linux-kernel - [PATCH v6 0/5] mfd: tps6586x: register restart handler

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 linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230327-tegra-pmic-reboot-v6-0-af44a4cd82e9@skidata.com>
Date:   Tue, 09 May 2023 21:02:58 +0200
From:   Benjamin Bara <bbara93@...il.com>
To:     Wolfram Sang <wsa@...nel.org>, Lee Jones <lee@...nel.org>,
        rafael.j.wysocki@...el.com
Cc:     dmitry.osipenko@...labora.com, peterz@...radead.org,
        jonathanh@...dia.com, richard.leitner@...ux.dev,
        treding@...dia.com, linux-kernel@...r.kernel.org,
        linux-i2c@...r.kernel.org, linux-tegra@...r.kernel.org,
        Benjamin Bara <benjamin.bara@...data.com>,
        stable@...r.kernel.org
Subject: [PATCH v6 0/5] mfd: tps6586x: register restart handler

Hi!

The Tegra20 requires an enabled VDE power domain during startup. As the
VDE is currently not used, it is disabled during runtime.
Since 8f0c714ad9be, there is a workaround for the "normal restart path"
which enables the VDE before doing PMC's warm reboot. This workaround is
not executed in the "emergency restart path", leading to a hang-up
during start.

This series implements and registers a new pmic-based restart handler
for boards with tps6586x. This cold reboot ensures that the VDE power
domain is enabled during startup on tegra20-based boards.

Since bae1d3a05a8b, i2c transfers are non-atomic while preemption is
disabled (which is e.g. done during panic()). This could lead to
warnings ("Voluntary context switch within RCU") in i2c-based restart
handlers during emergency restart. The state of preemption should be
detected by i2c_in_atomic_xfer_mode() to use atomic i2c xfer when
required. Beside the new system_state check, the check is the same as
the one pre v5.2.

v5: https://lore.kernel.org/r/20230327-tegra-pmic-reboot-v5-0-ab090e03284d@skidata.com

v6:
- drop 4/6 to abort restart on unexpected failure (suggested by Dmitry)
- 4,5: fix comments in handlers (suggested by Lee)
- 4,5: same delay for both handlers (suggested by Lee)

v5:
- introduce new 3 & 4, therefore 3 -> 5, 4 -> 6
- 3: provide dev to sys_off handler, if it is known
- 4: return NOTIFY_DONE from sys_off_notify, to avoid skipping
- 5: drop Reviewed-by from Dmitry, add poweroff timeout
- 5,6: return notifier value instead of direct errno from handler
- 5,6: use new dev field instead of passing dev as cb_data
- 5,6: increase timeout values based on error observations
- 6: skip unsupported reboot modes in restart handler

---
Benjamin Bara (5):
      kernel/reboot: emergency_restart: set correct system_state
      i2c: core: run atomic i2c xfer when !preemptible
      kernel/reboot: add device to sys_off_handler
      mfd: tps6586x: use devm-based power off handler
      mfd: tps6586x: register restart handler

 drivers/i2c/i2c-core.h |  2 +-
 drivers/mfd/tps6586x.c | 55 ++++++++++++++++++++++++++++++++++++++++++--------
 include/linux/reboot.h |  3 +++
 kernel/reboot.c        |  4 ++++
 4 files changed, 55 insertions(+), 9 deletions(-)
---
base-commit: 197b6b60ae7bc51dd0814953c562833143b292aa
change-id: 20230327-tegra-pmic-reboot-4175ff814a4b

Best regards,
-- 
Benjamin Bara <benjamin.bara@...data.com>