From patchwork Wed Mar 14 16:50:47 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 10282817 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 9F1DB60621 for ; Wed, 14 Mar 2018 16:52:07 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 914C7284B9 for ; Wed, 14 Mar 2018 16:52:07 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8F6BC2847D; Wed, 14 Mar 2018 16:52:07 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E301028534 for ; Wed, 14 Mar 2018 16:52:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932197AbeCNQwB (ORCPT ); Wed, 14 Mar 2018 12:52:01 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:55698 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752419AbeCNQv7 (ORCPT ); Wed, 14 Mar 2018 12:51:59 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 184BB1688; Wed, 14 Mar 2018 09:51:59 -0700 (PDT) Received: from approximate.cambridge.arm.com (approximate.cambridge.arm.com [10.1.207.62]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0582C3F53D; Wed, 14 Mar 2018 09:51:56 -0700 (PDT) From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Cc: Christoffer Dall , Mark Rutland , Catalin Marinas , Will Deacon , James Morse , Steve Capper , Peter Maydell , Andrew Jones , Kristina Martsenko Subject: [PATCH v6 24/26] arm64: Make BP hardening slot counter available Date: Wed, 14 Mar 2018 16:50:47 +0000 Message-Id: <20180314165049.30105-25-marc.zyngier@arm.com> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20180314165049.30105-1-marc.zyngier@arm.com> References: <20180314165049.30105-1-marc.zyngier@arm.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We're about to need to allocate hardening slots from other parts of the kernel (in order to support ARM64_HARDEN_EL2_VECTORS). Turn the counter into an atomic_t and make it available to the rest of the kernel. Also add BP_HARDEN_EL2_SLOTS as the number of slots instead of the hardcoded 4... Signed-off-by: Marc Zyngier Reviewed-by: Andrew Jones --- arch/arm64/include/asm/mmu.h | 3 +++ arch/arm64/kernel/bpi.S | 3 ++- arch/arm64/kernel/cpu_errata.c | 9 ++++----- 3 files changed, 9 insertions(+), 6 deletions(-) diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h index a050d4f3615d..3baf010fe883 100644 --- a/arch/arm64/include/asm/mmu.h +++ b/arch/arm64/include/asm/mmu.h @@ -21,6 +21,8 @@ #define USER_ASID_FLAG (UL(1) << USER_ASID_BIT) #define TTBR_ASID_MASK (UL(0xffff) << 48) +#define BP_HARDEN_EL2_SLOTS 4 + #ifndef __ASSEMBLY__ typedef struct { @@ -51,6 +53,7 @@ struct bp_hardening_data { #ifdef CONFIG_HARDEN_BRANCH_PREDICTOR extern char __bp_harden_hyp_vecs_start[], __bp_harden_hyp_vecs_end[]; +extern atomic_t arm64_el2_vector_last_slot; DECLARE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data); diff --git a/arch/arm64/kernel/bpi.S b/arch/arm64/kernel/bpi.S index dc51ef2ce98a..bb0b67722e86 100644 --- a/arch/arm64/kernel/bpi.S +++ b/arch/arm64/kernel/bpi.S @@ -20,6 +20,7 @@ #include #include +#include .macro hyp_ventry .align 7 @@ -66,7 +67,7 @@ alternative_cb_end .align 11 ENTRY(__bp_harden_hyp_vecs_start) - .rept 4 + .rept BP_HARDEN_EL2_SLOTS generate_vectors .endr ENTRY(__bp_harden_hyp_vecs_end) diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 52f15cd896e1..8cf6b60a085a 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -60,6 +60,8 @@ static int cpu_enable_trap_ctr_access(void *__unused) return 0; } +atomic_t arm64_el2_vector_last_slot = ATOMIC_INIT(-1); + #ifdef CONFIG_HARDEN_BRANCH_PREDICTOR #include #include @@ -90,7 +92,6 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn, const char *hyp_vecs_start, const char *hyp_vecs_end) { - static int last_slot = -1; static DEFINE_SPINLOCK(bp_lock); int cpu, slot = -1; @@ -103,10 +104,8 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn, } if (slot == -1) { - last_slot++; - BUG_ON(((__bp_harden_hyp_vecs_end - __bp_harden_hyp_vecs_start) - / SZ_2K) <= last_slot); - slot = last_slot; + slot = atomic_inc_return(&arm64_el2_vector_last_slot); + BUG_ON(slot >= BP_HARDEN_EL2_SLOTS); __copy_hyp_vect_bpi(slot, hyp_vecs_start, hyp_vecs_end); }