Commit Graph

361 Commits

Author SHA1 Message Date
Greg Kroah-Hartman
6ca04bd7ae Merge b250e6d141 ("Merge tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild") into android-mainline
Steps on the way to 5.15-rc1

Fixed up merge conflicts in:
	scripts/Makefile.modfinal

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I3a916b7267fc2e4ed2f2bd308b9cff8ca9430660
2021-09-14 14:41:11 +02:00
Greg Kroah-Hartman
c2b303f98f Merge 4e71add028 ("Merge branch 'stable/for-linus-5.15-rc0' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/ibft") into android-mainline
Steps on the way to 5.15-rc1

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ib3f181326491eb896547d802a6f0a1b3be54ce28
2021-09-14 14:35:23 +02:00
Linus Torvalds
b250e6d141 Merge tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:

 - Add -s option (strict mode) to merge_config.sh to make it fail when
   any symbol is redefined.

 - Show a warning if a different compiler is used for building external
   modules.

 - Infer --target from ARCH for CC=clang to let you cross-compile the
   kernel without CROSS_COMPILE.

 - Make the integrated assembler default (LLVM_IAS=1) for CC=clang.

 - Add <linux/stdarg.h> to the kernel source instead of borrowing
   <stdarg.h> from the compiler.

 - Add Nick Desaulniers as a Kbuild reviewer.

 - Drop stale cc-option tests.

 - Fix the combination of CONFIG_TRIM_UNUSED_KSYMS and CONFIG_LTO_CLANG
   to handle symbols in inline assembly.

 - Show a warning if 'FORCE' is missing for if_changed rules.

 - Various cleanups

* tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (39 commits)
  kbuild: redo fake deps at include/ksym/*.h
  kbuild: clean up objtool_args slightly
  modpost: get the *.mod file path more simply
  checkkconfigsymbols.py: Fix the '--ignore' option
  kbuild: merge vmlinux_link() between ARCH=um and other architectures
  kbuild: do not remove 'linux' link in scripts/link-vmlinux.sh
  kbuild: merge vmlinux_link() between the ordinary link and Clang LTO
  kbuild: remove stale *.symversions
  kbuild: remove unused quiet_cmd_update_lto_symversions
  gen_compile_commands: extract compiler command from a series of commands
  x86: remove cc-option-yn test for -mtune=
  arc: replace cc-option-yn uses with cc-option
  s390: replace cc-option-yn uses with cc-option
  ia64: move core-y in arch/ia64/Makefile to arch/ia64/Kbuild
  sparc: move the install rule to arch/sparc/Makefile
  security: remove unneeded subdir-$(CONFIG_...)
  kbuild: sh: remove unused install script
  kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y
  kbuild: Switch to 'f' variants of integrated assembler flag
  kbuild: Shuffle blank line to improve comment meaning
  ...
2021-09-03 15:33:47 -07:00
Masahiro Yamada
e54dd93a08 modpost: get the *.mod file path more simply
get_src_version() strips 'o' or 'lto.o' from the end of the object file
path (so, postfixlen is 1 or 5), then adds 'mod'.

If you look at the code closely, mod->name already holds the base path
with the extension stripped.

Most of the code changes made by commit 7ac204b545 ("modpost: lto:
strip .lto from module names") was actually unneeded.

sumversion.c does not need strends(), so it can get back local in
modpost.c again.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-09-03 08:17:21 +09:00
Christophe Leroy
1e688dd2a3 powerpc/bug: Provide better flexibility to WARN_ON/__WARN_FLAGS() with asm goto
Using asm goto in __WARN_FLAGS() and WARN_ON() allows more
flexibility to GCC.

For that add an entry to the exception table so that
program_check_exception() knowns where to resume execution
after a WARNING.

Here are two exemples. The first one is done on PPC32 (which
benefits from the previous patch), the second is on PPC64.

	unsigned long test(struct pt_regs *regs)
	{
		int ret;

		WARN_ON(regs->msr & MSR_PR);

		return regs->gpr[3];
	}

	unsigned long test9w(unsigned long a, unsigned long b)
	{
		if (WARN_ON(!b))
			return 0;
		return a / b;
	}

Before the patch:

	000003a8 <test>:
	 3a8:	81 23 00 84 	lwz     r9,132(r3)
	 3ac:	71 29 40 00 	andi.   r9,r9,16384
	 3b0:	40 82 00 0c 	bne     3bc <test+0x14>
	 3b4:	80 63 00 0c 	lwz     r3,12(r3)
	 3b8:	4e 80 00 20 	blr

	 3bc:	0f e0 00 00 	twui    r0,0
	 3c0:	80 63 00 0c 	lwz     r3,12(r3)
	 3c4:	4e 80 00 20 	blr

	0000000000000bf0 <.test9w>:
	 bf0:	7c 89 00 74 	cntlzd  r9,r4
	 bf4:	79 29 d1 82 	rldicl  r9,r9,58,6
	 bf8:	0b 09 00 00 	tdnei   r9,0
	 bfc:	2c 24 00 00 	cmpdi   r4,0
	 c00:	41 82 00 0c 	beq     c0c <.test9w+0x1c>
	 c04:	7c 63 23 92 	divdu   r3,r3,r4
	 c08:	4e 80 00 20 	blr

	 c0c:	38 60 00 00 	li      r3,0
	 c10:	4e 80 00 20 	blr

After the patch:

	000003a8 <test>:
	 3a8:	81 23 00 84 	lwz     r9,132(r3)
	 3ac:	71 29 40 00 	andi.   r9,r9,16384
	 3b0:	40 82 00 0c 	bne     3bc <test+0x14>
	 3b4:	80 63 00 0c 	lwz     r3,12(r3)
	 3b8:	4e 80 00 20 	blr

	 3bc:	0f e0 00 00 	twui    r0,0

	0000000000000c50 <.test9w>:
	 c50:	7c 89 00 74 	cntlzd  r9,r4
	 c54:	79 29 d1 82 	rldicl  r9,r9,58,6
	 c58:	0b 09 00 00 	tdnei   r9,0
	 c5c:	7c 63 23 92 	divdu   r3,r3,r4
	 c60:	4e 80 00 20 	blr

	 c70:	38 60 00 00 	li      r3,0
	 c74:	4e 80 00 20 	blr

In the first exemple, we see GCC doesn't need to duplicate what
happens after the trap.

In the second exemple, we see that GCC doesn't need to emit a test
and a branch in the likely path in addition to the trap.

We've got some WARN_ON() in .softirqentry.text section so it needs
to be added in the OTHER_TEXT_SECTIONS in modpost.c

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/389962b1b702e3c78d169e59bcfac56282889173.1618331882.git.christophe.leroy@csgroup.eu
2021-08-15 13:49:24 +10:00
Lee Jones
a8b636db7d Merge tag 'v5.14-rc1' into android-mainline
Linux 5.14-rc1

Change-Id: I9765cd4581f6683a6fca3580667017fff9cbaa2b
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2021-07-13 10:02:04 +01:00
Mark Brown
4a6795933a kbuild: modpost: Explicitly warn about unprototyped symbols
One common cause of modpost version generation failures is a failure to
prototype exported assembly functions - the tooling requires this for
exported functions even if they are not and should not be called from C
code in order to do the version mangling for symbols. Unfortunately the
error message is currently rather abstruse, simply saying that "version
generation failed" and even diving into the code doesn't directly show
what's going on since there's several steps between the problem and it
being observed.

Provide an explicit hint as to the likely cause of a version generation
failure to help anyone who runs into this in future more readily diagnose
and fix the problem.

Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-06-17 10:01:05 +09:00
Lee Jones
92f282f338 Merge 8ca5297e7e Merge tag 'kconfig-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild into android-mainline
A tiny step en route to v5.13-rc1

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Change-Id: I7eba2160e4a0e04beaf653dcce126a5b2e5a50ac
2021-05-11 15:20:06 +01:00
Yonghong Song
1fdd7433a9 kbuild: add an elfnote for whether vmlinux is built with lto
Currently, clang LTO built vmlinux won't work with pahole.
LTO introduced cross-cu dwarf tag references and broke
current pahole model which handles one cu as a time.
The solution is to merge all cu's as one pahole cu as in [1].
We would like to do this merging only if cross-cu dwarf
references happens. The LTO build mode is a pretty good
indication for that.

In earlier version of this patch ([2]), clang flag
-grecord-gcc-switches is proposed to add to compilation flags
so pahole could detect "-flto" and then merging cu's.
This will increate the binary size of 1% without LTO though.

Arnaldo suggested to use a note to indicate the vmlinux
is built with LTO. Such a cheap way to get whether the vmlinux
is built with LTO or not helps pahole but is also useful
for tracing as LTO may inline/delete/demote global functions,
promote static functions, etc.

So this patch added an elfnote with a new type LINUX_ELFNOTE_LTO_INFO.
The owner of the note is "Linux".

With gcc 8.4.1 and clang trunk, without LTO, I got
  $ readelf -n vmlinux
  Displaying notes found in: .notes
    Owner                Data size        Description
  ...
    Linux                0x00000004       func
     description data: 00 00 00 00
  ...
With "readelf -x ".notes" vmlinux", I can verify the above "func"
with type code 0x101.

With clang thin-LTO, I got the same as above except the following:
     description data: 01 00 00 00
which indicates the vmlinux is built with LTO.

  [1] https://lore.kernel.org/bpf/20210325065316.3121287-1-yhs@fb.com/
  [2] https://lore.kernel.org/bpf/20210331001623.2778934-1-yhs@fb.com/

Suggested-by: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM/Clang v12.0.0-rc4 (x86-64)
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:25:42 +09:00
Bhaskar Chowdhury
f3945833e4 scripts: modpost.c: Fix a few typos
s/agorithm/algorithm/
s/criterias/criteria/
s/targetting/targeting/   ....two different places.

Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:21:45 +09:00
Masahiro Yamada
4475dff55c kbuild: fix false-positive modpost warning when all symbols are trimmed
Nathan reports that the mips defconfig emits the following warning:

  WARNING: modpost: Symbol info of vmlinux is missing. Unresolved symbol check will be entirely skipped.

This false-positive happens when CONFIG_TRIM_UNUSED_KSYMS is enabled,
but no CONFIG option is set to 'm'.

Commit a0590473c5 ("nfs: fix PNFS_FLEXFILE_LAYOUT Kconfig default")
turned the last 'm' into 'y' for the mips defconfig, and uncovered
this issue.

In this case, the module feature itself is enabled, but we have no
module to build. As a result, CONFIG_TRIM_UNUSED_KSYMS drops all the
instances of EXPORT_SYMBOL. Then, modpost wrongly assumes vmlinux is
missing because vmlinux.symvers is empty. (As another false-positive
case, you can create a module that does not use any symbol of vmlinux).

The current behavior is to entirely suppress the unresolved symbol
warnings when vmlinux is missing just because there are too many.
I found the origin of this code in the historical git tree. [1]

If this is a matter of noisiness, I think modpost can display the
first 10 warnings, and the number of suppressed warnings at the end.

You will get a bit noisier logs when you run 'make modules' without
vmlinux, but such warnings are better to show because you never know
the resulting modules are actually loadable or not.

This commit changes the following:

 - If any of input *.symver files is missing, pass -w option to let
   the module build keep going with warnings instead of errors.

 - If there are too many (10+) unresolved symbol warnings, show only
   the first 10, and also the number of suppressed warnings.

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=1cc0e0529569bf6a94f6d49770aa6d4b599d2c46

Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:17:53 +09:00
Masahiro Yamada
69bc8d386a kbuild: generate Module.symvers only when vmlinux exists
The external module build shows the following warning if Module.symvers
is missing in the kernel tree.

  WARNING: Symbol version dump "Module.symvers" is missing.
           Modules may not have dependencies or modversions.

I think this is an important heads-up because the resulting modules may
not work as expected. This happens when you did not build the entire
kernel tree, for example, you might have prepared the minimal setups
for external modules by 'make defconfig && make modules_preapre'.

A problem is that 'make modules' creates Module.symvers even without
vmlinux. In this case, that warning is suppressed since Module.symvers
already exists in spite of its incomplete content.

The incomplete (i.e. invalid) Module.symvers should not be created.

This commit changes the second pass of modpost to dump symbols into
modules-only.symvers. The final Module.symvers is created by
concatenating vmlinux.symvers and modules-only.symvers if both exist.

Module.symvers is supposed to collect symbols from both vmlinux and
modules. It might be a bit confusing, and I am not quite sure if it
is an official interface, but presumably it is difficult to rename it
because some tools (e.g. kmod) parse it.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:17:02 +09:00
Greg Kroah-Hartman
368ecbcb2f Merge 21a6ab2131 ("Merge tag 'modules-for-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux") into android-mainline
Steps on the way to 5.12-rc1

Resolves conflicts in:
	include/linux/module.h

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I44772d65a5d6b1c5f4c33905554092c2cdc5b210
2021-03-06 08:45:21 +01:00
Linus Torvalds
21a6ab2131 Merge tag 'modules-for-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull module updates from Jessica Yu:

 - Retire EXPORT_UNUSED_SYMBOL() and EXPORT_SYMBOL_GPL_FUTURE(). These
   export types were introduced between 2006 - 2008. All the of the
   unused symbols have been long removed and gpl future symbols were
   converted to gpl quite a long time ago, and I don't believe these
   export types have been used ever since. So, I think it should be safe
   to retire those export types now (Christoph Hellwig)

 - Refactor and clean up some aged code cruft in the module loader
   (Christoph Hellwig)

 - Build {,module_}kallsyms_on_each_symbol only when livepatching is
   enabled, as it is the only caller (Christoph Hellwig)

 - Unexport find_module() and module_mutex and fix the last module
   callers to not rely on these anymore. Make module_mutex internal to
   the module loader (Christoph Hellwig)

 - Harden ELF checks on module load and validate ELF structures before
   checking the module signature (Frank van der Linden)

 - Fix undefined symbol warning for clang (Fangrui Song)

 - Fix smatch warning (Dan Carpenter)

* tag 'modules-for-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  module: potential uninitialized return in module_kallsyms_on_each_symbol()
  module: remove EXPORT_UNUSED_SYMBOL*
  module: remove EXPORT_SYMBOL_GPL_FUTURE
  module: move struct symsearch to module.c
  module: pass struct find_symbol_args to find_symbol
  module: merge each_symbol_section into find_symbol
  module: remove each_symbol_in_section
  module: mark module_mutex static
  kallsyms: only build {,module_}kallsyms_on_each_symbol when required
  kallsyms: refactor {,module_}kallsyms_on_each_symbol
  module: use RCU to synchronize find_module
  module: unexport find_module and module_mutex
  drm: remove drm_fb_helper_modinit
  powerpc/powernv: remove get_cxl_module
  module: harden ELF info handling
  module: Ignore _GLOBAL_OFFSET_TABLE_ when warning for undefined symbols
2021-02-23 10:15:33 -08:00
Will McVicker
4b9c11a373 ANDROID: modules: introduce the MODULE_SCMVERSION config
Config MODULE_SCMVERSION introduces a new module attribute --
`scmversion` -- which can be used to identify a given module's SCM
version.  This is very useful for developers that update their kernel
independently from their kernel modules or vice-versa since the SCM
version provided by UTS_RELEASE (`uname -r`) will now differ from the
module's vermagic attribute.

For example, we have a CI setup that tests new kernel changes on the
hikey960 and db845c devices without updating their kernel modules. When
these tests fail, we need to be able to identify the exact device
configuration the test was using. By including MODULE_SCMVERSION, we can
identify the exact kernel and modules' SCM versions for debugging the
failures.

Additionally, by exposing the SCM version via the sysfs node
/sys/module/MODULENAME/scmversion, one can also verify the SCM versions
of the modules loaded from the initramfs. Currently, modinfo can only
retrieve module attributes from the module's ko on disk and not from the
actual module that is loaded in RAM.

You can retrieve the SCM version in two ways,

1) By using modinfo:
    > modinfo -F scmversion MODULENAME
2) By module sysfs node:
    > cat /sys/module/MODULENAME/scmversion

Bug: 180027765
Link: https://lkml.org/lkml/2021/1/21/1388
Signed-off-by: Will McVicker <willmcvicker@google.com>
Change-Id: Ib7c72c72f95c4545adb7cd4e842729557039ce3a
2021-02-12 17:19:18 -08:00
Christoph Hellwig
367948220f module: remove EXPORT_UNUSED_SYMBOL*
EXPORT_UNUSED_SYMBOL* is not actually used anywhere.  Remove the
unused functionality as we generally just remove unused code anyway.

Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
2021-02-08 12:28:07 +01:00
Christoph Hellwig
f1c3d73e97 module: remove EXPORT_SYMBOL_GPL_FUTURE
As far as I can tell this has never been used at all, and certainly
not any time recently.

Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
2021-02-08 12:28:02 +01:00
Greg Kroah-Hartman
09059c6fca ANDROID: modpost.c: fix up incorrect merge resolution
When merging changes done in scripts/mod/modpost.c I picked the wrong
"side" of the merge branches.

This fixes things up to match what is upstream identically at this point
in time, as there should not be any need for any changes in this file
right now.

Reported-by: Matthias Maennich <maennich@google.com>
Cc: Quentin Perret <qperret@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I014adb697866bc15a893f7a108bec361c525d7ad
2021-02-03 14:58:23 +01:00
Melody Olvera
7c0551d428 Revert "FROMLIST: modpost: Make static exports fatal"
This reverts commit db78f3b149.

Reason for revert: Pulling upstream changes which accomplish the same thing. See https://android-review.googlesource.com/c/kernel/common/+/1559676

Change-Id: I924e794d9987994d88aa0e6c11e1062e2b046947
Signed-off-by: Melody Olvera <molvera@codeaurora.org>
2021-02-01 08:19:53 +00:00
Sami Tolvanen
7ac204b545 modpost: lto: strip .lto from module names
With LTO, everything is compiled into LLVM bitcode, so we have to link
each module into native code before modpost. Kbuild uses the .lto.o
suffix for these files, which also ends up in module information. This
change strips the unnecessary .lto suffix from the module name.

Suggested-by: Bill Wendling <morbo@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-11-samitolvanen@google.com
2021-01-14 08:21:09 -08:00
Greg Kroah-Hartman
a0196781fb Merge 7b95f0563a ("Merge tag 'kbuild-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild") into android-mainline
Steps on the way to 5.11-rc1

Resolves conflicts in:
	scripts/mod/modpost.c

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ie9f8da480668fbd2a47fd686c506bb538c8c024d
2021-01-13 11:32:21 +01:00
Quentin Perret
b9ed847b5a modpost: turn static exports into error
Using EXPORT_SYMBOL*() on static functions is fundamentally wrong.
Modpost currently reports that as a warning, but clearly this is not a
pattern we should allow, and all in-tree occurences should have been
fixed by now. So, promote the warn() message to error() to make sure
this never happens again.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21 13:57:08 +09:00
Masahiro Yamada
c7299d98c0 modpost: turn section mismatches to error from fatal()
There is code that reports static EXPORT_SYMBOL a few lines below.
It is not a good idea to bail out here.

I renamed sec_mismatch_fatal to sec_mismatch_warn_only (with logical
inversion) to match to CONFIG_SECTION_MISMATCH_WARN_ONLY.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21 13:57:08 +09:00
Masahiro Yamada
d6d692fa21 modpost: change license incompatibility to error() from fatal()
Change fatal() to error() to continue running to report more possible
issues.

There is no difference in the fact that modpost will fail anyway.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21 13:57:08 +09:00
Masahiro Yamada
1d6cd39293 modpost: turn missing MODULE_LICENSE() into error
Do not create modules with no license tag.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21 13:57:08 +09:00
Masahiro Yamada
0fd3fbadd9 modpost: refactor error handling and clarify error/fatal difference
We have 3 log functions. fatal() is special because it lets modpost bail
out immediately. The difference between warn() and error() is the only
prefix parts ("WARNING:" vs "ERROR:").

In my understanding, the expected handling of error() is to propagate
the return code of the function to the exit code of modpost, as
check_exports() etc. already does. This is a good manner in general
because we should display as many error messages as possible in a
single run of modpost.

What is annoying about fatal() is that it kills modpost at the first
error. People would need to run Kbuild again and again until they fix
all errors.

But, unfortunately, people tend to do:
"This case should not be allowed. Let's replace warn() with fatal()."

One of the reasons is probably it is tedious to manually hoist the error
code to the main() function.

This commit refactors error() so any single call for it automatically
makes modpost return the error code.

I also added comments in modpost.h for warn(), error(), and fatal().

Please use fatal() only when you have a strong reason to do so.
For example:

  - Memory shortage (i.e. malloc() etc. has failed)
  - The ELF file is broken, and there is no point to continue parsing
  - Something really odd has happened

For general coding errors, please use error().

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Quentin Perret <qperret@google.com>
2020-12-21 13:57:08 +09:00
Masahiro Yamada
bc72d723ec modpost: rename merror() to error()
The log function names, warn(), merror(), fatal() are inconsistent.

Commit 2a11665945 ("kbuild: distinguish between errors and warnings
in modpost") intentionally chose merror() to avoid the conflict with
the library function error(). See man page of error(3).

But, we are already causing the conflict with warn() because it is also
a library function. See man page of warn(3). err() would be a problem
for the same reason.

The common technique to work around name conflicts is to use macros.
For example:

    /* in a header */
    #define error(fmt, ...)  __error(fmt, ##__VA_ARGS__)
    #define warn(fmt, ...)   __warn(fmt, ##__VA_ARGS__)

    /* function definition */
    void __error(const char *fmt, ...)
    {
            <our implementation>
    }

    void __warn(const char *fmt, ...)
    {
            <our implementation>
    }

In this way, we can implement our own warn() and error(), still we can
include <error.h> and <err.h> with no problem.

And, commit 93c95e526a ("modpost: rework and consolidate logging
interface") already did that.

Since the log functions are all macros, we can use error() without
causing "conflicting types" errors.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21 13:57:08 +09:00
Quentin Perret
479488f5bf ANDROID: modpost: Forbid double exports
In the context of GKI we are exporting quite a few internal kernel
symbols, some of which may be static functions (yes this is bad, but
technically it works). As such, we need to be careful about conflicts
and we really should not allow a symbol to be exported more than once.

To ensure this is the case, turn the modpost check 'fatal' to bail out
immediately when such a situation is detected.

Bug: 174214891
Signed-off-by: Quentin Perret <qperret@google.com>
Change-Id: I674c9c9c327849503e94d79654e6288411a830af
2020-11-27 14:50:45 +00:00
Quentin Perret
db78f3b149 FROMLIST: modpost: Make static exports fatal
Using EXPORT_SYMBOL*() on static functions is fundamentally wrong.
Modpost currently reports that as a warning, but clearly this is not a
pattern we should allow, and all in-tree occurences should have been
fixed by now. So, promote the warn() message to fatal() to make sure
this never happens again.

Bug: 174214891
Link: https://lore.kernel.org/lkml/20201124182420.2202514-1-qperret@google.com/
Signed-off-by: Quentin Perret <qperret@google.com>
Change-Id: Ic1382bfa24db556161cf1a184a4d44724d7849a1
2020-11-27 14:50:37 +00:00
Joe Perches
33def8498f treewide: Convert macro and uses of __section(foo) to __section("foo")
Use a more generic form for __section that requires quotes to avoid
complications with clang and gcc differences.

Remove the quote operator # from compiler_attributes.h __section macro.

Convert all unquoted __section(foo) uses to quoted __section("foo").
Also convert __attribute__((section("foo"))) uses to __section("foo")
even if the __attribute__ has multiple list entry forms.

Conversion done using the script at:

    https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl

Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@gooogle.com>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-25 14:51:49 -07:00
Wolfram Sang
6020db504c modpost: explain why we can't use strsep
Mention why we open-code strsep, so it is clear that it is intentional.

Fixes: 736bb11898 ("modpost: remove use of non-standard strsep() in HOSTCC code")
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-07-27 13:38:38 +09:00
H. Nikolaus Schaller
736bb11898 modpost: remove use of non-standard strsep() in HOSTCC code
strsep() is neither standard C nor POSIX and used outside
the kernel code here. Using it here requires that the
build host supports it out of the box which is e.g.
not true for a Darwin build host and using a cross-compiler.
This leads to:

scripts/mod/modpost.c:145:2: warning: implicit declaration of function 'strsep' [-Wimplicit-function-declaration]
  return strsep(stringp, "\n");
  ^

and a segfault when running MODPOST.

See also: https://stackoverflow.com/a/7219504

So let's replace this by strchr() instead of using strsep().
It does not hurt kernel size or speed since this code is run
on the build host.

Fixes: ac5100f543 ("modpost: add read_text_file() and get_line() helpers")
Co-developed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-07-07 11:21:00 +09:00
Linus Torvalds
cff11abeca Merge tag 'kbuild-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:

 - fix warnings in 'make clean' for ARCH=um, hexagon, h8300, unicore32

 - ensure to rebuild all objects when the compiler is upgraded

 - exclude system headers from dependency tracking and fixdep processing

 - fix potential bit-size mismatch between the kernel and BPF user-mode
   helper

 - add the new syntax 'userprogs' to build user-space programs for the
   target architecture (the same arch as the kernel)

 - compile user-space sample code under samples/ for the target arch
   instead of the host arch

 - make headers_install fail if a CONFIG option is leaked to user-space

 - sanitize the output format of scripts/checkstack.pl

 - handle ARM 'push' instruction in scripts/checkstack.pl

 - error out before modpost if a module name conflict is found

 - error out when multiple directories are passed to M= because this
   feature is broken for a long time

 - add CONFIG_DEBUG_INFO_COMPRESSED to support compressed debug info

 - a lot of cleanups of modpost

 - dump vmlinux symbols out into vmlinux.symvers, and reuse it in the
   second pass of modpost

 - do not run the second pass of modpost if nothing in modules is
   updated

 - install modules.builtin(.modinfo) by 'make install' as well as by
   'make modules_install' because it is useful even when
   CONFIG_MODULES=n

 - add new command line variables, GZIP, BZIP2, LZOP, LZMA, LZ4, and XZ
   to allow users to use alternatives such as pigz, pbzip2, etc.

* tag 'kbuild-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (96 commits)
  kbuild: add variables for compression tools
  Makefile: install modules.builtin even if CONFIG_MODULES=n
  mksysmap: Fix the mismatch of '.L' symbols in System.map
  kbuild: doc: rename LDFLAGS to KBUILD_LDFLAGS
  modpost: change elf_info->size to size_t
  modpost: remove is_vmlinux() helper
  modpost: strip .o from modname before calling new_module()
  modpost: set have_vmlinux in new_module()
  modpost: remove mod->skip struct member
  modpost: add mod->is_vmlinux struct member
  modpost: remove is_vmlinux() call in check_for_{gpl_usage,unused}()
  modpost: remove mod->is_dot_o struct member
  modpost: move -d option in scripts/Makefile.modpost
  modpost: remove -s option
  modpost: remove get_next_text() and make {grab,release_}file static
  modpost: use read_text_file() and get_line() for reading text files
  modpost: avoid false-positive file open error
  modpost: fix potential mmap'ed file overrun in get_src_version()
  modpost: add read_text_file() and get_line() helpers
  modpost: do not call get_modinfo() for vmlinux(.o)
  ...
2020-06-06 12:00:25 -07:00
Masahiro Yamada
3b09efc4f0 modpost: change elf_info->size to size_t
Align with the mmap / munmap APIs.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:39:20 +09:00
Masahiro Yamada
4de7b62936 modpost: remove is_vmlinux() helper
Now that is_vmlinux() is called only in new_module(), we can inline
the function call.

modname is the basename with '.o' is stripped. No need to compare it
with 'vmlinux.o'.

vmlinux is always located at the current working directory. No need
to strip the directory path.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:39:20 +09:00
Masahiro Yamada
a82f794c41 modpost: strip .o from modname before calling new_module()
new_module() conditionally strips the .o because the modname has .o
suffix when it is called from read_symbols(), but no .o when it is
called from read_dump().

It is clearer to strip .o in read_symbols().

I also used flexible-array for mod->name.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:39:20 +09:00
Masahiro Yamada
858b937d28 modpost: set have_vmlinux in new_module()
Set have_vmlinux flag in a single place.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:39:20 +09:00
Masahiro Yamada
0b19d54cae modpost: remove mod->skip struct member
The meaning of 'skip' is obscure since it does not explain
"what to skip".

mod->skip is set when it is vmlinux or the module info came from
a dump file.

So, mod->skip is equivalent to (mod->is_vmlinux || mod->from_dump).

For the check in write_namespace_deps_files(), mod->is_vmlinux is
unneeded because the -d option is not passed in the first pass of
modpost.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:39:20 +09:00
Masahiro Yamada
5a438af9db modpost: add mod->is_vmlinux struct member
is_vmlinux() is called in several places to check whether the current
module is vmlinux or not.

It is faster and clearer to check mod->is_vmlinux flag.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:39:19 +09:00
Masahiro Yamada
1be5fa6c94 modpost: remove is_vmlinux() call in check_for_{gpl_usage,unused}()
check_exports() is never called for vmlinux because mod->skip is set
for vmlinux.

Hence, check_for_gpl_usage() and check_for_unused() are not called
for vmlinux, either. is_vmlinux() is always false here.

Remove the is_vmlinux() calls, and hard-code the ".ko" suffix.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:38:13 +09:00
Masahiro Yamada
3379576dd6 modpost: remove mod->is_dot_o struct member
Previously, there were two cases where mod->is_dot_o is unset:

[1] the executable 'vmlinux' in the second pass of modpost
[2] modules loaded by read_dump()

I think [1] was intended usage to distinguish 'vmlinux.o' and 'vmlinux'.
Now that modpost does not parse the executable 'vmlinux', this case
does not happen.

[2] is obscure, maybe a bug. Module.symver stores module paths without
extension. So, none of modules loaded by read_dump() has the .o suffix,
and new_module() unsets ->is_dot_o. Anyway, it is not a big deal because
handle_symbol() is not called for the case.

To sum up, all the parsed ELF files are .o files.

mod->is_dot_o is unneeded.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:38:13 +09:00
Masahiro Yamada
467b82d7ce modpost: remove -s option
The -s option was added by commit 8d8d8289df ("kbuild: do not do
section mismatch checks on vmlinux in 2nd pass").

Now that the second pass does not parse vmlinux, this option is
unneeded.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:38:13 +09:00
Masahiro Yamada
75893572d4 modpost: remove get_next_text() and make {grab,release_}file static
get_next_line() is no longer used. Remove.

grab_file() and release_file() are only used in modpost.c. Make them
static.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:38:13 +09:00
Masahiro Yamada
70f30cfe5b modpost: use read_text_file() and get_line() for reading text files
grab_file() mmaps a file, but it is not so efficient here because
get_next_line() copies every line to the temporary buffer anyway.

read_text_file() and get_line() are simpler. get_line() exploits the
library function strchr().

Going forward, the missing *.symvers or *.cmd is a fatal error.
This should not happen because scripts/Makefile.modpost guards the
-i option files with $(wildcard $(input-symdump)).

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:38:13 +09:00
Masahiro Yamada
ac5100f543 modpost: add read_text_file() and get_line() helpers
modpost uses grab_file() to open a file, but it is not suitable for
a text file because the mmap'ed file is not terminated by null byte.
Actually, I see some issues for the use of grab_file().

The new helper, read_text_file() loads the whole file content into a
malloc'ed buffer, and appends a null byte. Then, get_line() reads
each line.

To handle text files, I intend to replace as follows:

  grab_file()    -> read_text_file()
  get_new_line() -> get_line()

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:38:12 +09:00
Masahiro Yamada
4ddea2f8e8 modpost: do not call get_modinfo() for vmlinux(.o)
The three calls of get_modinfo() ("license", "import_ns", "version")
always return NULL for vmlinux(.o) because the built-in module info is
prefixed with __MODULE_INFO_PREFIX.

It is harmless to call get_modinfo(), but there is no point to search
for what apparently does not exist.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:38:12 +09:00
Masahiro Yamada
f693153519 modpost: drop RCS/CVS $Revision handling in MODULE_VERSION()
As far as I understood, this code gets rid of '$Revision$' or '$Revision:'
of CVS, RCS or whatever in MODULE_VERSION() tags.

Remove the primeval code.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:38:12 +09:00
Masahiro Yamada
7e8a323582 modpost: show warning if vmlinux is not found when processing modules
check_exports() does not print warnings about unresolved symbols if
vmlinux is missing because there would be too many.

This situation happens when you do 'make modules' from the clean
tree, or compile external modules against a kernel tree that has
not been completely built.

It is dangerous to not check unresolved symbols because you might be
building useless modules. At least it should be warned.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:38:12 +09:00
Masahiro Yamada
436b2ac603 modpost: invoke modpost only when input files are updated
Currently, the second pass of modpost is always invoked when you run
'make' or 'make modules' even if none of modules is changed.

Use if_changed to invoke it only when it is necessary.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:38:12 +09:00
Masahiro Yamada
e3fb4df7fe modpost: re-add -e to set external_module flag
Previously, the -i option had two functions; load a symbol dump file,
and set the external_module flag.

I want to assign a dedicate option for each of them.

Going forward, the -i is used to load a symbol dump file, and the -e
to set the external_module flag.

With this, we will be able to use -i for loading in-kernel symbols.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:38:12 +09:00