From patchwork Sun Sep 3 12:07:35 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 9936121 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 990FB6037D for ; Sun, 3 Sep 2017 12:09:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8B21C2866E for ; Sun, 3 Sep 2017 12:09:44 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7FEF4286B0; Sun, 3 Sep 2017 12:09:44 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 7E61D2866E for ; Sun, 3 Sep 2017 12:09:43 +0000 (UTC) Received: (qmail 10168 invoked by uid 550); 3 Sep 2017 12:08:52 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 10021 invoked from network); 3 Sep 2017 12:08:50 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=fouFkB02QaVsylENwgwALsIOy3KflFNC0G0jEBYzWk4=; b=IzC/GhzrpOtcOT4muXGs3sAvliQoW6NoeDM5bY8spYrzv84/aNy7YcMg25JWrUWDsR 3VHBNSJbXRtOgLc9dSWRzhfIElS811p4Bv653mvLDG0PeJvlEQs77XEr6zsD3t//AzDK kRgPpzqfSwemrObGHg1owIKwGyFJiNtESaGwM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=fouFkB02QaVsylENwgwALsIOy3KflFNC0G0jEBYzWk4=; b=CuGDSn95/y3K9N3fULPSSe0WkBGuO5YsG6iI0NSS6D0K9QVcsdqAA73g7t+hfVSIDq StWvnKkL9PJW2EhX9Vfg49MXUcIYFhm378/ebloTkmXnR687Kc85LQ5d89Pa+TjdHm+B eq6eHcxk5FQHTSRlbbTz4f1ZKBRBIaHuwOhj14nqpDHHC2ywPWiXng7BYWmZdeAvNqCy 6B8wJr88KRJHxx2/NIc6E0RkGHlCr0pAu4SZmLDFsaQDTTogKYcMZGMLJZSEBfb/0CM5 Ndha+ZH+ypS1pT9QU6UxNOsp1x1u8+aozQeUqe6WIwekUwqhHBBoSDjZYM219HQGVd0u FhQg== X-Gm-Message-State: AHPjjUgpVklt754DusL5raXnI+sxnNwDeN0nAr0AGQmoJ+xSlhEYU1iG kHHuAOayVATIWZ3H X-Google-Smtp-Source: ADKCNb6sm9rtpi9iPUYWwCVA5uABtEoBVYd7k8EH1b2c5CQcBeu+qKupFHIrGNoJ+BI/ZFXYOQqKeA== X-Received: by 10.223.195.140 with SMTP id p12mr4623226wrf.299.1504440519029; Sun, 03 Sep 2017 05:08:39 -0700 (PDT) From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org, kernel-hardening@lists.openwall.com Cc: Ard Biesheuvel , Arnd Bergmann , Nicolas Pitre , Russell King , Kees Cook , Thomas Garnier , Marc Zyngier , Mark Rutland , Tony Lindgren , Matt Fleming , Dave Martin Date: Sun, 3 Sep 2017 13:07:35 +0100 Message-Id: <20170903120757.14968-8-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170903120757.14968-1-ard.biesheuvel@linaro.org> References: <20170903120757.14968-1-ard.biesheuvel@linaro.org> Subject: [kernel-hardening] [PATCH v2 07/29] ARM: kernel: use relative references for UP/SMP alternatives X-Virus-Scanned: ClamAV using ClamSMTP To avoid absolute references that are subject to runtime relocation when running a kernel built with CONFIG_RELOCATABLE=y, use relative references in the smp.alt entries. Cc: Russell King Signed-off-by: Ard Biesheuvel Acked-by: Nicolas Pitre --- arch/arm/include/asm/assembler.h | 4 ++-- arch/arm/include/asm/processor.h | 2 +- arch/arm/kernel/head.S | 10 +++++----- 3 files changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index 341e4ed1ef84..a0906c1fc65d 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -260,7 +260,7 @@ */ #define ALT_UP(instr...) \ .pushsection ".alt.smp.init", "a" ;\ - .long 9998b ;\ + .long 9998b - . ;\ 9997: instr ;\ .if . - 9997b == 2 ;\ nop ;\ @@ -272,7 +272,7 @@ #define ALT_UP_B(label) \ .equ up_b_offset, label - 9998b ;\ .pushsection ".alt.smp.init", "a" ;\ - .long 9998b ;\ + .long 9998b - . ;\ W(b) . + up_b_offset ;\ .popsection #else diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h index c3d5fc124a05..3667b395bb17 100644 --- a/arch/arm/include/asm/processor.h +++ b/arch/arm/include/asm/processor.h @@ -92,7 +92,7 @@ unsigned long get_wchan(struct task_struct *p); #define __ALT_SMP_ASM(smp, up) \ "9998: " smp "\n" \ " .pushsection \".alt.smp.init\", \"a\"\n" \ - " .long 9998b\n" \ + " .long 9998b - .\n" \ " " up "\n" \ " .popsection\n" #else diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 6e9df3663a57..ec22f42fd8bb 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -548,14 +548,15 @@ smp_on_up: __do_fixup_smp_on_up: cmp r4, r5 reths lr - ldmia r4!, {r0, r6} - ARM( str r6, [r0, r3] ) - THUMB( add r0, r0, r3 ) + ldmia r4, {r0, r6} + ARM( str r6, [r0, r4] ) + THUMB( add r0, r0, r4 ) + add r4, r4, #8 #ifdef __ARMEB__ THUMB( mov r6, r6, ror #16 ) @ Convert word order for big-endian. #endif THUMB( strh r6, [r0], #2 ) @ For Thumb-2, store as two halfwords - THUMB( mov r6, r6, lsr #16 ) @ to be robust against misaligned r3. + THUMB( mov r6, r6, lsr #16 ) @ to be robust against misaligned r0. THUMB( strh r6, [r0] ) b __do_fixup_smp_on_up ENDPROC(__do_fixup_smp_on_up) @@ -564,7 +565,6 @@ ENTRY(fixup_smp) stmfd sp!, {r4 - r6, lr} mov r4, r0 add r5, r0, r1 - mov r3, #0 bl __do_fixup_smp_on_up ldmfd sp!, {r4 - r6, pc} ENDPROC(fixup_smp)