From: Ben Fradella <[email protected]>
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 <[email protected]>
---
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 3d66e1d4eb1f..1938a3ef9480 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);
--
2.43.0
[cc += Shin'ichiro, Klara, Andy, Danil]
On Thu, May 09, 2024 at 04:49:34PM +0000, [email protected] wrote:
> From: Ben Fradella <[email protected]>
>
> 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 <[email protected]>
> ---
> 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 3d66e1d4eb1f..1938a3ef9480 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);
> --
> 2.43.0
On Thu, May 09, 2024 at 07:04:32PM +0200, Lukas Wunner wrote:
> [cc += Shin'ichiro, Klara, Andy, Danil]
Thank you!
> On Thu, May 09, 2024 at 04:49:34PM +0000, [email protected] wrote:
> > From: Ben Fradella <[email protected]>
> >
> > 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.
..
> > /*
> > - * 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
PCI bus
> > + * 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)
> > */
This makes sense to me
Acked-by: Andy Shevchenko <[email protected]>
I assume others will conduct the proper review and testing.
--
With Best Regards,
Andy Shevchenko
On 2024-05-10 16:50, Andy Shevchenko wrote:
> On Thu, May 09, 2024 at 07:04:32PM +0200, Lukas Wunner wrote:
>> [cc += Shin'ichiro, Klara, Andy, Danil]
>
> Thank you!
>
>> On Thu, May 09, 2024 at 04:49:34PM +0000, [email protected] wrote:
>>> From: Ben Fradella <[email protected]>
>>>
>>> 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.
>
> ...
>
>>> /*
>>> - * 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
>
> PCI bus
>
>>> + * 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)
>>> */
>
> This makes sense to me
> Acked-by: Andy Shevchenko <[email protected]>
>
> I assume others will conduct the proper review and testing.
>
This patch did not introduce any new issues on my previously problematic
system.
Tested-by: Klara Modin <[email protected]>
On May 10, 2024 / 21:22, Klara Modin wrote:
> On 2024-05-10 16:50, Andy Shevchenko wrote:
> > On Thu, May 09, 2024 at 07:04:32PM +0200, Lukas Wunner wrote:
> > > [cc += Shin'ichiro, Klara, Andy, Danil]
> >
> > Thank you!
> >
> > > On Thu, May 09, 2024 at 04:49:34PM +0000, [email protected] wrote:
> > > > From: Ben Fradella <[email protected]>
> > > >
> > > > 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.
> >
> > ...
> >
> > > > /*
> > > > - * 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
> >
> > PCI bus
> >
> > > > + * 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)
> > > > */
> >
> > This makes sense to me
> > Acked-by: Andy Shevchenko <[email protected]>
> >
> > I assume others will conduct the proper review and testing.
> >
>
> This patch did not introduce any new issues on my previously problematic
> system.
>
> Tested-by: Klara Modin <[email protected]>
The changes look reasonable and good to me. I also confirmed that the patch
does not affect on my use case using two my test machines.
Reviewed-by: Shin'ichiro Kawasaki <[email protected]>
Hi,
On 5/9/24 6:49 PM, [email protected] wrote:
> From: Ben Fradella <[email protected]>
>
> 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 <[email protected]>
Thank you for your patch, I've applied this patch to my review-hans
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans
Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.
Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.
Regards,
Hans
> ---
> 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 3d66e1d4eb1f..1938a3ef9480 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);
> On 2024-05-13 07:03, [email protected] wrote:
>
> Thank you for your patch, I've applied this patch to my review-hans branch: https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans
>
> Note it will show up in my review-hans branch once I've pushed my local branch there, which might take a while.
>
> Once I've run some tests on this branch the patches there will be added to the platform-drivers-x86/for-next branch and eventually will be included in the pdx86 pull-request to Linus for the next merge-window.
>
>Regards,
>
>Hans
Thank you!