Messages in this thread Patch in this message | | | From | Marc Zyngier <> | Subject | [PATCH] firmware/psci: Don't register with debugfs if PSCI isn't available | Date | Thu, 5 Jan 2023 09:08:34 +0000 |
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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)); } -- 2.34.1
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