Messages in this thread | | | From | Linus Walleij <> | Date | Thu, 4 Oct 2018 10:34:03 +0200 | Subject | Re: protected pins and debugfs |
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On Wed, Oct 3, 2018 at 2:38 PM Sodagudi Prasad <psodagud@codeaurora.org> wrote:
> This is regarding the protected pins configuration reading and printing > from non-secure operating systems.
I do not think anyone with security in mind should have debugfs enabled. But maybe that is beside the point.
> GPIO framework is checking whether pin is in use(flag FLAG_REQUESTED) or > not in gpiolib_dbg_show(). > > If GPIO chip drivers are overriding the dbg_show callback, drivers are > not checking whether a pin is really in use or not to print > configuration details. > if (chip->dbg_show) > chip->dbg_show(s, chip); > else > gpiolib_dbg_show(s, gdev);
Ah that is right. Because some drivers can inspect all pins whether they are requested or not.
> Can we use a simple/common solution like below? It will check whether a > pin is in use or not before printing configuration data with the help of > gpiochip_is_requested().
In the msm case I think maybe you want to inspect the valid_mask instead, so you display debugfs info for all pins you can inspect in hardware but avoid the "invalid" ones which I half-guess is used by ACPI in your case.
Yours, Linus Walleij
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