From patchwork Fri Dec 21 17:30:32 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Diana Craciun X-Patchwork-Id: 1017657 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 43Lx4B5fFMz9sD9 for ; Sat, 22 Dec 2018 04:50:34 +1100 (AEDT) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=nxp.com Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 43Lx4B4KLfzDrQc for ; Sat, 22 Dec 2018 04:50:34 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=nxp.com 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=nxp.com (client-ip=92.121.34.21; helo=inva021.nxp.com; envelope-from=diana.craciun@nxp.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=nxp.com Received: from inva021.nxp.com (inva021.nxp.com [92.121.34.21]) (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 43Lwdy2DjDzDr34 for ; Sat, 22 Dec 2018 04:31:17 +1100 (AEDT) Received: from inva021.nxp.com (localhost [127.0.0.1]) by inva021.eu-rdc02.nxp.com (Postfix) with ESMTP id 58BCB2000CE; Fri, 21 Dec 2018 18:31:14 +0100 (CET) Received: from inva024.eu-rdc02.nxp.com (inva024.eu-rdc02.nxp.com [134.27.226.22]) by inva021.eu-rdc02.nxp.com (Postfix) with ESMTP id 4CC3A200002; Fri, 21 Dec 2018 18:31:14 +0100 (CET) Received: from fsr-ub1664-009.ea.freescale.net (fsr-ub1664-009.ea.freescale.net [10.171.71.77]) by inva024.eu-rdc02.nxp.com (Postfix) with ESMTP id 1EC68205E9; Fri, 21 Dec 2018 18:31:14 +0100 (CET) From: Diana Craciun To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH 06/11 v2] powerpc/fsl: Flush the branch predictor at each kernel entry (64bit) Date: Fri, 21 Dec 2018 19:30:32 +0200 Message-Id: <1545413437-5538-7-git-send-email-diana.craciun@nxp.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1545413437-5538-1-git-send-email-diana.craciun@nxp.com> References: <1545413437-5538-1-git-send-email-diana.craciun@nxp.com> X-Virus-Scanned: ClamAV using ClamSMTP 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: Diana Craciun Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" In order to protect against speculation attacks on indirect branches, the branch predictor is flushed at kernel entry to protect for the following situations: - userspace process attacking another userspace process - userspace process attacking the kernel Basically when the privillege level change (i.e. the kernel is entered), the branch predictor state is flushed. Signed-off-by: Diana Craciun --- v1-->v2 - no change arch/powerpc/kernel/entry_64.S | 5 +++++ arch/powerpc/kernel/exceptions-64e.S | 26 +++++++++++++++++++++++++- arch/powerpc/mm/tlb_low_64e.S | 7 +++++++ 3 files changed, 37 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 7b1693a..7c2032e 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -80,6 +80,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_TM) std r0,GPR0(r1) std r10,GPR1(r1) beq 2f /* if from kernel mode */ +#ifdef CONFIG_PPC_FSL_BOOK3E +START_BTB_FLUSH_SECTION + BTB_FLUSH(r10) +END_BTB_FLUSH_SECTION +#endif ACCOUNT_CPU_USER_ENTRY(r13, r10, r11) 2: std r2,GPR2(r1) std r3,GPR3(r1) diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S index 6d6e144..afb6387 100644 --- a/arch/powerpc/kernel/exceptions-64e.S +++ b/arch/powerpc/kernel/exceptions-64e.S @@ -296,7 +296,8 @@ ret_from_mc_except: andi. r10,r11,MSR_PR; /* save stack pointer */ \ beq 1f; /* branch around if supervisor */ \ ld r1,PACAKSAVE(r13); /* get kernel stack coming from usr */\ -1: cmpdi cr1,r1,0; /* check if SP makes sense */ \ +1: type##_BTB_FLUSH \ + cmpdi cr1,r1,0; /* check if SP makes sense */ \ bge- cr1,exc_##n##_bad_stack;/* bad stack (TODO: out of line) */ \ mfspr r10,SPRN_##type##_SRR0; /* read SRR0 before touching stack */ @@ -328,6 +329,29 @@ ret_from_mc_except: #define SPRN_MC_SRR0 SPRN_MCSRR0 #define SPRN_MC_SRR1 SPRN_MCSRR1 +#ifdef CONFIG_PPC_FSL_BOOK3E +#define GEN_BTB_FLUSH \ + START_BTB_FLUSH_SECTION \ + beq 1f; \ + BTB_FLUSH(r10) \ + 1: \ + END_BTB_FLUSH_SECTION + +#define CRIT_BTB_FLUSH \ + START_BTB_FLUSH_SECTION \ + BTB_FLUSH(r10) \ + END_BTB_FLUSH_SECTION + +#define DBG_BTB_FLUSH CRIT_BTB_FLUSH +#define MC_BTB_FLUSH CRIT_BTB_FLUSH +#define GDBELL_BTB_FLUSH GEN_BTB_FLUSH +#else +#define GEN_BTB_FLUSH +#define CRIT_BTB_FLUSH +#define DBG_BTB_FLUSH +#define GDBELL_BTB_FLUSH +#endif + #define NORMAL_EXCEPTION_PROLOG(n, intnum, addition) \ EXCEPTION_PROLOG(n, intnum, GEN, addition##_GEN(n)) diff --git a/arch/powerpc/mm/tlb_low_64e.S b/arch/powerpc/mm/tlb_low_64e.S index 7fd20c5..9ed9006 100644 --- a/arch/powerpc/mm/tlb_low_64e.S +++ b/arch/powerpc/mm/tlb_low_64e.S @@ -70,6 +70,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV) std r15,EX_TLB_R15(r12) std r10,EX_TLB_CR(r12) #ifdef CONFIG_PPC_FSL_BOOK3E +START_BTB_FLUSH_SECTION + mfspr r11, SPRN_SRR1 + andi. r10,r11,MSR_PR + beq 1f + BTB_FLUSH(r10) +1: +END_BTB_FLUSH_SECTION std r7,EX_TLB_R7(r12) #endif TLB_MISS_PROLOG_STATS