linux-kernel - Re: [PATCH v15 07/14] firmware: psci: Implement vendor-specific resets as reboot-mode

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

Message-ID: <9ba7562f-bf6a-4759-b4a3-aaa80c45e247@oss.qualcomm.com>
Date: Thu, 9 Oct 2025 09:44:51 +0530
From: Umang Chheda <umang.chheda@....qualcomm.com>
To: Shivendra Pratap <shivendra.pratap@....qualcomm.com>,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Sebastian Reichel <sre@...nel.org>, Rob Herring <robh@...nel.org>,
        Sudeep Holla <sudeep.holla@....com>,
        Souvik Chakravarty <Souvik.Chakravarty@....com>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
 <conor+dt@...nel.org>,
        Andy Yan <andy.yan@...k-chips.com>,
        Mark Rutland <mark.rutland@....com>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Arnd Bergmann <arnd@...db.de>, Konrad Dybcio <konradybcio@...nel.org>,
        cros-qcom-dts-watchers@...omium.org, Vinod Koul <vkoul@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Florian Fainelli <florian.fainelli@...adcom.com>,
        Moritz Fischer <moritz.fischer@...us.com>,
        John Stultz <john.stultz@...aro.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Krzysztof Kozlowski <krzk@...nel.org>
Cc: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
        Mukesh Ojha <mukesh.ojha@....qualcomm.com>,
        Stephen Boyd <swboyd@...omium.org>,
        Andre Draszik
 <andre.draszik@...aro.org>,
        Kathiravan Thirumoorthy <kathiravan.thirumoorthy@....qualcomm.com>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org,
        Elliot Berman <quic_eberman@...cinc.com>,
        Srinivas Kandagatla <srini@...nel.org>
Subject: Re: [PATCH v15 07/14] firmware: psci: Implement vendor-specific
 resets as reboot-mode


On 9/22/2025 7:10 PM, Shivendra Pratap wrote:
> SoC vendors have different types of resets which are controlled
> through various hardware registers. For instance, Qualcomm SoC
> may have a requirement that reboot with “bootloader” command
> should reboot the device to bootloader flashing mode and reboot
> with “edl” should reboot the device into Emergency flashing mode.
> Setting up such reboots on Qualcomm devices can be inconsistent
> across SoC platforms and may require setting different HW
> registers, where some of these registers may not be accessible to
> HLOS. These knobs evolve over product generations and require
> more drivers. PSCI spec defines, SYSTEM_RESET2, vendor-specific
> reset which can help align this requirement. Add support for PSCI
> SYSTEM_RESET2, vendor-specific resets and align the implementation
> to allow user-space initiated reboots to trigger these resets.
> 
> Implement the PSCI vendor-specific resets by registering to the
> reboot-mode framework. As psci init is done at early kernel init,
> reboot-mode registration cannot be done at the time of psci init.
> This is because reboot-mode creates a “reboot-mode” class for
> exposing sysfs, which can fail at early kernel init. To overcome
> this, introduce a late_initcall to register PSCI vendor-specific
> resets as reboot modes. Implement a reboot-mode write function
> that sets reset_type and cookie values during the reboot notifier
> callback.  Introduce a firmware-based call for SYSTEM_RESET2
> vendor-specific reset in the psci_sys_reset path, using
> reset_type and cookie if supported by secure firmware. Register a
> panic notifier and clear vendor_reset valid status during panic.
> This is needed for any kernel panic that occurs post
> reboot_notifiers.
> 
> By using the above implementation, userspace will be able to issue
> such resets using the reboot() system call with the "*arg"
> parameter as a string based command. The commands can be defined
> in PSCI device tree node under “reboot-mode” and are based on the
> reboot-mode based commands.
> 
> Signed-off-by: Shivendra Pratap <shivendra.pratap@....qualcomm.com>
> ---
>  drivers/firmware/psci/Kconfig |  2 +
>  drivers/firmware/psci/psci.c  | 89 ++++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 90 insertions(+), 1 deletion(-)
> 

Reviewed-by: Umang Chheda <umang.chheda@....qualcomm.com>

Thanks,
Umang