Re: [PATCH] platform_driver_register: warn if probe is in.init.text

From: Uwe Kleine-König
Date: Tue Jan 26 2010 - 03:47:51 EST


Hello,

On Mon, Jan 25, 2010 at 06:09:01AM +0900, OGAWA Hirofumi wrote:
> Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> writes:
>
> > +int platform_driver_register(struct platform_driver *drv)
> > +{
> > + int ret = __platform_driver_register(drv);
> > +
> > +#if defined(CONFIG_HOTPLUG)
> > + /*
> > + * drivers that are registered by platform_driver_register
> > + * should not have their probe function in .init.text. The
> > + * reason is that a probe can happen after .init.text is
> > + * discarded which then results in an oops. The alternatives
> > + * are using .devinit.text for the probe function or "register"
> > + * with platform_driver_probe.
> > + */
> > + if (drv->probe && kernel_init_text_address((unsigned long)drv->probe))
> > + pr_warning("oops-warning: probe function of platform driver %s"
> > + " lives in .init.text\n", drv->driver.name);
> > +#else
> > + /*
> > + * without HOTPLUG probe functions can be discarded after the driver is
> > + * loaded.
> > + * There is a little chance for false positives, namely if the driver is
> > + * registered after the .init sections are discarded.
> > + */
> > + if (drv->probe && !kernel_init_text_address((unsigned long)drv->probe))
> > + pr_info("probably the probe function of platform driver %s can"
> > + " be moved to .init.text\n", drv->driver.name);
> > +#endif
> > + return ret;
> > +}
>
> Um..., can't we extend modpost or such one for this? I think the static
> analysis is better (assume the changing ->probe dynamically is really
> rare).
I like the idea and will look later into modpost if this can be done
there.

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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