From: Ben Fradella bfradell@netapp.com
[ Upstream commit 2c6370e6607663fc5fa0fd9ed58e2e01014898c7 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/platform/x86/p2sb.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-)
diff --git a/drivers/platform/x86/p2sb.c b/drivers/platform/x86/p2sb.c index a64f56ddd4a44..053be5c5e0cad 100644 --- a/drivers/platform/x86/p2sb.c +++ b/drivers/platform/x86/p2sb.c @@ -56,12 +56,9 @@ static int p2sb_get_devfn(unsigned int *devfn) return 0; }
-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 */ @@ -220,16 +217,20 @@ 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);