load. This
should help with two things.
- It should allow kexec/kdump on secureboot enabled machines.
- In general it can help even without secureboot. By being able to verify
kernel image signature in kexec, it should help with avoiding module
signing restrictions. Matthew Garret showed how to boot into a custom
kernel, modify first kernel's memory and then jump back to old kernel and
bypass any policy one wants to.
This patch (of 15):
Kexec wants to use bin2c and it wants to use it really early in the build
process. See arch/x86/purgatory/ code in later patches.
So move bin2c in scripts/basic so that it can be built very early and
be usable by arch/x86/purgatory/
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current use-case for fixdep is: a source file is run through a single
processing step, which creates a single dependency file as a side-effect,
which fixdep transforms into the file used by the kernel build process.
In order to transparently run the C pre-processor on device-tree files,
we wish to run both gcc -E and dtc on a source file in a single rule.
This generates two dependency files, which must be transformed together
into the file used by the kernel build process. This change modifies
fixdep so it can process the concatenation of multiple separate input
dependency files, and produce a correct unified output.
The code changes have the slight benefit of transforming the loop in
parse_dep_file() into more of a lexer/tokenizer, with the loop body being
more of a parser. Previously, some of this logic was mixed together
before the loop. I also added some comments, which I hope are useful.
Benchmarking shows that on a cross-compiled ARM tegra_defconfig build,
there is less than 0.5 seconds speed decrease with this change, on top
of a build time of ~2m24s. This is probably within the noise.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Rob Herring <rob.herring@calxeda.com>
The introduction of include/linux/kconfig.h created 3 extraneous
dependencies:
include/config/.h
include/config/h.h
include/config/foo.h
Fix this by excluding kconfig.h from fixdep calculations.
Signed-off-by: Peter Foley <pefoley2@verizon.net>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Recent change to fixdep:
commit b7bd182176
Author: Michal Marek <mmarek@suse.cz>
Date: Thu Feb 17 15:13:54 2011 +0100
fixdep: Do not record dependency on the source file itself
changed the format of the *.cmd files without realizing that it is also
used by modpost. Put the path to the source file to the file back, in a
special variable, so that modpost sees all source files when calculating
srcversion for modules.
Reported-and-tested-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The dependency is already expressed by the Makefiles, storing it in the
.cmd file breaks build if a .c file is replaced by .S or vice versa,
because the .cmd file contains
foo/bar.o: foo/bar.c ...
foo/bar.c ... :
so the foo/bar.c -> foo/bar.o rule triggers even if there is no
foo/bar.c anymore.
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Michal Marek <mmarek@suse.cz>
I noticed fixdep uses ~2% of cpu time in kernel build, in function
use_config()
fixdep spends a lot of cpu cycles in linear searches in its internal
string array. With about 400 stored strings per dep file, this begins to
be noticeable.
Convert fixdep to use a hash table.
kbuild results on my x86_64 allmodconfig
Before patch :
real 10m30.414s
user 61m51.456s
sys 8m28.200s
real 10m12.334s
user 61m50.236s
sys 8m30.448s
real 10m42.947s
user 61m50.028s
sys 8m32.380s
After:
real 10m8.180s
user 61m22.506s
sys 8m32.384s
real 10m35.039s
user 61m21.654s
sys 8m32.212s
real 10m14.487s
user 61m23.498s
sys 8m32.312s
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
* 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6: (39 commits)
Revert "namespace: add source file location exceptions"
Coccinelle: Add contextual message
Coccinelle: Fix documentation
Coccinelle: Find doubled arguments to boolean or bit operators.
Coccinelle: Find nested lock+irqsave functions that use the same flags variables.
namespace: add source file location exceptions
scripts/extract-ikconfig: add support for bzip2, lzma and lzo
kbuild: check return value of asprintf()
scripts/namespace.pl: improve to get more correct results
scripts/namespace.pl: some bug fixes
scripts/namespace.pl: update file exclusion list
scripts/namespace.pl: fix wrong source path
Coccinelle: Use the -no_show_diff option for org and report mode
Coccinelle: Add a new mode named 'chain'
Coccinelle: Use new comment format to explain kfree.cocci
Coccinelle: Improve user information with a new kind of comment
Coccinelle: Update documentation
MAINTAINERS: Coccinelle: Update email address
Documentation/kbuild: modules.txt cleanup
Documentation/kbuild: major edit of modules.txt sections 5-8
...
Check return value of asprintf() in docsect() and exit if error
occurs. This removes following warning:
HOSTCC scripts/basic/docproc
scripts/basic/docproc.c: In function ‘docsect’:
scripts/basic/docproc.c:336: warning: ignoring return value of ‘asprintf’,
declared with attribute warn_unused_result
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
When you don't use !E or !I but only !F, then it's very easy to miss
including some functions, structs etc. in documentation. To help
finding which ones were missed, allow printing out the unused ones as
warnings.
For example, using this on mac80211 yields a lot of warnings like this:
Warning: didn't use docs for DOC: mac80211 workqueue
Warning: didn't use docs for ieee80211_max_queues
Warning: didn't use docs for ieee80211_bss_change
Warning: didn't use docs for ieee80211_bss_conf
when generating the documentation for it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
