Messages in this thread Patch in this message | | | Date | Thu, 05 Nov 2020 09:47:09 +0000 | From | Marc Zyngier <> | Subject | Re: [RFC PATCH 01/26] psci: Export configured PSCI version |
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On 2020-11-04 18:36, David Brazdil wrote: > The version of PSCI that the kernel should use to communicate with > firmware is typically obtained from probing PSCI_VERSION. However, that > doesn't work for PSCI v0.1 where the host gets the information from > DT/ACPI, or if PSCI is not supported / was disabled. > > KVM's PSCI proxy for the host needs to be configured with the same > version used by the host driver. Expose the PSCI version used by the > host. > > Signed-off-by: David Brazdil <dbrazdil@google.com> > --- > drivers/firmware/psci/psci.c | 6 ++++++ > include/linux/psci.h | 8 ++++++++ > 2 files changed, 14 insertions(+) > > diff --git a/drivers/firmware/psci/psci.c > b/drivers/firmware/psci/psci.c > index 00af99b6f97c..ff523bdbfe3f 100644 > --- a/drivers/firmware/psci/psci.c > +++ b/drivers/firmware/psci/psci.c > @@ -49,6 +49,8 @@ static int resident_cpu = -1; > struct psci_operations psci_ops; > static enum arm_smccc_conduit psci_conduit = SMCCC_CONDUIT_NONE; > > +int psci_driver_version = PSCI_VERSION(0, 0); > + > bool psci_tos_resident_on(int cpu) > { > return cpu == resident_cpu; > @@ -461,6 +463,8 @@ static int __init psci_probe(void) > return -EINVAL; > } > > + psci_driver_version = ver; > + > psci_0_2_set_functions(); > > psci_init_migrate(); > @@ -514,6 +518,8 @@ static int __init psci_0_1_init(struct device_node > *np) > > pr_info("Using PSCI v0.1 Function IDs from DT\n"); > > + psci_driver_version = PSCI_VERSION(0, 1); > + > if (!of_property_read_u32(np, "cpu_suspend", &id)) { > psci_function_id[PSCI_FN_CPU_SUSPEND] = id; > psci_ops.cpu_suspend = psci_cpu_suspend; > diff --git a/include/linux/psci.h b/include/linux/psci.h > index 2a1bfb890e58..cb35b90d1746 100644 > --- a/include/linux/psci.h > +++ b/include/linux/psci.h > @@ -21,6 +21,14 @@ bool psci_power_state_is_valid(u32 state); > int psci_set_osi_mode(bool enable); > bool psci_has_osi_support(void); > > +/** > + * The version of the PSCI specification followed by the driver. > + * This is equivalent to calling PSCI_VERSION except: > + * (a) it also works for PSCI v0.1, which does not support > PSCI_VERSION, and > + * (b) it is set to v0.0 if the PSCI driver was not initialized. > + */ > +extern int psci_driver_version; > + > struct psci_operations { > u32 (*get_version)(void); > int (*cpu_suspend)(u32 state, unsigned long entry_point);
How about providing a get_version callback for pre-0.2 implementations instead? This would avoid exposing more symbols (psci_ops is already global).
Thanks,
M.
diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c index 00af99b6f97c..b84454e12d92 100644 --- a/drivers/firmware/psci/psci.c +++ b/drivers/firmware/psci/psci.c @@ -500,6 +500,11 @@ static int __init psci_0_2_init(struct device_node *np) return psci_probe(); }
+static u32 psci_0_1_get_version(void) +{ + return PSCI_VERSION(0, 1); +} + /* * PSCI < v0.2 get PSCI Function IDs via DT. */ @@ -514,6 +519,8 @@ static int __init psci_0_1_init(struct device_node *np)
pr_info("Using PSCI v0.1 Function IDs from DT\n");
+ psci_ops.get_version = psci_0_1_get_version; + if (!of_property_read_u32(np, "cpu_suspend", &id)) { psci_function_id[PSCI_FN_CPU_SUSPEND] = id; psci_ops.cpu_suspend = psci_cpu_suspend; -- Jazz is not dead. It just smells funny...
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