linux-kernel - Re: [PATCH] gpio: pca953x: Improve interrupt support

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: <CAHN=yaaZ3L23JbsQ+fugG-iXdtt9dOss0pe7yT5EG029nsfXFQ@mail.gmail.com>
Date: Tue, 21 Jan 2025 11:11:55 +0100
From: lakabd <lakabd.work@...il.com>
To: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: mark.tomlinson@...iedtelesis.co.nz, brgl@...ev.pl, 
	linus.walleij@...aro.org, linux-gpio@...r.kernel.org, 
	linux-kernel@...r.kernel.org, Abderrahim LAKBIR <abderrahim.lakbir@...ia.fr>
Subject: Re: [PATCH] gpio: pca953x: Improve interrupt support

Le mar. 14 janv. 2025 à 16:44, work work <lakabd.work@...il.com> a écrit :
>
> Le mar. 14 janv. 2025 à 10:37, Andy Shevchenko
> <andy.shevchenko@...il.com> a écrit :
> >
> > On Tue, Jan 14, 2025 at 12:03 AM lakabd <lakabd.work@...il.com> wrote:
> > >
> ....
>
> > > +                             /* Store irq_mask for later use when checking pending IRQs */
> > > +                             bitmap_or(chip->unmasked_interrupts, chip->unmasked_interrupts, chip->irq_mask, gc->ngpio);
> >
> > This solution has a flaw. Where is any code that clears this new
> > bitmap? The code starts with 0 (obviously) and step by step it gets
> > saturated to all-1s.
> >
>
> Yes indeed, and actually the new bitmap is not necessary at all
> because what we need does already exist which is chip->irq_mask (I
> noticed it just now!).
> chip->irq_mask is updated whenever a pin is masked or unmasked via
> pca953x_irq_mask() and pca953x_irq_unmask().
>
> The solution should look like this:
>
> diff --git a/gpio-pca953x.c b/gpio-pca953x.c
> index 272febc..29e8c20 100644
> --- a/gpio-pca953x.c
> +++ b/gpio-pca953x.c
> @@ -842,11 +842,6 @@ static bool pca953x_irq_pending(struct
> pca953x_chip *chip, unsigned long *pendin
>   int ret;
>
>   if (chip->driver_data & PCA_PCAL) {
> - /* Read the current interrupt status from the device */
> - ret = pca953x_read_regs(chip, PCAL953X_INT_STAT, trigger);
> - if (ret)
> - return false;
> -
>   /* Check latched inputs and clear interrupt status */
>   ret = pca953x_read_regs(chip, chip->regs->input, cur_stat);
>   if (ret)
> @@ -855,7 +850,7 @@ static bool pca953x_irq_pending(struct
> pca953x_chip *chip, unsigned long *pendin
>   /* Apply filter for rising/falling edge selection */
>   bitmap_replace(new_stat, chip->irq_trig_fall, chip->irq_trig_raise,
> cur_stat, gc->ngpio);
>
> - bitmap_and(pending, new_stat, trigger, gc->ngpio);
> + bitmap_and(pending, new_stat, chip->irq_mask, gc->ngpio);
>
>   return !bitmap_empty(pending, gc->ngpio);
>   }
>

Hi Andy, do you have any other suggestions regarding the proposed fix ?

--
Best Regards
Abderrahim LAKBIR