From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 40rfWd5MntzF12N for ; Thu, 24 May 2018 03:24:13 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) by bilbo.ozlabs.org (Postfix) with ESMTP id 40rfWd4mHLz8tLb for ; Thu, 24 May 2018 03:24:13 +1000 (AEST) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 40rfWd0S8Yz9s1b for ; Thu, 24 May 2018 03:24:13 +1000 (AEST) Subject: Patch "powerpc/pseries: Fix clearing of security feature flags" has been added to the 4.16-stable tree To: greg@kroah.com, gregkh@linuxfoundation.org, linuxppc-dev@ozlabs.org, mauricfo@linux.vnet.ibm.com, mpe@ellerman.id.au, tglx@linutronix.de Cc: From: Date: Wed, 23 May 2018 19:23:13 +0200 In-Reply-To: <20180522144125.10345-13-mpe@ellerman.id.au> Message-ID: <152709619317274@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This is a note to let you know that I've just added the patch titled powerpc/pseries: Fix clearing of security feature flags to the 4.16-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-pseries-fix-clearing-of-security-feature-flags.patch and it can be found in the queue-4.16 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Wed May 23 19:18:22 CEST 2018 From: Michael Ellerman Date: Wed, 23 May 2018 00:41:23 +1000 Subject: powerpc/pseries: Fix clearing of security feature flags To: greg@kroah.com Cc: stable@vger.kernel.org, tglx@linutronix.de, linuxppc-dev@ozlabs.org Message-ID: <20180522144125.10345-13-mpe@ellerman.id.au> From: Mauricio Faria de Oliveira commit 0f9bdfe3c77091e8704d2e510eb7c2c2c6cde524 upstream. The H_CPU_BEHAV_* flags should be checked for in the 'behaviour' field of 'struct h_cpu_char_result' -- 'character' is for H_CPU_CHAR_* flags. Found by playing around with QEMU's implementation of the hypercall: H_CPU_CHAR=0xf000000000000000 H_CPU_BEHAV=0x0000000000000000 This clears H_CPU_BEHAV_FAVOUR_SECURITY and H_CPU_BEHAV_L1D_FLUSH_PR so pseries_setup_rfi_flush() disables 'rfi_flush'; and it also clears H_CPU_CHAR_L1D_THREAD_PRIV flag. So there is no RFI flush mitigation at all for cpu_show_meltdown() to report; but currently it does: Original kernel: # cat /sys/devices/system/cpu/vulnerabilities/meltdown Mitigation: RFI Flush Patched kernel: # cat /sys/devices/system/cpu/vulnerabilities/meltdown Not affected H_CPU_CHAR=0x0000000000000000 H_CPU_BEHAV=0xf000000000000000 This sets H_CPU_BEHAV_BNDS_CHK_SPEC_BAR so cpu_show_spectre_v1() should report vulnerable; but currently it doesn't: Original kernel: # cat /sys/devices/system/cpu/vulnerabilities/spectre_v1 Not affected Patched kernel: # cat /sys/devices/system/cpu/vulnerabilities/spectre_v1 Vulnerable Brown-paper-bag-by: Michael Ellerman Fixes: f636c14790ea ("powerpc/pseries: Set or clear security feature flags") Signed-off-by: Mauricio Faria de Oliveira Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/platforms/pseries/setup.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/arch/powerpc/platforms/pseries/setup.c +++ b/arch/powerpc/platforms/pseries/setup.c @@ -484,13 +484,13 @@ static void init_cpu_char_feature_flags( * The features below are enabled by default, so we instead look to see * if firmware has *disabled* them, and clear them if so. */ - if (!(result->character & H_CPU_BEHAV_FAVOUR_SECURITY)) + if (!(result->behaviour & H_CPU_BEHAV_FAVOUR_SECURITY)) security_ftr_clear(SEC_FTR_FAVOUR_SECURITY); - if (!(result->character & H_CPU_BEHAV_L1D_FLUSH_PR)) + if (!(result->behaviour & H_CPU_BEHAV_L1D_FLUSH_PR)) security_ftr_clear(SEC_FTR_L1D_FLUSH_PR); - if (!(result->character & H_CPU_BEHAV_BNDS_CHK_SPEC_BAR)) + if (!(result->behaviour & H_CPU_BEHAV_BNDS_CHK_SPEC_BAR)) security_ftr_clear(SEC_FTR_BNDS_CHK_SPEC_BAR); } Patches currently in stable-queue which might be from mpe@ellerman.id.au are queue-4.16/powerpc-pseries-fix-clearing-of-security-feature-flags.patch queue-4.16/powerpc-powernv-set-or-clear-security-feature-flags.patch queue-4.16/powerpc-64s-move-cpu_show_meltdown.patch queue-4.16/powerpc-pseries-set-or-clear-security-feature-flags.patch queue-4.16/powerpc-move-default-security-feature-flags.patch queue-4.16/powerpc-powernv-use-the-security-flags-in-pnv_setup_rfi_flush.patch queue-4.16/powerpc-add-security-feature-flags-for-spectre-meltdown.patch queue-4.16/powerpc-pseries-use-the-security-flags-in-pseries_setup_rfi_flush.patch queue-4.16/powerpc-64s-enhance-the-information-in-cpu_show_meltdown.patch queue-4.16/powerpc-rfi-flush-always-enable-fallback-flush-on-pseries.patch queue-4.16/powerpc-pseries-add-new-h_get_cpu_characteristics-flags.patch queue-4.16/powerpc-64s-add-support-for-a-store-forwarding-barrier-at-kernel-entry-exit.patch queue-4.16/powerpc-64s-wire-up-cpu_show_spectre_v1.patch queue-4.16/powerpc-64s-wire-up-cpu_show_spectre_v2.patch