Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757569Ab3JJPuH (ORCPT ); Thu, 10 Oct 2013 11:50:07 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:53011 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757521Ab3JJPt7 (ORCPT ); Thu, 10 Oct 2013 11:49:59 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Madhavan Srinivasan , Benjamin Herrenschmidt , Kamal Mostafa Subject: [PATCH 099/104] powerpc/sysfs: Disable writing to PURR in guest mode Date: Thu, 10 Oct 2013 08:42:27 -0700 Message-Id: <1381419752-29733-100-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1381419752-29733-1-git-send-email-kamal@canonical.com> References: <1381419752-29733-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2617 Lines: 79 3.8.13.11 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Madhavan Srinivasan commit d1211af3049f4c9c1d8d4eb8f8098cc4f4f0d0c7 upstream. arch/powerpc/kernel/sysfs.c exports PURR with write permission. This may be valid for kernel in phyp mode. But writing to the file in guest mode causes crash due to a priviledge violation Signed-off-by: Madhavan Srinivasan Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Kamal Mostafa --- arch/powerpc/kernel/sysfs.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c index 3ce1f86..62eec1e 100644 --- a/arch/powerpc/kernel/sysfs.c +++ b/arch/powerpc/kernel/sysfs.c @@ -17,6 +17,7 @@ #include #include #include +#include #include "cacheinfo.h" @@ -179,15 +180,25 @@ SYSFS_PMCSETUP(spurr, SPRN_SPURR); SYSFS_PMCSETUP(dscr, SPRN_DSCR); SYSFS_PMCSETUP(pir, SPRN_PIR); +/* + Lets only enable read for phyp resources and + enable write when needed with a separate function. + Lets be conservative and default to pseries. +*/ static DEVICE_ATTR(mmcra, 0600, show_mmcra, store_mmcra); static DEVICE_ATTR(spurr, 0600, show_spurr, NULL); static DEVICE_ATTR(dscr, 0600, show_dscr, store_dscr); -static DEVICE_ATTR(purr, 0600, show_purr, store_purr); +static DEVICE_ATTR(purr, 0400, show_purr, store_purr); static DEVICE_ATTR(pir, 0400, show_pir, NULL); unsigned long dscr_default = 0; EXPORT_SYMBOL(dscr_default); +static void add_write_permission_dev_attr(struct device_attribute *attr) +{ + attr->attr.mode |= 0200; +} + static ssize_t show_dscr_default(struct device *dev, struct device_attribute *attr, char *buf) { @@ -394,8 +405,11 @@ static void __cpuinit register_cpu_online(unsigned int cpu) if (cpu_has_feature(CPU_FTR_MMCRA)) device_create_file(s, &dev_attr_mmcra); - if (cpu_has_feature(CPU_FTR_PURR)) + if (cpu_has_feature(CPU_FTR_PURR)) { + if (!firmware_has_feature(FW_FEATURE_LPAR)) + add_write_permission_dev_attr(&dev_attr_purr); device_create_file(s, &dev_attr_purr); + } if (cpu_has_feature(CPU_FTR_SPURR)) device_create_file(s, &dev_attr_spurr); -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/