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arm64: Call ARCH_WORKAROUND_2 on transitions between EL0 and EL1

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In order for the kernel to protect itself, let's call the SSBD mitigation
implemented by the higher exception level (either hypervisor or firmware)
on each transition between userspace and kernel.

We must take the PSCI conduit into account in order to target the
right exception level, hence the introduction of a runtime patching
callback.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Marc Zyngier
2018-05-29 13:11:06 +01:00
committed by Catalin Marinas
parent eff0e9e107
commit 8e2906245f
3 changed files with 51 additions and 0 deletions
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24
arch/arm64/kernel/cpu_errata.c
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@@ -232,6 +232,30 @@ enable_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry)
}
#endif /* CONFIG_HARDEN_BRANCH_PREDICTOR */
#ifdef CONFIG_ARM64_SSBD
void __init arm64_update_smccc_conduit(struct alt_instr *alt,
__le32 *origptr, __le32 *updptr,
int nr_inst)
{
u32 insn;
BUG_ON(nr_inst != 1);
switch (psci_ops.conduit) {
case PSCI_CONDUIT_HVC:
insn = aarch64_insn_get_hvc_value();
break;
case PSCI_CONDUIT_SMC:
insn = aarch64_insn_get_smc_value();
break;
default:
return;
}
*updptr = cpu_to_le32(insn);
}
#endif /* CONFIG_ARM64_SSBD */
#define CAP_MIDR_RANGE(model, v_min, r_min, v_max, r_max) \
.matches = is_affected_midr_range, \
.midr_range = MIDR_RANGE(model, v_min, r_min, v_max, r_max)