Commit 2c6370e6 authored by Ben Fradella's avatar Ben Fradella Committed by Hans de Goede
Browse files

platform/x86: p2sb: Don't init until unassigned resources have been assigned 



The P2SB could get an invalid BAR from the BIOS, and that won't be fixed
up until pcibios_assign_resources(), which is an fs_initcall().

- Move p2sb_fs_init() to an fs_initcall_sync(). This is still early
  enough to avoid a race with any dependent drivers.

- Add a check for IORESOURCE_UNSET in p2sb_valid_resource() to catch
  unset BARs going forward.

- Return error values from p2sb_fs_init() so that the 'initcall_debug'
  cmdline arg provides useful data.

Signed-off-by: default avatarBen Fradella <bfradell@netapp.com>
Acked-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: default avatarKlara Modin <klarasmodin@gmail.com>
Reviewed-by: default avatarShin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Link: https://lore.kernel.org/r/20240509164905.41016-1-bcfradella@proton.me


Reviewed-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
parent 7c4cd2af

drivers/platform/x86/p2sb.c

+15 −14
Original line number Diff line number Diff line
@@ -55,12 +55,9 @@ static void p2sb_get_devfn(unsigned int *devfn) 
	*devfn = fn;

}



static bool p2sb_valid_resource(struct resource *res)

static bool p2sb_valid_resource(const struct resource *res)

{

	if (res->flags)

		return true;



	return false;

	return res->flags & ~IORESOURCE_UNSET;

}



/* Copy resource from the first BAR of the device in question */
@@ -213,16 +210,20 @@ EXPORT_SYMBOL_GPL(p2sb_bar); 


static int __init p2sb_fs_init(void)

{

	p2sb_cache_resources();

	return 0;

	return p2sb_cache_resources();

}



/*

 * pci_rescan_remove_lock to avoid access to unhidden P2SB devices can

 * not be locked in sysfs pci bus rescan path because of deadlock. To

 * avoid the deadlock, access to P2SB devices with the lock at an early

 * step in kernel initialization and cache required resources. This

 * should happen after subsys_initcall which initializes PCI subsystem

 * and before device_initcall which requires P2SB resources.

 * pci_rescan_remove_lock() can not be locked in sysfs PCI bus rescan path

 * because of deadlock. To avoid the deadlock, access P2SB devices with the lock

 * at an early step in kernel initialization and cache required resources.

 *

 * We want to run as early as possible. If the P2SB was assigned a bad BAR,

 * we'll need to wait on pcibios_assign_resources() to fix it. So, our list of

 * initcall dependencies looks something like this:

 *

 * ...

 * subsys_initcall (pci_subsys_init)

 * fs_initcall     (pcibios_assign_resources)

 */

fs_initcall(p2sb_fs_init);
 
fs_initcall_sync(p2sb_fs_init);