From 1e8ca62b79dec20aeded4fe283f4890e5016767a Mon Sep 17 00:00:00 2001 From: Daniel Mentz Date: Wed, 13 Apr 2022 16:36:49 -0700 Subject: kheaders: Have cpio unconditionally replace files 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 Signed-off-by: Masahiro Yamada --- kernel/gen_kheaders.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/gen_kheaders.sh b/kernel/gen_kheaders.sh index 1966a749e0d9..0c78e64f747d 100755 --- a/kernel/gen_kheaders.sh +++ b/kernel/gen_kheaders.sh @@ -74,7 +74,7 @@ fi # of tree builds having stale headers in srctree. Just silence CPIO for now. for f in $dir_list; do find "$f" -name "*.h"; -done | cpio --quiet -pd $cpio_dir >/dev/null 2>&1 +done | cpio --quiet -pdu $cpio_dir >/dev/null 2>&1 # Remove comments except SDPX lines find $cpio_dir -type f -print0 | -- cgit v1.3-18-gd494 From 7b4537199a4a8480b8c3ba37a2d44765ce76cd9b Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Fri, 13 May 2022 20:39:22 +0900 Subject: kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS 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 Tested-by: Nathan Chancellor Tested-by: Nicolas Schier Reviewed-by: Nicolas Schier Tested-by: Sedat Dilek # LLVM-14 (x86-64) --- arch/m68k/include/asm/Kbuild | 1 + arch/m68k/include/asm/export.h | 2 -- arch/powerpc/Kconfig | 1 - arch/s390/Kconfig | 1 - arch/um/Kconfig | 1 - include/asm-generic/export.h | 22 ++++++++-------------- include/linux/export-internal.h | 17 +++++++++++++++++ include/linux/export.h | 30 ++++++++---------------------- init/Kconfig | 4 ---- kernel/module.c | 10 +--------- scripts/Makefile.build | 27 ++++----------------------- scripts/Makefile.vmlinux | 32 ++++++++++++++++++++++++++++++++ scripts/genksyms/genksyms.c | 18 ++++-------------- scripts/link-vmlinux.sh | 10 +++++++++- scripts/mod/modpost.c | 28 ++++++++++++++++++++++++---- 15 files changed, 108 insertions(+), 96 deletions(-) delete mode 100644 arch/m68k/include/asm/export.h create mode 100644 include/linux/export-internal.h create mode 100644 scripts/Makefile.vmlinux (limited to 'kernel') diff --git a/arch/m68k/include/asm/Kbuild b/arch/m68k/include/asm/Kbuild index 0dbf9c5c6fae..1b720299deb1 100644 --- a/arch/m68k/include/asm/Kbuild +++ b/arch/m68k/include/asm/Kbuild @@ -1,5 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 generated-y += syscall_table.h +generic-y += export.h generic-y += extable.h generic-y += kvm_para.h generic-y += mcs_spinlock.h diff --git a/arch/m68k/include/asm/export.h b/arch/m68k/include/asm/export.h deleted file mode 100644 index b53008b67ce1..000000000000 --- a/arch/m68k/include/asm/export.h +++ /dev/null @@ -1,2 +0,0 @@ -#define KCRC_ALIGN 2 -#include diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 174edabb74fa..a4e8dd889e29 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -566,7 +566,6 @@ config RELOCATABLE bool "Build a relocatable kernel" depends on PPC64 || (FLATMEM && (44x || FSL_BOOKE)) select NONSTATIC_KERNEL - select MODULE_REL_CRCS if MODVERSIONS help This builds a kernel image that is capable of running at the location the kernel is loaded at. For ppc32, there is no any diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 77b5a03de13a..aa5848004c76 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -567,7 +567,6 @@ endchoice config RELOCATABLE bool "Build a relocatable kernel" - select MODULE_REL_CRCS if MODVERSIONS default y help This builds a kernel image that retains relocation information diff --git a/arch/um/Kconfig b/arch/um/Kconfig index 4d398b80aea8..e8983d098e73 100644 --- a/arch/um/Kconfig +++ b/arch/um/Kconfig @@ -106,7 +106,6 @@ config LD_SCRIPT_DYN bool default y depends on !LD_SCRIPT_STATIC - select MODULE_REL_CRCS if MODVERSIONS config LD_SCRIPT_DYN_RPATH bool "set rpath in the binary" if EXPERT diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h index 07a36a874dca..5e4b1f2369d2 100644 --- a/include/asm-generic/export.h +++ b/include/asm-generic/export.h @@ -2,6 +2,14 @@ #ifndef __ASM_GENERIC_EXPORT_H #define __ASM_GENERIC_EXPORT_H +/* + * This comment block is used by fixdep. Please do not remove. + * + * When CONFIG_MODVERSIONS is changed from n to y, all source files having + * EXPORT_SYMBOL variants must be re-compiled because genksyms is run as a + * side effect of the *.o build rule. + */ + #ifndef KSYM_FUNC #define KSYM_FUNC(x) x #endif @@ -12,9 +20,6 @@ #else #define KSYM_ALIGN 4 #endif -#ifndef KCRC_ALIGN -#define KCRC_ALIGN 4 -#endif .macro __put, val, name #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS @@ -43,17 +48,6 @@ __ksymtab_\name: __kstrtab_\name: .asciz "\name" .previous -#ifdef CONFIG_MODVERSIONS - .section ___kcrctab\sec+\name,"a" - .balign KCRC_ALIGN -#if defined(CONFIG_MODULE_REL_CRCS) - .long __crc_\name - . -#else - .long __crc_\name -#endif - .weak __crc_\name - .previous -#endif #endif .endm diff --git a/include/linux/export-internal.h b/include/linux/export-internal.h new file mode 100644 index 000000000000..c2b1d4fd5987 --- /dev/null +++ b/include/linux/export-internal.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Please do not include this explicitly. + * This is used by C files generated by modpost. + */ + +#ifndef __LINUX_EXPORT_INTERNAL_H__ +#define __LINUX_EXPORT_INTERNAL_H__ + +#include +#include + +/* __used is needed to keep __crc_* for LTO */ +#define SYMBOL_CRC(sym, crc, sec) \ + u32 __section("___kcrctab" sec "+" #sym) __used __crc_##sym = crc + +#endif /* __LINUX_EXPORT_INTERNAL_H__ */ diff --git a/include/linux/export.h b/include/linux/export.h index 27d848712b90..565c5ffcb26f 100644 --- a/include/linux/export.h +++ b/include/linux/export.h @@ -11,6 +11,14 @@ * hackers place grumpy comments in header files. */ +/* + * This comment block is used by fixdep. Please do not remove. + * + * When CONFIG_MODVERSIONS is changed from n to y, all source files having + * EXPORT_SYMBOL variants must be re-compiled because genksyms is run as a + * side effect of the *.o build rule. + */ + #ifndef __ASSEMBLY__ #ifdef MODULE extern struct module __this_module; @@ -19,26 +27,6 @@ extern struct module __this_module; #define THIS_MODULE ((struct module *)0) #endif -#ifdef CONFIG_MODVERSIONS -/* Mark the CRC weak since genksyms apparently decides not to - * generate a checksums for some symbols */ -#if defined(CONFIG_MODULE_REL_CRCS) -#define __CRC_SYMBOL(sym, sec) \ - asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \ - " .weak __crc_" #sym " \n" \ - " .long __crc_" #sym " - . \n" \ - " .previous \n") -#else -#define __CRC_SYMBOL(sym, sec) \ - asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \ - " .weak __crc_" #sym " \n" \ - " .long __crc_" #sym " \n" \ - " .previous \n") -#endif -#else -#define __CRC_SYMBOL(sym, sec) -#endif - #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS #include /* @@ -85,7 +73,6 @@ struct kernel_symbol { /* * For every exported symbol, do the following: * - * - If applicable, place a CRC entry in the __kcrctab section. * - Put the name of the symbol and namespace (empty string "" for none) in * __ksymtab_strings. * - Place a struct kernel_symbol entry in the __ksymtab section. @@ -98,7 +85,6 @@ struct kernel_symbol { extern typeof(sym) sym; \ extern const char __kstrtab_##sym[]; \ extern const char __kstrtabns_##sym[]; \ - __CRC_SYMBOL(sym, sec); \ asm(" .section \"__ksymtab_strings\",\"aMS\",%progbits,1 \n" \ "__kstrtab_" #sym ": \n" \ " .asciz \"" #sym "\" \n" \ diff --git a/init/Kconfig b/init/Kconfig index ddcbefe535e9..f5b14318dfcb 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -2136,10 +2136,6 @@ config ASM_MODVERSIONS assembly. This can be enabled only when the target architecture supports it. -config MODULE_REL_CRCS - bool - depends on MODVERSIONS - config MODULE_SRCVERSION_ALL bool "Source checksum for all modules" help diff --git a/kernel/module.c b/kernel/module.c index 6cea788fd965..c9e2342da28e 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1231,11 +1231,6 @@ static int try_to_force_load(struct module *mod, const char *reason) #ifdef CONFIG_MODVERSIONS -static u32 resolve_rel_crc(const s32 *crc) -{ - return *(u32 *)((void *)crc + *crc); -} - static int check_version(const struct load_info *info, const char *symname, struct module *mod, @@ -1264,10 +1259,7 @@ static int check_version(const struct load_info *info, if (strcmp(versions[i].name, symname) != 0) continue; - if (IS_ENABLED(CONFIG_MODULE_REL_CRCS)) - crcval = resolve_rel_crc(crc); - else - crcval = *crc; + crcval = *crc; if (versions[i].crc == crcval) return 1; pr_debug("Found checksum %X vs module %lX\n", diff --git a/scripts/Makefile.build b/scripts/Makefile.build index a1023868775f..ddd9080fc028 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -128,7 +128,6 @@ $(obj)/%.i: $(src)/%.c FORCE genksyms = scripts/genksyms/genksyms \ $(if $(1), -T $(2)) \ - $(if $(CONFIG_MODULE_REL_CRCS), -R) \ $(if $(KBUILD_PRESERVE), -p) \ -r $(or $(wildcard $(2:.symtypes=.symref)), /dev/null) @@ -162,19 +161,11 @@ ifdef CONFIG_MODVERSIONS # o if .o doesn't contain a __ksymtab version, i.e. does # not export symbols, it's done. # o otherwise, we calculate symbol versions using the good old -# genksyms on the preprocessed source and postprocess them in a way -# that they are usable as a linker script -# o generate .tmp_.o from .o using the linker to -# replace the unresolved symbols __crc_exported_symbol with -# the actual value of the checksum generated by genksyms -# o remove .tmp_.o to .o +# genksyms on the preprocessed source and dump them into the .cmd file. +# o modpost will extract versions from that file and create *.c files that will +# be compiled and linked to the kernel and/or modules. -# Generate .o.symversions files for each .o with exported symbols, and link these -# to the kernel and/or modules at the end. - -genksyms_format_rel_crc := [^_]*__crc_\([^ ]*\) = \.; LONG(\([^)]*\)).* -genksyms_format_normal := __crc_\(.*\) = \(.*\); -genksyms_format := $(if $(CONFIG_MODULE_REL_CRCS),$(genksyms_format_rel_crc),$(genksyms_format_normal)) +genksyms_format := __crc_\(.*\) = \(.*\); gen_symversions = \ if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \ @@ -188,12 +179,6 @@ gen_symversions = \ cmd_gen_symversions_c = $(call gen_symversions,c) -cmd_modversions = \ - if [ -r $@.symversions ]; then \ - $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ - -T $@.symversions; \ - mv -f $(@D)/.tmp_$(@F) $@; \ - fi endif ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT @@ -273,7 +258,6 @@ define rule_cc_o_c $(call cmd,checkdoc) $(call cmd,gen_objtooldep) $(call cmd,gen_symversions_c) - $(if $(CONFIG_LTO_CLANG),,$(call cmd,modversions)) $(call cmd,record_mcount) endef @@ -282,7 +266,6 @@ define rule_as_o_S $(call cmd,gen_ksymdeps) $(call cmd,gen_objtooldep) $(call cmd,gen_symversions_S) - $(call cmd,modversions) endef # Built-in and composite module parts @@ -296,8 +279,6 @@ ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) quiet_cmd_cc_prelink_modules = LD [M] $@ cmd_cc_prelink_modules = \ $(LD) $(ld_flags) -r -o $@ \ - $(shell [ -s $(@:.prelink.o=.o.symversions) ] && \ - echo -T $(@:.prelink.o=.o.symversions)) \ --whole-archive $(filter-out FORCE,$^) \ $(cmd_objtool) diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux new file mode 100644 index 000000000000..7a63abf22399 --- /dev/null +++ b/scripts/Makefile.vmlinux @@ -0,0 +1,32 @@ +# SPDX-License-Identifier: GPL-2.0-only + +include include/config/auto.conf +include $(srctree)/scripts/Kbuild.include + +# for c_flags +include $(srctree)/scripts/Makefile.lib + +quiet_cmd_cc_o_c = CC $@ + cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< + +%.o: %.c FORCE + $(call if_changed_dep,cc_o_c) + +targets := $(MAKECMDGOALS) + +# Add FORCE to the prequisites of a target to force it to be always rebuilt. +# --------------------------------------------------------------------------- + +PHONY += FORCE +FORCE: + +# Read all saved command lines and dependencies for the $(targets) we +# may be building above, using $(if_changed{,_dep}). As an +# optimization, we don't need to read them if the target does not +# exist, we will rebuild anyway in that case. + +existing-targets := $(wildcard $(sort $(targets))) + +-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) + +.PHONY: $(PHONY) diff --git a/scripts/genksyms/genksyms.c b/scripts/genksyms/genksyms.c index 4827c5abe5b7..67b23cc0df0f 100644 --- a/scripts/genksyms/genksyms.c +++ b/scripts/genksyms/genksyms.c @@ -33,7 +33,7 @@ char *cur_filename; int in_source_file; static int flag_debug, flag_dump_defs, flag_reference, flag_dump_types, - flag_preserve, flag_warnings, flag_rel_crcs; + flag_preserve, flag_warnings; static int errors; static int nsyms; @@ -680,11 +680,7 @@ void export_symbol(const char *name) if (flag_dump_defs) fputs(">\n", debugfile); - /* Used as a linker script. */ - printf(!flag_rel_crcs ? "__crc_%s = 0x%08lx;\n" : - "SECTIONS { .rodata : ALIGN(4) { " - "__crc_%s = .; LONG(0x%08lx); } }\n", - name, crc); + printf("__crc_%s = 0x%08lx;\n", name, crc); } } @@ -733,7 +729,6 @@ static void genksyms_usage(void) " -q, --quiet Disable warnings (default)\n" " -h, --help Print this message\n" " -V, --version Print the release version\n" - " -R, --relative-crc Emit section relative symbol CRCs\n" #else /* __GNU_LIBRARY__ */ " -s Select symbol prefix\n" " -d Increment the debug level (repeatable)\n" @@ -745,7 +740,6 @@ static void genksyms_usage(void) " -q Disable warnings (default)\n" " -h Print this message\n" " -V Print the release version\n" - " -R Emit section relative symbol CRCs\n" #endif /* __GNU_LIBRARY__ */ , stderr); } @@ -766,14 +760,13 @@ int main(int argc, char **argv) {"preserve", 0, 0, 'p'}, {"version", 0, 0, 'V'}, {"help", 0, 0, 'h'}, - {"relative-crc", 0, 0, 'R'}, {0, 0, 0, 0} }; - while ((o = getopt_long(argc, argv, "s:dwqVDr:T:phR", + while ((o = getopt_long(argc, argv, "s:dwqVDr:T:ph", &long_opts[0], NULL)) != EOF) #else /* __GNU_LIBRARY__ */ - while ((o = getopt(argc, argv, "s:dwqVDr:T:phR")) != EOF) + while ((o = getopt(argc, argv, "s:dwqVDr:T:ph")) != EOF) #endif /* __GNU_LIBRARY__ */ switch (o) { case 'd': @@ -813,9 +806,6 @@ int main(int argc, char **argv) case 'h': genksyms_usage(); return 0; - case 'R': - flag_rel_crcs = 1; - break; default: genksyms_usage(); return 1; diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index eceb3ee7ec06..db34dc3163ae 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -90,7 +90,6 @@ modpost_link() if is_enabled CONFIG_MODVERSIONS; then gen_symversions - lds="${lds} -T .tmp_symversions.lds" fi # This might take a while, so indicate that we're doing @@ -183,6 +182,10 @@ vmlinux_link() libs="${KBUILD_VMLINUX_LIBS}" fi + if is_enabled CONFIG_MODULES; then + objs="${objs} .vmlinux.export.o" + fi + if [ "${SRCARCH}" = "um" ]; then wl=-Wl, ld="${CC}" @@ -312,6 +315,7 @@ cleanup() rm -f vmlinux.o rm -f .vmlinux.d rm -f .vmlinux.objs + rm -f .vmlinux.export.c } # Use "make V=1" to debug this script @@ -363,6 +367,10 @@ info GEN modules.builtin tr '\0' '\n' < modules.builtin.modinfo | sed -n 's/^[[:alnum:]:_]*\.file=//p' | tr ' ' '\n' | uniq | sed -e 's:^:kernel/:' -e 's/$/.ko/' > modules.builtin +if is_enabled CONFIG_MODULES; then + ${MAKE} -f "${srctree}/scripts/Makefile.vmlinux" .vmlinux.export.o +fi + btf_vmlinux_bin_o="" if is_enabled CONFIG_DEBUG_INFO_BTF; then btf_vmlinux_bin_o=.btf.vmlinux.bin.o diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 1e2949775e1b..42e949cbc255 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -2234,6 +2234,7 @@ static void add_header(struct buffer *b, struct module *mod) buf_printf(b, "#define INCLUDE_VERMAGIC\n"); buf_printf(b, "#include \n"); buf_printf(b, "#include \n"); + buf_printf(b, "#include \n"); buf_printf(b, "#include \n"); buf_printf(b, "#include \n"); buf_printf(b, "\n"); @@ -2268,20 +2269,26 @@ static void add_header(struct buffer *b, struct module *mod) buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n"); } -static void check_symversions(struct module *mod) +static void add_exported_symbols(struct buffer *buf, struct module *mod) { struct symbol *sym; if (!modversions) return; + /* record CRCs for exported symbols */ + buf_printf(buf, "\n"); list_for_each_entry(sym, &mod->exported_symbols, list) { if (!sym->crc_valid) { warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n" "Is \"%s\" prototyped in ?\n", sym->name, mod->name, mod->is_vmlinux ? "" : ".ko", sym->name); + continue; } + + buf_printf(buf, "SYMBOL_CRC(%s, 0x%08x, \"%s\");\n", + sym->name, sym->crc, sym->is_gpl_only ? "_gpl" : ""); } } @@ -2418,6 +2425,18 @@ static void write_if_changed(struct buffer *b, const char *fname) write_buf(b, fname); } +static void write_vmlinux_export_c_file(struct module *mod) +{ + struct buffer buf = { }; + + buf_printf(&buf, + "#include \n"); + + add_exported_symbols(&buf, mod); + write_if_changed(&buf, ".vmlinux.export.c"); + free(buf.p); +} + /* do sanity checks, and generate *.mod.c file */ static void write_mod_c_file(struct module *mod) { @@ -2429,6 +2448,7 @@ static void write_mod_c_file(struct module *mod) check_exports(mod); add_header(&buf, mod); + add_exported_symbols(&buf, mod); add_versions(&buf, mod); add_depends(&buf, mod); add_moddevtable(&buf, mod); @@ -2626,9 +2646,9 @@ int main(int argc, char **argv) if (mod->from_dump) continue; - check_symversions(mod); - - if (!mod->is_vmlinux) + if (mod->is_vmlinux) + write_vmlinux_export_c_file(mod); + else write_mod_c_file(mod); } -- cgit v1.3-18-gd494