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authorLinus Torvalds <torvalds@linux-foundation.org>2021-02-23 15:13:45 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-23 15:13:45 -0800
commit414eece95b98b209cef0f49cfcac108fd00b8ced (patch)
tree82de6f145dee0b6261d4a62cb2f9d7d143ace44b /scripts
parent6dd580b93da8de5cab4ac1f24f343086318b664e (diff)
parent5e95325fbbbdea96de91e7bdb05fe95a3031e37d (diff)
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 'scripts')
-rw-r--r--scripts/Makefile.build19
-rw-r--r--scripts/Makefile.lib12
-rw-r--r--scripts/Makefile.modfinal19
-rwxr-xr-xscripts/link-vmlinux.sh28
4 files changed, 55 insertions, 23 deletions
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index d94fc9ab819d..3f6bf0ea7c0e 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -218,27 +218,11 @@ cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)),
endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
ifdef CONFIG_STACK_VALIDATION
+ifndef CONFIG_LTO_CLANG
ifneq ($(SKIP_STACK_VALIDATION),1)
__objtool_obj := $(objtree)/tools/objtool/objtool
-objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
-
-objtool_args += $(if $(part-of-module), --module,)
-
-ifndef CONFIG_FRAME_POINTER
-objtool_args += --no-fp
-endif
-ifdef CONFIG_GCOV_KERNEL
-objtool_args += --no-unreachable
-endif
-ifdef CONFIG_RETPOLINE
- objtool_args += --retpoline
-endif
-ifdef CONFIG_X86_SMAP
- objtool_args += --uaccess
-endif
-
# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
@@ -250,6 +234,7 @@ objtool_obj = $(if $(patsubst y%,, \
$(__objtool_obj))
endif # SKIP_STACK_VALIDATION
+endif # CONFIG_LTO_CLANG
endif # CONFIG_STACK_VALIDATION
# Rebuild all objects when objtool changes, or is enabled/disabled.
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 2301babd3fbc..9f2531567c0e 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -222,6 +222,18 @@ dtc_cpp_flags = -Wp,-MMD,$(depfile).pre.tmp -nostdinc \
$(addprefix -I,$(DTC_INCLUDE)) \
-undef -D__DTS__
+# Objtool arguments are also needed for modfinal with LTO, so we define
+# then here to avoid duplication.
+objtool_args = \
+ $(if $(CONFIG_UNWINDER_ORC),orc generate,check) \
+ $(if $(part-of-module), --module,) \
+ $(if $(CONFIG_FRAME_POINTER),, --no-fp) \
+ $(if $(or $(CONFIG_GCOV_KERNEL),$(CONFIG_LTO_CLANG)), \
+ --no-unreachable,) \
+ $(if $(CONFIG_RETPOLINE), --retpoline,) \
+ $(if $(CONFIG_X86_SMAP), --uaccess,) \
+ $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount,)
+
# Useful for describing the dependency of composite objects
# Usage:
# $(call multi_depend, multi_used_targets, suffix_to_remove, suffix_to_add)
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index 6de2c35b64e8..735e11e9041b 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -9,7 +9,7 @@ __modfinal:
include include/config/auto.conf
include $(srctree)/scripts/Kbuild.include
-# for c_flags
+# for c_flags and objtool_args
include $(srctree)/scripts/Makefile.lib
# find all modules listed in modules.order
@@ -34,10 +34,23 @@ ifdef CONFIG_LTO_CLANG
# With CONFIG_LTO_CLANG, reuse the object file we compiled for modpost to
# avoid a second slow LTO link
prelink-ext := .lto
-endif
+
+# ELF processing was skipped earlier because we didn't have native code,
+# so let's now process the prelinked binary before we link the module.
+
+ifdef CONFIG_STACK_VALIDATION
+ifneq ($(SKIP_STACK_VALIDATION),1)
+cmd_ld_ko_o += \
+ $(objtree)/tools/objtool/objtool $(objtool_args) \
+ $(@:.ko=$(prelink-ext).o);
+
+endif # SKIP_STACK_VALIDATION
+endif # CONFIG_STACK_VALIDATION
+
+endif # CONFIG_LTO_CLANG
quiet_cmd_ld_ko_o = LD [M] $@
- cmd_ld_ko_o = \
+ cmd_ld_ko_o += \
$(LD) -r $(KBUILD_LDFLAGS) \
$(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
-T scripts/module.lds -o $@ $(filter %.o, $^); \
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index c5919d5a0b4f..3b261b0f74f0 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -103,14 +103,36 @@ modpost_link()
objtool_link()
{
+ local objtoolcmd;
local objtoolopt;
+ if [ "${CONFIG_LTO_CLANG} ${CONFIG_STACK_VALIDATION}" = "y y" ]; then
+ # Don't perform vmlinux validation unless explicitly requested,
+ # but run objtool on vmlinux.o now that we have an object file.
+ if [ -n "${CONFIG_UNWINDER_ORC}" ]; then
+ objtoolcmd="orc generate"
+ fi
+
+ objtoolopt="${objtoolopt} --duplicate"
+
+ if [ -n "${CONFIG_FTRACE_MCOUNT_USE_OBJTOOL}" ]; then
+ objtoolopt="${objtoolopt} --mcount"
+ fi
+ fi
+
if [ -n "${CONFIG_VMLINUX_VALIDATION}" ]; then
- objtoolopt="check"
+ objtoolopt="${objtoolopt} --noinstr"
+ fi
+
+ if [ -n "${objtoolopt}" ]; then
+ if [ -z "${objtoolcmd}" ]; then
+ objtoolcmd="check"
+ fi
+ objtoolopt="${objtoolopt} --vmlinux"
if [ -z "${CONFIG_FRAME_POINTER}" ]; then
objtoolopt="${objtoolopt} --no-fp"
fi
- if [ -n "${CONFIG_GCOV_KERNEL}" ]; then
+ if [ -n "${CONFIG_GCOV_KERNEL}" ] || [ -n "${CONFIG_LTO_CLANG}" ]; then
objtoolopt="${objtoolopt} --no-unreachable"
fi
if [ -n "${CONFIG_RETPOLINE}" ]; then
@@ -120,7 +142,7 @@ objtool_link()
objtoolopt="${objtoolopt} --uaccess"
fi
info OBJTOOL ${1}
- tools/objtool/objtool ${objtoolopt} ${1}
+ tools/objtool/objtool ${objtoolcmd} ${objtoolopt} ${1}
fi
}