From: Sami Tolvanen <samitolvanen@google.com>
To: Masahiro Yamada <masahiroy@kernel.org>,
Will Deacon <will@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Kees Cook <keescook@chromium.org>,
Nick Desaulniers <ndesaulniers@google.com>,
clang-built-linux@googlegroups.com,
kernel-hardening@lists.openwall.com, linux-arch@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, x86@kernel.org,
Sami Tolvanen <samitolvanen@google.com>
Subject: [PATCH v4 13/29] kbuild: lto: postpone objtool
Date: Tue, 29 Sep 2020 14:46:15 -0700 [thread overview]
Message-ID: <20200929214631.3516445-14-samitolvanen@google.com> (raw)
In-Reply-To: <20200929214631.3516445-1-samitolvanen@google.com>
With LTO, LLVM bitcode won't be compiled into native code until
modpost_link, or modfinal for modules. This change postpones calls
to objtool until after these steps, and moves objtool_args to
Makefile.lib, so the arguments can be reused in Makefile.modfinal.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
arch/Kconfig | 2 +-
scripts/Makefile.build | 19 ++-----------------
scripts/Makefile.lib | 11 +++++++++++
scripts/Makefile.modfinal | 19 ++++++++++++++++---
scripts/link-vmlinux.sh | 23 ++++++++++++++++++++++-
5 files changed, 52 insertions(+), 22 deletions(-)
diff --git a/arch/Kconfig b/arch/Kconfig
index 520e900efc75..db57ea19649b 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -600,7 +600,7 @@ config LTO_CLANG
depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
depends on ARCH_SUPPORTS_LTO_CLANG
- depends on !FTRACE_MCOUNT_RECORD
+ depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT
depends on !KASAN
depends on !GCOV_KERNEL
select LTO
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index eae2f5386a03..ab0ddf4884fd 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%,, \
$(__objtool_obj))
endif # SKIP_STACK_VALIDATION
+endif # CONFIG_LTO_CLANG
endif # CONFIG_STACK_VALIDATION
# Rebuild all objects when objtool changes, or is enabled/disabled.
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 3d599716940c..ecb97c9f5feb 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -216,6 +216,17 @@ dtc_cpp_flags = -Wp,-MMD,$(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 $(CONFIG_GCOV_KERNEL), --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 2cb9a1d88434..1bd2953b11c4 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -9,7 +9,7 @@ __modfinal:
include $(objtree)/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, $^); \
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 3e99a19b9195..96cf5a5d19df 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -93,8 +93,29 @@ objtool_link()
{
local objtoolopt;
+ if [ "${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
+ objtoolopt="orc generate"
+ else
+ objtoolopt="check"
+ fi
+
+ if [ -n ${CONFIG_FTRACE_MCOUNT_USE_OBJTOOL} ]; then
+ objtoolopt="${objtoolopt} --mcount"
+ fi
+ fi
+
if [ -n "${CONFIG_VMLINUX_VALIDATION}" ]; then
- objtoolopt="check --vmlinux"
+ if [ -z "${objtoolopt}" ]; then
+ objtoolopt="check --vmlinux"
+ else
+ objtoolopt="${objtoolopt} --vmlinux"
+ fi
+ fi
+
+ if [ -n "${objtoolopt}" ]; then
if [ -z "${CONFIG_FRAME_POINTER}" ]; then
objtoolopt="${objtoolopt} --no-fp"
fi
--
2.28.0.709.gb0816b6eb0-goog
next prev parent reply other threads:[~2020-09-29 21:47 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-29 21:46 [PATCH v4 00/29] Add support for Clang LTO Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 01/29] RAS/CEC: Fix cec_init() prototype Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 02/29] x86/asm: Replace __force_order with memory clobber Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 03/29] kbuild: preprocess module linker script Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 04/29] objtool: Add a pass for generating __mcount_loc Sami Tolvanen
2020-10-01 13:17 ` Miroslav Benes
2020-10-01 13:36 ` Peter Zijlstra
2020-10-02 14:13 ` Josh Poimboeuf
2020-10-05 7:10 ` Miroslav Benes
2020-09-29 21:46 ` [PATCH v4 05/29] objtool: Don't autodetect vmlinux.o Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 06/29] tracing: move function tracer options to Kconfig Sami Tolvanen
2020-09-30 0:12 ` Steven Rostedt
2020-09-30 16:05 ` Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 07/29] tracing: add support for objtool mcount Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 08/29] x86, build: use " Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 09/29] arm64: disable recordmcount with DYNAMIC_FTRACE_WITH_REGS Sami Tolvanen
2020-09-30 9:58 ` Mark Rutland
2020-09-30 17:10 ` Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 10/29] treewide: remove DISABLE_LTO Sami Tolvanen
2020-09-30 20:45 ` Kees Cook
2020-09-29 21:46 ` [PATCH v4 11/29] kbuild: add support for Clang LTO Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 12/29] kbuild: lto: fix module versioning Sami Tolvanen
2020-09-29 21:46 ` Sami Tolvanen [this message]
2020-09-29 21:46 ` [PATCH v4 14/29] kbuild: lto: limit inlining Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 15/29] kbuild: lto: merge module sections Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 16/29] kbuild: lto: remove duplicate dependencies from .mod files Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 17/29] init: lto: ensure initcall ordering Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 18/29] init: lto: fix PREL32 relocations Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 19/29] PCI: Fix PREL32 relocations for LTO Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 20/29] modpost: lto: strip .lto from module names Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 21/29] scripts/mod: disable LTO for empty.c Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 22/29] efi/libstub: disable LTO Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 23/29] drivers/misc/lkdtm: disable LTO for rodata.o Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 24/29] arm64: vdso: disable LTO Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 25/29] KVM: arm64: disable LTO for the nVHE directory Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 26/29] arm64: allow LTO_CLANG and THINLTO to be selected Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 27/29] x86, vdso: disable LTO only for vDSO Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 28/29] x86, cpu: disable LTO for cpu.c Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 29/29] x86, build: allow LTO_CLANG and THINLTO to be selected Sami Tolvanen
2020-09-30 21:10 ` [PATCH v4 00/29] Add support for Clang LTO Kees Cook
2020-09-30 21:58 ` Nick Desaulniers
2020-09-30 22:12 ` Sami Tolvanen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200929214631.3516445-14-samitolvanen@google.com \
--to=samitolvanen@google.com \
--cc=clang-built-linux@googlegroups.com \
--cc=gregkh@linuxfoundation.org \
--cc=keescook@chromium.org \
--cc=kernel-hardening@lists.openwall.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=masahiroy@kernel.org \
--cc=ndesaulniers@google.com \
--cc=paulmck@kernel.org \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=will@kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).