Re: [PATCH] platform_driver_register: warn if probe is in .init.text
From: Dmitry Torokhov
Date: Fri Jan 22 2010 - 18:49:52 EST
On Fri, Jan 22, 2010 at 08:49:18PM +0100, Uwe Kleine-König wrote:
> +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.
> + */
What about CONFIG_MODULE case (without hotplug)? The driver may be
compiled in (and thus probe will be discarded) but device might be
created by a loadable module which is loaded later.
> + 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);
> + /*
> + * 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);
It really depends on the user's (or rather builder's) local
configuration so how can we make this suggestion?
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