On 1 February 2018 at 11:46, Marc Zyngier <marc.zyngier@xxxxxxx> wrote:
> Since PSCI 1.0 allows the SMCCC version to be (indirectly) probed,
> let's do that at boot time, and expose the version of the calling
> convention as part of the psci_ops structure.
>
> Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> ---
> drivers/firmware/psci.c | 19 +++++++++++++++++++
> include/linux/psci.h | 6 ++++++
> 2 files changed, 25 insertions(+)
>
> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
> index e9493da2b111..8631906c414c 100644
> --- a/drivers/firmware/psci.c
> +++ b/drivers/firmware/psci.c
> @@ -61,6 +61,7 @@ bool psci_tos_resident_on(int cpu)
>
> struct psci_operations psci_ops = {
> .conduit = PSCI_CONDUIT_NONE,
> + .smccc_version = SMCCC_VERSION_1_0,
> };
>
> typedef unsigned long (psci_fn)(unsigned long, unsigned long,
> @@ -511,6 +512,23 @@ static void __init psci_init_migrate(void)
> pr_info("Trusted OS resident on physical CPU 0x%lx\n", cpuid);
> }
>
> +static void __init psci_init_smccc(u32 ver)
> +{
> + int feature;
> +
> + feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
> +
> + if (feature != PSCI_RET_NOT_SUPPORTED) {
> + ver = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
> + if (ver != ARM_SMCCC_VERSION_1_1)
> + psci_ops.smccc_version = SMCCC_VERSION_1_0;
> + else
> + psci_ops.smccc_version = SMCCC_VERSION_1_1;
> + }
> +
> + pr_info("SMC Calling Convention v1.%d\n", psci_ops.smccc_version);
This is a bit nasty: you are returning the numeric value of the enum
as the minor number, and hardcoding the major version number as 1,
while the return value of ARM_SMCCC_VERSION_FUNC_ID gives you the
exact numbers. I assume nobody is expecting SMCCC v2.3 anytime soon,
but it would still be a lot nicer to simply decode the value of 'ver'
(and make it default to ARM_SMCCC_VERSION_1_0 if the PSCI feature call
fails)
> +}
> +
> static void __init psci_0_2_set_functions(void)
> {
> pr_info("Using standard PSCI v0.2 function IDs\n");
> @@ -559,6 +577,7 @@ static int __init psci_probe(void)
> psci_init_migrate();
>
> if (PSCI_VERSION_MAJOR(ver) >= 1) {
> + psci_init_smccc(ver);
> psci_init_cpu_suspend();
> psci_init_system_suspend();
> }
> diff --git a/include/linux/psci.h b/include/linux/psci.h
> index f2679e5faa4f..8b1b3b5935ab 100644
> --- a/include/linux/psci.h
> +++ b/include/linux/psci.h
> @@ -31,6 +31,11 @@ enum psci_conduit {
> PSCI_CONDUIT_HVC,
> };
>
> +enum smccc_version {
> + SMCCC_VERSION_1_0,
> + SMCCC_VERSION_1_1,
> +};
> +
> struct psci_operations {
> u32 (*get_version)(void);
> int (*cpu_suspend)(u32 state, unsigned long entry_point);
> @@ -41,6 +46,7 @@ struct psci_operations {
> unsigned long lowest_affinity_level);
> int (*migrate_info_type)(void);
> enum psci_conduit conduit;
> + enum smccc_version smccc_version;
> };
>
> extern struct psci_operations psci_ops;
> --
> 2.14.2
>
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