172 Commits

Author SHA1 Message Date
Alexey Gladkov
3328d39a8d kbuild: vmlinux.unstripped should always depend on .vmlinux.export.o
Since .vmlinux.export.c is used to add generated by modpost modaliases
for builtin modules the .vmlinux.export.o is no longer optional and
should always be created. The generation of this file is not dependent
on CONFIG_MODULES.

Signed-off-by: Alexey Gladkov <legion@kernel.org>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Link: https://patch.msgid.link/0e63a9c7741fe8217e4fd7c60afcf057ffa2ef5a.1758182101.git.legion@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
2025-09-24 09:10:45 -07:00
Linus Torvalds
f4d2ef4825 Merge tag 'kbuild-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:

 - Improve performance in gendwarfksyms

 - Remove deprecated EXTRA_*FLAGS and KBUILD_ENABLE_EXTRA_GCC_CHECKS

 - Support CONFIG_HEADERS_INSTALL for ARCH=um

 - Use more relative paths to sources files for better reproducibility

 - Support the loong64 Debian architecture

 - Add Kbuild bash completion

 - Introduce intermediate vmlinux.unstripped for architectures that need
   static relocations to be stripped from the final vmlinux

 - Fix versioning in Debian packages for -rc releases

 - Treat missing MODULE_DESCRIPTION() as an error

 - Convert Nios2 Makefiles to use the generic rule for built-in DTB

 - Add debuginfo support to the RPM package

* tag 'kbuild-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (40 commits)
  kbuild: rpm-pkg: build a debuginfo RPM
  kconfig: merge_config: use an empty file as initfile
  nios2: migrate to the generic rule for built-in DTB
  rust: kbuild: skip `--remap-path-prefix` for `rustdoc`
  kbuild: pacman-pkg: hardcode module installation path
  kbuild: deb-pkg: don't set KBUILD_BUILD_VERSION unconditionally
  modpost: require a MODULE_DESCRIPTION()
  kbuild: make all file references relative to source root
  x86: drop unnecessary prefix map configuration
  kbuild: deb-pkg: add comment about future removal of KDEB_COMPRESS
  kbuild: Add a help message for "headers"
  kbuild: deb-pkg: remove "version" variable in mkdebian
  kbuild: deb-pkg: fix versioning for -rc releases
  Documentation/kbuild: Fix indentation in modules.rst example
  x86: Get rid of Makefile.postlink
  kbuild: Create intermediate vmlinux build with relocations preserved
  kbuild: Introduce Kconfig symbol for linking vmlinux with relocations
  kbuild: link-vmlinux.sh: Make output file name configurable
  kbuild: do not generate .tmp_vmlinux*.map when CONFIG_VMLINUX_MAP=y
  Revert "kheaders: Ignore silly-rename files"
  ...
2025-04-05 15:46:50 -07:00
Linus Torvalds
dd161f74f8 Merge tag 'trace-sorttable-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing / sorttable updates from Steven Rostedt:

 - Implement arm64 build time sorting of the mcount location table

   When gcc is used to build arm64, the mcount_loc section is all zeros
   in the vmlinux elf file. The addresses are stored in the Elf_Rela
   location.

   To sort at build time, an array is allocated and the addresses are
   added to it via the content of the mcount_loc section as well as he
   Elf_Rela data. After sorting, the information is put back into the
   Elf_Rela which now has the section sorted.

 - Make sorting of mcount location table for arm64 work with clang as
   well

   When clang is used, the mcount_loc section contains the addresses,
   unlike the gcc build. An array is still created and the sorting works
   for both methods.

 - Remove weak functions from the mcount_loc section

   Have the sorttable code pass in the data of functions defined via
   'nm -S' which shows the functions as well as their sizes. Using this
   information the sorttable code can determine if a function in the
   mcount_loc section was weak and overridden. If the function is not
   found, it is set to be zero. On boot, when the mcount_loc section is
   read and the ftrace table is created, if the address in the
   mcount_loc is not in the kernel core text then it is removed and not
   added to the ftrace_filter_functions (the functions that can be
   attached by ftrace callbacks).

 - Update and fix the reporting of how much data is used for ftrace
   functions

   On boot, a report of how many pages were used by the ftrace table as
   well as how they were grouped (the table holds a list of sections
   that are groups of pages that were able to be allocated). The
   removing of the weak functions required the accounting to be updated.

* tag 'trace-sorttable-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  scripts/sorttable: Allow matches to functions before function entry
  scripts/sorttable: Use normal sort if theres no relocs in the mcount section
  ftrace: Check against is_kernel_text() instead of kaslr_offset()
  ftrace: Test mcount_loc addr before calling ftrace_call_addr()
  ftrace: Have ftrace pages output reflect freed pages
  ftrace: Update the mcount_loc check of skipped entries
  scripts/sorttable: Zero out weak functions in mcount_loc table
  scripts/sorttable: Always use an array for the mcount_loc sorting
  scripts/sorttable: Have mcount rela sort use direct values
  arm64: scripts/sorttable: Implement sorting mcount_loc at boot for arm64
2025-03-27 15:44:34 -07:00
Ard Biesheuvel
e22bbb8e97 kbuild: link-vmlinux.sh: Make output file name configurable
In order to introduce an intermediate, non-stripped vmlinux build that
can be used by other build steps as an input, pass the output file name
to link-vmlinux.sh via its command line.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-03-17 00:29:45 +09:00
Masahiro Yamada
ba4d705046 kbuild: do not generate .tmp_vmlinux*.map when CONFIG_VMLINUX_MAP=y
Commit 5cc1247204 ("kbuild: add CONFIG_VMLINUX_MAP expert option")
mentioned that "the .map file can be rather large (several MB), and
that's a waste of space when one isn't interested in these things."

If that is the case, generating map files for the intermediate
tmp_vmlinux* files is also a waste of space. It is unlikely that
anyone would be interested in the .tmp_vmlinux*.map files.

This commit stops passing the -Map= option when linking the .tmp_vmlinux*
intermediates.

I also hard-coded the file name 'vmlinux.map' instead of ${output}.map
because a later commit will introduce vmlinux.unstripped but I want to
keep the current name of the map file.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
2025-03-15 21:22:52 +09:00
Steven Rostedt
ef378c3b82 scripts/sorttable: Zero out weak functions in mcount_loc table
When a function is annotated as "weak" and is overridden, the code is not
removed. If it is traced, the fentry/mcount location in the weak function
will be referenced by the "__mcount_loc" section. This will then be added
to the available_filter_functions list. Since only the address of the
functions are listed, to find the name to show, a search of kallsyms is
used.

Since kallsyms will return the function by simply finding the function
that the address is after but before the next function, an address of a
weak function will show up as the function before it. This is because
kallsyms does not save names of weak functions. This has caused issues in
the past, as now the traced weak function will be listed in
available_filter_functions with the name of the function before it.

At best, this will cause the previous function's name to be listed twice.
At worse, if the previous function was marked notrace, it will now show up
as a function that can be traced. Note that it only shows up that it can
be traced but will not be if enabled, which causes confusion.

 https://lore.kernel.org/all/20220412094923.0abe90955e5db486b7bca279@kernel.org/

The commit b39181f7c6 ("ftrace: Add FTRACE_MCOUNT_MAX_OFFSET to avoid
adding weak function") was a workaround to this by checking the function
address before printing its name. If the address was too far from the
function given by the name then instead of printing the name it would
print: __ftrace_invalid_address___<invalid-offset>

The real issue is that these invalid addresses are listed in the ftrace
table look up which available_filter_functions is derived from. A place
holder must be listed in that file because set_ftrace_filter may take a
series of indexes into that file instead of names to be able to do O(1)
lookups to enable filtering (many tools use this method).

Even if kallsyms saved the size of the function, it does not remove the
need of having these place holders. The real solution is to not add a weak
function into the ftrace table in the first place.

To solve this, the sorttable.c code that sorts the mcount regions during
the build is modified to take a "nm -S vmlinux" input, sort it, and any
function listed in the mcount_loc section that is not within a boundary of
the function list given by nm is considered a weak function and is zeroed
out.

Note, this does not mean they will remain zero when booting as KASLR
will still shift those addresses. To handle this, the entries in the
mcount_loc section will be ignored if they are zero or match the
kaslr_offset() value.

Before:

 ~# grep __ftrace_invalid_address___ /sys/kernel/tracing/available_filter_functions | wc -l
 551

After:

 ~# grep __ftrace_invalid_address___ /sys/kernel/tracing/available_filter_functions | wc -l
 0

Cc: bpf <bpf@vger.kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: Zheng Yejian <zhengyejian1@huawei.com>
Cc: Martin  Kelly <martin.kelly@crowdstrike.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Link: https://lore.kernel.org/20250218200022.883095980@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-02-18 17:12:03 -05:00
Brian Gerst
01157ddc58 kallsyms: Remove KALLSYMS_ABSOLUTE_PERCPU
x86-64 was the only user.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250123190747.745588-16-brgerst@gmail.com
2025-02-18 10:16:04 +01:00
Thomas Weißschuh
6e8ba494d8 kbuild/btf: Propagate CONFIG_WERROR to resolve_btfids
Use CONFIG_WERROR to also fail on warnings emitted by resolve_btfids.
Allow the CI bots to prevent the introduction of new warnings.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20241204-resolve_btfids-v3-2-e6a279a74cfd@weissschuh.net
2024-12-10 17:57:42 +01:00
Linus Torvalds
6a34dfa15d Merge tag 'kbuild-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:

 - Add generic support for built-in boot DTB files

 - Enable TAB cycling for dialog buttons in nconfig

 - Fix issues in streamline_config.pl

 - Refactor Kconfig

 - Add support for Clang's AutoFDO (Automatic Feedback-Directed
   Optimization)

 - Add support for Clang's Propeller, a profile-guided optimization.

 - Change the working directory to the external module directory for M=
   builds

 - Support building external modules in a separate output directory

 - Enable objtool for *.mod.o and additional kernel objects

 - Use lz4 instead of deprecated lz4c

 - Work around a performance issue with "git describe"

 - Refactor modpost

* tag 'kbuild-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (85 commits)
  kbuild: rename .tmp_vmlinux.kallsyms0.syms to .tmp_vmlinux0.syms
  gitignore: Don't ignore 'tags' directory
  kbuild: add dependency from vmlinux to resolve_btfids
  modpost: replace tdb_hash() with hash_str()
  kbuild: deb-pkg: add python3:native to build dependency
  genksyms: reduce indentation in export_symbol()
  modpost: improve error messages in device_id_check()
  modpost: rename alias symbol for MODULE_DEVICE_TABLE()
  modpost: rename variables in handle_moddevtable()
  modpost: move strstarts() to modpost.h
  modpost: convert do_usb_table() to a generic handler
  modpost: convert do_of_table() to a generic handler
  modpost: convert do_pnp_device_entry() to a generic handler
  modpost: convert do_pnp_card_entries() to a generic handler
  modpost: call module_alias_printf() from all do_*_entry() functions
  modpost: pass (struct module *) to do_*_entry() functions
  modpost: remove DEF_FIELD_ADDR_VAR() macro
  modpost: deduplicate MODULE_ALIAS() for all drivers
  modpost: introduce module_alias_printf() helper
  modpost: remove unnecessary check in do_acpi_entry()
  ...
2024-11-30 13:41:50 -08:00
Sedat Dilek
e6064da646 kbuild: rename .tmp_vmlinux.kallsyms0.syms to .tmp_vmlinux0.syms
Change the naming for consistency.

While at this, fix the comments in scripts/link-vmlinux.sh.

Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-11-28 08:46:03 +09:00
Masahiro Yamada
654102df2a kbuild: add generic support for built-in boot DTBs
Some architectures embed boot DTBs in vmlinux. A potential issue for
these architectures is a race condition during parallel builds because
Kbuild descends into arch/*/boot/dts/ twice.

One build thread is initiated by the 'dtbs' target, which is a
prerequisite of the 'all' target in the top-level Makefile:

  ifdef CONFIG_OF_EARLY_FLATTREE
  all: dtbs
  endif

For architectures that support the built-in boot dtb, arch/*/boot/dts/
is visited also during the ordinary directory traversal in order to
build obj-y objects that wrap DTBs.

Since these build threads are unaware of each other, they can run
simultaneously during parallel builds.

This commit introduces a generic build rule to scripts/Makefile.vmlinux
to support embedded boot DTBs in a race-free way. Architectures that
want to use this rule need to select CONFIG_GENERIC_BUILTIN_DTB.

After the migration, Makefiles under arch/*/boot/dts/ will be visited
only once to build only *.dtb files.

This change also aims to unify the CONFIG options used for built-in DTBs
support. Currently, different architectures use different CONFIG options
for the same purposes.

With this commit, the CONFIG options will be unified as follows:

 - CONFIG_GENERIC_BUILTIN_DTB

   This enables the generic rule for built-in boot DTBs. This will be
   renamed to CONFIG_BUILTIN_DTB after all architectures migrate to the
   generic rule.

 - CONFIG_BUILTIN_DTB_NAME

   This specifies the path to the embedded DTB.
   (relative to arch/*/boot/dts/)

 - CONFIG_BUILTIN_DTB_ALL

   If this is enabled, all DTB files compiled under arch/*/boot/dts/ are
   embedded into vmlinux. Only used by MIPS.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-11-04 17:53:09 +09:00
Naveen N Rao
1198c9c689 kbuild: Add generic hook for architectures to use before the final vmlinux link
On powerpc, we would like to be able to make a pass on vmlinux.o and
generate a new object file to be linked into vmlinux. Add a generic pass
in Makefile.vmlinux that architectures can use for this purpose.

Architectures need to select CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX and must
provide arch/<arch>/tools/Makefile with .arch.vmlinux.o target, which
will be invoked prior to the final vmlinux link step.

Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://patch.msgid.link/20241030070850.1361304-12-hbathini@linux.ibm.com
2024-10-31 11:00:54 +11:00
Linus Torvalds
68e5c7d4ce Merge tag 'kbuild-v6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:

 - Support cross-compiling linux-headers Debian package and kernel-devel
   RPM package

 - Add support for the linux-debug Pacman package

 - Improve module rebuilding speed by factoring out the common code to
   scripts/module-common.c

 - Separate device tree build rules into scripts/Makefile.dtbs

 - Add a new script to generate modules.builtin.ranges, which is useful
   for tracing tools to find symbols in built-in modules

 - Refactor Kconfig and misc tools

 - Update Kbuild and Kconfig documentation

* tag 'kbuild-v6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (51 commits)
  kbuild: doc: replace "gcc" in external module description
  kbuild: doc: describe the -C option precisely for external module builds
  kbuild: doc: remove the description about shipped files
  kbuild: doc: drop section numbering, use references in modules.rst
  kbuild: doc: throw out the local table of contents in modules.rst
  kbuild: doc: remove outdated description of the limitation on -I usage
  kbuild: doc: remove description about grepping CONFIG options
  kbuild: doc: update the description about Kbuild/Makefile split
  kbuild: remove unnecessary export of RUST_LIB_SRC
  kbuild: remove append operation on cmd_ld_ko_o
  kconfig: cache expression values
  kconfig: use hash table to reuse expressions
  kconfig: refactor expr_eliminate_dups()
  kconfig: add comments to expression transformations
  kconfig: change some expr_*() functions to bool
  scripts: move hash function from scripts/kconfig/ to scripts/include/
  kallsyms: change overflow variable to bool type
  kallsyms: squash output_address()
  kbuild: add install target for modules.builtin.ranges
  scripts: add verifier script for builtin module range data
  ...
2024-09-24 13:02:06 -07:00
Linus Torvalds
440b652328 Merge tag 'bpf-next-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Pull bpf updates from Alexei Starovoitov:

 - Introduce '__attribute__((bpf_fastcall))' for helpers and kfuncs with
   corresponding support in LLVM.

   It is similar to existing 'no_caller_saved_registers' attribute in
   GCC/LLVM with a provision for backward compatibility. It allows
   compilers generate more efficient BPF code assuming the verifier or
   JITs will inline or partially inline a helper/kfunc with such
   attribute. bpf_cast_to_kern_ctx, bpf_rdonly_cast,
   bpf_get_smp_processor_id are the first set of such helpers.

 - Harden and extend ELF build ID parsing logic.

   When called from sleepable context the relevants parts of ELF file
   will be read to find and fetch .note.gnu.build-id information. Also
   harden the logic to avoid TOCTOU, overflow, out-of-bounds problems.

 - Improvements and fixes for sched-ext:
    - Allow passing BPF iterators as kfunc arguments
    - Make the pointer returned from iter_next method trusted
    - Fix x86 JIT convergence issue due to growing/shrinking conditional
      jumps in variable length encoding

 - BPF_LSM related:
    - Introduce few VFS kfuncs and consolidate them in
      fs/bpf_fs_kfuncs.c
    - Enforce correct range of return values from certain LSM hooks
    - Disallow attaching to other LSM hooks

 - Prerequisite work for upcoming Qdisc in BPF:
    - Allow kptrs in program provided structs
    - Support for gen_epilogue in verifier_ops

 - Important fixes:
    - Fix uprobe multi pid filter check
    - Fix bpf_strtol and bpf_strtoul helpers
    - Track equal scalars history on per-instruction level
    - Fix tailcall hierarchy on x86 and arm64
    - Fix signed division overflow to prevent INT_MIN/-1 trap on x86
    - Fix get kernel stack in BPF progs attached to tracepoint:syscall

 - Selftests:
    - Add uprobe bench/stress tool
    - Generate file dependencies to drastically improve re-build time
    - Match JIT-ed and BPF asm with __xlated/__jited keywords
    - Convert older tests to test_progs framework
    - Add support for RISC-V
    - Few fixes when BPF programs are compiled with GCC-BPF backend
      (support for GCC-BPF in BPF CI is ongoing in parallel)
    - Add traffic monitor
    - Enable cross compile and musl libc

* tag 'bpf-next-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (260 commits)
  btf: require pahole 1.21+ for DEBUG_INFO_BTF with default DWARF version
  btf: move pahole check in scripts/link-vmlinux.sh to lib/Kconfig.debug
  btf: remove redundant CONFIG_BPF test in scripts/link-vmlinux.sh
  bpf: Call the missed kfree() when there is no special field in btf
  bpf: Call the missed btf_record_free() when map creation fails
  selftests/bpf: Add a test case to write mtu result into .rodata
  selftests/bpf: Add a test case to write strtol result into .rodata
  selftests/bpf: Rename ARG_PTR_TO_LONG test description
  selftests/bpf: Fix ARG_PTR_TO_LONG {half-,}uninitialized test
  bpf: Zero former ARG_PTR_TO_{LONG,INT} args in case of error
  bpf: Improve check_raw_mode_ok test for MEM_UNINIT-tagged types
  bpf: Fix helper writes to read-only maps
  bpf: Remove truncation test in bpf_strtol and bpf_strtoul helpers
  bpf: Fix bpf_strtol and bpf_strtoul helpers for 32bit
  selftests/bpf: Add tests for sdiv/smod overflow cases
  bpf: Fix a sdiv overflow issue
  libbpf: Add bpf_object__token_fd accessor
  docs/bpf: Add missing BPF program types to docs
  docs/bpf: Add constant values for linkages
  bpf: Use fake pt_regs when doing bpf syscall tracepoint tracing
  ...
2024-09-21 09:27:50 -07:00
Masahiro Yamada
42450f7a90 btf: move pahole check in scripts/link-vmlinux.sh to lib/Kconfig.debug
When DEBUG_INFO_DWARF5 is selected, pahole 1.21+ is required to enable
DEBUG_INFO_BTF.

When DEBUG_INFO_DWARF4 or DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT is selected,
DEBUG_INFO_BTF can be enabled without pahole installed, but a build error
will occur in scripts/link-vmlinux.sh:

    LD      .tmp_vmlinux1
  BTF: .tmp_vmlinux1: pahole (pahole) is not available
  Failed to generate BTF for vmlinux
  Try to disable CONFIG_DEBUG_INFO_BTF

We did not guard DEBUG_INFO_BTF by PAHOLE_VERSION when previously
discussed [1].

However, commit 613fe16923 ("kbuild: Add CONFIG_PAHOLE_VERSION")
added CONFIG_PAHOLE_VERSION after all. Now several CONFIG options, as
well as the combination of DEBUG_INFO_BTF and DEBUG_INFO_DWARF5, are
guarded by PAHOLE_VERSION.

The remaining compile-time check in scripts/link-vmlinux.sh now appears
to be an awkward inconsistency.

This commit adopts Nathan's original work.

[1]: https://lore.kernel.org/lkml/20210111180609.713998-1-natechancellor@gmail.com/

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20240913173759.1316390-2-masahiroy@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-09-13 20:03:29 -07:00
Masahiro Yamada
c980dc9c67 btf: remove redundant CONFIG_BPF test in scripts/link-vmlinux.sh
CONFIG_DEBUG_INFO_BTF depends on CONFIG_BPF_SYSCALL, which in turn
selects CONFIG_BPF.

When CONFIG_DEBUG_INFO_BTF=y, CONFIG_BPF=y is always met.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20240913173759.1316390-1-masahiroy@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-09-13 20:03:29 -07:00
Tony Battersby
dde60e7d10 kbuild: remove recent dependency on "truncate" program
Remove the recently-added dependency on the truncate program for
building the kernel. truncate is not available when building the kernel
under Yocto. It could be added, but it would be better just to avoid
the unnecessary dependency.

Fixes: 1472464c62 ("kbuild: avoid scripts/kallsyms parsing /dev/null")
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-09-07 17:24:08 +09:00
Linus Torvalds
3f44ae972a Merge tag 'kbuild-fixes-v6.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild fixes from Masahiro Yamada:

 - Eliminate the fdtoverlay command duplication in scripts/Makefile.lib

 - Fix 'make compile_commands.json' for external modules

 - Ensure scripts/kconfig/merge_config.sh handles missing newlines

 - Fix some build errors on macOS

* tag 'kbuild-fixes-v6.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: fix typos "prequisites" to "prerequisites"
  Documentation/llvm: turn make command for ccache into code block
  kbuild: avoid scripts/kallsyms parsing /dev/null
  treewide: remove unnecessary <linux/version.h> inclusion
  scripts: kconfig: merge_config: config files: add a trailing newline
  Makefile: add $(srctree) to dependency of compile_commands.json target
  kbuild: clean up code duplication in cmd_fdtoverlay
2024-08-23 07:43:15 +08:00
Song Liu
020925ce92 kallsyms: Do not cleanup .llvm.<hash> suffix before sorting symbols
Cleaning up the symbols causes various issues afterwards. Let's sort
the list based on original name.

Signed-off-by: Song Liu <song@kernel.org>
Fixes: 8cc32a9bbf ("kallsyms: strip LTO-only suffixes from promoted global functions")
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Tested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20240807220513.3100483-2-song@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
2024-08-15 09:33:34 -07:00
Masahiro Yamada
1472464c62 kbuild: avoid scripts/kallsyms parsing /dev/null
On macOS, as reported by Daniel Gomez, getline() sets ENOTTY to errno
if it is requested to read from /dev/null.

If this is worth fixing, I would rather pass an empty file to
scripts/kallsyms instead of adding the ugly #ifdef __APPLE__.

Fixes: c442db3f49 ("kbuild: remove PROVIDE() for kallsyms symbols")
Reported-by: Daniel Gomez <da.gomez@samsung.com>
Closes: https://lore.kernel.org/all/20240807-macos-build-support-v1-12-4cd1ded85694@samsung.com/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Reviewed-by: Daniel Gomez <da.gomez@samsung.com>
2024-08-12 18:37:27 +09:00
Jann Horn
64e166099b kallsyms: get rid of code for absolute kallsyms
Commit cf8e865810 ("arch: Remove Itanium (IA-64) architecture")
removed the last use of the absolute kallsyms.

Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/all/20240221202655.2423854-1-jannh@google.com/
[masahiroy@kernel.org: rebase the code and reword the commit description]
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-07-20 16:33:21 +09:00
Masahiro Yamada
b1a9a5e047 kbuild: merge temporary vmlinux for BTF and kallsyms
CONFIG_DEBUG_INFO_BTF=y requires one additional link step.
(.tmp_vmlinux.btf)

CONFIG_KALLSYMS=y requires two additional link steps.
(.tmp_vmlinux.kallsyms1 and .tmp_vmlinux.kallsyms2)

Enabling both requires three additional link steps.

When CONFIG_DEBUG_INFO_BTF=y and CONFIG_KALLSYMS=y, the current build
process is as follows:

    KSYMS   .tmp_vmlinux.kallsyms0.S
    AS      .tmp_vmlinux.kallsyms0.o
    LD      .tmp_vmlinux.btf             # temporary vmlinux for BTF
    BTF     .btf.vmlinux.bin.o
    LD      .tmp_vmlinux.kallsyms1       # temporary vmlinux for kallsyms step 1
    NM      .tmp_vmlinux.kallsyms1.syms
    KSYMS   .tmp_vmlinux.kallsyms1.S
    AS      .tmp_vmlinux.kallsyms1.o
    LD      .tmp_vmlinux.kallsyms2       # temporary vmlinux for kallsyms step 2
    NM      .tmp_vmlinux.kallsyms2.syms
    KSYMS   .tmp_vmlinux.kallsyms2.S
    AS      .tmp_vmlinux.kallsyms2.o
    LD      vmlinux                      # final vmlinux

This is redundant because the BTF generation and the kallsyms step 1 can
be performed against the same temporary vmlinux.

When both CONFIG_DEBUG_INFO_BTF and CONFIG_KALLSYMS are enabled, we can
reduce the number of link steps by one.

This commit changes the build process as follows:

    KSYMS   .tmp_vmlinux0.kallsyms.S
    AS      .tmp_vmlinux0.kallsyms.o
    LD      .tmp_vmlinux1                # temporary vmlinux for BTF and kallsyms step 1
    BTF     .tmp_vmlinux1.btf.o
    NM      .tmp_vmlinux1.syms
    KSYMS   .tmp_vmlinux1.kallsyms.S
    AS      .tmp_vmlinux1.kallsyms.o
    LD      .tmp_vmlinux2                # temporary vmlinux for kallsyms step 2
    NM      .tmp_vmlinux2.syms
    KSYMS   .tmp_vmlinux2.kallsyms.S
    AS      .tmp_vmlinux2.kallsyms.o
    LD      vmlinux                      # final vmlinux

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
2024-07-16 01:08:36 +09:00
Masahiro Yamada
c442db3f49 kbuild: remove PROVIDE() for kallsyms symbols
This reimplements commit 951bcae6c5 ("kallsyms: Avoid weak references
for kallsyms symbols") because I am not a big fan of PROVIDE().

As an alternative solution, this commit prepends one more kallsyms step.

    KSYMS   .tmp_vmlinux.kallsyms0.S          # added
    AS      .tmp_vmlinux.kallsyms0.o          # added
    LD      .tmp_vmlinux.btf
    BTF     .btf.vmlinux.bin.o
    LD      .tmp_vmlinux.kallsyms1
    NM      .tmp_vmlinux.kallsyms1.syms
    KSYMS   .tmp_vmlinux.kallsyms1.S
    AS      .tmp_vmlinux.kallsyms1.o
    LD      .tmp_vmlinux.kallsyms2
    NM      .tmp_vmlinux.kallsyms2.syms
    KSYMS   .tmp_vmlinux.kallsyms2.S
    AS      .tmp_vmlinux.kallsyms2.o
    LD      vmlinux

Step 0 takes /dev/null as input, and generates .tmp_vmlinux.kallsyms0.o,
which has a valid kallsyms format with the empty symbol list, and can be
linked to vmlinux. Since it is really small, the added compile-time cost
is negligible.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2024-07-16 01:08:36 +09:00
Masahiro Yamada
ddf4132983 kbuild: refactor variables in scripts/link-vmlinux.sh
Clean up the variables in scripts/link-vmlinux.sh

 - Specify the extra objects directly in vmlinux_link()
 - Move the AS rule to kallsyms()
 - Set kallsymso and btf_vmlinux_bin_o where they are generated
 - Remove unneeded variable, kallsymso_prev
 - Introduce the btf_data variable
 - Introduce the strip_debug flag instead of checking the output name

No functional change intended.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2024-07-16 01:08:36 +09:00
Richard Acayan
96c965667b kbuild: explicitly run mksysmap as sed script from link-vmlinux.sh
In commit b18b047002 ("kbuild: change scripts/mksysmap into sed
script"), the mksysmap script was transformed into a sed script,
made directly executable with "#!/bin/sed -f". Apparently, the path to
sed is different on NixOS.

The shebang can't use the env command, otherwise the "sed -f" command
would be treated as a single argument. This can be solved with the -S
flag, but that is a GNU extension. Explicitly use sed instead of relying
on the executable shebang to fix NixOS builds without breaking build
environments using Busybox.

Fixes: b18b047002 ("kbuild: change scripts/mksysmap into sed script")
Reported-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Richard Acayan <mailingradian@gmail.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-06-07 08:42:14 +09:00