diff options
| author | Will Deacon <will.deacon@arm.com> | 2018-08-07 13:47:06 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2018-09-14 17:46:19 +0100 |
| commit | 8f04e8e6e29c93421a95b61cad62e3918425eac7 (patch) | |
| tree | d933a8bd5c9e9a3094019c9bc51d5b5178eb768e /arch/arm64/kernel/cpu_errata.c | |
| parent | 0bf0f444b2c49241b2b39aa3cf210d7c95ef6c34 (diff) | |
arm64: ssbd: Add support for PSTATE.SSBS rather than trapping to EL3
On CPUs with support for PSTATE.SSBS, the kernel can toggle the SSBD
state without needing to call into firmware.
This patch hooks into the existing SSBD infrastructure so that SSBS is
used on CPUs that support it, but it's all made horribly complicated by
the very real possibility of big/little systems that don't uniformly
provide the new capability.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/cpu_errata.c')
| -rw-r--r-- | arch/arm64/kernel/cpu_errata.c | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index dec10898d688..c063490d7b51 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -312,6 +312,14 @@ void __init arm64_enable_wa2_handling(struct alt_instr *alt, void arm64_set_ssbd_mitigation(bool state) { + if (this_cpu_has_cap(ARM64_SSBS)) { + if (state) + asm volatile(SET_PSTATE_SSBS(0)); + else + asm volatile(SET_PSTATE_SSBS(1)); + return; + } + switch (psci_ops.conduit) { case PSCI_CONDUIT_HVC: arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_WORKAROUND_2, state, NULL); @@ -336,6 +344,11 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry, WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible()); + if (this_cpu_has_cap(ARM64_SSBS)) { + required = false; + goto out_printmsg; + } + if (psci_ops.smccc_version == SMCCC_VERSION_1_0) { ssbd_state = ARM64_SSBD_UNKNOWN; return false; @@ -384,7 +397,6 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry, switch (ssbd_state) { case ARM64_SSBD_FORCE_DISABLE: - pr_info_once("%s disabled from command-line\n", entry->desc); arm64_set_ssbd_mitigation(false); required = false; break; @@ -397,7 +409,6 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry, break; case ARM64_SSBD_FORCE_ENABLE: - pr_info_once("%s forced from command-line\n", entry->desc); arm64_set_ssbd_mitigation(true); required = true; break; @@ -407,6 +418,17 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry, break; } +out_printmsg: + switch (ssbd_state) { + case ARM64_SSBD_FORCE_DISABLE: + pr_info_once("%s disabled from command-line\n", entry->desc); + break; + + case ARM64_SSBD_FORCE_ENABLE: + pr_info_once("%s forced from command-line\n", entry->desc); + break; + } + return required; } #endif /* CONFIG_ARM64_SSBD */ |