lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Thu, 17 Dec 2020 19:17:03 -0800
From:   Saravana Kannan <saravanak@...gle.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Saravana Kannan <saravanak@...gle.com>, kernel-team@...roid.com,
        linux-kernel@...r.kernel.org,
        Jisheng Zhang <Jisheng.Zhang@...aptics.com>,
        Kevin Hilman <khilman@...libre.com>,
        John Stultz <john.stultz@...aro.org>,
        Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
        Marc Zyngier <maz@...nel.org>
Subject: [PATCH v1 5/5] driver core: Set fw_devlink=on by default

Cyclic dependencies in some firmware was one of the last remaining
reasons fw_devlink=on couldn't be set by default. Now that cyclic
dependencies don't block probing, set fw_devlink=on by default.

Setting fw_devlink=on by default brings a bunch of benefits (currently,
only for systems with device tree firmware):
* Significantly cuts down deferred probes.
* Device probe is effectively attempted in graph order.
* Makes it much easier to load drivers as modules without having to
  worry about functional dependencies between modules (depmod is still
  needed for symbol dependencies).

If this patch prevents some devices from probing, it's very likely due
to the system having one or more device drivers that "probe"/set up a
device (DT node with compatible property) without creating a struct
device for it.  If we hit such cases, the device drivers need to be
fixed so that they populate struct devices and probe them like normal
device drivers so that the driver core is aware of the devices and their
status. See [1] for an example of such a case.

[1] - https://lore.kernel.org/lkml/CAGETcx9PiX==mLxB9PO8Myyk6u2vhPVwTMsA5NkD-ywH5xhusw@mail.gmail.com/
Signed-off-by: Saravana Kannan <saravanak@...gle.com>
---
 drivers/base/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 4cc030361165..803bfa6eb823 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1457,7 +1457,7 @@ static void device_links_purge(struct device *dev)
 #define FW_DEVLINK_FLAGS_RPM		(FW_DEVLINK_FLAGS_ON | \
 					 DL_FLAG_PM_RUNTIME)
 
-static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
+static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
 static int __init fw_devlink_setup(char *arg)
 {
 	if (!arg)
-- 
2.29.2.684.gfbc64c5ab5-goog

Powered by blists - more mailing lists