linux-kernel - Re: [PATCH v11 2/8] power: reset: reboot-mode: Add support for 64 bit magic

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: <8d4a42b6-657f-4c30-8e25-4213d8d53a89@lunn.ch>
Date: Sat, 19 Jul 2025 18:57:36 +0200
From: Andrew Lunn <andrew@...n.ch>
To: Shivendra Pratap <shivendra.pratap@....qualcomm.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@....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>,
	Mukesh Ojha <mukesh.ojha@....qualcomm.com>,
	Stephen Boyd <swboyd@...omium.org>,
	Andre Draszik <andre.draszik@...aro.org>, 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 v11 2/8] power: reset: reboot-mode: Add support for 64
 bit magic

> >> +static int qcom_pon_reboot_mode_write(struct reboot_mode_driver *reboot, u64 magic)
> >>  {
> >>  	struct qcom_pon *pon = container_of
> >>  			(reboot, struct qcom_pon, reboot_mode);
> >> @@ -37,7 +36,7 @@ static int qcom_pon_reboot_mode_write(struct reboot_mode_driver *reboot,
> >>  	ret = regmap_update_bits(pon->regmap,
> >>  				 pon->baseaddr + PON_SOFT_RB_SPARE,
> >>  				 GENMASK(7, pon->reason_shift),
> >> -				 magic << pon->reason_shift);
> >> +				 ((u32)magic) << pon->reason_shift);

As a general rule of thumb, code with casts is poor quality code. Try
to write the code without casts.

Maybe something like

      If (magic > MAX_U32)
      	   return -EINVAL;

      magic_32 = magic;

You might be able to go further, and validate that magic actually fits
into the field when you consider the << pon->reason_shift.

	Andrew