On Wed, Oct 3, 2018 at 2:38 PM Sodagudi Prasad <psodagud@xxxxxxxxxxxxxx> 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
