iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

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

Browse Source 
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: Ben Fradella <bfradell@netapp.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Klara Modin <klarasmodin@gmail.com>
Reviewed-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Link: https://lore.kernel.org/r/20240509164905.41016-1-bcfradella@proton.me
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
This commit is contained in:
Ben Fradella 2024-05-09 16:49:34 +00:00 committed by Hans de Goede
parent 7c4cd2afee
commit 2c6370e660
1 changed files with 15 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
drivers/platform/x86/p2sb.c
View File

@ -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);