On Thu, Sep 18, 2025 at 10:05:51AM +0200, Alexey Gladkov wrote: > For some modules, modalias is generated using the modpost utility and > the section is added to the module file. > > When a module is added inside vmlinux, modpost does not generate > modalias for such modules and the information is lost. > > As a result kmod (which uses modules.builtin.modinfo in userspace) > cannot determine that modalias is handled by a builtin kernel module. > > $ cat /sys/devices/pci0000:00/0000:00:14.0/modalias > pci:v00008086d0000A36Dsv00001043sd00008694bc0Csc03i30 > > $ modinfo xhci_pci > name: xhci_pci > filename: (builtin) > license: GPL > file: drivers/usb/host/xhci-pci > description: xHCI PCI Host Controller Driver > > Missing modalias "pci:v*d*sv*sd*bc0Csc03i30*" which will be generated by > modpost if the module is built separately. > > To fix this it is necessary to generate the same modalias for vmlinux as > for the individual modules. Fortunately '.vmlinux.export.o' is already > generated from which '.modinfo' can be extracted in the same way as for > vmlinux.o.
Hi - This patch broke RISC-V builds for me. During the final objcopy where the new symbols are supposed to be stripped, an error occurs producing lots of error messages similar to this one: riscv64-linux-gnu-objcopy: not stripping symbol `__mod_device_table__...' because it is named in a relocation It does not occur using defconfig, but I was able to bisect my way to this commit and then reduce my config delta w.r.t defconfig until I landed on: cat > .config <<'EOF' CONFIG_RELOCATABLE=y CONFIG_KASAN=y EOF ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- make olddefconfig ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- make -j $(nproc) ... LD vmlinux.unstripped NM System.map SORTTAB vmlinux.unstripped CHKREL vmlinux.unstripped OBJCOPY vmlinux OBJCOPY modules.builtin.modinfo GEN modules.builtin riscv64-linux-gnu-objcopy: not stripping symbol `<long symbol name>' because it is named in a relocation <repeats with different symbol names about a dozen times> make[3]: *** [scripts/Makefile.vmlinux:97: vmlinux] Error 1 make[3]: *** Deleting file 'vmlinux' make[2]: *** [Makefile:1242: vmlinux] Error 2 make[1]: *** [/tmp/linux/Makefile:369: __build_one_by_one] Error 2 make: *** [Makefile:248: __sub-make] Error 2 I confirmed that reverting this commit fixes the issue. > > Signed-off-by: Masahiro Yamada <[email protected]> > Signed-off-by: Alexey Gladkov <[email protected]> > Tested-by: Stephen Rothwell <[email protected]> > --- > include/linux/module.h | 4 ---- > scripts/Makefile.vmlinux | 4 +++- > scripts/mksysmap | 3 +++ > scripts/mod/file2alias.c | 19 ++++++++++++++++++- > scripts/mod/modpost.c | 15 +++++++++++++++ > scripts/mod/modpost.h | 2 ++ > 6 files changed, 41 insertions(+), 6 deletions(-) > > diff --git a/include/linux/module.h b/include/linux/module.h > index e31ee29fac6b7..e135cc79aceea 100644 > --- a/include/linux/module.h > +++ b/include/linux/module.h > @@ -256,14 +256,10 @@ struct module_kobject > *lookup_or_create_module_kobject(const char *name); > __PASTE(type, \ > __PASTE(__, name))))) > > -#ifdef MODULE > /* Creates an alias so file2alias.c can find device table. */ > #define MODULE_DEVICE_TABLE(type, name) > \ > static typeof(name) __mod_device_table(type, name) \ > __attribute__ ((used, alias(__stringify(name)))) > -#else /* !MODULE */ > -#define MODULE_DEVICE_TABLE(type, name) > -#endif > > /* Version of form [<epoch>:]<version>[-<extra-version>]. > * Or for CVS/RCS ID version, everything but the number is stripped. > diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux > index ce79461714979..1e5e37aadcd05 100644 > --- a/scripts/Makefile.vmlinux > +++ b/scripts/Makefile.vmlinux > @@ -89,11 +89,13 @@ endif > remove-section-y := .modinfo > remove-section-$(CONFIG_ARCH_VMLINUX_NEEDS_RELOCS) += '.rel*' > > +remove-symbols := -w --strip-symbol='__mod_device_table__*' > + > # To avoid warnings: "empty loadable segment detected at ..." from GNU > objcopy, > # it is necessary to remove the PT_LOAD flag from the segment. > quiet_cmd_strip_relocs = OBJCOPY $@ > cmd_strip_relocs = $(OBJCOPY) $(patsubst %,--set-section-flags > %=noload,$(remove-section-y)) $< $@; \ > - $(OBJCOPY) $(addprefix > --remove-section=,$(remove-section-y)) $@ > + $(OBJCOPY) $(addprefix > --remove-section=,$(remove-section-y)) $(remove-symbols) $@ > > targets += vmlinux > vmlinux: vmlinux.unstripped FORCE > diff --git a/scripts/mksysmap b/scripts/mksysmap > index a607a0059d119..c4531eacde202 100755 > --- a/scripts/mksysmap > +++ b/scripts/mksysmap > @@ -59,6 +59,9 @@ > # EXPORT_SYMBOL (namespace) > / __kstrtabns_/d > > +# MODULE_DEVICE_TABLE (symbol name) > +/ __mod_device_table__/d > + > # --------------------------------------------------------------------------- > # Ignored suffixes > # (do not forget '$' after each pattern) > diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c > index 1260bc2287fba..7da9735e7ab3e 100644 > --- a/scripts/mod/file2alias.c > +++ b/scripts/mod/file2alias.c > @@ -1477,7 +1477,7 @@ void handle_moddevtable(struct module *mod, struct > elf_info *info, > void *symval; > char *zeros = NULL; > const char *type, *name, *modname; > - size_t typelen; > + size_t typelen, modnamelen; > static const char *prefix = "__mod_device_table__"; > > /* We're looking for a section relative symbol */ > @@ -1500,6 +1500,7 @@ void handle_moddevtable(struct module *mod, struct > elf_info *info, > type = strstr(modname, "__"); > if (!type) > return; > + modnamelen = type - modname; > type += strlen("__"); > > name = strstr(type, "__"); > @@ -1526,5 +1527,21 @@ void handle_moddevtable(struct module *mod, struct > elf_info *info, > } > } > > + if (mod->is_vmlinux) { > + struct module_alias *alias; > + > + /* > + * If this is vmlinux, record the name of the builtin module. > + * Traverse the linked list in the reverse order, and set the > + * builtin_modname unless it has already been set in the > + * previous call. > + */ > + list_for_each_entry_reverse(alias, &mod->aliases, node) { > + if (alias->builtin_modname) > + break; > + alias->builtin_modname = xstrndup(modname, modnamelen); > + } > + } > + > free(zeros); > } > diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c > index 5ca7c268294eb..47c8aa2a69392 100644 > --- a/scripts/mod/modpost.c > +++ b/scripts/mod/modpost.c > @@ -2067,11 +2067,26 @@ static void write_if_changed(struct buffer *b, const > char *fname) > static void write_vmlinux_export_c_file(struct module *mod) > { > struct buffer buf = { }; > + struct module_alias *alias, *next; > > buf_printf(&buf, > "#include <linux/export-internal.h>\n"); > > add_exported_symbols(&buf, mod); > + > + buf_printf(&buf, > + "#include <linux/module.h>\n" > + "#undef __MODULE_INFO_PREFIX\n" > + "#define __MODULE_INFO_PREFIX\n"); > + > + list_for_each_entry_safe(alias, next, &mod->aliases, node) { > + buf_printf(&buf, "MODULE_INFO(%s.alias, \"%s\");\n", > + alias->builtin_modname, alias->str); > + list_del(&alias->node); > + free(alias->builtin_modname); > + free(alias); > + } > + > write_if_changed(&buf, ".vmlinux.export.c"); > free(buf.p); > } > diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h > index 9133e4c3803f0..2aecb8f25c87e 100644 > --- a/scripts/mod/modpost.h > +++ b/scripts/mod/modpost.h > @@ -99,10 +99,12 @@ buf_write(struct buffer *buf, const char *s, int len); > * struct module_alias - auto-generated MODULE_ALIAS() > * > * @node: linked to module::aliases > + * @modname: name of the builtin module (only for vmlinux) > * @str: a string for MODULE_ALIAS() > */ > struct module_alias { > struct list_head node; > + char *builtin_modname; > char str[]; > }; > > -- > 2.51.0 >
