From patchwork Tue Sep 10 09:16:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 1160179 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 46SKhw0Njfz9s7T for ; Tue, 10 Sep 2019 19:38:24 +1000 (AEST) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=c-s.fr header.i=@c-s.fr header.b="S7mFrYdv"; dkim-atps=neutral Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 46SKhv6c46zDrSH for ; Tue, 10 Sep 2019 19:38:23 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=c-s.fr (client-ip=93.17.236.30; helo=pegase1.c-s.fr; envelope-from=christophe.leroy@c-s.fr; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=c-s.fr header.i=@c-s.fr header.b="S7mFrYdv"; dkim-atps=neutral Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 46SKDh1Ts2zDr0w for ; Tue, 10 Sep 2019 19:17:23 +1000 (AEST) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 46SKDV1D6Hz9txW9; Tue, 10 Sep 2019 11:17:14 +0200 (CEST) Authentication-Results: localhost; dkim=pass reason="1024-bit key; insecure key" header.d=c-s.fr header.i=@c-s.fr header.b=S7mFrYdv; 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 6jDuEqSCV0Ej; Tue, 10 Sep 2019 11:17:14 +0200 (CEST) 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 46SKDT73zHz9txW4; Tue, 10 Sep 2019 11:17:13 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1568107034; bh=jNmfqUiR6RqXmiQTG6K5uIMb23KSAJSDA4eXKm1fAe0=; h=In-Reply-To:References:From:Subject:To:Cc:Date:From; b=S7mFrYdvpN19TBxqJAGQ0Jg5uesInBi+v54y7dUc63yBH45Q9Bahy/qdTq8sLIxF4 4dKn40ZEVKFF0BR5idGxftsdjDdTVYHD9/1886DIe+5bZNp7ZqbgKaNRVb3H2o9D5p GllL15yizzvZstSlb4dmpinkKYSeQe14s26uKwJA= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id BF68F8B87D; Tue, 10 Sep 2019 11:17:14 +0200 (CEST) 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 dbBywxEym2uK; Tue, 10 Sep 2019 11:17:14 +0200 (CEST) Received: from pc16032vm.idsi0.si.c-s.fr (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 88A178B890; Tue, 10 Sep 2019 11:16:26 +0200 (CEST) Received: by pc16032vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 2E8106B739; Tue, 10 Sep 2019 09:16:26 +0000 (UTC) Message-Id: <4ddb131f8a1db7eb01b65dc057234c824e889dd3.1568106758.git.christophe.leroy@c-s.fr> In-Reply-To: References: From: Christophe Leroy Subject: [PATCH v3 07/15] powerpc: align stack to 2 * THREAD_SIZE with VMAP_STACK To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , npiggin@gmail.com, dja@axtens.net Date: Tue, 10 Sep 2019 09:16:26 +0000 (UTC) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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 a7541edf0cdb..180e658c1a6b 100644 --- a/arch/powerpc/kernel/setup_32.c +++ b/arch/powerpc/kernel/setup_32.c @@ -137,7 +137,7 @@ 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 44b4c432a273..f630fe4d36a8 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -644,7 +644,7 @@ 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)