| 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
| ||
|
Message-ID: <CAPDyKFpsfzdarSz5h_XuyLbfXKCWPQdV5M+mOb_Q6GhhgzCXAA@mail.gmail.com>
Date: Mon, 6 Nov 2023 16:41:18 +0100
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Viresh Kumar <viresh.kumar@...aro.org>
Cc: Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
Stephen Boyd <sboyd@...nel.org>,
"Rafael J. Wysocki" <rafael@...nel.org>, linux-pm@...r.kernel.org,
Vincent Guittot <vincent.guittot@...aro.org>,
Stephan Gerhold <stephan.gerhold@...nkonzept.com>,
Konrad Dybcio <konrad.dybcio@...aro.org>,
Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2 1/3] OPP: Level zero is valid
On Mon, 30 Oct 2023 at 11:24, Viresh Kumar <viresh.kumar@...aro.org> wrote:
>
> The level zero can be used by some OPPs to drop performance state vote
> for the device. It is perfectly fine to allow the same.
>
> _set_opp_level() considers it as an invalid value currently and returns
> early.
>
> In order to support this properly, initialize the level field with
> U32_MAX, which denotes unused level field.
>
> Reported-by: Stephan Gerhold <stephan.gerhold@...nkonzept.com>
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>
Kind regards
Uffe
> ---
> drivers/opp/core.c | 24 ++++++++++++++++++++----
> drivers/opp/of.c | 8 +++++++-
> include/linux/pm_opp.h | 5 ++++-
> 3 files changed, 31 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/opp/core.c b/drivers/opp/core.c
> index 84f345c69ea5..f2e2aa07b431 100644
> --- a/drivers/opp/core.c
> +++ b/drivers/opp/core.c
> @@ -201,7 +201,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq_indexed);
> * @opp: opp for which level value has to be returned for
> *
> * Return: level read from device tree corresponding to the opp, else
> - * return 0.
> + * return U32_MAX.
> */
> unsigned int dev_pm_opp_get_level(struct dev_pm_opp *opp)
> {
> @@ -221,7 +221,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_level);
> * @index: index of the required opp
> *
> * Return: performance state read from device tree corresponding to the
> - * required opp, else return 0.
> + * required opp, else return U32_MAX.
> */
> unsigned int dev_pm_opp_get_required_pstate(struct dev_pm_opp *opp,
> unsigned int index)
> @@ -808,6 +808,14 @@ struct dev_pm_opp *dev_pm_opp_find_level_ceil(struct device *dev,
> struct dev_pm_opp *opp;
>
> opp = _find_key_ceil(dev, &temp, 0, true, _read_level, NULL);
> +
> + /* False match */
> + if (temp == OPP_LEVEL_UNSET) {
> + dev_err(dev, "%s: OPP levels aren't available\n", __func__);
> + dev_pm_opp_put(opp);
> + return ERR_PTR(-ENODEV);
> + }
> +
> *level = temp;
> return opp;
> }
> @@ -1049,12 +1057,18 @@ static int _set_opp_bw(const struct opp_table *opp_table,
> static int _set_performance_state(struct device *dev, struct device *pd_dev,
> struct dev_pm_opp *opp, int i)
> {
> - unsigned int pstate = likely(opp) ? opp->required_opps[i]->level: 0;
> + unsigned int pstate = 0;
> int ret;
>
> if (!pd_dev)
> return 0;
>
> + if (likely(opp)) {
> + pstate = opp->required_opps[i]->level;
> + if (pstate == OPP_LEVEL_UNSET)
> + return 0;
> + }
> +
> ret = dev_pm_domain_set_performance_state(pd_dev, pstate);
> if (ret) {
> dev_err(dev, "Failed to set performance state of %s: %d (%d)\n",
> @@ -1135,7 +1149,7 @@ static int _set_opp_level(struct device *dev, struct opp_table *opp_table,
> int ret = 0;
>
> if (opp) {
> - if (!opp->level)
> + if (opp->level == OPP_LEVEL_UNSET)
> return 0;
>
> level = opp->level;
> @@ -1867,6 +1881,8 @@ struct dev_pm_opp *_opp_allocate(struct opp_table *opp_table)
>
> INIT_LIST_HEAD(&opp->node);
>
> + opp->level = OPP_LEVEL_UNSET;
> +
> return opp;
> }
>
> diff --git a/drivers/opp/of.c b/drivers/opp/of.c
> index 81fa27599d58..85fad7ca0007 100644
> --- a/drivers/opp/of.c
> +++ b/drivers/opp/of.c
> @@ -1393,8 +1393,14 @@ int of_get_required_opp_performance_state(struct device_node *np, int index)
>
> opp = _find_opp_of_np(opp_table, required_np);
> if (opp) {
> - pstate = opp->level;
> + if (opp->level == OPP_LEVEL_UNSET) {
> + pr_err("%s: OPP levels aren't available for %pOF\n",
> + __func__, np);
> + } else {
> + pstate = opp->level;
> + }
> dev_pm_opp_put(opp);
> +
> }
>
> dev_pm_opp_put_opp_table(opp_table);
> diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
> index ccd97bcef269..af53101a1383 100644
> --- a/include/linux/pm_opp.h
> +++ b/include/linux/pm_opp.h
> @@ -92,9 +92,12 @@ struct dev_pm_opp_config {
> struct device ***virt_devs;
> };
>
> +#define OPP_LEVEL_UNSET U32_MAX
> +
> /**
> * struct dev_pm_opp_data - The data to use to initialize an OPP.
> - * @level: The performance level for the OPP.
> + * @level: The performance level for the OPP. Set level to OPP_LEVEL_UNSET if
> + * level field isn't used.
> * @freq: The clock rate in Hz for the OPP.
> * @u_volt: The voltage in uV for the OPP.
> */
> --
> 2.31.1.272.g89b43f80a514
>
Powered by blists - more mailing lists