From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751683AbeBTKfG (ORCPT ); Tue, 20 Feb 2018 05:35:06 -0500 Received: from terminus.zytor.com ([198.137.202.136]:47767 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751665AbeBTKfD (ORCPT ); Tue, 20 Feb 2018 05:35:03 -0500 Date: Tue, 20 Feb 2018 02:29:38 -0800 From: tip-bot for David Woodhouse Message-ID: Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, hpa@zytor.com, torvalds@linux-foundation.org, mingo@kernel.org, tglx@linutronix.de, dwmw@amazon.co.uk Reply-To: mingo@kernel.org, dwmw@amazon.co.uk, tglx@linutronix.de, linux-kernel@vger.kernel.org, peterz@infradead.org, torvalds@linux-foundation.org, hpa@zytor.com In-Reply-To: <1519037457-7643-5-git-send-email-dwmw@amazon.co.uk> References: <1519037457-7643-5-git-send-email-dwmw@amazon.co.uk> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/pti] x86/retpoline: Support retpoline builds with Clang Git-Commit-ID: 87358710c1fb4f1bf96bbe2349975ff9953fc9b2 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 87358710c1fb4f1bf96bbe2349975ff9953fc9b2 Gitweb: https://git.kernel.org/tip/87358710c1fb4f1bf96bbe2349975ff9953fc9b2 Author: David Woodhouse AuthorDate: Mon, 19 Feb 2018 10:50:57 +0000 Committer: Ingo Molnar CommitDate: Tue, 20 Feb 2018 11:17:58 +0100 x86/retpoline: Support retpoline builds with Clang Signed-off-by: David Woodhouse Reviewed-by: Thomas Gleixner Cc: Linus Torvalds Cc: Peter Zijlstra Cc: arjan.van.de.ven@intel.com Cc: bp@alien8.de Cc: dave.hansen@intel.com Cc: jmattson@google.com Cc: karahmed@amazon.de Cc: kvm@vger.kernel.org Cc: pbonzini@redhat.com Cc: rkrcmar@redhat.com Link: http://lkml.kernel.org/r/1519037457-7643-5-git-send-email-dwmw@amazon.co.uk Signed-off-by: Ingo Molnar --- arch/x86/Makefile | 5 ++++- include/linux/compiler-clang.h | 5 +++++ include/linux/compiler-gcc.h | 4 ++++ include/linux/init.h | 8 ++++---- 4 files changed, 17 insertions(+), 5 deletions(-) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index fad5516..dbc7d0e 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -232,7 +232,10 @@ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables # Avoid indirect branches in kernel to deal with Spectre ifdef CONFIG_RETPOLINE - RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register) + RETPOLINE_CFLAGS_GCC := -mindirect-branch=thunk-extern -mindirect-branch-register + RETPOLINE_CFLAGS_CLANG := -mretpoline-external-thunk + + RETPOLINE_CFLAGS += $(call cc-option,$(RETPOLINE_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_CFLAGS_CLANG))) ifneq ($(RETPOLINE_CFLAGS),) KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) -DRETPOLINE endif diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h index d02a4df..d3f264a 100644 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -27,3 +27,8 @@ #if __has_feature(address_sanitizer) #define __SANITIZE_ADDRESS__ #endif + +/* Clang doesn't have a way to turn it off per-function, yet. */ +#ifdef __noretpoline +#undef __noretpoline +#endif diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 73bc63e..673fbf9 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -93,6 +93,10 @@ #define __weak __attribute__((weak)) #define __alias(symbol) __attribute__((alias(#symbol))) +#ifdef RETPOLINE +#define __noretpoline __attribute__((indirect_branch("keep"))) +#endif + /* * it doesn't make sense on ARM (currently the only user of __naked) * to trace naked functions because then mcount is called without diff --git a/include/linux/init.h b/include/linux/init.h index 506a981..bc27cf0 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -6,10 +6,10 @@ #include /* Built-in __init functions needn't be compiled with retpoline */ -#if defined(RETPOLINE) && !defined(MODULE) -#define __noretpoline __attribute__((indirect_branch("keep"))) +#if defined(__noretpoline) && !defined(MODULE) +#define __noinitretpoline __noretpoline #else -#define __noretpoline +#define __noinitretpoline #endif /* These macros are used to mark some functions or @@ -47,7 +47,7 @@ /* These are for everybody (although not all archs will actually discard it in modules) */ -#define __init __section(.init.text) __cold __latent_entropy __noretpoline +#define __init __section(.init.text) __cold __latent_entropy __noinitretpoline #define __initdata __section(.init.data) #define __initconst __section(.init.rodata) #define __exitdata __section(.exit.data)