Comment 4 for bug 1911376

I check ubuntu bionic branch （4.15.0-130.134), this error of backporting patch (arm64: cpufeature: Detect SSBS and advertise to userspace) still exist. Can you refer to this follow patch to fix this issue?

--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1070,6 +1070,19 @@ static const struct arm64_cpu_capabilities arm64_features
[] = {
                .cpu_enable = cpu_enable_pan,
        },
 #endif /* CONFIG_ARM64_PAN */
+#ifdef CONFIG_ARM64_SSBD
+ {
+ .desc = "Speculative Store Bypassing Safe (SSBS)",
+ .capability = ARM64_SSBS,
+ .type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,
+ .matches = has_cpuid_feature,
+ .sys_reg = SYS_ID_AA64PFR1_EL1,
+ .field_pos = ID_AA64PFR1_SSBS_SHIFT,
+ .sign = FTR_UNSIGNED,
+ .min_field_value = ID_AA64PFR1_SSBS_PSTATE_ONLY,
+ .cpu_enable = cpu_enable_ssbs,
+ },
+#endif
 #if defined(CONFIG_AS_LSE) && defined(CONFIG_ARM64_LSE_ATOMICS)
        {
                .desc = "LSE atomic instructions",
@@ -1253,19 +1266,6 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
 #ifdef CONFIG_ARM64_SVE
        HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_SVE_SHIFT, FTR_UNSIGNED, ID_AA64PFR0_SVE, CAP_HWCAP, HWCAP_SVE),
 #endif
-#ifdef CONFIG_ARM64_SSBD
- {
- .desc = "Speculative Store Bypassing Safe (SSBS)",
- .capability = ARM64_SSBS,
- .type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,
- .matches = has_cpuid_feature,
- .sys_reg = SYS_ID_AA64PFR1_EL1,
- .field_pos = ID_AA64PFR1_SSBS_SHIFT,
- .sign = FTR_UNSIGNED,
- .min_field_value = ID_AA64PFR1_SSBS_PSTATE_ONLY,
- .cpu_enable = cpu_enable_ssbs,
- },
-#endif