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2022-05-24kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCSMasahiro Yamada15-96/+108
include/{linux,asm-generic}/export.h defines a weak symbol, __crc_* as a placeholder. Genksyms writes the version CRCs into the linker script, which will be used for filling the __crc_* symbols. The linker script format depends on CONFIG_MODULE_REL_CRCS. If it is enabled, __crc_* holds the offset to the reference of CRC. It is time to get rid of this complexity. Now that modpost parses text files (.*.cmd) to collect all the CRCs, it can generate C code that will be linked to the vmlinux or modules. Generate a new C file, .vmlinux.export.c, which contains the CRCs of symbols exported by vmlinux. It is compiled and linked to vmlinux in scripts/link-vmlinux.sh. Put the CRCs of symbols exported by modules into the existing *.mod.c files. No additional build step is needed for modules. As before, *.mod.c are compiled and linked to *.ko in scripts/Makefile.modfinal. No linker magic is used here. The new C implementation works in the same way, whether CONFIG_RELOCATABLE is enabled or not. CONFIG_MODULE_REL_CRCS is no longer needed. Previously, Kbuild invoked additional $(LD) to update the CRCs in objects, but this step is unneeded too. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nicolas Schier <nicolas@fjasle.eu> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
2022-05-24modpost: extract symbol versions from *.cmd filesMasahiro Yamada1-48/+131
Currently, CONFIG_MODVERSIONS needs extra link to embed the symbol versions into ELF objects. Then, modpost extracts the version CRCs from them. The following figures show how it currently works, and how I am trying to change it. Current implementation ====================== |----------| embed CRC -------------------------->| final | $(CC) $(LD) / |---------| | link for | -----> *.o -------> *.o -->| modpost | | vmlinux | / / | |-- *.mod.c -->| or | / genksyms / |---------| | module | *.c ------> *.symversions |----------| Genksyms outputs the calculated CRCs in the form of linker script (*.symversions), which is used by $(LD) to update the object. If CONFIG_LTO_CLANG=y, the build process is much more complex. Embedding the CRCs is postponed until the LLVM bitcode is converted into ELF, creating another intermediate *.prelink.o. However, this complexity is unneeded. There is no reason why we must embed version CRCs in objects so early. There is final link stage for vmlinux (scripts/link-vmlinux.sh) and modules (scripts/Makefile.modfinal). We can link CRCs at the very last moment. New implementation ================== |----------| --------------------------------------->| final | $(CC) / |---------| | link for | -----> *.o ---->| | | vmlinux | / | modpost |--- .vmlinux.export.c -->| or | / genksyms | |--- *.mod.c ------------>| module | *.c ------> *.cmd -->|---------| |----------| Pass the symbol versions to modpost as separate text data, which are available in *.cmd files. This commit changes modpost to extract CRCs from *.cmd files instead of from ELF objects. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
2022-05-24modpost: add sym_find_with_module() helperMasahiro Yamada1-2/+7
find_symbol() returns the first symbol found in the hash table. This table is global, so it may return a symbol from an unexpected module. There is a case where we want to search for a symbol with a given name in a specified module. Add sym_find_with_module(), which receives the module pointer as the second argument. It is equivalent to find_module() if NULL is passed as the module pointer. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
2022-05-11modpost: change the license of EXPORT_SYMBOL to bool typeMasahiro Yamada1-78/+30
There were more EXPORT_SYMBOL types in the past. The following commits removed unused ones. - f1c3d73e973c ("module: remove EXPORT_SYMBOL_GPL_FUTURE") - 367948220fce ("module: remove EXPORT_UNUSED_SYMBOL*") There are 3 remaining in enum export, but export_unknown does not make any sense because we never expect such a situation like "we do not know how it was exported". If the symbol name starts with "__ksymtab_", but the section name does not start with "___ksymtab+" or "___ksymtab_gpl+", it is not an exported symbol. It occurs when a variable starting with "__ksymtab_" is directly defined: int __ksymtab_foo; Presumably, there is no practical issue for using such a weird variable name (but there is no good reason for doing so, either). Anyway, that is not an exported symbol. Setting export_unknown is not the right thing to do. Do not call sym_add_exported() in this case. With pointless export_unknown removed, the export type finally becomes boolean (either EXPORT_SYMBOL or EXPORT_SYMBOL_GPL). I renamed the field name to is_gpl_only. EXPORT_SYMBOL_GPL sets it true. Only GPL-compatible modules can use it. I removed the orphan comment, "How a symbol is exported", which is unrelated to sec_mismatch_count. It is about enum export. See commit bd5cbcedf446 ("kbuild: export-type enhancement to modpost.c") Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org>
2022-05-11modpost: remove left-over cross_compile declarationMasahiro Yamada1-1/+0
This is a remnant of commit 6543becf26ff ("mod/file2alias: make modalias generation safe for cross compiling"). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-11kbuild: record symbol versions in *.cmd filesMasahiro Yamada1-0/+7
When CONFIG_MODVERSIONS=y, the output from genksyms is saved in separate *.symversions files, and will be used much later when CONFIG_LTO_CLANG=y because it is impossible to update LLVM bit code here. This approach is not robust because: - *.symversions may or may not exist. If *.symversions does not exist, we never know if it is missing for legitimate reason (i.e. no EXPORT_SYMBOL) or something bad has happened (for example, the user accidentally deleted it). Once it occurs, it is not self-healing because *.symversions is generated as a side effect. - stale (i.e. invalid) *.symversions might be picked up if an object is generated in a non-ordinary way, and corresponding *.symversions (, which was generated by old builds) just happen to exist. A more robust approach is to save symbol versions in *.cmd files because: - *.cmd always exists (if the object is generated by if_changed rule or friends). Even if the user accidentally deletes it, it will be regenerated in the next build. - *.cmd is always re-generated when the object is updated. This avoid stale version information being picked up. I will remove *.symversions later. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nicolas Schier <nicolas@fjasle.eu> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org>
2022-05-11kbuild: generate a list of objects in vmlinuxMasahiro Yamada1-0/+11
A *.mod file lists the member objects of a module, but vmlinux does not have such a file. Generate this list to allow modpost to know all the member objects. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org>
2022-05-11modpost: move *.mod.c generation to write_mod_c_files()Masahiro Yamada1-25/+31
A later commit will add more code to this list_for_each_entry loop. Before that, move the loop body into a separate helper function. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org>
2022-05-11modpost: merge add_{intree_flag,retpoline,staging_flag} to add_headerMasahiro Yamada1-18/+7
add_intree_flag(), add_retpoline(), and add_staging_flag() are small enough to be merged into add_header(). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org>
2022-05-11scripts/prune-kernel: Use kernel-install if availableReza Arbab1-1/+5
If the new-kernel-pkg utility isn't present, try using kernel-install. This is what the %preun scriptlet in scripts/package/mkspec does too. Signed-off-by: Reza Arbab <arbab@linux.ibm.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-05-11kbuild: factor out the common installation code into scripts/install.shMasahiro Yamada24-247/+63
Many architectures have similar install.sh scripts. The first half is really generic; it verifies that the kernel image and System.map exist, then executes ~/bin/${INSTALLKERNEL} or /sbin/${INSTALLKERNEL} if available. The second half is kind of arch-specific; it copies the kernel image and System.map to the destination, but the code is slightly different. Factor out the generic part into scripts/install.sh. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <n.schier@avm.de>
2022-05-08modpost: split new_symbol() to symbol allocation and hash table additionMasahiro Yamada1-10/+8
new_symbol() does two things; allocate a new symbol and register it to the hash table. Using a separate function for each is easier to understand. Replace new_symbol() with hash_add_symbol(). Remove the second parameter of alloc_symbol(). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: make sym_add_exported() always allocate a new symbolMasahiro Yamada1-6/+4
Currently, sym_add_exported() does not allocate a symbol if the same name symbol already exists in the hash table. This does not reflect the real use cases. You can let an external module override the in-tree one. In this case, the external module will export the same name symbols as the in-tree one. However, modpost simply ignores those symbols, then Module.symvers for the external module loses its symbols. sym_add_exported() should allocate a new symbol. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: make multiple export errorMasahiro Yamada1-3/+3
This is currently a warning, but I think modpost should stop building in this case. If the same symbol is exported multiple times and we let it keep going, the sanity check becomes difficult. Only the legitimate case is that an external module overrides the corresponding in-tree module to provide a different implementation with the same interface. Also, there exists an upstream example that exploits this feature. $ make M=tools/testing/nvdimm ... builds tools/testing/nvdimm/libnvdimm.ko. This is a mocked module that overrides the symbols from drivers/nvdimm/libnvdimm.ko. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: dump Module.symvers in the same order of modules.orderMasahiro Yamada2-16/+14
modpost dumps the exported symbols into Module.symvers, but currently in random order because it iterates in the hash table. Add a linked list of exported symbols in struct module, so we can iterate on symbols per module. This commit makes Module.symvers much more readable; the outer loop in write_dump() iterates over the modules in the order of modules.order, and the inner loop dumps symbols in each module. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: traverse the namespace_list in orderMasahiro Yamada2-20/+17
Use the doubly linked list to traverse the list in the added order. This makes the code more consistent. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: use doubly linked list for dump_listsMasahiro Yamada1-14/+10
This looks easier to understand (just because this is a pattern in the kernel code). No functional change is intended. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: traverse unresolved symbols in orderMasahiro Yamada2-7/+15
Currently, modpost manages unresolved in a singly linked list; it adds a new node to the head, and traverses the list from new to old. Use a doubly linked list to keep the order in the symbol table in the ELF file. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: add sym_add_unresolved() helperMasahiro Yamada1-8/+11
Add a small helper, sym_add_unresolved() to ease the further refactoring. Remove the 'weak' argument from alloc_symbol() because it is sensible only for unresolved symbols. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: traverse modules in orderMasahiro Yamada2-10/+10
Currently, modpost manages modules in a singly linked list; it adds a new node to the head, and traverses the list from new to old. It works, but the error messages are shown in the reverse order. If you have a Makefile like this: obj-m += foo.o bar.o then, modpost shows error messages in bar.o, foo.o, in this order. Use a doubly linked list to keep the order in modules.order; use list_add_tail() for the node addition and list_for_each_entry() for the list traverse. Now that the kernel's list macros have been imported to modpost, I will use them actively going forward. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: import include/linux/list.hMasahiro Yamada1-0/+213
Import include/linux/list.h to use convenient list macros in modpost. I dropped kernel-space code such as {WRITE,READ}_ONCE etc. and unneeded macros. I also imported container_of() from include/linux/container_of.h and type definitions from include/linux/types.h. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: change mod->gpl_compatible to bool typeMasahiro Yamada2-7/+12
Currently, mod->gpl_compatible is tristate; it is set to -1 by default, then to 1 or 0 when MODULE_LICENSE() is found. Maybe, -1 was chosen to represent the 'unknown' license, but it is not useful. The current code: if (!mod->gpl_compatible) check_for_gpl_usage(exp->export, basename, exp->name); ... only cares whether gpl_compatible is zero or not. Change it to a bool type with the initial value 'true', which has no functional change. The default value should be 'true' instead of 'false'. Since commit 1d6cd3929360 ("modpost: turn missing MODULE_LICENSE() into error"), unknown module license is an error. The error message, "missing MODULE_LICENSE()" is enough to explain the issue. It is not sensible to show another message, "GPL-incompatible module ... uses GPL-only symbol". Add comments to explain this. While I was here, I renamed gpl_compatible to is_gpl_compatible for clarification, and also slightly refactored the code. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: use bool type where appropriateMasahiro Yamada3-38/+37
Use 'bool' to clarify that the valid value is true or false. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08ia64: make the install target not depend on any build artifactMasahiro Yamada1-2/+2
The install target should not depend on any build artifact. The reason is explained in commit 19514fc665ff ("arm, kbuild: make "make install" not depend on vmlinux"). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-05-08kbuild: drop $(objtree)/ prefix support for clean-filesMasahiro Yamada2-9/+3
I think this hack is a bad idea. arch/powerpc/boot/Makefile is the only and last user. Let's stop doing this. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
2022-05-08Makefile: fix 2 typosRandy Dunlap1-2/+2
Fix typos in comments so that they make sense. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-05-08modpost: move struct namespace_list to modpost.cMasahiro Yamada2-5/+5
There is no good reason to define struct namespace_list in modpost.h struct module has pointers to struct namespace_list, but that does not require the definition of struct namespace_list. Move it to modpost.c. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: retrieve the module dependency and CRCs in check_exports()Masahiro Yamada1-10/+6
Do not repeat the similar code. It is simpler to do this in check_exports() instead of add_versions(). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: add a separate error for exported symbols without definitionMasahiro Yamada1-1/+6
It took me a while to understand the intent of "exp->module == mod". This code goes back to 2003. [1] The commit is not in this git repository, and might be worth a little explanation. You can add EXPORT_SYMBOL() without having its definition in the same file (but you need to put a declaration). This is typical when EXPORT_SYMBOL() is added in a C file, but the actual implementation is in a separate assembly file. One example is arch/arm/kernel/armksyms.c In the old days, EXPORT_SYMBOL() was only available in C files (but this limitation does not exist any more). If you forget to add the definition, this error occurs. Add a separate, clearer message for this case. It should be an error even if KBUILD_MODPOST_WARN is given. [1]: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=2763b6bcb96e6a38a2fe31108fe5759ec5bcc80a Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: remove stale comment about sym_add_exported()Masahiro Yamada1-4/+0
The description, it may have already been added without a CRC, in this case just update the CRC ... is no longer valid. In the old days, this function was used to update the CRC as well. Commit 040fcc819a2e ("kbuild: improved modversioning support for external modules") started to use a separate function (sym_update_crc) for updating the CRC. The first part, "Add an exported symbol" is correct, but it is too obvious from the function name. Drop this comment entirely. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: do not write out any file when error occurredMasahiro Yamada1-0/+3
If an error occurs, modpost will fail anyway. Do not write out any content (, which might be invalid). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: use snprintf() instead of sprintf() for safetyMasahiro Yamada1-1/+7
Use snprintf() to avoid the potential buffer overflow, and also check the return value to detect the too long path. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08checksyscalls: ignore -Wunused-macrosVincent Mailhol1-1/+1
The macros defined in this file are for testing only and are purposely not used. When compiled with W=2, both gcc and clang yield some -Wunused-macros warnings. Ignore them. Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-05-08scripts: dummy-tools, add paholeJiri Slaby1-0/+4
CONFIG_PAHOLE_VERSION is a part of a config since the commit below. And when multiple people update the config, this value constantly changes. Even if they use dummy scripts. To fix this, add a pahole dummy script returning v99.99. (This is translated into 9999 later in the process.) Thereafter, this script can be invoked easily for example as: make PAHOLE=scripts/dummy-tools/pahole oldconfig Fixes: 613fe1692377 (kbuild: Add CONFIG_PAHOLE_VERSION) Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-05-08kheaders: Have cpio unconditionally replace filesDaniel Mentz1-1/+1
For out-of-tree builds, this script invokes cpio twice to copy header files from the srctree and subsequently from the objtree. According to a comment in the script, there might be situations in which certain files already exist in the destination directory when header files are copied from the objtree: "The second CPIO can complain if files already exist which can happen with out of tree builds having stale headers in srctree. Just silence CPIO for now." GNU cpio might simply print a warning like "newer or same age version exists", but toybox cpio exits with a non-zero exit code unless the command line option "-u" is specified. To improve compatibility with toybox cpio, add the command line option "-u" to unconditionally replace existing files in the destination directory. Signed-off-by: Daniel Mentz <danielmentz@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-05-08kbuild: support W=e to make build abort in case of warningYann Droneaud2-2/+12
When developing new code/feature, CONFIG_WERROR is most often turned off, especially for people using make W=12 to get more warnings. In such case, turning on -Werror temporarily would require switching on CONFIG_WERROR in the configuration, building, then switching off CONFIG_WERROR. For this use case, this patch introduces a new 'e' modifier to W= as a short hand for KCFLAGS+=-Werror" so that -Werror got added to the kernel (built-in) and modules' CFLAGS. Signed-off-by: Yann Droneaud <ydroneaud@opteya.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-05-08kbuild: read *.mod to get objects passed to $(LD) or $(AR)Masahiro Yamada1-7/+3
ld and ar support @file, which command-line options are read from. Now that *.mod lists the member objects in the correct order, without duplication, it is ready to be passed to ld and ar. By using the @file syntax, people will not be worried about the pitfall described in the NOTE. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08kbuild: make *.mod not depend on *.oMasahiro Yamada2-4/+4
The dependency $(obj)/%.mod: $(obj)/%$(mod-prelink-ext).o ... exists because *.mod files previously contained undefined symbols, which are computed from *.o files when CONFIG_TRIM_UNUSED_KSYMS=y. Now that the undefined symbols are put into separate *.usyms files, there is no reason to make *.mod depend on *.o files. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-05-08kbuild: get rid of duplication in *.mod filesMasahiro Yamada2-2/+3
It is allowed to add the same objects multiple times to obj-y / obj-m: obj-y += foo.o foo.o foo.o obj-m += bar.o bar.o bar.o It is also allowed to add the same objects multiple times to a composite module: obj-m += foo.o foo-y := foo1.o foo2.o foo2.o foo1.o This flexibility is useful because the same object might be selected by different CONFIG options, like this: obj-m += foo.o foo-y := foo1.o foo-$(CONFIG_FOO_X) += foo2.o foo-$(CONFIG_FOO_Y) += foo2.o The duplicated objects are omitted at link time. It works naturally in Makefiles because GNU Make removes duplication in $^ without changing the order. It is working well, almost... A small flaw I notice is, *.mod contains duplication in such a case. This is probably not a big deal. As far as I know, the only small problem is scripts/mod/sumversion.c parses the same file multiple times. I am fixing this because I plan to reuse *.mod for other purposes, where the duplication can be problematic. The code change is quite simple. We already use awk to drop duplicated lines in modules.order (see cmd_modules_order in the same file). I copied the code, but changed RS to use spaces as record separators. I also changed the file format to list one object per line. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-05-08kbuild: split the second line of *.mod into *.usymsMasahiro Yamada6-26/+25
The *.mod files have two lines; the first line lists the member objects of the module, and the second line, if CONFIG_TRIM_UNUSED_KSYMS=y, lists the undefined symbols. Currently, we generate *.mod after constructing composite modules, otherwise, we cannot compute the second line. No prerequisite is required to print the first line. They are orthogonal. Splitting them into separate commands will ease further cleanups. This commit splits the list of undefined symbols out to *.usyms files. Previously, the list of undefined symbols ended up with a very long line, but now it has one symbol per line. Use sed like we did before commit 7d32358be8ac ("kbuild: avoid split lines in .mod files"). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2022-05-08kbuild: reuse real-search to simplify cmd_modMasahiro Yamada1-1/+1
The first command in cmd_mod is similar to the real-search macro. Reuse it. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08kbuild: make multi_depend work with targets in subdirectoryMasahiro Yamada1-3/+3
Precisely speaking, when you get the stem of the path, you should use $(patsubst $(obj)/%,%,...) instead of $(notdir ...). I do not see this usecase, but if you create a composite object in a subdirectory, the Makefile should look like this: obj-$(CONFIG_FOO) += dir/foo.o dir/foo-objs := dir/foo1.o dir/foo2.o The member objects should be assigned to dir/foo-objs instead of foo-objs. This syntax is more consistent with commit 54b8ae66ae1a ("kbuild: change *FLAGS_<basetarget>.o to take the path relative to $(obj)"). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08kbuild: reuse suffix-search to refactor multi_dependMasahiro Yamada1-1/+1
The complicated part of multi_depend is the same as suffix-search. Reuse it. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08kbuild: refactor cmd_modversions_SMasahiro Yamada1-11/+4
Split the code into two macros, cmd_gen_symversions_S for running genksyms, and cmd_modversions for running $(LD) to update the object with CRCs. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08kbuild: refactor cmd_modversions_cMasahiro Yamada1-14/+11
cmd_modversions_c implements two parts; run genksyms to calculate CRCs of exported symbols, run $(LD) to update the object with the CRCs. The latter is not executed for CONFIG_LTO_CLANG=y since the object is not ELF but LLVM bit code at this point. The first part can be unified because we can always use $(NM) instead of "$(OBJDUMP) -h" to dump the symbols. Split the code into the two macros, cmd_gen_symversions_c and cmd_modversions. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: remove annoying namespace_from_kstrtabns()Masahiro Yamada1-12/+2
There are two call sites for sym_update_namespace(). When the symbol has no namespace, s->namespace is set to NULL, but the conversion from "" to NULL is done in two different places. [1] read_symbols() This gets the namespace from __kstrtabns_<symbol>. If the symbol has no namespace, sym_get_data(info, sym) returns the empty string "". namespace_from_kstrtabns() converts it to NULL before it is passed to sym_update_namespace(). [2] read_dump() This gets the namespace from the dump file, *.symvers. If the symbol has no namespace, the 'namespace' is the empty string "", which is directly passed into sym_update_namespace(). The conversion from "" to NULL is done in sym_update_namespace(). namespace_from_kstrtabns() exists only for creating this inconsistency. Remove namespace_from_kstrtabns() so that sym_update_namespace() is consistently passed with "" instead of NULL. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: remove redundant initializes for static variablesMasahiro Yamada1-5/+5
These are initialized with zeros without explicit initializers. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: move export_from_secname() call to more relevant placeMasahiro Yamada1-6/+4
The assigned 'export' is only used when if (strstarts(symname, "__ksymtab_")) is met. The else-part of the assignment is the dead code. Move the export_from_secname() call to where it is used. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-05-08modpost: remove useless export_from_sec()Masahiro Yamada2-17/+2
With commit 1743694eb235 ("modpost: stop symbol preloading for modversion CRC") applied, now export_from_sec() is useless. handle_symbol() is called for every symbol in the ELF. When 'symname' does not start with "__ksymtab", export_from_sec() is called, and the returned value is stored in 'export'. It is used in the last part of handle_symbol(): if (strstarts(symname, "__ksymtab_")) { name = symname + strlen("__ksymtab_"); sym_add_exported(name, mod, export); } 'export' is used only when 'symname' starts with "__ksymtab_". So, the value returned by export_from_sec() is never used. Remove useless export_from_sec(). This makes further cleanups possible. I put the temporary code: export = export_unknown; Otherwise, I would get the compiler warning: warning: 'export' may be used uninitialized in this function [-Wmaybe-uninitialized] This is apparently false positive because if (strstarts(symname, "__ksymtab_") ... is a stronger condition than: if (strstarts(symname, "__ksymtab") Anyway, this part will be cleaned up by the next commit. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-04-06kbuild: do not remove empty *.symtypes explicitlyMasahiro Yamada1-6/+2
Presumably, 'test -s $@ || rm -f $@' intends to remove the output when the genksyms command fails. It is unneeded because .DELETE_ON_ERROR automatically removes the output on failure. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>