Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752556Ab2HMQPt (ORCPT ); Mon, 13 Aug 2012 12:15:49 -0400 Received: from e35.co.us.ibm.com ([32.97.110.153]:43889 "EHLO e35.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752491Ab2HMQPq (ORCPT ); Mon, 13 Aug 2012 12:15:46 -0400 Message-ID: <1344874518.4430.12.camel@footlong> Subject: Re: [PATCH V2 3/3] drivers/char/tpm: Add securityfs support for event log From: Ashley Lai To: Michael Ellerman Cc: linux-kernel@vger.kernel.org, rcj@linux.vnet.ibm.com, linux-security-module@vger.kernel.org, tpmdd-devel@lists.sourceforge.net, adlai@us.ibm.com, key@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org Date: Mon, 13 Aug 2012 11:15:18 -0500 In-Reply-To: <1344583401.27290.15.camel@concordia> References: <1344553253.28791.7.camel@footlong> <1344553986.28791.13.camel@footlong> <1344583401.27290.15.camel@concordia> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.2- Content-Transfer-Encoding: 7bit Mime-Version: 1.0 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12081316-6148-0000-0000-00000893DED7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6363 Lines: 221 Thank you so much for reviewing the code. Please see my reply below. On Fri, 2012-08-10 at 17:23 +1000, Michael Ellerman wrote: > On Thu, 2012-08-09 at 18:13 -0500, Ashley Lai wrote: > > This patch retrieves the event log data from the device tree > > during file open. The event log data will then displayed through > > securityfs. > > Hi Ashley, > > Comments inline .. > > > diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile > > index 547509d..b53da57 100644 > > --- a/drivers/char/tpm/Makefile > > +++ b/drivers/char/tpm/Makefile > > @@ -2,9 +2,15 @@ > > # Makefile for the kernel tpm device drivers. > > # > > obj-$(CONFIG_TCG_TPM) += tpm.o > > +obj-$(CONFIG_TCG_TPM) += tpm_bios.o > > ifdef CONFIG_ACPI > > - obj-$(CONFIG_TCG_TPM) += tpm_bios.o > > tpm_bios-objs += tpm_eventlog.o tpm_acpi.o > > +else > > +ifdef CONFIG_TCG_IBMVTPM > > + tpm_bios-objs += tpm_eventlog.o tpm_of.o > > +else > > + tpm_bios-objs += tpm_eventlog.o tpm_noeventlog.o > > What does it mean to build tpm_eventlog and tpm_noeventlog ? This is the case where the event log is not available. I agree it does not look clean. I'm thinking of moving tpm_noeventlog into header file to eliminate this file. > > > > > diff --git a/drivers/char/tpm/tpm_eventlog.h b/drivers/char/tpm/tpm_eventlog.h > > index 8e23ccd..21ac6af 100644 > > --- a/drivers/char/tpm/tpm_eventlog.h > > +++ b/drivers/char/tpm/tpm_eventlog.h > > @@ -68,4 +68,18 @@ enum tcpa_pc_event_ids { > > }; > > > > int read_log(struct tpm_bios_log *log); > > + > > +extern struct dentry **tpm_bios_log_setup(char *); > > +extern void tpm_bios_log_teardown(struct dentry **); > > + > > +#ifdef CONFIG_PPC64 > > +#define TPM_NO_EVENT_LOG !of_find_node_by_name(NULL, "ibm,vtpm") > > +#else > > +#ifdef CONFIG_ACPI > > +#define TPM_NO_EVENT_LOG 0 > > +#else > > +#define TPM_NO_EVENT_LOG 1 > > +#endif > > +#endif > > This should be a static inline, with the ifdefs inside. I just realized that it does not need to call of_find_node_by_name() here because if ibm,vtpm is not there it does not go to probe. Thanks for pointing this out. > > How often is this called? of_find_node_by_name() is not particularly > efficient. It might be better to search once and save a flag indicating > whether you found it. This is called during load and unload of the driver. I'll remove the call to of_find_node_by_name() in next version. See above. > > Also you must call of_node_put() on the result of > of_find_node_by_name(), so at the least you must do: Nice catch!!! I will fix other places in the code in the next version. > > struct device_node *np; > np = of_find_node_by_name(NULL, "ibm,vtpm"); > of_node_put(np); > return (np != NULL); > > > #endif > > diff --git a/drivers/char/tpm/tpm_noeventlog.c b/drivers/char/tpm/tpm_noeventlog.c > > new file mode 100644 > > index 0000000..f30a2bf > > --- /dev/null > > +++ b/drivers/char/tpm/tpm_noeventlog.c > > @@ -0,0 +1,21 @@ > > +/* > > + * Copyright (C) 2012 IBM Corporation > ^^ > Don't use (C) Will remove it. > > > + * > > + * Author: Ashley Lai > > + * > > + * Maintained by: > > + * > > + * This program is free software; you can redistribute it and/or > > + * modify it under the terms of the GNU General Public License > > + * as published by the Free Software Foundation; either version > > + * 2 of the License, or (at your option) any later version. > > + * > > + */ > > + > > +#include > > +#include "tpm_eventlog.h" > > + > > +int read_log(struct tpm_bios_log *log) > > +{ > > + return -EINVAL; > > +} > > Wouldn't it be simpler to put this in a header with the appropriate > ifdefs, and then you'd need less logic in the Makefile? Will move this to header file. Thanks. > > > > diff --git a/drivers/char/tpm/tpm_of.c b/drivers/char/tpm/tpm_of.c > > new file mode 100644 > > index 0000000..6d44adb > > --- /dev/null > > +++ b/drivers/char/tpm/tpm_of.c > > @@ -0,0 +1,68 @@ > > +/* > > + * Copyright 2012 IBM Corporation > > + * > > + * Author: Ashley Lai > > + * > > + * Maintained by: > > + * > > + * Read the event log created by the firmware on PPC64 > > + * > > + * This program is free software; you can redistribute it and/or > > + * modify it under the terms of the GNU General Public License > > + * as published by the Free Software Foundation; either version > > + * 2 of the License, or (at your option) any later version. > > + * > > + */ > > + > > +#include > > +#include > > + > > +#include "tpm.h" > > +#include "tpm_eventlog.h" > > + > > +int read_log(struct tpm_bios_log *log) > > +{ > > + struct device_node *np; > > + const u32 *sizep; > > + const __be64 *basep; > > + > > + if (log->bios_event_log != NULL) { > > + pr_err("%s: ERROR - Eventlog already initialized\n", __func__); > > + return -EFAULT; > > + } > > + > > + np = of_find_node_by_name(NULL, "ibm,vtpm"); > > + if (!np) { > > + pr_err("%s: ERROR - IBMVTPM not supported\n", __func__); > > + return -ENODEV; > > + } > > All your return paths below here must call of_node_put(np). I'll fix it in next version. Thanks. > > > + sizep = of_get_property(np, "linux,sml-size", NULL); > > + if (sizep == NULL) { > > + pr_err("%s: ERROR - SML size not found\n", __func__); > > + return -EIO; > > + } > > + if (*sizep == 0) { > > + pr_err("%s: ERROR - event log area empty\n", __func__); > > + return -EIO; > > + } > > + > > + basep = of_get_property(np, "linux,sml-base", NULL); > > + if (basep == NULL) { > > + pr_err(KERN_ERR "%s: ERROR - SML not found\n", __func__); > > + return -EIO; > > + } > > + > > + log->bios_event_log = kmalloc(*sizep, GFP_KERNEL); > > + if (!log->bios_event_log) { > > + pr_err("%s: ERROR - Not enough memory for BIOS measurements\n", > > + __func__); > > + return -ENOMEM; > > + } > > + > > + log->bios_event_log_end = log->bios_event_log + *sizep; > > + > > + memcpy(log->bios_event_log, __va(be64_to_cpup(basep)), *sizep); > > + > > + return 0; > > +} > > > cheers > -- 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/