As mentioned in commit 397586506c ("modpost: Add '.ltext' and
'.ltext.*' to TEXT_SECTIONS"), modpost can result in a segmentation
fault due to a NULL pointer dereference in default_mismatch_handler().
find_tosym() can return the original symbol pointer instead of NULL
if a better one is not found.
This fixes the reported segmentation fault.
Fixes: a23e7584ec ("modpost: unify 'sym' and 'to' in default_mismatch_handler()")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
- Generate a list of built DTB files (arch/*/boot/dts/dtbs-list)
- Use more threads when building Debian packages in parallel
- Fix warnings shown during the RPM kernel package uninstallation
- Change OBJECT_FILES_NON_STANDARD_*.o etc. to take a relative path to
Makefile
- Support GCC's -fmin-function-alignment flag
- Fix a null pointer dereference bug in modpost
- Add the DTB support to the RPM package
- Various fixes and cleanups in Kconfig
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Merge tag 'kbuild-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Generate a list of built DTB files (arch/*/boot/dts/dtbs-list)
- Use more threads when building Debian packages in parallel
- Fix warnings shown during the RPM kernel package uninstallation
- Change OBJECT_FILES_NON_STANDARD_*.o etc. to take a relative path to
Makefile
- Support GCC's -fmin-function-alignment flag
- Fix a null pointer dereference bug in modpost
- Add the DTB support to the RPM package
- Various fixes and cleanups in Kconfig
* tag 'kbuild-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (67 commits)
kconfig: tests: test dependency after shuffling choices
kconfig: tests: add a test for randconfig with dependent choices
kconfig: tests: support KCONFIG_SEED for the randconfig runner
kbuild: rpm-pkg: add dtb files in kernel rpm
kconfig: remove unneeded menu_is_visible() call in conf_write_defconfig()
kconfig: check prompt for choice while parsing
kconfig: lxdialog: remove unused dialog colors
kconfig: lxdialog: fix button color for blackbg theme
modpost: fix null pointer dereference
kbuild: remove GCC's default -Wpacked-bitfield-compat flag
kbuild: unexport abs_srctree and abs_objtree
kbuild: Move -Wenum-{compare-conditional,enum-conversion} into W=1
kconfig: remove named choice support
kconfig: use linked list in get_symbol_str() to iterate over menus
kconfig: link menus to a symbol
kbuild: fix inconsistent indentation in top Makefile
kbuild: Use -fmin-function-alignment when available
alpha: merge two entries for CONFIG_ALPHA_GAMMA
alpha: merge two entries for CONFIG_ALPHA_EV4
kbuild: change DTC_FLAGS_<basetarget>.o to take the path relative to $(obj)
...
If the find_fromsym() call fails and returns NULL, the warn() call
will dereference this NULL pointer and cause the program to crash.
This happened when I tried to build with "test_user_copy" module.
With this fix, it prints lots of warnings like this:
WARNING: modpost: lib/test_user_copy: section mismatch in reference: (unknown)+0x4 (section: .text.fixup) -> (unknown) (section: .init.text)
masahiroy@kernel.org:
The issue is reproduced with ARCH=arm allnoconfig + CONFIG_MODULES=y +
CONFIG_RUNTIME_TESTING_MENU=y + CONFIG_TEST_USER_COPY=m
Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Aiden Leong reported modpost fails to build on macOS since commit
16a473f60e ("modpost: inform compilers that fatal() never returns"):
scripts/mod/modpost.c:93:21: error: aliases are not supported on darwin
Nathan's research indicates that Darwin seems to support weak aliases
at least [1]. Although the situation might be improved in future Clang
versions, we can achieve a similar outcome without relying on it.
This commit makes fatal() a macro of error() + exit(1) in modpost.h, as
compilers recognize that exit() never returns.
[1]: https://github.com/llvm/llvm-project/issues/71001
Fixes: 16a473f60e ("modpost: inform compilers that fatal() never returns")
Reported-by: Aiden Leong <aiden.leong@aibsd.com>
Closes: https://lore.kernel.org/all/d9ac2960-6644-4a87-b5e4-4bfb6e0364a8@aibsd.com/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
After the linked LLVM change, building ARCH=um defconfig results in a
segmentation fault in modpost. Prior to commit a23e7584ec ("modpost:
unify 'sym' and 'to' in default_mismatch_handler()"), there was a
warning:
WARNING: modpost: vmlinux.o(__ex_table+0x88): Section mismatch in reference to the .ltext:(unknown)
WARNING: modpost: The relocation at __ex_table+0x88 references
section ".ltext" which is not in the list of
authorized sections. If you're adding a new section
and/or if this reference is valid, add ".ltext" to the
list of authorized sections to jump to on fault.
This can be achieved by adding ".ltext" to
OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.
The linked LLVM change moves global objects to the '.ltext' (and
'.ltext.*' with '-ffunction-sections') sections with '-mcmodel=large',
which ARCH=um uses. These sections should be handled just as '.text'
and '.text.*' are, so add them to TEXT_SECTIONS.
Cc: stable@vger.kernel.org
Closes: https://github.com/ClangBuiltLinux/linux/issues/1981
Link: 4bf8a68895
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
1, Raise minimum clang version to 18.0.0;
2, Enable initial Rust support for LoongArch;
3, Add built-in dtb support for LoongArch;
4, Use generic interface to support crashkernel=X,[high,low];
5, Some bug fixes and other small changes;
6, Update the default config file.
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Merge tag 'loongarch-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
Pull LoongArch updates from Huacai Chen:
- Raise minimum clang version to 18.0.0
- Enable initial Rust support for LoongArch
- Add built-in dtb support for LoongArch
- Use generic interface to support crashkernel=X,[high,low]
- Some bug fixes and other small changes
- Update the default config file.
* tag 'loongarch-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson: (22 commits)
MAINTAINERS: Add BPF JIT for LOONGARCH entry
LoongArch: Update Loongson-3 default config file
LoongArch: BPF: Prevent out-of-bounds memory access
LoongArch: BPF: Support 64-bit pointers to kfuncs
LoongArch: Fix definition of ftrace_regs_set_instruction_pointer()
LoongArch: Use generic interface to support crashkernel=X,[high,low]
LoongArch: Fix and simplify fcsr initialization on execve()
LoongArch: Let cores_io_master cover the largest NR_CPUS
LoongArch: Change SHMLBA from SZ_64K to PAGE_SIZE
LoongArch: Add a missing call to efi_esrt_init()
LoongArch: Parsing CPU-related information from DTS
LoongArch: dts: DeviceTree for Loongson-2K2000
LoongArch: dts: DeviceTree for Loongson-2K1000
LoongArch: dts: DeviceTree for Loongson-2K0500
LoongArch: Allow device trees be built into the kernel
dt-bindings: interrupt-controller: loongson,liointc: Fix dtbs_check warning for interrupt-names
dt-bindings: interrupt-controller: loongson,liointc: Fix dtbs_check warning for reg-names
dt-bindings: loongarch: Add Loongson SoC boards compatibles
dt-bindings: loongarch: Add CPU bindings for LoongArch
LoongArch: Enable initial Rust support
...
With recent trunk versions of binutils and gcc, alignment directives are
represented with R_LARCH_ALIGN relocs on LoongArch, which is necessary
for the linker to maintain alignment requirements during its relaxation
passes. And even though the kernel is built with relaxation disabled, so
far a small number of R_LARCH_RELAX marker relocs are still emitted as
part of la.* pseudo instructions in assembly. These two kinds of relocs
do not refer to symbols, which can trip up modpost's section mismatch
checks, because the r_offset of said relocs can be zero or any other
meaningless value, eventually leading to a `from == NULL` condition in
default_mismatch_handler and SIGSEGV.
As the two kinds of relocs are not concerned with symbols, just ignore
them for section mismatch check purposes.
Signed-off-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Step 5/10 of the namespace unification of CPU mitigations related Kconfig options.
[ mingo: Converted a few more uses in comments/messages as well. ]
Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ariel Miculas <amiculas@cisco.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-6-leitao@debian.org
Now compilers can recognize fatal() never returns.
While GCC 4.5 dropped support for -Wunreachable-code, Clang is capable
of detecting the unreachable code.
$ make HOSTCC=clang HOSTCFLAGS=-Wunreachable-code-return
[snip]
HOSTCC scripts/mod/modpost.o
scripts/mod/modpost.c:520:11: warning: 'return' will never be executed [-Wunreachable-code-return]
return 0;
^
scripts/mod/modpost.c:477:10: warning: 'return' will never be executed [-Wunreachable-code-return]
return 0;
^
2 warnings generated.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
This initializer was added to avoid -Wmaybe-uninitialized (gcc) and
-Wsometimes-uninitialized (clang) warnings.
Now that compilers recognize fatal() never returns, it is unneeded.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
The function fatal() never returns because modpost_log() calls exit(1)
when LOG_FATAL is passed.
Inform compilers of this fact so that unreachable code flow can be
identified at compile time.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
This attribute must be added to the function declaration in a header
for comprehensive checking of all the callsites.
Fixes: 6d9a89ea4b ("kbuild: declare the modpost error functions as printf like")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
The section mismatch check prints a bogus symbol name on some
architectures.
[test code]
#include <linux/init.h>
int __initdata foo;
int get_foo(void) { return foo; }
If you compile it with GCC for riscv or loongarch, modpost will show an
incorrect symbol name:
WARNING: modpost: vmlinux: section mismatch in reference: get_foo+0x8 (section: .text) -> done (section: .init.data)
To get the correct symbol address, the st_value must be added.
This issue has never been noticed since commit 93684d3b80 ("kbuild:
include symbol names in section mismatch warnings") presumably because
st_value becomes zero on most architectures when the referenced symbol
is looked up. It is not true for riscv or loongarch, at least.
With this fix, modpost will show the correct symbol name:
WARNING: modpost: vmlinux: section mismatch in reference: get_foo+0x8 (section: .text) -> foo (section: .init.data)
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
ALL_INIT_TEXT_SECTIONS and ALL_EXIT_TEXT_SECTIONS are only used in
the macro definition of ALL_TEXT_SECTIONS.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
ALL_INIT_SECTIONS is defined as follows:
#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Theoretically, we could export conditionally-discarded code sections,
such as .meminit*, if all the users can become modular under a certain
condition. However, that would be difficult to control and such a tricky
case has never occurred.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
These symbol patterns were whitelisted to allow them to reference to
functions with the old __devinit and __devexit annotations.
We stopped doing this a long time ago, for example, commit 6f03979051
("Drivers: scsi: remove __dev* attributes.") remove those annotations
from the scsi drivers.
Keep *_ops, *_probe, and *_console, otherwise they will really cause
section mismatch warnings.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Drivers must not reference .meminit* sections, which are discarded
when CONFIG_MEMORY_HOTPLUG=n.
The reason for whitelisting "*driver" in the section mismatch check
was to allow drivers to reference symbols annotated as __devinit or
__devexit that existed in the past.
Those annotations were removed by the following commits:
- 54b956b903 ("Remove __dev* markings from init.h")
- 92e9e6d1f9 ("modpost.c: Stop checking __dev* section mismatches")
Remove the stale whitelist.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
We have never used __memexit, __memexitdata, or __memexitconst.
These were unneeded.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
The first few lines of section_rel() and section_rela() are the same.
They both retrieve the index of the section to which the relocaton
applies, and skip known-good sections. This common code should be moved
to check_sec_ref().
Avoid ugly casts when computing 'start' and 'stop', and also make the
Elf_Rel and Elf_Rela pointers const.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
We can replace &elf->sechdrs[i] with &sechdrs[i] to slightly shorten
the code because we already have the local variable 'sechdrs'.
However, defining 'sechdr' instead shortens the code further.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
The current TO_NATIVE() has some limitations:
1) You cannot cast the argument.
2) You cannot pass a variable marked as 'const'.
3) Passing an array is a bug, but it is not detected.
Impelement TO_NATIVE() using bswap_*() functions. These are GNU
extensions. If we face portability issues, we can port the code from
include/uapi/linux/swab.h.
With this change, get_rel_type_and_sym() can be simplified by casting
the arguments directly.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Modify modpost to use binary search for converting addresses back
into symbol references. Previously it used linear search.
This change saves a few seconds of wall time for defconfig builds,
but can save several minutes on allyesconfigs.
Before:
$ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error"
$ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o
198.38user 1.27system 3:19.71elapsed
After:
$ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error"
$ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o
11.91user 0.85system 0:12.78elapsed
Signed-off-by: Jack Brennen <jbrennen@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Drivers must not reference functions marked with __exit as these likely
are not available when the code is built-in.
There are few creative offenders uncovered for example in ARCH=amd64
allmodconfig builds. So only trigger the section mismatch warning for
W=1 builds.
The dual rule that drivers must not reference .init.* is implemented
since commit 0db2524523 ("modpost: don't allow *driver to reference
.init.*") which however missed that .exit.* should be handled in the
same way.
Thanks to Masahiro Yamada and Arnd Bergmann who gave valuable hints to
find this improvement.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
* fix reference to exported symbols for parisc64 [Masahiro Yamada]
* Block-TLB (BTLB) support on 32-bit CPUs
* sparse and build-warning fixes
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Merge tag 'parisc-for-6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
Pull parisc architecture fixes from Helge Deller:
- fix reference to exported symbols for parisc64 [Masahiro Yamada]
- Block-TLB (BTLB) support on 32-bit CPUs
- sparse and build-warning fixes
* tag 'parisc-for-6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
linux/export: fix reference to exported functions for parisc64
parisc: BTLB: Initialize BTLB tables at CPU startup
parisc: firmware: Simplify calling non-PA20 functions
parisc: BTLB: _edata symbol has to be page aligned for BTLB support
parisc: BTLB: Add BTLB insert and purge firmware function wrappers
parisc: BTLB: Clear possibly existing BTLB entries
parisc: Prepare for Block-TLB support on 32-bit kernel
parisc: shmparam.h: Document aliasing requirements of PA-RISC
parisc: irq: Make irq_stack_union static to avoid sparse warning
parisc: drivers: Fix sparse warning
parisc: iosapic.c: Fix sparse warnings
parisc: ccio-dma: Fix sparse warnings
parisc: sba-iommu: Fix sparse warnigs
parisc: sba: Fix compile warning wrt list of SBA devices
parisc: sba_iommu: Fix build warning if procfs if disabled
John David Anglin reported parisc has been broken since commit
ddb5cdbafa ("kbuild: generate KSYMTAB entries by modpost").
Like ia64, parisc64 uses a function descriptor. The function
references must be prefixed with P%.
Also, symbols prefixed $$ from the library have the symbol type
STT_LOPROC instead of STT_FUNC. They should be handled as functions
too.
Fixes: ddb5cdbafa ("kbuild: generate KSYMTAB entries by modpost")
Reported-by: John David Anglin <dave.anglin@bell.net>
Tested-by: John David Anglin <dave.anglin@bell.net>
Tested-by: Helge Deller <deller@gmx.de>
Closes: https://lore.kernel.org/linux-parisc/1901598a-e11d-f7dd-a5d9-9a69d06e6b6e@bell.net/T/#u
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Helge Deller <deller@gmx.de>
.llvm.call-graph-profile section is added by clang when the kernel is
built with profiles (e.g. -fprofile-sample-use= or -fprofile-use=).
Note that .llvm.call-graph-profile intentionally uses REL relocations
to decrease the object size, for more details see
https://reviews.llvm.org/D104080.
The section contains edge information derived from text sections,
so .llvm.call-graph-profile itself doesn't need more analysis as
the text sections have been analyzed.
This change fixes the kernel build with clang and a sample profile
which currently fails with:
"FATAL: modpost: Please add code to calculate addend for this architecture"
Signed-off-by: Denis Nikitin <denik@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Fangrui Song <maskray@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Remove the Elf_Rela variables used in the for-loop in section_rel().
This makes the code consistent; section_rel() only uses Elf_Rel,
section_rela() only uses Elf_Rela.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
MIPS64 little endian target has an odd encoding of r_info.
This commit makes the special handling less ugly. It is still ugly,
but #if conditionals will go away, at least.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
All of addend_*_rel() need the Elf_Rela pointer just for calculating
ELF_R_TYPE(r->r_info).
You can do it on the caller to de-duplicate the code.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Now that none of addend_*_rel() returns a meaningful value (the return
value is always 0), change all of them to return the value of r_addend.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Currently, all files with EXPORT_SYMBOL() are rebuilt when CONFIG_MODULES
is flipped due to <linux/export.h> depending on CONFIG_MODULES.
Now that modpost can make a final decision about export symbols,
<linux/export.h> does not need to make EXPORT_SYMBOL() no-op.
Instead, modpost can skip emitting KSYMTAB when CONFIG_MODULES is unset.
This commit will reduce the number of recompilation when CONFIG_MODULES
is toggled.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
- Remove the deprecated rule to build *.dtbo from *.dts
- Refactor section mismatch detection in modpost
- Fix bogus ARM section mismatch detections
- Fix error of 'make gtags' with O= option
- Add Clang's target triple to KBUILD_CPPFLAGS to fix a build error with
the latest LLVM version
- Rebuild the built-in initrd when KBUILD_BUILD_TIMESTAMP is changed
- Ignore more compiler-generated symbols for kallsyms
- Fix 'make local*config' to handle the ${CONFIG_FOO} form in Makefiles
- Enable more kernel-doc warnings with W=2
- Refactor <linux/export.h> by generating KSYMTAB data by modpost
- Deprecate <asm/export.h> and <asm-generic/export.h>
- Remove the EXPORT_DATA_SYMBOL macro
- Move the check for static EXPORT_SYMBOL back to modpost, which makes
the build faster
- Re-implement CONFIG_TRIM_UNUSED_KSYMS with one-pass algorithm
- Warn missing MODULE_DESCRIPTION when building modules with W=1
- Make 'make clean' robust against too long argument error
- Exclude more objects from GCOV to fix CFI failures with GCOV
- Allow 'make modules_install' to install modules.builtin and
modules.builtin.modinfo even when CONFIG_MODULES is disabled
- Include modules.builtin and modules.builtin.modinfo in the linux-image
Debian package even when CONFIG_MODULES is disabled
- Revive "Entering directory" logging for the latest Make version
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Merge tag 'kbuild-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Remove the deprecated rule to build *.dtbo from *.dts
- Refactor section mismatch detection in modpost
- Fix bogus ARM section mismatch detections
- Fix error of 'make gtags' with O= option
- Add Clang's target triple to KBUILD_CPPFLAGS to fix a build error
with the latest LLVM version
- Rebuild the built-in initrd when KBUILD_BUILD_TIMESTAMP is changed
- Ignore more compiler-generated symbols for kallsyms
- Fix 'make local*config' to handle the ${CONFIG_FOO} form in Makefiles
- Enable more kernel-doc warnings with W=2
- Refactor <linux/export.h> by generating KSYMTAB data by modpost
- Deprecate <asm/export.h> and <asm-generic/export.h>
- Remove the EXPORT_DATA_SYMBOL macro
- Move the check for static EXPORT_SYMBOL back to modpost, which makes
the build faster
- Re-implement CONFIG_TRIM_UNUSED_KSYMS with one-pass algorithm
- Warn missing MODULE_DESCRIPTION when building modules with W=1
- Make 'make clean' robust against too long argument error
- Exclude more objects from GCOV to fix CFI failures with GCOV
- Allow 'make modules_install' to install modules.builtin and
modules.builtin.modinfo even when CONFIG_MODULES is disabled
- Include modules.builtin and modules.builtin.modinfo in the
linux-image Debian package even when CONFIG_MODULES is disabled
- Revive "Entering directory" logging for the latest Make version
* tag 'kbuild-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (72 commits)
modpost: define more R_ARM_* for old distributions
kbuild: revive "Entering directory" for Make >= 4.4.1
kbuild: set correct abs_srctree and abs_objtree for package builds
scripts/mksysmap: Ignore prefixed KCFI symbols
kbuild: deb-pkg: remove the CONFIG_MODULES check in buildeb
kbuild: builddeb: always make modules_install, to install modules.builtin*
modpost: continue even with unknown relocation type
modpost: factor out Elf_Sym pointer calculation to section_rel()
modpost: factor out inst location calculation to section_rel()
kbuild: Disable GCOV for *.mod.o
kbuild: Fix CFI failures with GCOV
kbuild: make clean rule robust against too long argument error
script: modpost: emit a warning when the description is missing
kbuild: make modules_install copy modules.builtin(.modinfo)
linux/export.h: rename 'sec' argument to 'license'
modpost: show offset from symbol for section mismatch warnings
modpost: merge two similar section mismatch warnings
kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion
modpost: use null string instead of NULL pointer for default namespace
modpost: squash sym_update_namespace() into sym_add_exported()
...
On CentOS 7, the following build error occurs.
scripts/mod/modpost.c: In function 'addend_arm_rel':
scripts/mod/modpost.c:1312:7: error: 'R_ARM_MOVW_ABS_NC' undeclared (first use in this function); did you mean 'R_ARM_THM_ABS5'?
case R_ARM_MOVW_ABS_NC:
^~~~~~~~~~~~~~~~~
R_ARM_THM_ABS5
scripts/mod/modpost.c:1312:7: note: each undeclared identifier is reported only once for each function it appears in
scripts/mod/modpost.c:1313:7: error: 'R_ARM_MOVT_ABS' undeclared (first use in this function); did you mean 'R_ARM_THM_ABS5'?
case R_ARM_MOVT_ABS:
^~~~~~~~~~~~~~
R_ARM_THM_ABS5
scripts/mod/modpost.c:1326:7: error: 'R_ARM_THM_MOVW_ABS_NC' undeclared (first use in this function); did you mean 'R_ARM_THM_ABS5'?
case R_ARM_THM_MOVW_ABS_NC:
^~~~~~~~~~~~~~~~~~~~~
R_ARM_THM_ABS5
scripts/mod/modpost.c:1327:7: error: 'R_ARM_THM_MOVT_ABS' undeclared (first use in this function); did you mean 'R_ARM_THM_ABS5'?
case R_ARM_THM_MOVT_ABS:
^~~~~~~~~~~~~~~~~~
R_ARM_THM_ABS5
Fixes: 12ca2c67d7 ("modpost: detect section mismatch for R_ARM_{MOVW_ABS_NC,MOVT_ABS}")
Fixes: cd1824fb7a ("modpost: detect section mismatch for R_ARM_THM_{MOVW_ABS_NC,MOVT_ABS}")
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Currently, unknown relocation types are just skipped.
The value of r_addend is only needed to get the symbol name in case
is_valid_name(elf, sym) returns false.
Even if we do not know how to calculate r_addend, we should continue.
At worst, we will get "(unknown)" as the symbol name, but it is better
than failing to detect section mismatches.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pass the Elf_Sym pointer to addend_arm_rel() as well as to
check_section_mismatch().
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
All the addend_*_rel() functions calculate the instruction location in
the same way.
Factor out the similar code to the caller. Squash reloc_location() too.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Emit a warning when the mod description is missed and only
when the W=1 is enabled.
Reported-by: Roland Kletzing <devzero@web.de>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=10770
Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Tested-by: Nicolas Schier <n.schier@avm.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Currently, modpost only shows the symbol names and section names, so it
repeats the same message if there are multiple relocations in the same
symbol. It is common the relocation spans across multiple instructions.
It is better to show the offset from the symbol.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
In case of section mismatch, modpost shows slightly different messages.
For extable section mismatch:
"%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n"
For the other cases:
"%s: section mismatch in reference: %s (section: %s) -> %s (section: %s)\n"
They are similar. Merge them.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses
the directory tree to determine which EXPORT_SYMBOL to trim. If an
EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the
second traverse, where some source files are recompiled with their
EXPORT_SYMBOL() tuned into a no-op.
Linus stated negative opinions about this slowness in commits:
- 5cf0fd591f ("Kbuild: disable TRIM_UNUSED_KSYMS option")
- a555bdd0c5 ("Kbuild: enable TRIM_UNUSED_KSYMS again, with some guarding")
We can do this better now. The final data structures of EXPORT_SYMBOL
are generated by the modpost stage, so modpost can selectively emit
KSYMTAB entries that are really used by modules.
Commit f73edc8951 ("kbuild: unify two modpost invocations") is another
ground-work to do this in a one-pass algorithm. With the list of modules,
modpost sets sym->used if it is used by a module. modpost emits KSYMTAB
only for symbols with sym->used==true.
BTW, Nicolas explained why the trimming was implemented with recursion:
https://lore.kernel.org/all/2o2rpn97-79nq-p7s2-nq5-8p83391473r@syhkavp.arg/
Actually, we never achieved that level of optimization where the chain
reaction of trimming comes into play because:
- CONFIG_LTO_CLANG cannot remove any unused symbols
- CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is enabled only for vmlinux,
but not modules
If deeper trimming is required, we need to revisit this, but I guess
that is unlikely to happen.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
The default namespace is the null string, "".
When set, the null string "" is converted to NULL:
s->namespace = namespace[0] ? NOFAIL(strdup(namespace)) : NULL;
When printed, the NULL pointer is get back to the null string:
sym->namespace ?: ""
This saves 1 byte memory allocated for "", but loses the readability.
In kernel-space, we strive to save memory, but modpost is a userspace
tool used to build the kernel. On modern systems, such small piece of
memory is not a big deal.
Handle the namespace string as is.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Pass a set of the name, license, and namespace to sym_add_exported().
sym_update_namespace() is unneeded.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Commit 31cb50b559 ("kbuild: check static EXPORT_SYMBOL* by script
instead of modpost") moved the static EXPORT_SYMBOL* check from the
mostpost to a shell script because I thought it must be checked per
compilation unit to avoid false negatives.
I came up with an idea to do this in modpost, against combined ELF
files. The relocation entries in ELF will find the correct exported
symbol even if there exist symbols with the same name in different
compilation units.
Again, the same sample code.
Makefile:
obj-y += foo1.o foo2.o
foo1.c:
#include <linux/export.h>
static void foo(void) {}
EXPORT_SYMBOL(foo);
foo2.c:
void foo(void) {}
Then, modpost can catch it correctly.
MODPOST Module.symvers
ERROR: modpost: vmlinux: local symbol 'foo' was exported
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Commit 7b4537199a ("kbuild: link symbol CRCs at final link, removing
CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way
whether the EXPORT_SYMBOL() is placed in *.c or *.S.
For further cleanups, this commit applies a similar approach to the
entire data structure of EXPORT_SYMBOL().
The EXPORT_SYMBOL() compilation is split into two stages.
When a source file is compiled, EXPORT_SYMBOL() will be converted into
a dummy symbol in the .export_symbol section.
For example,
EXPORT_SYMBOL(foo);
EXPORT_SYMBOL_NS_GPL(bar, BAR_NAMESPACE);
will be encoded into the following assembly code:
.section ".export_symbol","a"
__export_symbol_foo:
.asciz "" /* license */
.asciz "" /* name space */
.balign 8
.quad foo /* symbol reference */
.previous
.section ".export_symbol","a"
__export_symbol_bar:
.asciz "GPL" /* license */
.asciz "BAR_NAMESPACE" /* name space */
.balign 8
.quad bar /* symbol reference */
.previous
They are mere markers to tell modpost the name, license, and namespace
of the symbols. They will be dropped from the final vmlinux and modules
because the *(.export_symbol) will go into /DISCARD/ in the linker script.
Then, modpost extracts all the information about EXPORT_SYMBOL() from the
.export_symbol section, and generates the final C code:
KSYMTAB_FUNC(foo, "", "");
KSYMTAB_FUNC(bar, "_gpl", "BAR_NAMESPACE");
KSYMTAB_FUNC() (or KSYMTAB_DATA() if it is data) is expanded to struct
kernel_symbol that will be linked to the vmlinux or a module.
With this change, EXPORT_SYMBOL() works in the same way for *.c and *.S
files, providing the following benefits.
[1] Deprecate EXPORT_DATA_SYMBOL()
In the old days, EXPORT_SYMBOL() was only available in C files. To export
a symbol in *.S, EXPORT_SYMBOL() was placed in a separate *.c file.
arch/arm/kernel/armksyms.c is one example written in the classic manner.
Commit 22823ab419 ("EXPORT_SYMBOL() for asm") removed this limitation.
Since then, EXPORT_SYMBOL() can be placed close to the symbol definition
in *.S files. It was a nice improvement.
However, as that commit mentioned, you need to use EXPORT_DATA_SYMBOL()
for data objects on some architectures.
In the new approach, modpost checks symbol's type (STT_FUNC or not),
and outputs KSYMTAB_FUNC() or KSYMTAB_DATA() accordingly.
There are only two users of EXPORT_DATA_SYMBOL:
EXPORT_DATA_SYMBOL_GPL(empty_zero_page) (arch/ia64/kernel/head.S)
EXPORT_DATA_SYMBOL(ia64_ivt) (arch/ia64/kernel/ivt.S)
They are transformed as follows and output into .vmlinux.export.c
KSYMTAB_DATA(empty_zero_page, "_gpl", "");
KSYMTAB_DATA(ia64_ivt, "", "");
The other EXPORT_SYMBOL users in ia64 assembly are output as
KSYMTAB_FUNC().
EXPORT_DATA_SYMBOL() is now deprecated.
[2] merge <linux/export.h> and <asm-generic/export.h>
There are two similar header implementations:
include/linux/export.h for .c files
include/asm-generic/export.h for .S files
Ideally, the functionality should be consistent between them, but they
tend to diverge.
Commit 8651ec01da ("module: add support for symbol namespaces.") did
not support the namespace for *.S files.
This commit shifts the essential implementation part to C, which supports
EXPORT_SYMBOL_NS() for *.S files.
<asm/export.h> and <asm-generic/export.h> will remain as a wrapper of
<linux/export.h> for a while.
They will be removed after #include <asm/export.h> directives are all
replaced with #include <linux/export.h>.
[3] Implement CONFIG_TRIM_UNUSED_KSYMS in one-pass algorithm (by a later commit)
When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses
the directory tree to determine which EXPORT_SYMBOL to trim. If an
EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the
second traverse, where some source files are recompiled with their
EXPORT_SYMBOL() tuned into a no-op.
We can do this better now; modpost can selectively emit KSYMTAB entries
that are really used by modules.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Masahiro Yamada