The following commit has been merged into the x86/core branch of tip: Commit-ID: d31ed5d767c0452b4f49846d80a0bfeafa3a4ded Gitweb: https://git.kernel.org/tip/d31ed5d767c0452b4f49846d80a0bfeafa3a4ded Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx> AuthorDate: Fri, 18 Mar 2022 12:19:27 +01:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Tue, 22 Mar 2022 21:12:04 +01:00 kbuild: Fixup the IBT kbuild changes Masahiro-san deemed my kbuild changes to support whole module objtool runs too terrible to live and gracefully provided an alternative. Suggested-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: https://lkml.kernel.org/r/CAK7LNAQ2mYMnOKMQheVi+6byUFE3KEkjm1zcndNUfe0tORGvug@xxxxxxxxxxxxxx --- scripts/Makefile.build | 66 +++++++++++------------------------------ scripts/Makefile.lib | 4 +- scripts/mod/modpost.c | 12 +++---- 3 files changed, 27 insertions(+), 55 deletions(-) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 926d254..2173a67 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -86,18 +86,12 @@ ifdef need-builtin targets-for-builtin += $(obj)/built-in.a endif -targets-for-modules := +targets-for-modules := $(patsubst %.o, %.mod, $(filter %.o, $(obj-m))) -ifdef CONFIG_LTO_CLANG -targets-for-modules += $(patsubst %.o, %.lto.o, $(filter %.o, $(obj-m))) -endif - -ifdef CONFIG_X86_KERNEL_IBT -targets-for-modules += $(patsubst %.o, %.objtool, $(filter %.o, $(obj-m))) +ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) +targets-for-modules += $(patsubst %.o, %.prelink.o, $(filter %.o, $(obj-m))) endif -targets-for-modules += $(patsubst %.o, %.mod, $(filter %.o, $(obj-m))) - ifdef need-modorder targets-for-modules += $(obj)/modules.order endif @@ -244,31 +238,16 @@ objtool_args = \ $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \ $(if $(CONFIG_SLS), --sls) -cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $(@:.objtool=.o)) -cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$(@:.objtool=.o): $$(wildcard $(objtool))' ; } >> $(dot-target).cmd) +cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $@) +cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd) endif # CONFIG_STACK_VALIDATION -ifdef CONFIG_LTO_CLANG +ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) # Skip objtool for LLVM bitcode $(obj)/%.o: objtool-enabled := -# objtool was skipped for LLVM bitcode, run it now that we have compiled -# modules into native code -$(obj)/%.lto.o: objtool-enabled = y -$(obj)/%.lto.o: part-of-module := y - -else ifdef CONFIG_X86_KERNEL_IBT - -# Skip objtool on individual files -$(obj)/%.o: objtool-enabled := - -# instead run objtool on the module as a whole, right before -# the final link pass with the linker script. -$(obj)/%.objtool: objtool-enabled = y -$(obj)/%.objtool: part-of-module := y - else # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory @@ -310,19 +289,24 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE $(call if_changed_rule,cc_o_c) $(call cmd,force_checksrc) -ifdef CONFIG_LTO_CLANG +ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) # Module .o files may contain LLVM bitcode, compile them into native code # before ELF processing -quiet_cmd_cc_lto_link_modules = LTO [M] $@ - cmd_cc_lto_link_modules = \ +quiet_cmd_cc_prelink_modules = LD [M] $@ + cmd_cc_prelink_modules = \ $(LD) $(ld_flags) -r -o $@ \ - $(shell [ -s $(@:.lto.o=.o.symversions) ] && \ - echo -T $(@:.lto.o=.o.symversions)) \ + $(shell [ -s $(@:.prelink.o=.o.symversions) ] && \ + echo -T $(@:.prelink.o=.o.symversions)) \ --whole-archive $(filter-out FORCE,$^) \ $(cmd_objtool) -$(obj)/%.lto.o: $(obj)/%.o FORCE - $(call if_changed,cc_lto_link_modules) +# objtool was skipped for LLVM bitcode, run it now that we have compiled +# modules into native code +$(obj)/%.prelink.o: objtool-enabled = y +$(obj)/%.prelink.o: part-of-module := y + +$(obj)/%.prelink.o: $(obj)/%.o FORCE + $(call if_changed,cc_prelink_modules) endif cmd_mod = { \ @@ -333,18 +317,6 @@ cmd_mod = { \ $(obj)/%.mod: $(obj)/%$(mod-prelink-ext).o FORCE $(call if_changed,mod) -# -# Since objtool will re-write the file it will change the timestamps, therefore -# it is critical that the %.objtool file gets a timestamp *after* objtool runs. -# -# Additionally, care must be had with ordering this rule against the other rules -# that take %.o as a dependency. -# -cmd_objtool_mod = true $(cmd_objtool) ; touch $@ - -$(obj)/%.objtool: $(obj)/%$(mod-prelink-ext).o FORCE - $(call if_changed,objtool_mod) - quiet_cmd_cc_lst_c = MKLST $@ cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ @@ -498,7 +470,7 @@ $(obj)/lib.a: $(lib-y) FORCE # Do not replace $(filter %.o,^) with $(real-prereqs). When a single object # module is turned into a multi object module, $^ will contain header file # dependencies recorded in the .*.cmd file. -ifdef CONFIG_LTO_CLANG +ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) quiet_cmd_link_multi-m = AR [M] $@ cmd_link_multi-m = \ $(cmd_update_lto_symversions); \ diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 79be57f..8bfc923 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -230,11 +230,11 @@ dtc_cpp_flags = -Wp,-MMD,$(depfile).pre.tmp -nostdinc \ $(addprefix -I,$(DTC_INCLUDE)) \ -undef -D__DTS__ -ifeq ($(CONFIG_LTO_CLANG),y) +ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) # With CONFIG_LTO_CLANG, .o files in modules might be LLVM bitcode, so we # need to run LTO to compile them into native code (.lto.o) before further # processing. -mod-prelink-ext := .lto +mod-prelink-ext := .prelink endif # Useful for describing the dependency of composite objects diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 6bfa332..09c3ab0 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1989,9 +1989,9 @@ static char *remove_dot(char *s) if (m && (s[n + m] == '.' || s[n + m] == 0)) s[n] = 0; - /* strip trailing .lto */ - if (strends(s, ".lto")) - s[strlen(s) - 4] = '\0'; + /* strip trailing .prelink */ + if (strends(s, ".prelink")) + s[strlen(s) - 8] = '\0'; } return s; } @@ -2015,9 +2015,9 @@ static void read_symbols(const char *modname) /* strip trailing .o */ tmp = NOFAIL(strdup(modname)); tmp[strlen(tmp) - 2] = '\0'; - /* strip trailing .lto */ - if (strends(tmp, ".lto")) - tmp[strlen(tmp) - 4] = '\0'; + /* strip trailing .prelink */ + if (strends(tmp, ".prelink")) + tmp[strlen(tmp) - 8] = '\0'; mod = new_module(tmp); free(tmp); }
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