lkml.org 
[lkml]   [2022]   [May]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4/4] kbuild: factor out the common objtool arguments
Date
scripts/Makefile.build and scripts/link-vmlinux.sh have similar setups
for the objtool arguments.

It is difficult to factor out them because the vmlinux build rule is
written in a shell script. It is somewhat tedious to touch the two
files every time a new objtool option is supported.

To reduce the code duplication, implement everything about objtool in
Makefile.

Move the objtool for vmlinux.o into scripts/Makefile.vmlinux_o.

Move the common macros to Makefile.lib so they are shared by
Makefile.build and Makefile.vmlinux_o.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

scripts/Makefile.build | 26 --------------
scripts/Makefile.lib | 26 ++++++++++++++
scripts/Makefile.vmlinux_o | 26 ++++++++++++++
scripts/link-vmlinux.sh | 71 --------------------------------------
4 files changed, 52 insertions(+), 97 deletions(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 4cb7145071b9..1f01ac65c0cd 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -210,38 +210,12 @@ cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)),
$(sub_cmd_record_mcount))
endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT

-ifdef CONFIG_OBJTOOL
-
-objtool := $(objtree)/tools/objtool/objtool
-
-objtool_args = \
- $(if $(CONFIG_HAVE_JUMP_LABEL_HACK), --hacks=jump_label) \
- $(if $(CONFIG_HAVE_NOINSTR_HACK), --hacks=noinstr) \
- $(if $(CONFIG_X86_KERNEL_IBT), --ibt) \
- $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \
- $(if $(CONFIG_UNWINDER_ORC), --orc) \
- $(if $(CONFIG_RETPOLINE), --retpoline) \
- $(if $(CONFIG_SLS), --sls) \
- $(if $(CONFIG_STACK_VALIDATION), --stackval) \
- $(if $(CONFIG_HAVE_STATIC_CALL_INLINE), --static-call) \
- --uaccess \
- $(if $(delay-objtool), --link) \
- $(if $(part-of-module), --module) \
- $(if $(CONFIG_GCOV_KERNEL), --no-unreachable)
-
-cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $@)
-cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd)
-
-endif # CONFIG_OBJTOOL
-
# '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

is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y)

-delay-objtool := $(or $(CONFIG_LTO_CLANG),$(CONFIG_X86_KERNEL_IBT))
-
$(obj)/%.o: objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y))

ifdef CONFIG_TRIM_UNUSED_KSYMS
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index f75138385449..f691fb231ce5 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -225,6 +225,32 @@ dtc_cpp_flags = -Wp,-MMD,$(depfile).pre.tmp -nostdinc \
$(addprefix -I,$(DTC_INCLUDE)) \
-undef -D__DTS__

+ifdef CONFIG_OBJTOOL
+
+objtool := $(objtree)/tools/objtool/objtool
+
+objtool_args = \
+ $(if $(CONFIG_HAVE_JUMP_LABEL_HACK), --hacks=jump_label) \
+ $(if $(CONFIG_HAVE_NOINSTR_HACK), --hacks=noinstr) \
+ $(if $(CONFIG_X86_KERNEL_IBT), --ibt) \
+ $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \
+ $(if $(CONFIG_UNWINDER_ORC), --orc) \
+ $(if $(CONFIG_RETPOLINE), --retpoline) \
+ $(if $(CONFIG_SLS), --sls) \
+ $(if $(CONFIG_STACK_VALIDATION), --stackval) \
+ $(if $(CONFIG_HAVE_STATIC_CALL_INLINE), --static-call) \
+ --uaccess \
+ $(if $(delay-objtool), --link) \
+ $(if $(part-of-module), --module) \
+ $(if $(CONFIG_GCOV_KERNEL), --no-unreachable)
+
+delay-objtool := $(or $(CONFIG_LTO_CLANG),$(CONFIG_X86_KERNEL_IBT))
+
+cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $@)
+cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd)
+
+endif # CONFIG_OBJTOOL
+
# 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.vmlinux_o b/scripts/Makefile.vmlinux_o
index a9b375ca86d5..3c97a1564947 100644
--- a/scripts/Makefile.vmlinux_o
+++ b/scripts/Makefile.vmlinux_o
@@ -6,6 +6,9 @@ __default: vmlinux.o
include include/config/auto.conf
include $(srctree)/scripts/Kbuild.include

+# for objtool
+include $(srctree)/scripts/Makefile.lib
+
# Generate a linker script to ensure correct ordering of initcalls for Clang LTO
# ---------------------------------------------------------------------------

@@ -24,6 +27,27 @@ ifdef CONFIG_LTO_CLANG
initcalls-lds := .tmp_initcalls.lds
endif

+# objtool for vmlinux.o
+# ---------------------------------------------------------------------------
+#
+# For LTO and IBT, objtool doesn't run on individual translation units.
+# Run everything on vmlinux instead.
+
+objtool-enabled := $(or $(delay-objtool),$(CONFIG_NOINSTR_VALIDATION))
+
+# Reuse objtool_args defined in scripts/Makefile.lib if LTO or IBT is enabled.
+#
+# Add some more flags as needed.
+# --no-unreachable and --link might be added twice, but it is fine.
+#
+# Expand objtool_args to a simple variable to avoid circular reference.
+
+objtool_args := \
+ $(if $(delay-objtool),$(objtool_args)) \
+ $(if $(CONFIG_NOINSTR_VALIDATION), --noinstr) \
+ $(if $(CONFIG_GCOV_KERNEL), --no-unreachable) \
+ --link
+
# Link of vmlinux.o used for section mismatch analysis
# ---------------------------------------------------------------------------

@@ -33,9 +57,11 @@ quiet_cmd_ld_vmlinux.o = LD $@
$(addprefix -T , $(initcalls-lds)) \
--whole-archive $(KBUILD_VMLINUX_OBJS) --no-whole-archive \
--start-group $(KBUILD_VMLINUX_LIBS) --end-group \
+ $(cmd_objtool)

define rule_ld_vmlinux.o
$(call cmd_and_savecmd,ld_vmlinux.o)
+ $(call cmd,gen_objtooldep)
endef

vmlinux.o: $(initcalls-lds) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 90680b6bd710..1ac4e180fa3f 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -45,76 +45,6 @@ info()
printf " %-7s %s\n" "${1}" "${2}"
}

-objtool_link()
-{
- local objtoolcmd;
- local objtoolopt;
-
- if ! is_enabled CONFIG_OBJTOOL; then
- return;
- fi
-
- if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT; then
-
- # For LTO and IBT, objtool doesn't run on individual
- # translation units. Run everything on vmlinux instead.
-
- if is_enabled CONFIG_HAVE_JUMP_LABEL_HACK; then
- objtoolopt="${objtoolopt} --hacks=jump_label"
- fi
-
- if is_enabled CONFIG_HAVE_NOINSTR_HACK; then
- objtoolopt="${objtoolopt} --hacks=noinstr"
- fi
-
- if is_enabled CONFIG_X86_KERNEL_IBT; then
- objtoolopt="${objtoolopt} --ibt"
- fi
-
- if is_enabled CONFIG_FTRACE_MCOUNT_USE_OBJTOOL; then
- objtoolopt="${objtoolopt} --mcount"
- fi
-
- if is_enabled CONFIG_UNWINDER_ORC; then
- objtoolopt="${objtoolopt} --orc"
- fi
-
- if is_enabled CONFIG_RETPOLINE; then
- objtoolopt="${objtoolopt} --retpoline"
- fi
-
- if is_enabled CONFIG_SLS; then
- objtoolopt="${objtoolopt} --sls"
- fi
-
- if is_enabled CONFIG_STACK_VALIDATION; then
- objtoolopt="${objtoolopt} --stackval"
- fi
-
- if is_enabled CONFIG_HAVE_STATIC_CALL_INLINE; then
- objtoolopt="${objtoolopt} --static-call"
- fi
-
- objtoolopt="${objtoolopt} --uaccess"
- fi
-
- if is_enabled CONFIG_NOINSTR_VALIDATION; then
- objtoolopt="${objtoolopt} --noinstr"
- fi
-
- if [ -n "${objtoolopt}" ]; then
-
- if is_enabled CONFIG_GCOV_KERNEL; then
- objtoolopt="${objtoolopt} --no-unreachable"
- fi
-
- objtoolopt="${objtoolopt} --link"
-
- info OBJTOOL ${1}
- tools/objtool/objtool ${objtoolopt} ${1}
- fi
-}
-
# Link of vmlinux
# ${1} - output file
# ${2}, ${3}, ... - optional extra .o files
@@ -298,7 +228,6 @@ ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init need-builtin=1

#link vmlinux.o
${MAKE} -f "${srctree}/scripts/Makefile.vmlinux_o"
-objtool_link vmlinux.o

# Generate the list of objects in vmlinux
for f in ${KBUILD_VMLINUX_OBJS} ${KBUILD_VMLINUX_LIBS}; do
--
2.32.0
\
 
 \ /
  Last update: 2022-05-28 17:49    [W:0.109 / U:0.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site