Pull Kbuild updates from Masahiro Yamada:
- Change V=1 option to print both short log and full command log
- Allow V=1 and V=2 to be combined as V=12
- Make W=1 detect wrong .gitignore files
- Tree-wide cleanups for unused command line arguments passed to Clang
- Stop using -Qunused-arguments with Clang
- Make scripts/setlocalversion handle only correct release tags instead
of any arbitrary annotated tag
- Create Debian and RPM source packages without cleaning the source
tree
- Various cleanups for packaging
* tag 'kbuild-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (74 commits)
kbuild: rpm-pkg: remove unneeded KERNELRELEASE from modules/headers_install
docs: kbuild: remove description of KBUILD_LDS_MODULE
.gitattributes: use 'dts' diff driver for *.dtso files
kbuild: deb-pkg: improve the usability of source package
kbuild: deb-pkg: fix binary-arch and clean in debian/rules
kbuild: tar-pkg: use tar rules in scripts/Makefile.package
kbuild: make perf-tar*-src-pkg work without relying on git
kbuild: deb-pkg: switch over to source format 3.0 (quilt)
kbuild: deb-pkg: make .orig tarball a hard link if possible
kbuild: deb-pkg: hide KDEB_SOURCENAME from Makefile
kbuild: srcrpm-pkg: create source package without cleaning
kbuild: rpm-pkg: build binary packages from source rpm
kbuild: deb-pkg: create source package without cleaning
kbuild: add a tool to list files ignored by git
Documentation/llvm: add Chimera Linux, Google and Meta datacenters
setlocalversion: use only the correct release tag for git-describe
setlocalversion: clean up the construction of version output
.gitignore: ignore *.cover and *.mbx
kbuild: remove --include-dir MAKEFLAG from top Makefile
kbuild: fix trivial typo in comment
...
After commit 8d9acfce33 ("kbuild: Stop using '-Qunused-arguments' with
clang"), the PowerPC vDSO shows the following error with clang-13 and
older when CONFIG_INIT_STACK_ALL_ZERO is enabled:
clang: error: argument unused during compilation: '-enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang' [-Werror,-Wunused-command-line-argument]
clang-14 added a change to make sure this flag never triggers
-Wunused-command-line-argument, so it is fixed with newer releases. For
older releases that the kernel still supports building with, just filter
out this flag, as has been done for other flags.
Fixes: f0a42fbab4 ("powerpc/vdso: Improve linker flags")
Fixes: 8d9acfce33 ("kbuild: Stop using '-Qunused-arguments' with clang")
Link: ca6d5813d1
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
When clang's -Qunused-arguments is dropped from KBUILD_CPPFLAGS, it
warns:
clang-16: error: argument unused during compilation: '-fno-stack-clash-protection' [-Werror,-Wunused-command-line-argument]
This warning happens because vgettimeofday-32.c gets its base CFLAGS
from the main kernel, which may contain flags that are only supported on
a 64-bit target but not a 32-bit one, which is the case here.
-fstack-clash-protection and its negation are only suppported by the
64-bit powerpc target but that flag is included in an invocation for a
32-bit powerpc target, so clang points out that while the flag is one
that it recognizes, it is not actually used by this compiler job.
To eliminate the warning, remove -fno-stack-clash-protection from
vgettimeofday-32.c's CFLAGS when using clang, as has been done for other
flags previously.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
When clang's -Qunused-arguments is dropped from KBUILD_CPPFLAGS, there
are several warnings in the PowerPC vDSO:
clang-16: error: -Wl,-soname=linux-vdso32.so.1: 'linker' input unused [-Werror,-Wunused-command-line-argument]
clang-16: error: -Wl,--hash-style=both: 'linker' input unused [-Werror,-Wunused-command-line-argument]
clang-16: error: argument unused during compilation: '-shared' [-Werror,-Wunused-command-line-argument]
clang-16: error: argument unused during compilation: '-nostdinc' [-Werror,-Wunused-command-line-argument]
clang-16: error: argument unused during compilation: '-Wa,-maltivec' [-Werror,-Wunused-command-line-argument]
The first group of warnings point out that linker flags were being added
to all invocations of $(CC), even though they will only be used during
the final vDSO link. Move those flags to ldflags-y.
The second group of warnings are compiler or assembler flags that will
be unused during linking. Filter them out from KBUILD_CFLAGS so that
they are not used during linking.
Additionally, '-z noexecstack' was added directly to the ld_and_check
rule in commit 1d53c0192b ("powerpc/vdso: link with -z noexecstack")
but now that there is a common ldflags variable, it can be moved there.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
When clang's -Qunused-arguments is dropped from KBUILD_CPPFLAGS, it
warns:
clang-16: error: argument unused during compilation: '-s' [-Werror,-Wunused-command-line-argument]
The compiler's '-s' flag is a linking option (it is passed along to the
linker directly), which means it does nothing when the linker is not
invoked by the compiler. The kernel builds all .o files with '-c', which
stops the compilation pipeline before linking, so '-s' can be safely
dropped from ASFLAGS.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
With recent binutils, the following warning appears:
VDSO32L arch/powerpc/kernel/vdso/vdso32.so.dbg
/opt/gcc-12.2.0-nolibc/powerpc64-linux/bin/../lib/gcc/powerpc64-linux/12.2.0/../../../../powerpc64-linux/bin/ld: warning: arch/powerpc/kernel/vdso/getcpu-32.o: missing .note.GNU-stack section implies executable stack
/opt/gcc-12.2.0-nolibc/powerpc64-linux/bin/../lib/gcc/powerpc64-linux/12.2.0/../../../../powerpc64-linux/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker
To avoid that, explicitly tell the linker we don't want executable
stack.
For more explanations, see commit ffcf9c5700 ("x86: link vdso
and boot with -z noexecstack --no-warn-rwx-segments")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b95f2e3216a574837dd61208444e9515c3423da4.1662132312.git.christophe.leroy@csgroup.eu
Processors with coherent icache require the sequence sync ; icbi ; isync
to entire store->execute coherency. icbi (to any address) must be
executed to ensure isync flushes the pipeline. See "POWER9 Processor
User's Manual, 4.6.2.2 Instruction Cache Block Invalidate (icbi)" for
details.
__kernel_sync_dicache is missing icbi for the coherent icache path.
Add it.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220520123649.258440-1-npiggin@gmail.com
The PowerPC vDSO uses $(CC) to link, which differs from the rest of the
kernel, which uses $(LD) directly. As a result, the default linker of
the compiler is used, which may differ from the linker requested by the
builder. For example:
$ make ARCH=powerpc LLVM=1 mrproper defconfig arch/powerpc/kernel/vdso/
...
$ llvm-readelf -p .comment arch/powerpc/kernel/vdso/vdso{32,64}.so.dbg
File: arch/powerpc/kernel/vdso/vdso32.so.dbg
String dump of section '.comment':
[ 0] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
File: arch/powerpc/kernel/vdso/vdso64.so.dbg
String dump of section '.comment':
[ 0] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
LLVM=1 sets LD=ld.lld but ld.lld is not used to link the vDSO; GNU ld is
because "ld" is the default linker for clang on most Linux platforms.
This is a problem for Clang's Link Time Optimization as implemented in
the kernel because use of GNU ld with LTO requires the LLVMgold plugin,
which is not technically supported for ld.bfd per
https://llvm.org/docs/GoldPlugin.html. Furthermore, if LLVMgold.so is
missing from a user's system, the build will fail, even though LTO as it
is implemented in the kernel requires ld.lld to avoid this dependency in
the first place.
Ultimately, the PowerPC vDSO should be converted to compiling and
linking with $(CC) and $(LD) respectively but there were issues last
time this was tried, potentially due to older but supported tool
versions. To avoid regressing GCC + binutils, use the compiler option
'-fuse-ld', which tells the compiler which linker to use when it is
invoked as both the compiler and linker. Use '-fuse-ld=lld' when
LD=ld.lld has been specified (CONFIG_LD_IS_LLD) so that the vDSO is
linked with the same linker as the rest of the kernel.
$ llvm-readelf -p .comment arch/powerpc/kernel/vdso/vdso{32,64}.so.dbg
File: arch/powerpc/kernel/vdso/vdso32.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
File: arch/powerpc/kernel/vdso/vdso64.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
LD can be a full path to ld.lld, which will not be handled properly by
'-fuse-ld=lld' if the full path to ld.lld is outside of the compiler's
search path. '-fuse-ld' can take a path to the linker but it is
deprecated in clang 12.0.0; '--ld-path' is preferred for this scenario.
Use '--ld-path' if it is supported, as it will handle a full path or
just 'ld.lld' properly. See the LLVM commit below for the full details
of '--ld-path'.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://github.com/ClangBuiltLinux/linux/issues/774
Link: 1bc5c84710
Link: https://lore.kernel.org/r/20220511185001.3269404-3-nathan@kernel.org
When linking vdso{32,64}.so.dbg with ld.lld, there is a warning about
not finding _start for the starting address:
ld.lld: warning: cannot find entry symbol _start; not setting start address
ld.lld: warning: cannot find entry symbol _start; not setting start address
Looking at GCC + GNU ld, the entry point address is 0x0:
$ llvm-readelf -h vdso{32,64}.so.dbg &| rg "(File|Entry point address):"
File: vdso32.so.dbg
Entry point address: 0x0
File: vdso64.so.dbg
Entry point address: 0x0
This matches what ld.lld emits:
$ powerpc64le-linux-gnu-readelf -p .comment vdso{32,64}.so.dbg
File: vdso32.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
File: vdso64.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
$ llvm-readelf -h vdso{32,64}.so.dbg &| rg "(File|Entry point address):"
File: vdso32.so.dbg
Entry point address: 0x0
File: vdso64.so.dbg
Entry point address: 0x0
Remove ENTRY to remove the warning, as it is unnecessary for the vDSO to
function correctly.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220511185001.3269404-2-nathan@kernel.org
As reported by Alan, the CFI (Call Frame Information) in the VDSO time
routines is incorrect since commit ce7d8056e3 ("powerpc/vdso: Prepare
for switching VDSO to generic C implementation.").
DWARF has a concept called the CFA (Canonical Frame Address), which on
powerpc is calculated as an offset from the stack pointer (r1). That
means when the stack pointer is changed there must be a corresponding
CFI directive to update the calculation of the CFA.
The current code is missing those directives for the changes to r1,
which prevents gdb from being able to generate a backtrace from inside
VDSO functions, eg:
Breakpoint 1, 0x00007ffff7f804dc in __kernel_clock_gettime ()
(gdb) bt
#0 0x00007ffff7f804dc in __kernel_clock_gettime ()
#1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6
#2 0x00007fffffffd960 in ?? ()
#3 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6
Backtrace stopped: frame did not save the PC
Alan helpfully describes some rules for correctly maintaining the CFI information:
1) Every adjustment to the current frame address reg (ie. r1) must be
described, and exactly at the instruction where r1 changes. Why?
Because stack unwinding might want to access previous frames.
2) If a function changes LR or any non-volatile register, the save
location for those regs must be given. The CFI can be at any
instruction after the saves up to the point that the reg is
changed.
(Exception: LR save should be described before a bl. not after)
3) If asychronous unwind info is needed then restores of LR and
non-volatile regs must also be described. The CFI can be at any
instruction after the reg is restored up to the point where the
save location is (potentially) trashed.
Fix the inability to backtrace by adding CFI directives describing the
changes to r1, ie. satisfying rule 1.
Also change the information for LR to point to the copy saved on the
stack, not the value in r0 that will be overwritten by the function
call.
Finally, add CFI directives describing the save/restore of r2.
With the fix gdb can correctly back trace and navigate up and down the stack:
Breakpoint 1, 0x00007ffff7f804dc in __kernel_clock_gettime ()
(gdb) bt
#0 0x00007ffff7f804dc in __kernel_clock_gettime ()
#1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6
#2 0x0000000100015b60 in gettime ()
#3 0x000000010000c8bc in print_long_format ()
#4 0x000000010000d180 in print_current_files ()
#5 0x00000001000054ac in main ()
(gdb) up
#1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6
(gdb)
#2 0x0000000100015b60 in gettime ()
(gdb)
#3 0x000000010000c8bc in print_long_format ()
(gdb)
#4 0x000000010000d180 in print_current_files ()
(gdb)
#5 0x00000001000054ac in main ()
(gdb)
Initial frame selected; you cannot go up.
(gdb) down
#4 0x000000010000d180 in print_current_files ()
(gdb)
#3 0x000000010000c8bc in print_long_format ()
(gdb)
#2 0x0000000100015b60 in gettime ()
(gdb)
#1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6
(gdb)
#0 0x00007ffff7f804dc in __kernel_clock_gettime ()
(gdb)
Fixes: ce7d8056e3 ("powerpc/vdso: Prepare for switching VDSO to generic C implementation.")
Cc: stable@vger.kernel.org # v5.11+
Reported-by: Alan Modra <amodra@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Link: https://lore.kernel.org/r/20220502125010.1319370-1-mpe@ellerman.id.au
