From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754299AbdK2K2E (ORCPT ); Wed, 29 Nov 2017 05:28:04 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:56668 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752892AbdK2K2C (ORCPT ); Wed, 29 Nov 2017 05:28:02 -0500 Date: Wed, 29 Nov 2017 11:28:04 +0100 From: Greg KH To: "Luis R. Rodriguez" Cc: akpm@linux-foundation.org, keescook@chromium.org, mfuzzey@parkeon.com, zohar@linux.vnet.ibm.com, dhowells@redhat.com, pali.rohar@gmail.com, tiwai@suse.de, arend.vanspriel@broadcom.com, zajec5@gmail.com, nbroeking@me.com, markivx@codeaurora.org, stephen.boyd@linaro.org, broonie@kernel.org, dmitry.torokhov@gmail.com, dwmw2@infradead.org, torvalds@linux-foundation.org, Abhay_Salunke@dell.com, bjorn.andersson@linaro.org, jewalt@lgsinnovations.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v2 19/23] firmware: add debug facility to emulate forcing sysfs fallback Message-ID: <20171129102804.GA12916@kroah.com> References: <20171120182409.27348-1-mcgrof@kernel.org> <20171120182409.27348-20-mcgrof@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171120182409.27348-20-mcgrof@kernel.org> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 20, 2017 at 10:24:05AM -0800, Luis R. Rodriguez wrote: > The CONFIG_FW_LOADER_USER_HELPER_FALLBACK kernel config is not > enabled my major distros, however its known to be enabled on > some Android kernels. Testing the firmware API properly then > means to test at least two different kernel configurations. > > Since CONFIG_FW_LOADER_USER_HELPER_FALLBACK only does a simple > enablement under certain situations we can just emulate this > behaviour through a debugfs knob. This enables testing two of > the tree possible kernel configs with the firmware loader with > one kernel build. > > Signed-off-by: Luis R. Rodriguez > --- > drivers/base/Kconfig | 6 ++++++ > drivers/base/Makefile | 1 + > drivers/base/firmware_debug.c | 34 ++++++++++++++++++++++++++++++++ > drivers/base/firmware_debug.h | 44 ++++++++++++++++++++++++++++++++++++++++++ > drivers/base/firmware_loader.c | 13 ++++++++++++- > 5 files changed, 97 insertions(+), 1 deletion(-) > create mode 100644 drivers/base/firmware_debug.c > create mode 100644 drivers/base/firmware_debug.h > > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig > index 2f6614c9a229..ab6889ac6787 100644 > --- a/drivers/base/Kconfig > +++ b/drivers/base/Kconfig > @@ -149,6 +149,12 @@ config EXTRA_FIRMWARE_DIR > config FW_LOADER_USER_HELPER > bool > > +config FW_LOADER_DEBUG > + bool "Firmware loader debugging interface" > + help > + If you are hacking on the firmware API of the kernel, firmware_class, > + you can enable this to help debug the kernel. > + > config FW_LOADER_USER_HELPER_FALLBACK > bool "Fallback user-helper invocation for firmware loading" > depends on FW_LOADER > diff --git a/drivers/base/Makefile b/drivers/base/Makefile > index f261143fafbf..64eaa4f9cb02 100644 > --- a/drivers/base/Makefile > +++ b/drivers/base/Makefile > @@ -14,6 +14,7 @@ obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o > obj-$(CONFIG_ISA_BUS_API) += isa.o > obj-$(CONFIG_FW_LOADER) += firmware_class.o > firmware_class-objs := firmware_loader.o > +firmware_class-$(CONFIG_FW_LOADER_DEBUG) += firmware_debug.o > obj-$(CONFIG_NUMA) += node.o > obj-$(CONFIG_MEMORY_HOTPLUG_SPARSE) += memory.o > ifeq ($(CONFIG_SYSFS),y) > diff --git a/drivers/base/firmware_debug.c b/drivers/base/firmware_debug.c > new file mode 100644 > index 000000000000..f2817eb6f480 > --- /dev/null > +++ b/drivers/base/firmware_debug.c > @@ -0,0 +1,34 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* Firmware dubugging interface */ > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > + > +#include > +#include "firmware_debug.h" > + > +struct firmware_debug fw_debug; > + > +static struct dentry *debugfs_firmware; > + > +int __init register_fw_debugfs(void) > +{ > + debugfs_firmware = debugfs_create_dir("firmware", NULL); > + if (!debugfs_firmware) > + return -ENOMEM; You never need to check the return value of a debugfs call, you should not care about it, nor do anything different in your code. The value returned can always be passed back into any other debugfs call when needed. > + > + if (!debugfs_create_bool("force_sysfs_fallback", S_IRUSR | S_IWUSR, > + debugfs_firmware, > + &fw_debug.force_sysfs_fallback)) Same here, you don't care. > + goto err_out; > + > + return 0; > +err_out: > + debugfs_remove_recursive(debugfs_firmware); You didn't create any files, why recursive? Anyway, not needed. > + debugfs_firmware = NULL; > + return -ENOMEM; > +} > + > +void unregister_fw_debugfs(void) > +{ > + debugfs_remove_recursive(debugfs_firmware); > + debugfs_firmware = NULL; Why set this to NULL? > +} > diff --git a/drivers/base/firmware_debug.h b/drivers/base/firmware_debug.h > new file mode 100644 > index 000000000000..bc41bbca9a54 > --- /dev/null > +++ b/drivers/base/firmware_debug.h > @@ -0,0 +1,44 @@ > +// SPDX-License-Identifier: GPL-2.0 > +#ifndef __FIRMWARE_DEBUG_H > +#define __FIRMWARE_DEBUG_H > + > +#ifdef CONFIG_FW_LOADER_DEBUG > +/** > + * struct firmware_debug - firmware debugging configuration > + * > + * Provided to help debug the firmware API. > + * > + * @force_sysfs_fallback: force the sysfs fallback mechanism to be used > + * as if one had enabled CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y. > + * Useful to help debug a CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y > + * functionality on a kernel where that config entry has been disabled. > + */ > +struct firmware_debug { > + bool force_sysfs_fallback; > +}; > + > +extern struct firmware_debug fw_debug; > + > +int register_fw_debugfs(void); > +void unregister_fw_debugfs(void); > + > +static inline bool fw_debug_force_sysfs_fallback(void) > +{ > + return fw_debug.force_sysfs_fallback; > +} > +#else > +static inline int register_fw_debugfs(void) > +{ > + return 0; > +} > +static inline void unregister_fw_debugfs(void) > +{ > +} > + > +static inline bool fw_debug_force_sysfs_fallback(void) > +{ > + return false; > +} > +#endif /* CONFIG_FW_LOADER_DEBUG */ > + > +#endif /* __FIRMWARE_DEBUG_H */ > diff --git a/drivers/base/firmware_loader.c b/drivers/base/firmware_loader.c > index 43b97a8137f7..b2b52ba9f245 100644 > --- a/drivers/base/firmware_loader.c > +++ b/drivers/base/firmware_loader.c > @@ -36,6 +36,7 @@ > #include > > #include "base.h" > +#include "firmware_debug.h" > > MODULE_AUTHOR("Manuel Estrada Sainz"); > MODULE_DESCRIPTION("Multi purpose firmware loading support"); > @@ -1158,6 +1159,9 @@ static bool fw_force_sysfs_fallback(unsigned int opt_flags) > #else > static bool fw_force_sysfs_fallback(unsigned int opt_flags) > { > + if (fw_debug_force_sysfs_fallback()) > + return true; > + > if (!(opt_flags & FW_OPT_USERHELPER)) > return false; > return true; > @@ -1913,10 +1917,14 @@ static int __init firmware_class_init(void) > /* No need to unfold these on exit */ > fw_cache_init(); > > - ret = register_fw_pm_ops(); > + ret = register_fw_debugfs(); > if (ret) > return ret; Again you don't care about the state of debugfs. Did you test this on a system without CONFIG_DEBUGFS enabled? thanks, greg k-h