[PATCH 8/9] arm/arm64: Make use of the SMCCC 1.1 wrapper

Steven Price
2019-08-02T14:50:53Z

Rather than directly choosing which function to use based on
psci_ops.conduit, use the new arm_smccc_1_1 wrapper instead.

In some cases we still need to do some operations based on the
conduit, but the code duplication is removed.

No functional change.

Signed-off-by: Steven Price <steven.price@arm.com>
---
arch/arm/mm/proc-v7-bugs.c | 13 +++---
arch/arm64/kernel/cpu_errata.c | 80 ++++++++++++----------------------
2 files changed, 33 insertions(+), 60 deletions(-)

diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c
index 9a07916af8dd..8eb52f3385e7 100644
--- a/arch/arm/mm/proc-v7-bugs.c
+++ b/arch/arm/mm/proc-v7-bugs.c
@@ -78,12 +78,13 @@ static void cpu_v7_spectre_init(void)
if (psci_ops.smccc_version == SMCCC_VERSION_1_0)
break;

+ arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
+ ARM_SMCCC_ARCH_WORKAROUND_1, &res);
+ if ((int)res.a0 != 0)
+ return;
+
switch (psci_ops.conduit) {
case PSCI_CONDUIT_HVC:
- arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
- ARM_SMCCC_ARCH_WORKAROUND_1, &res);
- if ((int)res.a0 != 0)
- break;
per_cpu(harden_branch_predictor_fn, cpu) =
call_hvc_arch_workaround_1;
cpu_do_switch_mm = cpu_v7_hvc_switch_mm;
@@ -91,10 +92,6 @@ static void cpu_v7_spectre_init(void)
break;

case PSCI_CONDUIT_SMC:
- arm_smccc_1_1_smc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
- ARM_SMCCC_ARCH_WORKAROUND_1, &res);
- if ((int)res.a0 != 0)
- break;
per_cpu(harden_branch_predictor_fn, cpu) =
call_smc_arch_workaround_1;
cpu_do_switch_mm = cpu_v7_smc_switch_mm;
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 1e43ba5c79b7..400a49aaae85 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -215,40 +215,31 @@ static int detect_harden_bp_fw(void)
if (psci_ops.smccc_version == SMCCC_VERSION_1_0)
return -1;

+ arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
+ ARM_SMCCC_ARCH_WORKAROUND_1, &res);
+
+ switch ((int)res.a0) {
+ case 1:
+ /* Firmware says we're just fine */
+ return 0;
+ case 0:
+ break;
+ default:
+ return -1;
+ }
+
switch (psci_ops.conduit) {
case PSCI_CONDUIT_HVC:
- arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
- ARM_SMCCC_ARCH_WORKAROUND_1, &res);
- switch ((int)res.a0) {
- case 1:
- /* Firmware says we're just fine */
- return 0;
- case 0:
- cb = call_hvc_arch_workaround_1;
- /* This is a guest, no need to patch KVM vectors */
- smccc_start = NULL;
- smccc_end = NULL;
- break;
- default:
- return -1;
- }
+ cb = call_hvc_arch_workaround_1;
+ /* This is a guest, no need to patch KVM vectors */
+ smccc_start = NULL;
+ smccc_end = NULL;
break;

case PSCI_CONDUIT_SMC:
- arm_smccc_1_1_smc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
- ARM_SMCCC_ARCH_WORKAROUND_1, &res);
- switch ((int)res.a0) {
- case 1:
- /* Firmware says we're just fine */
- return 0;
- case 0:
- cb = call_smc_arch_workaround_1;
- smccc_start = __smccc_workaround_1_smc_start;
- smccc_end = __smccc_workaround_1_smc_end;
- break;
- default:
- return -1;
- }
+ cb = call_smc_arch_workaround_1;
+ smccc_start = __smccc_workaround_1_smc_start;
+ smccc_end = __smccc_workaround_1_smc_end;
break;

default:
@@ -338,6 +329,7 @@ void __init arm64_enable_wa2_handling(struct alt_instr *alt,

void arm64_set_ssbd_mitigation(bool state)
{
+ int conduit;
if (!IS_ENABLED(CONFIG_ARM64_SSBD)) {
pr_info_once("SSBD disabled by kernel configuration\n");
return;
@@ -351,19 +343,10 @@ void arm64_set_ssbd_mitigation(bool state)
return;
}

- switch (psci_ops.conduit) {
- case PSCI_CONDUIT_HVC:
- arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_WORKAROUND_2, state, NULL);
- break;
+ conduit = arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_WORKAROUND_2, state,
+ NULL);

- case PSCI_CONDUIT_SMC:
- arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_2, state, NULL);
- break;
-
- default:
- WARN_ON_ONCE(1);
- break;
- }
+ WARN_ON_ONCE(conduit == PSCI_CONDUIT_NONE);
}

static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
@@ -373,6 +356,7 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
bool required = true;
s32 val;
bool this_cpu_safe = false;
+ int conduit;

WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible());

@@ -397,18 +381,10 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
return false;
}

- switch (psci_ops.conduit) {
- case PSCI_CONDUIT_HVC:
- arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
- ARM_SMCCC_ARCH_WORKAROUND_2, &res);
- break;
-
- case PSCI_CONDUIT_SMC:
- arm_smccc_1_1_smc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
- ARM_SMCCC_ARCH_WORKAROUND_2, &res);
- break;
+ conduit = arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
+ ARM_SMCCC_ARCH_WORKAROUND_2, &res);

- default:
+ if (conduit == PSCI_CONDUIT_NONE) {
ssbd_state = ARM64_SSBD_UNKNOWN;
if (!this_cpu_safe)
__ssb_safe = false;
--
2.20.1