From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Luis R. Rodriguez" Subject: [PATCH 5/5] firmware: add DECLARE_FW_CUSTOM_FALLBACK() annotation Date: Mon, 12 Dec 2016 19:08:28 -0800 Message-ID: <20161213030828.17820-6-mcgrof@kernel.org> References: <20161213030828.17820-1-mcgrof@kernel.org> Return-path: In-Reply-To: <20161213030828.17820-1-mcgrof@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: gregkh@linuxfoundation.org, ming.lei@canonical.com Cc: daniel.wagner@bmw-carit.de, teg@jklm.no, mchehab@osg.samsung.com, zajec5@gmail.com, linux-kernel@vger.kernel.org, markivx@codeaurora.org, stephen.boyd@linaro.org, broonie@kernel.org, zohar@linux.vnet.ibm.com, tiwai@suse.de, johannes@sipsolutions.net, chunkeey@googlemail.com, hauke@hauke-m.de, jwboyer@fedoraproject.org, dmitry.torokhov@gmail.com, dwmw2@infradead.org, jslaby@suse.com, torvalds@linux-foundation.org, luto@amacapital.net, fengguang.wu@intel.com, rpurdie@rpsys.net, j.anaszewski@samsung.com, Abhay_Salunke@dell.com, Julia.Lawall@lip6.fr, Gilles.Muller@lip6.fr, nicolas.palix@imag.fr, dhowells@redhat.com, bjorn.andersson@linaro.org, arend.vanspriel@broadcom.com, kvalo@codeaurora.org, "Luis R. Rodriguez" , linux-leds@vger.kernel.org List-Id: linux-leds@vger.kernel.org We need to ensure that when driver developers use the custom firmware fallback mechanism it was not a copy and paste bug. These use cases on upstream drivers are rare, we only have 2 upstream users and its for really old drivers. Since valid uses are rare but possible enable a white-list for its use, and use this same white-list annotation to refer to the documentation covering the custom use case. New faulty users can be reported via 0-day now. Cc: Fengguang Wu Cc: Richard Purdie Cc: Jacek Anaszewski Cc: linux-leds@vger.kernel.org Cc: Abhay Salunke Signed-off-by: Luis R. Rodriguez --- Documentation/driver-api/firmware/fallback-mechanisms.rst | 7 +++++-- drivers/firmware/dell_rbu.c | 1 + drivers/leds/leds-lp55xx-common.c | 1 + include/linux/firmware.h | 7 +++++++ scripts/coccinelle/api/request_firmware-custom-fallback.cocci | 9 ++++++++- 5 files changed, 22 insertions(+), 3 deletions(-) diff --git a/Documentation/driver-api/firmware/fallback-mechanisms.rst b/Documentation/driver-api/firmware/fallback-mechanisms.rst index 955c11d6ff9d..b51673e40439 100644 --- a/Documentation/driver-api/firmware/fallback-mechanisms.rst +++ b/Documentation/driver-api/firmware/fallback-mechanisms.rst @@ -184,8 +184,11 @@ load firmware for you through a custom path. The custom fallback mechanism can often be enabled by mistake. We currently have only 2 users of it, and little justification to enable it for other users. -Since it is a common driver developer mistake to enable it, help police for -new users of the custom fallback mechanism with:: +Since it is a common driver developer mistake to enable it, driver developers +should use DECLARE_FW_CUSTOM_FALLBACK() to both white-list and validate their +use and also refer to the documentation for the custom loading solution. + +Invalid users of the custom fallback mechanism can be policed using:: $ export COCCI=scripts/coccinelle/api/request_firmware-avoid-init-probe-init.cocci $ make coccicheck MODE=report diff --git a/drivers/firmware/dell_rbu.c b/drivers/firmware/dell_rbu.c index 2f452f1f7c8a..3f2aa35bc54d 100644 --- a/drivers/firmware/dell_rbu.c +++ b/drivers/firmware/dell_rbu.c @@ -586,6 +586,7 @@ static ssize_t read_rbu_image_type(struct file *filp, struct kobject *kobj, return size; } +DECLARE_FW_CUSTOM_FALLBACK("Documentation/dell_rbu.txt"); static ssize_t write_rbu_image_type(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buffer, loff_t pos, size_t count) diff --git a/drivers/leds/leds-lp55xx-common.c b/drivers/leds/leds-lp55xx-common.c index 5377f22ff994..04161428ee3b 100644 --- a/drivers/leds/leds-lp55xx-common.c +++ b/drivers/leds/leds-lp55xx-common.c @@ -219,6 +219,7 @@ static void lp55xx_firmware_loaded(const struct firmware *fw, void *context) release_firmware(chip->fw); } +DECLARE_FW_CUSTOM_FALLBACK("Documentation/leds/leds-lp55xx.txt"); static int lp55xx_request_firmware(struct lp55xx_chip *chip) { const char *name = chip->cl->name; diff --git a/include/linux/firmware.h b/include/linux/firmware.h index b1f9f0ccb8ac..e6ca19c03dcc 100644 --- a/include/linux/firmware.h +++ b/include/linux/firmware.h @@ -8,6 +8,13 @@ #define FW_ACTION_NOHOTPLUG 0 #define FW_ACTION_HOTPLUG 1 +/* + * Helper for scripts/coccinelle/api/request_firmware-custom-fallback.cocci + * and so users can also easily search for the documentation for the + * respectively needed custom fallback mechanism. + */ +#define DECLARE_FW_CUSTOM_FALLBACK(__usermode_helper) + struct firmware { size_t size; const u8 *data; diff --git a/scripts/coccinelle/api/request_firmware-custom-fallback.cocci b/scripts/coccinelle/api/request_firmware-custom-fallback.cocci index c7598cfc4780..68cacab35b76 100644 --- a/scripts/coccinelle/api/request_firmware-custom-fallback.cocci +++ b/scripts/coccinelle/api/request_firmware-custom-fallback.cocci @@ -17,6 +17,13 @@ virtual report virtual context +@ r0 depends on report || context @ +declarer name DECLARE_FW_CUSTOM_FALLBACK; +expression E; +@@ + +DECLARE_FW_CUSTOM_FALLBACK(E); + @ r1 depends on report || context @ expression mod, name, dev, gfp, drv, cb; position p; @@ -30,7 +37,7 @@ position p; *request_firmware_nowait@p(mod, FW_ACTION_NOHOTPLUG, name, dev, gfp, drv, cb) ) -@script:python depends on report@ +@script:python depends on report && !r0 @ p << r1.p; @@ -- 2.10.1