diff options
Diffstat (limited to 'arch/x86/kernel/cpu/bugs.c')
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 27 |
1 files changed, 23 insertions, 4 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index d02f73c5339d..f081d26616ac 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -63,6 +63,8 @@ EXPORT_SYMBOL_GPL(x86_pred_cmd); static DEFINE_MUTEX(spec_ctrl_mutex); +void (*x86_return_thunk)(void) __ro_after_init = &__x86_return_thunk; + /* Update SPEC_CTRL MSR and its cached copy unconditionally */ static void update_spec_ctrl(u64 val) { @@ -165,6 +167,11 @@ void __init cpu_select_mitigations(void) md_clear_select_mitigation(); srbds_select_mitigation(); l1d_flush_select_mitigation(); + + /* + * srso_select_mitigation() depends and must run after + * retbleed_select_mitigation(). + */ srso_select_mitigation(); gds_select_mitigation(); } @@ -1035,6 +1042,9 @@ do_cmd_auto: setup_force_cpu_cap(X86_FEATURE_RETHUNK); setup_force_cpu_cap(X86_FEATURE_UNRET); + if (IS_ENABLED(CONFIG_RETHUNK)) + x86_return_thunk = retbleed_return_thunk; + if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD && boot_cpu_data.x86_vendor != X86_VENDOR_HYGON) pr_err(RETBLEED_UNTRAIN_MSG); @@ -1044,6 +1054,7 @@ do_cmd_auto: case RETBLEED_MITIGATION_IBPB: setup_force_cpu_cap(X86_FEATURE_ENTRY_IBPB); + setup_force_cpu_cap(X86_FEATURE_IBPB_ON_VMEXIT); mitigate_smt = true; break; @@ -2417,9 +2428,10 @@ static void __init srso_select_mitigation(void) * Zen1/2 with SMT off aren't vulnerable after the right * IBPB microcode has been applied. */ - if ((boot_cpu_data.x86 < 0x19) && - (!cpu_smt_possible() || (cpu_smt_control == CPU_SMT_DISABLED))) + if (boot_cpu_data.x86 < 0x19 && !cpu_smt_possible()) { setup_force_cpu_cap(X86_FEATURE_SRSO_NO); + return; + } } if (retbleed_mitigation == RETBLEED_MITIGATION_IBPB) { @@ -2448,11 +2460,15 @@ static void __init srso_select_mitigation(void) * like ftrace, static_call, etc. */ setup_force_cpu_cap(X86_FEATURE_RETHUNK); + setup_force_cpu_cap(X86_FEATURE_UNRET); - if (boot_cpu_data.x86 == 0x19) + if (boot_cpu_data.x86 == 0x19) { setup_force_cpu_cap(X86_FEATURE_SRSO_ALIAS); - else + x86_return_thunk = srso_alias_return_thunk; + } else { setup_force_cpu_cap(X86_FEATURE_SRSO); + x86_return_thunk = srso_return_thunk; + } srso_mitigation = SRSO_MITIGATION_SAFE_RET; } else { pr_err("WARNING: kernel not compiled with CPU_SRSO.\n"); @@ -2696,6 +2712,9 @@ static ssize_t retbleed_show_state(char *buf) static ssize_t srso_show_state(char *buf) { + if (boot_cpu_has(X86_FEATURE_SRSO_NO)) + return sysfs_emit(buf, "Mitigation: SMT disabled\n"); + return sysfs_emit(buf, "%s%s\n", srso_strings[srso_mitigation], (cpu_has_ibpb_brtype_microcode() ? "" : ", no microcode")); |