From: Peter Zijlstra <peterz@infradead.org>
To: David Woodhouse <dwmw2@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-kernel@vger.kernel.org, Dave Hansen <dave.hansen@intel.com>,
Ashok Raj <ashok.raj@intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Greg KH <gregkh@linuxfoundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Andi Kleen <ak@linux.intel.com>,
Arjan Van De Ven <arjan.van.de.ven@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Jun Nakajima <jun.nakajima@intel.com>,
Asit Mallick <asit.k.mallick@intel.com>,
Peter Zijlstra <peterz@infradead.org>
Subject: [PATCH v2 4/8] objtool: Retpoline validation tweaks
Date: Mon, 12 Feb 2018 13:48:59 +0100 [thread overview]
Message-ID: <20180212125033.448828374@infradead.org> (raw)
In-Reply-To: 20180212124855.882405399@infradead.org
[-- Attachment #1: peterz-objtool-config.patch --]
[-- Type: text/plain, Size: 1460 bytes --]
Disable retpoline validation if your compiler sucks, and otherwise
select the validation stuff for RETPOLINE (most builds would already
have it set due to ORC).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
Makefile | 5 +++++
arch/x86/Kconfig | 1 +
scripts/Makefile.build | 2 ++
3 files changed, 8 insertions(+)
--- a/Makefile
+++ b/Makefile
@@ -486,6 +486,11 @@ KBUILD_CFLAGS += $(CLANG_TARGET) $(CLANG
KBUILD_AFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC)
endif
+ifneq ($(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register),)
+ CC_HAS_RETPOLINE := 1
+endif
+export CC_HAS_RETPOLINE
+
ifeq ($(config-targets),1)
# ===========================================================================
# *config targets only - make sure prerequisites are updated, and descend
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -432,6 +432,7 @@ config GOLDFISH
config RETPOLINE
bool "Avoid speculative indirect branches in kernel"
default y
+ select STACK_VALIDATION
help
Compile kernel with the retpoline compiler options to guard against
kernel-to-user data leaks by avoiding speculative indirect
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -267,8 +267,10 @@ else
objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)
endif
ifdef CONFIG_RETPOLINE
+ifdef CC_HAS_RETPOLINE
objtool_args += --retpoline
endif
+endif
ifdef CONFIG_MODVERSIONS
next prev parent reply other threads:[~2018-02-12 12:48 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-12 12:48 [PATCH v2 0/8] objtool: retpoline validation Peter Zijlstra
2018-02-12 12:48 ` [PATCH v2 1/8] objtool: Use existing global variables for options Peter Zijlstra
2018-02-12 12:48 ` [PATCH v2 2/8] objtool: Add retpoline validation Peter Zijlstra
2018-02-12 12:48 ` [PATCH v2 3/8] objtool: Add module specific retpoline rules Peter Zijlstra
2018-02-12 13:01 ` David Woodhouse
2018-02-12 13:07 ` Peter Zijlstra
2018-02-12 12:48 ` Peter Zijlstra [this message]
2018-02-12 12:57 ` [PATCH v2 4/8] objtool: Retpoline validation tweaks David Woodhouse
2018-02-12 14:59 ` Peter Zijlstra
2018-02-12 12:49 ` [PATCH v2 5/8] x86,nospec: Annotate indirect calls/jumps Peter Zijlstra
2018-02-12 12:49 ` [PATCH v2 6/8] x86/paravirt: Annotate indirect calls Peter Zijlstra
2018-02-12 12:49 ` [PATCH v2 7/8] x86: Annotate indirect jump in head_64.S Peter Zijlstra
2018-02-12 12:49 ` [PATCH v2 8/8] x86,sme: Annotate indirect call Peter Zijlstra
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