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Date: Thu, 12 Jan 2017 06:42:50 -0800 From: "Luis R. Rodriguez" <mcgrof@...nel.org> To: gregkh@...uxfoundation.org, ming.lei@...onical.com Cc: bp@...en8.de, wagi@...om.org, teg@...m.no, mchehab@....samsung.com, zajec5@...il.com, linux-kernel@...r.kernel.org, markivx@...eaurora.org, stephen.boyd@...aro.org, broonie@...nel.org, zohar@...ux.vnet.ibm.com, tiwai@...e.de, johannes@...solutions.net, chunkeey@...glemail.com, hauke@...ke-m.de, jwboyer@...oraproject.org, dmitry.torokhov@...il.com, dwmw2@...radead.org, jslaby@...e.com, torvalds@...ux-foundation.org, luto@...capital.net, fengguang.wu@...el.com, rpurdie@...ys.net, j.anaszewski@...sung.com, Abhay_Salunke@...l.com, Julia.Lawall@...6.fr, Gilles.Muller@...6.fr, nicolas.palix@...g.fr, dhowells@...hat.com, bjorn.andersson@...aro.org, arend.vanspriel@...adcom.com, kvalo@...eaurora.org, "Luis R. Rodriguez" <mcgrof@...nel.org>, linux-leds@...r.kernel.org Subject: [PATCH v4 2/2] firmware: add DECLARE_FW_CUSTOM_FALLBACK() annotation 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. v2: change dependencies on rules make more sense, and fixed context mode Cc: Fengguang Wu <fengguang.wu@...el.com> Cc: Richard Purdie <rpurdie@...ys.net> Cc: Jacek Anaszewski <j.anaszewski@...sung.com> Cc: linux-leds@...r.kernel.org Cc: Abhay Salunke <Abhay_Salunke@...l.com> Acked-by: Jacek Anaszewski <j.anaszewski@...sung.com> Signed-off-by: Luis R. Rodriguez <mcgrof@...nel.org> --- 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 b87a292153c6..73f509a8d2de 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 0188d446b611..a1ed9d633441 100644 --- a/scripts/coccinelle/api/request_firmware-custom-fallback.cocci +++ b/scripts/coccinelle/api/request_firmware-custom-fallback.cocci @@ -15,7 +15,14 @@ virtual report virtual context -@ r1 depends on report || context @ +@ r0 depends on report || context @ +declarer name DECLARE_FW_CUSTOM_FALLBACK; +expression E; +@@ + +DECLARE_FW_CUSTOM_FALLBACK(E); + +@ r1 depends on !r0 && (report || context) @ expression mod, name, dev, gfp, drv, cb; position p; @@ -- 2.11.0
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