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authorLinus Torvalds <torvalds@linux-foundation.org>2021-02-24 02:13:45 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-24 02:13:45 +0300
commit414eece95b98b209cef0f49cfcac108fd00b8ced (patch)
tree82de6f145dee0b6261d4a62cb2f9d7d143ace44b /Makefile
parent6dd580b93da8de5cab4ac1f24f343086318b664e (diff)
parent5e95325fbbbdea96de91e7bdb05fe95a3031e37d (diff)
downloadlinux-414eece95b98b209cef0f49cfcac108fd00b8ced.tar.xz
Merge tag 'clang-lto-v5.12-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull more clang LTO updates from Kees Cook: "Clang LTO x86 enablement. Full disclosure: while this has _not_ been in linux-next (since it initially looked like the objtool dependencies weren't going to make v5.12), it has been under daily build and runtime testing by Sami for quite some time. These x86 portions have been discussed on lkml, with Peter, Josh, and others helping nail things down. The bulk of the changes are to get objtool working happily. The rest of the x86 enablement is very small. Summary: - Generate __mcount_loc in objtool (Peter Zijlstra) - Support running objtool against vmlinux.o (Sami Tolvanen) - Clang LTO enablement for x86 (Sami Tolvanen)" Link: https://lore.kernel.org/lkml/20201013003203.4168817-26-samitolvanen@google.com/ Link: https://lore.kernel.org/lkml/cover.1611263461.git.jpoimboe@redhat.com/ * tag 'clang-lto-v5.12-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: kbuild: lto: force rebuilds when switching CONFIG_LTO x86, build: allow LTO to be selected x86, cpu: disable LTO for cpu.c x86, vdso: disable LTO only for vDSO kbuild: lto: postpone objtool objtool: Split noinstr validation from --vmlinux x86, build: use objtool mcount tracing: add support for objtool mcount objtool: Don't autodetect vmlinux.o objtool: Fix __mcount_loc generation with Clang's assembler objtool: Add a pass for generating __mcount_loc
Diffstat (limited to 'Makefile')
-rw-r--r--Makefile10
1 files changed, 9 insertions, 1 deletions
diff --git a/Makefile b/Makefile
index 441fe2b223ac..b18dbc634690 100644
--- a/Makefile
+++ b/Makefile
@@ -862,6 +862,9 @@ ifdef CONFIG_FTRACE_MCOUNT_USE_CC
endif
endif
endif
+ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL
+ CC_FLAGS_USING += -DCC_USING_NOP_MCOUNT
+endif
ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
ifdef CONFIG_HAVE_C_RECORDMCOUNT
BUILD_C_RECORDMCOUNT := y
@@ -909,7 +912,8 @@ KBUILD_LDFLAGS += -mllvm -import-instr-limit=5
endif
ifdef CONFIG_LTO
-KBUILD_CFLAGS += $(CC_FLAGS_LTO)
+KBUILD_CFLAGS += -fno-lto $(CC_FLAGS_LTO)
+KBUILD_AFLAGS += -fno-lto
export CC_FLAGS_LTO
endif
@@ -1243,6 +1247,10 @@ uapi-asm-generic:
PHONY += prepare-objtool prepare-resolve_btfids
prepare-objtool: $(objtool_target)
ifeq ($(SKIP_STACK_VALIDATION),1)
+ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL
+ @echo "error: Cannot generate __mcount_loc for CONFIG_DYNAMIC_FTRACE=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2
+ @false
+endif
ifdef CONFIG_UNWINDER_ORC
@echo "error: Cannot generate ORC metadata for CONFIG_UNWINDER_ORC=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2
@false