From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELuKpwA7QMSm9+sGtE7uXFLZce8lxHaEUkPT6KaDwWIg7bao0p8FkuZIVRPKJ5J/BxXxrOdp ARC-Seal: i=1; a=rsa-sha256; t=1520955108; cv=none; d=google.com; s=arc-20160816; b=HHXOLm/FN0M4drr3gpO2i6yjrasMMp4lnS2RvxvvWxS4zgK+Qk2yGyKDsYk6kl+JC5 hmBCvZvNYgVmqBWSQsD4dFrLLZrW19B1r2zIvYbGcPy/ajozVT6k9bZWy8fd4eIA0QXs 4D6fRpLbGadBSgflgR/tfotg56lJ+3kAY8oxvpD1zCoQFuxZacCcsdMsZBnkgaZTICMO 79C4igc3nSCSq0zJOCEWiYOIs5EEXct25C5/dhGxwMHIQHrAqYkgesEZIdNy4COgqAyV 5p5ZCMC9GTjgi+Fp9sxTx6DpLI3iUx6WIfGwmjYXGXLZ4vQG6t2VUI3sQeBcJSkfFJye 0u/g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=jCA/zebqQAE58sMLIAFHP525SFBFZZpsfzuQTtIZ+AQ=; b=hUOE9QVRRyRSecEZfEhdBvb03qow/5BHDrz6Z/SkplXeyhHqTfiq4ZBPaEnGoTlAKu +7R1ARHLvMoBv1hAcOJbdsGk0OuY7uawedwNWPl6E6wb23il4L5ki8HhIJ3XhODjriX8 6BsYBZUYYeKX/B4Tb1/WiQFb97EWlW4BjP7zAcXz1+OgsaK4Nas0nGoZFe60hPBSsnn9 4KbKaVzxsnEQTxuZ11Xq74QOkBdIyOhHF+CEJAcFy45gSzrndwyImEkSAodaMiRDkWwA jIco0mEJAtB+WK12rVE67K/1fnhiEFOKOXzhnwRcDX6GCifTFBLFAt15GvWVKIwcDbhz R+dw== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Woodhouse , Thomas Gleixner , Linus Torvalds , Peter Zijlstra , arjan.van.de.ven@intel.com, bp@alien8.de, dave.hansen@intel.com, jmattson@google.com, karahmed@amazon.de, kvm@vger.kernel.org, pbonzini@redhat.com, rkrcmar@redhat.com, Ingo Molnar Subject: [PATCH 4.15 091/146] x86/retpoline: Support retpoline builds with Clang Date: Tue, 13 Mar 2018 16:24:18 +0100 Message-Id: <20180313152327.711568974@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180313152320.439085687@linuxfoundation.org> References: <20180313152320.439085687@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1594837024182823103?= X-GMAIL-MSGID: =?utf-8?q?1594837024182823103?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Woodhouse commit 87358710c1fb4f1bf96bbe2349975ff9953fc9b2 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- 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(-) --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -232,7 +232,10 @@ KBUILD_CFLAGS += -fno-asynchronous-unwin # 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 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -19,3 +19,8 @@ #define randomized_struct_fields_start struct { #define randomized_struct_fields_end }; + +/* Clang doesn't have a way to turn it off per-function, yet. */ +#ifdef __noretpoline +#undef __noretpoline +#endif --- 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 --- 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)