diff options
Diffstat (limited to 'arch/x86/kernel/cpu/bugs.c')
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 29 |
1 files changed, 24 insertions, 5 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 1e13dbfc0919..7c946a9af947 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -56,6 +56,10 @@ u64 __ro_after_init x86_amd_ls_cfg_ssbd_mask; /* Control conditional STIPB in switch_to() */ DEFINE_STATIC_KEY_FALSE(switch_to_cond_stibp); +/* Control conditional IBPB in switch_mm() */ +DEFINE_STATIC_KEY_FALSE(switch_mm_cond_ibpb); +/* Control unconditional IBPB in switch_mm() */ +DEFINE_STATIC_KEY_FALSE(switch_mm_always_ibpb); void __init check_bugs(void) { @@ -331,7 +335,17 @@ spectre_v2_user_select_mitigation(enum spectre_v2_mitigation_cmd v2_cmd) /* Initialize Indirect Branch Prediction Barrier */ if (boot_cpu_has(X86_FEATURE_IBPB)) { setup_force_cpu_cap(X86_FEATURE_USE_IBPB); - pr_info("Spectre v2 mitigation: Enabling Indirect Branch Prediction Barrier\n"); + + switch (mode) { + case SPECTRE_V2_USER_STRICT: + static_branch_enable(&switch_mm_always_ibpb); + break; + default: + break; + } + + pr_info("mitigation: Enabling %s Indirect Branch Prediction Barrier\n", + mode == SPECTRE_V2_USER_STRICT ? "always-on" : "conditional"); } /* If enhanced IBRS is enabled no STIPB required */ @@ -955,10 +969,15 @@ static char *stibp_state(void) static char *ibpb_state(void) { - if (boot_cpu_has(X86_FEATURE_USE_IBPB)) - return ", IBPB"; - else - return ""; + if (boot_cpu_has(X86_FEATURE_IBPB)) { + switch (spectre_v2_user) { + case SPECTRE_V2_USER_NONE: + return ", IBPB: disabled"; + case SPECTRE_V2_USER_STRICT: + return ", IBPB: always-on"; + } + } + return ""; } static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr, |