Messages in this thread | | | Date | Fri, 21 Jul 2023 07:49:55 +0200 | From | Uwe Kleine-König <> | Subject | Re: [PATCH v6] pwm: atmel: Enable clk when pwm already enabled in bootloader |
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On Thu, Jul 20, 2023 at 05:12:30PM +0200, Thierry Reding wrote: > On Sun, Jul 16, 2023 at 10:06:52AM +0800, Guiting Shen wrote: > > +static int atmel_pwm_enable_clk_if_on(struct atmel_pwm_chip *atmel_pwm, bool on) > > +{ > > + unsigned int i, cnt = 0; > > + int ret = 0; > > + u32 sr; > > + > > + sr = atmel_pwm_readl(atmel_pwm, PWM_SR) & PWM_SR_ALL_CH_MASK; > > + if (!sr) > > + return 0; > > + > > + cnt = bitmap_weight((unsigned long *)&sr, atmel_pwm->chip.npwm); > > Tiny nit here: not sure if that cast is safe to do. You've got a 32-bit > variable, but if you cast &sr to unsigned long * on a 64-bit machine it > would cause hweight64() to get called and that would then read 64 bits > from a 32-bit variable. This probably works most of the time because we > don't read any of the upper bits, but it is strictly an illegal access > and could be unaligned as well.
While relevance of BE systems ceases slowly, such a machine would evaluate the wrong bits.
> Should we just turn sr into an unsigned long to be safe here?
yes please.
Best regards Uwe
-- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ | [unhandled content-type:application/pgp-signature] | |