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@xxxxxxx>
---
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.
Robin.
+ } else {
+ ver = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
+ if (ver != ARM_SMCCC_VERSION_1_1)
+ psci_ops.variant = SMCCC_VARIANT_1_0;
+ else
+ psci_ops.variant = SMCCC_VARIANT_1_1;
+ }
+
+ pr_info("SMC Calling Convention v1.%d\n", psci_ops.variant);
+}
+
static void __init psci_0_2_set_functions(void)
{
pr_info("Using standard PSCI v0.2 function IDs\n");
@@ -557,6 +577,7 @@ static int __init psci_probe(void)
psci_0_2_set_functions();
psci_init_migrate();
+ psci_init_smccc(ver);
if (PSCI_VERSION_MAJOR(ver) >= 1) {
psci_init_cpu_suspend();
diff --git a/include/linux/psci.h b/include/linux/psci.h
index f2679e5faa4f..83fd16a37be3 100644
--- a/include/linux/psci.h
+++ b/include/linux/psci.h
@@ -31,6 +31,11 @@ enum psci_conduit {
PSCI_CONDUIT_HVC,
};
+enum smccc_variant {
+ SMCCC_VARIANT_1_0,
+ SMCCC_VARIANT_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_variant variant;
};
extern struct psci_operations psci_ops;
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