kernel/linux.git/scripts/Makefile.modfinal, branch v6.12.80

kbuild: remove append operation on cmd_ld_ko_o

2024-09-20T00:21:53+00:00

The append operation was introduced in commit b1a1a1a09b46 ("kbuild: lto: postpone objtool") when the command was created from two parts. In commit 850ded46c642 ("kbuild: Fix TRIM_UNUSED_KSYMS with LTO_CLANG") however the first part was removed again, making the append operation unnecessary. To keep this command definition aligned with all other command definitions, remove the append again. Signed-off-by: Thomas Weißschuh Signed-off-by: Masahiro Yamada

kbuild: compile constant module information only once

2024-09-07T08:24:08+00:00

Various information about modules is compiled into the info sections. For that a dedicated .mod.c file is generated by modpost for each module and then linked into the module. However most of the information in the .mod.c is the same for all modules, internal and external. Split the shared information into a dedicated source file that is compiled once and then linked into all modules. This avoids frequent rebuilds for all .mod.c files when using CONFIG_LOCALVERSION_AUTO because the local version ends up in .mod.c through UTS_RELEASE and VERMAGIC_STRING. The modules are still relinked in this case. The code is also easier to maintain as it's now in a proper source file instead of an inline string literal. Signed-off-by: Thomas Weißschuh Signed-off-by: Masahiro Yamada

kbuild: fix typos "prequisites" to "prerequisites"

2024-08-22T17:41:02+00:00

This typo in scripts/Makefile.build has been present for more than 20 years. It was accidentally copy-pasted to other scripts/Makefile.* files. Fix them all. Signed-off-by: Masahiro Yamada Reviewed-by: Nathan Chancellor

kbuild,bpf: Add module-specific pahole flags for distilled base BTF

2024-06-21T21:45:07+00:00

Support creation of module BTF along with distilled base BTF; the latter is stored in a .BTF.base ELF section and supplements split BTF references to base BTF with information about base types, allowing for later relocation of split BTF with a (possibly changed) base. resolve_btfids detects the presence of a .BTF.base section and will use it instead of the base BTF it is passed in BTF id resolution. Modules will be built with a distilled .BTF.base section for external module build, i.e. make -C. -M=path2/module ...while in-tree module build as part of a normal kernel build will not generate distilled base BTF; this is because in-tree modules change with the kernel and do not require BTF relocation for the running vmlinux. Signed-off-by: Alan Maguire Signed-off-by: Andrii Nakryiko Reviewed-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/20240620091733.1967885-6-alan.maguire@oracle.com

kbuild: use GCOV_PROFILE and KCSAN_SANITIZE in scripts/Makefile.modfinal

2024-05-14T14:36:12+00:00

Instead of filtering out the GCOV and KCSAN flags, let's set GCOV_PROFILE and KCSAN_SANITIZE to 'n', as in other Makefiles. Signed-off-by: Masahiro Yamada Reviewed-by: Kees Cook Tested-by: Roberto Sassu

kbuild: Disable KCSAN for autogenerated *.mod.c intermediaries

2024-03-31T12:09:41+00:00

When KCSAN and CONSTRUCTORS are enabled, one can trigger the "Unpatched return thunk in use. This should not happen!" catch-all warning. Usually, when objtool runs on the .o objects, it does generate a section .return_sites which contains all offsets in the objects to the return thunks of the functions present there. Those return thunks then get patched at runtime by the alternatives. KCSAN and CONSTRUCTORS add this to the object file's .text.startup section: ------------------- Disassembly of section .text.startup: ... 0000000000000010 <_sub_I_00099_0>: 10: f3 0f 1e fa endbr64 14: e8 00 00 00 00 call 19 <_sub_I_00099_0+0x9> 15: R_X86_64_PLT32 __tsan_init-0x4 19: e9 00 00 00 00 jmp 1e <__UNIQUE_ID___addressable_cryptd_alloc_aead349+0x6> 1a: R_X86_64_PLT32 __x86_return_thunk-0x4 ------------------- which, if it is built as a module goes through the intermediary stage of creating a .mod.c file which, when translated, receives a second constructor: ------------------- Disassembly of section .text.startup: 0000000000000010 <_sub_I_00099_0>: 10: f3 0f 1e fa endbr64 14: e8 00 00 00 00 call 19 <_sub_I_00099_0+0x9> 15: R_X86_64_PLT32 __tsan_init-0x4 19: e9 00 00 00 00 jmp 1e <_sub_I_00099_0+0xe> 1a: R_X86_64_PLT32 __x86_return_thunk-0x4 ... 0000000000000030 <_sub_I_00099_0>: 30: f3 0f 1e fa endbr64 34: e8 00 00 00 00 call 39 <_sub_I_00099_0+0x9> 35: R_X86_64_PLT32 __tsan_init-0x4 39: e9 00 00 00 00 jmp 3e <__ksymtab_cryptd_alloc_ahash+0x2> 3a: R_X86_64_PLT32 __x86_return_thunk-0x4 ------------------- in the .ko file. Objtool has run already so that second constructor's return thunk cannot be added to the .return_sites section and thus the return thunk remains unpatched and the warning rightfully fires. Drop KCSAN flags from the mod.c generation stage as those constructors do not contain data races one would be interested about. Debugged together with David Kaplan and Nikolay Borisov . Reported-by: Paul Menzel Closes: https://lore.kernel.org/r/0851a207-7143-417e-be31-8bf2b3afb57d@molgen.mpg.de Signed-off-by: Borislav Petkov (AMD) Tested-by: Paul Menzel # Dell XPS 13 Reviewed-by: Nikolay Borisov Reviewed-by: Marco Elver Signed-off-by: Masahiro Yamada

kbuild: remove ARCH_POSTLINK from module builds

2023-10-28T12:10:08+00:00

The '%.ko' rule in arch/*/Makefile.postlink does nothing but call the 'true' command. Remove the unneeded code. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier

btf, scripts: rust: drop is_rust_module.sh

2023-08-10T20:28:04+00:00

With commit c1177979af9c ("btf, scripts: Exclude Rust CUs with pahole") we are now able to use pahole directly to identify Rust compilation units (CUs) and exclude them from generating BTF debugging information (when DEBUG_INFO_BTF is enabled). And if pahole doesn't support the --lang-exclude flag, we can't enable both RUST and DEBUG_INFO_BTF at the same time. So, in any case, the script is_rust_module.sh is just redundant and we can drop it. NOTE: we may also be able to drop the "Rust loadable module" mark inside Rust modules, but it seems safer to keep it for now to make sure we are not breaking any external tool that may potentially rely on it. Signed-off-by: Andrea Righi Reviewed-by: Nathan Chancellor Tested-by: Eric Curtin Reviewed-by: Eric Curtin Reviewed-by: Neal Gompa Reviewed-by: Masahiro Yamada Reviewed-by: Martin Rodriguez Reboredo Acked-by: Daniel Xu Link: https://lore.kernel.org/r/20230704052136.155445-1-andrea.righi@canonical.com [ Picked the `Reviewed-by`s from the old patch too. ] Signed-off-by: Miguel Ojeda

kbuild: Disable GCOV for *.mod.o

2023-06-25T14:12:20+00:00

With GCOV_PROFILE_ALL, Clang injects __llvm_gcov_* functions to each object file, including the *.mod.o. As we filter out CC_FLAGS_CFI for *.mod.o, the compiler won't generate type hashes for the injected functions, and therefore indirectly calling them during module loading trips indirect call checking. Enabling CFI for *.mod.o isn't sufficient to fix this issue after commit 0c3e806ec0f9 ("x86/cfi: Add boot time hash randomization"), as *.mod.o aren't processed by objtool, which means any hashes emitted there won't be randomized. Therefore, in addition to disabling CFI for *.mod.o, also disable GCOV, as the object files don't otherwise contain any executable code. Fixes: cf68fffb66d6 ("add support for Clang CFI") Reported-by: Joe Fradley Signed-off-by: Sami Tolvanen Acked-by: Peter Zijlstra (Intel) Reviewed-by: Kees Cook Reviewed-by: Nick Desaulniers Signed-off-by: Masahiro Yamada

kbuild: rename cmd_$@ to savedcmd_$@ in *.cmd files

2023-01-22T14:43:33+00:00

The cmd-check macro compares $(cmd_$@) and $(cmd_$1), but a pitfall is that you cannot use cmd_ as the variable name for the command. For example, the following code will not work in the top Makefile or ./Kbuild. quiet_cmd_foo = GEN $@ cmd_foo = touch $@ targets += foo foo: FORCE $(call if_changed,foo) In this case, both $@ and $1 are expanded to 'foo', so $(cmd_check) is always empty. We do not need to use the same prefix for cmd_$@ and cmd_$1. Rename the former to savedcmd_$@. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier