| Message ID | 20230105090834.630238-1-maz@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | firmware/psci: Don't register with debugfs if PSCI isn't available | expand |
On Thu, Jan 05, 2023 at 09:08:34AM +0000, Marc Zyngier wrote: > Contrary to popular belief, PSCI is not a universal property of an > ARM/arm64 system. There is a garden variety of systems out there > that don't (or even cannot) implement it. > > I'm the first one deplore such a situation, but hey... > > On such systems, a "cat /sys/kernel/debug/psci" results in > fireworks, as no invocation callback is registered. > > Check for the invoke_psci_fn and psci_ops.get_version pointers > before registering with the debugfs subsystem, avoiding the > issue altogether. > > Fixes: 3137f2e60098 ("firmware/psci: Add debugfs support to ease debugging") > Reported-by: Hector Martin <marcan@marcan.st> > Signed-off-by: Marc Zyngier <maz@kernel.org> > Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> > Cc: Mark Brown <broonie@kernel.org> > Cc: Ulf Hansson <ulf.hansson@linaro.org> > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Lorenzo Pieralisi <lpieralisi@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Mark. > --- > drivers/firmware/psci/psci.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c > index e7bcfca4159f..447ee4ea5c90 100644 > --- a/drivers/firmware/psci/psci.c > +++ b/drivers/firmware/psci/psci.c > @@ -440,6 +440,9 @@ static const struct file_operations psci_debugfs_ops = { > > static int __init psci_debugfs_init(void) > { > + if (!invoke_psci_fn || !psci_ops.get_version) > + return 0; > + > return PTR_ERR_OR_ZERO(debugfs_create_file("psci", 0444, NULL, NULL, > &psci_debugfs_ops)); > } > -- > 2.34.1 >
On 05/01/2023 11:08, Marc Zyngier wrote: > Contrary to popular belief, PSCI is not a universal property of an > ARM/arm64 system. There is a garden variety of systems out there > that don't (or even cannot) implement it. > > I'm the first one deplore such a situation, but hey... > > On such systems, a "cat /sys/kernel/debug/psci" results in > fireworks, as no invocation callback is registered. > > Check for the invoke_psci_fn and psci_ops.get_version pointers > before registering with the debugfs subsystem, avoiding the > issue altogether. > > Fixes: 3137f2e60098 ("firmware/psci: Add debugfs support to ease debugging") > Reported-by: Hector Martin <marcan@marcan.st> > Signed-off-by: Marc Zyngier <maz@kernel.org> > Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> > Cc: Mark Brown <broonie@kernel.org> > Cc: Ulf Hansson <ulf.hansson@linaro.org> > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Lorenzo Pieralisi <lpieralisi@kernel.org> Acked-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
On 05/01/2023 18.08, Marc Zyngier wrote: > Contrary to popular belief, PSCI is not a universal property of an > ARM/arm64 system. There is a garden variety of systems out there > that don't (or even cannot) implement it. > > I'm the first one deplore such a situation, but hey... > > On such systems, a "cat /sys/kernel/debug/psci" results in > fireworks, as no invocation callback is registered. > > Check for the invoke_psci_fn and psci_ops.get_version pointers > before registering with the debugfs subsystem, avoiding the > issue altogether. > > Fixes: 3137f2e60098 ("firmware/psci: Add debugfs support to ease debugging") > Reported-by: Hector Martin <marcan@marcan.st> > Signed-off-by: Marc Zyngier <maz@kernel.org> > Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> > Cc: Mark Brown <broonie@kernel.org> > Cc: Ulf Hansson <ulf.hansson@linaro.org> > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Lorenzo Pieralisi <lpieralisi@kernel.org> > --- > drivers/firmware/psci/psci.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c > index e7bcfca4159f..447ee4ea5c90 100644 > --- a/drivers/firmware/psci/psci.c > +++ b/drivers/firmware/psci/psci.c > @@ -440,6 +440,9 @@ static const struct file_operations psci_debugfs_ops = { > > static int __init psci_debugfs_init(void) > { > + if (!invoke_psci_fn || !psci_ops.get_version) > + return 0; > + > return PTR_ERR_OR_ZERO(debugfs_create_file("psci", 0444, NULL, NULL, > &psci_debugfs_ops)); > } Reviewed-by: Hector Martin <marcan@marcan.st> - Hector
On Thu, 5 Jan 2023 09:08:34 +0000, Marc Zyngier wrote: > Contrary to popular belief, PSCI is not a universal property of an > ARM/arm64 system. There is a garden variety of systems out there > that don't (or even cannot) implement it. > > I'm the first one deplore such a situation, but hey... > > On such systems, a "cat /sys/kernel/debug/psci" results in > fireworks, as no invocation callback is registered. > > [...] Applied to arm64 (for-next/fixes), thanks! [1/1] firmware/psci: Don't register with debugfs if PSCI isn't available https://git.kernel.org/arm64/c/cef139299fd8 Cheers,
diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c index e7bcfca4159f..447ee4ea5c90 100644 --- a/drivers/firmware/psci/psci.c +++ b/drivers/firmware/psci/psci.c @@ -440,6 +440,9 @@ static const struct file_operations psci_debugfs_ops = { static int __init psci_debugfs_init(void) { + if (!invoke_psci_fn || !psci_ops.get_version) + return 0; + return PTR_ERR_OR_ZERO(debugfs_create_file("psci", 0444, NULL, NULL, &psci_debugfs_ops)); }
Contrary to popular belief, PSCI is not a universal property of an ARM/arm64 system. There is a garden variety of systems out there that don't (or even cannot) implement it. I'm the first one deplore such a situation, but hey... On such systems, a "cat /sys/kernel/debug/psci" results in fireworks, as no invocation callback is registered. Check for the invoke_psci_fn and psci_ops.get_version pointers before registering with the debugfs subsystem, avoiding the issue altogether. Fixes: 3137f2e60098 ("firmware/psci: Add debugfs support to ease debugging") Reported-by: Hector Martin <marcan@marcan.st> Signed-off-by: Marc Zyngier <maz@kernel.org> Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> Cc: Mark Brown <broonie@kernel.org> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Lorenzo Pieralisi <lpieralisi@kernel.org> --- drivers/firmware/psci/psci.c | 3 +++ 1 file changed, 3 insertions(+)