From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7DA02C43215 for ; Tue, 26 Nov 2019 12:36:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3904620722 for ; Tue, 26 Nov 2019 12:36:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=c-s.fr header.i=@c-s.fr header.b="PnPyQyQ0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3904620722 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 61C276B02F2; Tue, 26 Nov 2019 07:36:13 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5CDC36B02F3; Tue, 26 Nov 2019 07:36:13 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 497A96B02F4; Tue, 26 Nov 2019 07:36:13 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0090.hostedemail.com [216.40.44.90]) by kanga.kvack.org (Postfix) with ESMTP id 321BE6B02F2 for ; Tue, 26 Nov 2019 07:36:13 -0500 (EST) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id D3FDA2C98 for ; Tue, 26 Nov 2019 12:36:12 +0000 (UTC) X-FDA: 76198376184.01.maid09_706607181bd4a X-HE-Tag: maid09_706607181bd4a X-Filterd-Recvd-Size: 5328 Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) by imf14.hostedemail.com (Postfix) with ESMTP for ; Tue, 26 Nov 2019 12:36:12 +0000 (UTC) Received: from localhost (mailhub1-ext [192.168.12.233]) by localhost (Postfix) with ESMTP id 47Mk0T6mvNz9v0GC; Tue, 26 Nov 2019 13:36:09 +0100 (CET) Authentication-Results: localhost; dkim=pass reason="1024-bit key; insecure key" header.d=c-s.fr header.i=@c-s.fr header.b=PnPyQyQ0; dkim-adsp=pass; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id PtuDK7RrT_qk; Tue, 26 Nov 2019 13:36:09 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 47Mk0T5lz7z9v0G3; Tue, 26 Nov 2019 13:36:09 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1574771769; bh=gOKxrtnFAgRuj43vPkwpnRsML3n0B7clWBuAh6m562Y=; h=In-Reply-To:References:From:Subject:To:Cc:Date:From; b=PnPyQyQ04mngmpm+Thv3+/K8x1FG75fVbSBF1KM3i+WrO6Qb9OaPFjP5oNeeyzR9s HcMx3OBvoR20fF6He9obZJQQjOQD7YULSiTqVWnWChzOsoYzs1PDGy8jWocFqUcc6R tVG2d4UEHAC58vv9yBq4sm3lFTpyDvrZBEO0Tfq4= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 099468B7FC; Tue, 26 Nov 2019 13:36:11 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id y-1AHrQMGz9a; Tue, 26 Nov 2019 13:36:10 +0100 (CET) Received: from po16098vm.idsi0.si.c-s.fr (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id C83918B771; Tue, 26 Nov 2019 13:36:10 +0100 (CET) Received: by po16098vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 94CDE6B76A; Tue, 26 Nov 2019 12:36:10 +0000 (UTC) Message-Id: In-Reply-To: References: From: Christophe Leroy Subject: [PATCH v4 07/16] powerpc: align stack to 2 * THREAD_SIZE with VMAP_STACK To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org Date: Tue, 26 Nov 2019 12:36:10 +0000 (UTC) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: In order to ease stack overflow detection, align stack to 2 * THREAD_SIZE when using VMAP_STACK. This allows overflow detection using a single bit check. Signed-off-by: Christophe Leroy --- arch/powerpc/include/asm/thread_info.h | 13 +++++++++++++ arch/powerpc/kernel/setup_32.c | 2 +- arch/powerpc/kernel/setup_64.c | 2 +- arch/powerpc/kernel/vmlinux.lds.S | 2 +- 4 files changed, 16 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h index 488d5c4670ff..a2270749b282 100644 --- a/arch/powerpc/include/asm/thread_info.h +++ b/arch/powerpc/include/asm/thread_info.h @@ -22,6 +22,19 @@ #define THREAD_SIZE (1 << THREAD_SHIFT) +/* + * By aligning VMAP'd stacks to 2 * THREAD_SIZE, we can detect overflow by + * checking sp & (1 << THREAD_SHIFT), which we can do cheaply in the entry + * assembly. + */ +#ifdef CONFIG_VMAP_STACK +#define THREAD_ALIGN_SHIFT (THREAD_SHIFT + 1) +#else +#define THREAD_ALIGN_SHIFT THREAD_SHIFT +#endif + +#define THREAD_ALIGN (1 << THREAD_ALIGN_SHIFT) + #ifndef __ASSEMBLY__ #include #include diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c index dcffe927f5b9..f014c4f7a337 100644 --- a/arch/powerpc/kernel/setup_32.c +++ b/arch/powerpc/kernel/setup_32.c @@ -140,7 +140,7 @@ arch_initcall(ppc_init); static void *__init alloc_stack(void) { - void *ptr = memblock_alloc(THREAD_SIZE, THREAD_SIZE); + void *ptr = memblock_alloc(THREAD_SIZE, THREAD_ALIGN); if (!ptr) panic("cannot allocate %d bytes for stack at %pS\n", diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index 6104917a282d..e05e6dd67ae6 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -633,7 +633,7 @@ static void *__init alloc_stack(unsigned long limit, int cpu) BUILD_BUG_ON(STACK_INT_FRAME_SIZE % 16); - ptr = memblock_alloc_try_nid(THREAD_SIZE, THREAD_SIZE, + ptr = memblock_alloc_try_nid(THREAD_SIZE, THREAD_ALIGN, MEMBLOCK_LOW_LIMIT, limit, early_cpu_to_node(cpu)); if (!ptr) diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index 060a1acd7c6d..d38335129c06 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -346,7 +346,7 @@ SECTIONS #endif /* The initial task and kernel stack */ - INIT_TASK_DATA_SECTION(THREAD_SIZE) + INIT_TASK_DATA_SECTION(THREAD_ALIGN) .data..page_aligned : AT(ADDR(.data..page_aligned) - LOAD_OFFSET) { PAGE_ALIGNED_DATA(PAGE_SIZE) -- 2.13.3