Messages in this thread |  | | Subject | Re: [PATCH v2 13/16] firmware/psci: Expose SMCCC version through psci_ops | From | Marc Zyngier <> | Date | Tue, 30 Jan 2018 13:51:22 +0000 |
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On 30/01/18 12:55, Robin Murphy wrote: > On 29/01/18 17:45, Marc Zyngier 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. >> >> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> >> --- >> drivers/firmware/psci.c | 21 +++++++++++++++++++++ >> include/linux/psci.h | 6 ++++++ >> 2 files changed, 27 insertions(+) >> >> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c >> index e9493da2b111..dd035aaa1c33 100644 >> --- a/drivers/firmware/psci.c >> +++ b/drivers/firmware/psci.c >> @@ -511,6 +511,26 @@ 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 = PSCI_RET_NOT_SUPPORTED; >> + >> + if (PSCI_VERSION_MAJOR(ver) >= 1) >> + feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID); >> + >> + if (feature == PSCI_RET_NOT_SUPPORTED) { >> + psci_ops.variant = SMCCC_VARIANT_1_0; > > Presumably at some point in the future we might want to update PSCI > itself to use 'fast' calls if available, at which point this > initialisation is a bit backwards given that you've already made a call > using *some* convention. Even I think relying on the enum value working > out OK is a bit subtle, so perhaps it's best to default-initialise > psci_ops.variant to 1.0 (either statically, or dynamically before the > first call), then only update it to 1.1 if and when we discover that.
Indeed. Lorenzo already suggested something along those lines, and I now (statically) default to 1.0.
Thanks,
M. -- Jazz is not dead. It just smells funny...
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