[PATCH 45/45] arm64: Kill PSCI_GET_VERSION as a variant-2 workaround
From: Alex Shi
Date: Thu Mar 01 2018 - 08:01:27 EST
From: Marc Zyngier <marc.zyngier@xxxxxxx>
commit 3a0a397ff5ff upstream.
Now that we've standardised on SMCCC v1.1 to perform the branch
prediction invalidation, let's drop the previous band-aid.
If vendors haven't updated their firmware to do SMCCC 1.1, they
haven't updated PSCI either, so we don't loose anything.
Tested-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxx>
---
arch/arm64/kernel/bpi.S | 24 ------------------------
arch/arm64/kernel/cpu_errata.c | 41 +++++++++++------------------------------
arch/arm64/kvm/hyp/switch.c | 14 --------------
3 files changed, 11 insertions(+), 68 deletions(-)
diff --git a/arch/arm64/kernel/bpi.S b/arch/arm64/kernel/bpi.S
index c72f261..dc4eb15 100644
--- a/arch/arm64/kernel/bpi.S
+++ b/arch/arm64/kernel/bpi.S
@@ -54,30 +54,6 @@ ENTRY(__bp_harden_hyp_vecs_start)
vectors __kvm_hyp_vector
.endr
ENTRY(__bp_harden_hyp_vecs_end)
-ENTRY(__psci_hyp_bp_inval_start)
- sub sp, sp, #(8 * 18)
- stp x16, x17, [sp, #(16 * 0)]
- stp x14, x15, [sp, #(16 * 1)]
- stp x12, x13, [sp, #(16 * 2)]
- stp x10, x11, [sp, #(16 * 3)]
- stp x8, x9, [sp, #(16 * 4)]
- stp x6, x7, [sp, #(16 * 5)]
- stp x4, x5, [sp, #(16 * 6)]
- stp x2, x3, [sp, #(16 * 7)]
- stp x0, x1, [sp, #(16 * 8)]
- mov x0, #0x84000000
- smc #0
- ldp x16, x17, [sp, #(16 * 0)]
- ldp x14, x15, [sp, #(16 * 1)]
- ldp x12, x13, [sp, #(16 * 2)]
- ldp x10, x11, [sp, #(16 * 3)]
- ldp x8, x9, [sp, #(16 * 4)]
- ldp x6, x7, [sp, #(16 * 5)]
- ldp x4, x5, [sp, #(16 * 6)]
- ldp x2, x3, [sp, #(16 * 7)]
- ldp x0, x1, [sp, #(16 * 8)]
- add sp, sp, #(8 * 18)
-ENTRY(__psci_hyp_bp_inval_end)
.macro smccc_workaround_1 inst
sub sp, sp, #(8 * 4)
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 9632319..8b74f80 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -53,7 +53,6 @@ static int cpu_enable_trap_ctr_access(void *__unused)
DEFINE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data);
#ifdef CONFIG_KVM
-extern char __psci_hyp_bp_inval_start[], __psci_hyp_bp_inval_end[];
extern char __smccc_workaround_1_smc_start[];
extern char __smccc_workaround_1_smc_end[];
extern char __smccc_workaround_1_hvc_start[];
@@ -100,8 +99,6 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn,
spin_unlock(&bp_lock);
}
#else
-#define __psci_hyp_bp_inval_start NULL
-#define __psci_hyp_bp_inval_end NULL
#define __smccc_workaround_1_smc_start NULL
#define __smccc_workaround_1_smc_end NULL
#define __smccc_workaround_1_hvc_start NULL
@@ -146,24 +143,25 @@ static void call_hvc_arch_workaround_1(void)
arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL);
}
-static bool check_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry)
+static int enable_smccc_arch_workaround_1(void *data)
{
+ const struct arm64_cpu_capabilities *entry = data;
bp_hardening_cb_t cb;
void *smccc_start, *smccc_end;
struct arm_smccc_res res;
if (!entry->matches(entry, SCOPE_LOCAL_CPU))
- return false;
+ return 0;
if (psci_ops.smccc_version == SMCCC_VERSION_1_0)
- return false;
+ return 0;
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 (res.a0)
- return false;
+ return 0;
cb = call_hvc_arch_workaround_1;
smccc_start = __smccc_workaround_1_hvc_start;
smccc_end = __smccc_workaround_1_hvc_end;
@@ -173,35 +171,18 @@ static bool check_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *e
arm_smccc_1_1_smc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
ARM_SMCCC_ARCH_WORKAROUND_1, &res);
if (res.a0)
- return false;
+ return 0;
cb = call_smc_arch_workaround_1;
smccc_start = __smccc_workaround_1_smc_start;
smccc_end = __smccc_workaround_1_smc_end;
break;
default:
- return false;
+ return 0;
}
install_bp_hardening_cb(entry, cb, smccc_start, smccc_end);
- return true;
-}
-
-static int enable_psci_bp_hardening(void *data)
-{
- const struct arm64_cpu_capabilities *entry = data;
-
- if (psci_ops.get_version) {
- if (check_smccc_arch_workaround_1(entry))
- return 0;
-
- install_bp_hardening_cb(entry,
- (bp_hardening_cb_t)psci_ops.get_version,
- __psci_hyp_bp_inval_start,
- __psci_hyp_bp_inval_end);
- }
-
return 0;
}
#endif /* CONFIG_HARDEN_BRANCH_PREDICTOR */
@@ -301,22 +282,22 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
{
.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
MIDR_ALL_VERSIONS(MIDR_CORTEX_A57),
- .enable = enable_psci_bp_hardening,
+ .enable = enable_smccc_arch_workaround_1,
},
{
.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
MIDR_ALL_VERSIONS(MIDR_CORTEX_A72),
- .enable = enable_psci_bp_hardening,
+ .enable = enable_smccc_arch_workaround_1,
},
{
.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
MIDR_ALL_VERSIONS(MIDR_CORTEX_A73),
- .enable = enable_psci_bp_hardening,
+ .enable = enable_smccc_arch_workaround_1,
},
{
.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
MIDR_ALL_VERSIONS(MIDR_CORTEX_A75),
- .enable = enable_psci_bp_hardening,
+ .enable = enable_smccc_arch_workaround_1,
},
#endif
{
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 996328e..154b471 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -311,20 +311,6 @@ int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu)
if (exit_code == ARM_EXCEPTION_TRAP && !__populate_fault_info(vcpu))
goto again;
- if (exit_code == ARM_EXCEPTION_TRAP &&
- (kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_HVC64 ||
- kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_HVC32)) {
- u32 val = vcpu_get_reg(vcpu, 0);
-
- if (val == PSCI_0_2_FN_PSCI_VERSION) {
- val = kvm_psci_version(vcpu, kern_hyp_va(vcpu->kvm));
- if (unlikely(val == KVM_ARM_PSCI_0_1))
- val = PSCI_RET_NOT_SUPPORTED;
- vcpu_set_reg(vcpu, 0, val);
- goto again;
- }
- }
-
if (static_branch_unlikely(&vgic_v2_cpuif_trap) &&
exit_code == ARM_EXCEPTION_TRAP) {
bool valid;
--
2.7.4