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Diffstat (limited to 'arch/x86/kernel/cpu/bugs.c')
-rw-r--r--arch/x86/kernel/cpu/bugs.c117
1 files changed, 62 insertions, 55 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 48ae44cf7795..af748d1c78d4 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1153,19 +1153,21 @@ spectre_v2_user_select_mitigation(void)
}
/*
- * If no STIBP, enhanced IBRS is enabled, or SMT impossible, STIBP
+ * If no STIBP, Intel enhanced IBRS is enabled, or SMT impossible, STIBP
* is not required.
*
- * Enhanced IBRS also protects against cross-thread branch target
+ * Intel's Enhanced IBRS also protects against cross-thread branch target
* injection in user-mode as the IBRS bit remains always set which
* implicitly enables cross-thread protections. However, in legacy IBRS
* mode, the IBRS bit is set only on kernel entry and cleared on return
- * to userspace. This disables the implicit cross-thread protection,
- * so allow for STIBP to be selected in that case.
+ * to userspace. AMD Automatic IBRS also does not protect userspace.
+ * These modes therefore disable the implicit cross-thread protection,
+ * so allow for STIBP to be selected in those cases.
*/
if (!boot_cpu_has(X86_FEATURE_STIBP) ||
!smt_possible ||
- spectre_v2_in_eibrs_mode(spectre_v2_enabled))
+ (spectre_v2_in_eibrs_mode(spectre_v2_enabled) &&
+ !boot_cpu_has(X86_FEATURE_AUTOIBRS)))
return;
/*
@@ -1187,9 +1189,9 @@ static const char * const spectre_v2_strings[] = {
[SPECTRE_V2_NONE] = "Vulnerable",
[SPECTRE_V2_RETPOLINE] = "Mitigation: Retpolines",
[SPECTRE_V2_LFENCE] = "Mitigation: LFENCE",
- [SPECTRE_V2_EIBRS] = "Mitigation: Enhanced IBRS",
- [SPECTRE_V2_EIBRS_LFENCE] = "Mitigation: Enhanced IBRS + LFENCE",
- [SPECTRE_V2_EIBRS_RETPOLINE] = "Mitigation: Enhanced IBRS + Retpolines",
+ [SPECTRE_V2_EIBRS] = "Mitigation: Enhanced / Automatic IBRS",
+ [SPECTRE_V2_EIBRS_LFENCE] = "Mitigation: Enhanced / Automatic IBRS + LFENCE",
+ [SPECTRE_V2_EIBRS_RETPOLINE] = "Mitigation: Enhanced / Automatic IBRS + Retpolines",
[SPECTRE_V2_IBRS] = "Mitigation: IBRS",
};
@@ -1258,7 +1260,7 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
cmd == SPECTRE_V2_CMD_EIBRS_LFENCE ||
cmd == SPECTRE_V2_CMD_EIBRS_RETPOLINE) &&
!boot_cpu_has(X86_FEATURE_IBRS_ENHANCED)) {
- pr_err("%s selected but CPU doesn't have eIBRS. Switching to AUTO select\n",
+ pr_err("%s selected but CPU doesn't have Enhanced or Automatic IBRS. Switching to AUTO select\n",
mitigation_options[i].option);
return SPECTRE_V2_CMD_AUTO;
}
@@ -1436,8 +1438,12 @@ static void __init spectre_v2_select_mitigation(void)
pr_err(SPECTRE_V2_EIBRS_EBPF_MSG);
if (spectre_v2_in_ibrs_mode(mode)) {
- x86_spec_ctrl_base |= SPEC_CTRL_IBRS;
- update_spec_ctrl(x86_spec_ctrl_base);
+ if (boot_cpu_has(X86_FEATURE_AUTOIBRS)) {
+ msr_set_bit(MSR_EFER, _EFER_AUTOIBRS);
+ } else {
+ x86_spec_ctrl_base |= SPEC_CTRL_IBRS;
+ update_spec_ctrl(x86_spec_ctrl_base);
+ }
}
switch (mode) {
@@ -1521,8 +1527,8 @@ static void __init spectre_v2_select_mitigation(void)
/*
* Retpoline protects the kernel, but doesn't protect firmware. IBRS
* and Enhanced IBRS protect firmware too, so enable IBRS around
- * firmware calls only when IBRS / Enhanced IBRS aren't otherwise
- * enabled.
+ * firmware calls only when IBRS / Enhanced / Automatic IBRS aren't
+ * otherwise enabled.
*
* Use "mode" to check Enhanced IBRS instead of boot_cpu_has(), because
* the user might select retpoline on the kernel command line and if
@@ -2144,69 +2150,69 @@ static const char * const l1tf_vmx_states[] = {
static ssize_t l1tf_show_state(char *buf)
{
if (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_AUTO)
- return sprintf(buf, "%s\n", L1TF_DEFAULT_MSG);
+ return sysfs_emit(buf, "%s\n", L1TF_DEFAULT_MSG);
if (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_EPT_DISABLED ||
(l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_NEVER &&
sched_smt_active())) {
- return sprintf(buf, "%s; VMX: %s\n", L1TF_DEFAULT_MSG,
- l1tf_vmx_states[l1tf_vmx_mitigation]);
+ return sysfs_emit(buf, "%s; VMX: %s\n", L1TF_DEFAULT_MSG,
+ l1tf_vmx_states[l1tf_vmx_mitigation]);
}
- return sprintf(buf, "%s; VMX: %s, SMT %s\n", L1TF_DEFAULT_MSG,
- l1tf_vmx_states[l1tf_vmx_mitigation],
- sched_smt_active() ? "vulnerable" : "disabled");
+ return sysfs_emit(buf, "%s; VMX: %s, SMT %s\n", L1TF_DEFAULT_MSG,
+ l1tf_vmx_states[l1tf_vmx_mitigation],
+ sched_smt_active() ? "vulnerable" : "disabled");
}
static ssize_t itlb_multihit_show_state(char *buf)
{
if (itlb_multihit_kvm_mitigation)
- return sprintf(buf, "KVM: Mitigation: Split huge pages\n");
+ return sysfs_emit(buf, "KVM: Mitigation: Split huge pages\n");
else
- return sprintf(buf, "KVM: Vulnerable\n");
+ return sysfs_emit(buf, "KVM: Vulnerable\n");
}
#else
static ssize_t l1tf_show_state(char *buf)
{
- return sprintf(buf, "%s\n", L1TF_DEFAULT_MSG);
+ return sysfs_emit(buf, "%s\n", L1TF_DEFAULT_MSG);
}
static ssize_t itlb_multihit_show_state(char *buf)
{
- return sprintf(buf, "Processor vulnerable\n");
+ return sysfs_emit(buf, "Processor vulnerable\n");
}
#endif
static ssize_t mds_show_state(char *buf)
{
if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
- return sprintf(buf, "%s; SMT Host state unknown\n",
- mds_strings[mds_mitigation]);
+ return sysfs_emit(buf, "%s; SMT Host state unknown\n",
+ mds_strings[mds_mitigation]);
}
if (boot_cpu_has(X86_BUG_MSBDS_ONLY)) {
- return sprintf(buf, "%s; SMT %s\n", mds_strings[mds_mitigation],
- (mds_mitigation == MDS_MITIGATION_OFF ? "vulnerable" :
- sched_smt_active() ? "mitigated" : "disabled"));
+ return sysfs_emit(buf, "%s; SMT %s\n", mds_strings[mds_mitigation],
+ (mds_mitigation == MDS_MITIGATION_OFF ? "vulnerable" :
+ sched_smt_active() ? "mitigated" : "disabled"));
}
- return sprintf(buf, "%s; SMT %s\n", mds_strings[mds_mitigation],
- sched_smt_active() ? "vulnerable" : "disabled");
+ return sysfs_emit(buf, "%s; SMT %s\n", mds_strings[mds_mitigation],
+ sched_smt_active() ? "vulnerable" : "disabled");
}
static ssize_t tsx_async_abort_show_state(char *buf)
{
if ((taa_mitigation == TAA_MITIGATION_TSX_DISABLED) ||
(taa_mitigation == TAA_MITIGATION_OFF))
- return sprintf(buf, "%s\n", taa_strings[taa_mitigation]);
+ return sysfs_emit(buf, "%s\n", taa_strings[taa_mitigation]);
if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
- return sprintf(buf, "%s; SMT Host state unknown\n",
- taa_strings[taa_mitigation]);
+ return sysfs_emit(buf, "%s; SMT Host state unknown\n",
+ taa_strings[taa_mitigation]);
}
- return sprintf(buf, "%s; SMT %s\n", taa_strings[taa_mitigation],
- sched_smt_active() ? "vulnerable" : "disabled");
+ return sysfs_emit(buf, "%s; SMT %s\n", taa_strings[taa_mitigation],
+ sched_smt_active() ? "vulnerable" : "disabled");
}
static ssize_t mmio_stale_data_show_state(char *buf)
@@ -2228,7 +2234,8 @@ static ssize_t mmio_stale_data_show_state(char *buf)
static char *stibp_state(void)
{
- if (spectre_v2_in_eibrs_mode(spectre_v2_enabled))
+ if (spectre_v2_in_eibrs_mode(spectre_v2_enabled) &&
+ !boot_cpu_has(X86_FEATURE_AUTOIBRS))
return "";
switch (spectre_v2_user_stibp) {
@@ -2274,33 +2281,33 @@ static char *pbrsb_eibrs_state(void)
static ssize_t spectre_v2_show_state(char *buf)
{
if (spectre_v2_enabled == SPECTRE_V2_LFENCE)
- return sprintf(buf, "Vulnerable: LFENCE\n");
+ return sysfs_emit(buf, "Vulnerable: LFENCE\n");
if (spectre_v2_enabled == SPECTRE_V2_EIBRS && unprivileged_ebpf_enabled())
- return sprintf(buf, "Vulnerable: eIBRS with unprivileged eBPF\n");
+ return sysfs_emit(buf, "Vulnerable: eIBRS with unprivileged eBPF\n");
if (sched_smt_active() && unprivileged_ebpf_enabled() &&
spectre_v2_enabled == SPECTRE_V2_EIBRS_LFENCE)
- return sprintf(buf, "Vulnerable: eIBRS+LFENCE with unprivileged eBPF and SMT\n");
+ return sysfs_emit(buf, "Vulnerable: eIBRS+LFENCE with unprivileged eBPF and SMT\n");
- return sprintf(buf, "%s%s%s%s%s%s%s\n",
- spectre_v2_strings[spectre_v2_enabled],
- ibpb_state(),
- boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "",
- stibp_state(),
- boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "",
- pbrsb_eibrs_state(),
- spectre_v2_module_string());
+ return sysfs_emit(buf, "%s%s%s%s%s%s%s\n",
+ spectre_v2_strings[spectre_v2_enabled],
+ ibpb_state(),
+ boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "",
+ stibp_state(),
+ boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "",
+ pbrsb_eibrs_state(),
+ spectre_v2_module_string());
}
static ssize_t srbds_show_state(char *buf)
{
- return sprintf(buf, "%s\n", srbds_strings[srbds_mitigation]);
+ return sysfs_emit(buf, "%s\n", srbds_strings[srbds_mitigation]);
}
static ssize_t retbleed_show_state(char *buf)
{
- return sprintf(buf, "%s\n", retbleed_strings[retbleed_mitigation]);
+ return sysfs_emit(buf, "%s\n", retbleed_strings[retbleed_mitigation]);
}
static ssize_t gds_show_state(char *buf)
@@ -2312,26 +2319,26 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr
char *buf, unsigned int bug)
{
if (!boot_cpu_has_bug(bug))
- return sprintf(buf, "Not affected\n");
+ return sysfs_emit(buf, "Not affected\n");
switch (bug) {
case X86_BUG_CPU_MELTDOWN:
if (boot_cpu_has(X86_FEATURE_PTI))
- return sprintf(buf, "Mitigation: PTI\n");
+ return sysfs_emit(buf, "Mitigation: PTI\n");
if (hypervisor_is_type(X86_HYPER_XEN_PV))
- return sprintf(buf, "Unknown (XEN PV detected, hypervisor mitigation required)\n");
+ return sysfs_emit(buf, "Unknown (XEN PV detected, hypervisor mitigation required)\n");
break;
case X86_BUG_SPECTRE_V1:
- return sprintf(buf, "%s\n", spectre_v1_strings[spectre_v1_mitigation]);
+ return sysfs_emit(buf, "%s\n", spectre_v1_strings[spectre_v1_mitigation]);
case X86_BUG_SPECTRE_V2:
return spectre_v2_show_state(buf);
case X86_BUG_SPEC_STORE_BYPASS:
- return sprintf(buf, "%s\n", ssb_strings[ssb_mode]);
+ return sysfs_emit(buf, "%s\n", ssb_strings[ssb_mode]);
case X86_BUG_L1TF:
if (boot_cpu_has(X86_FEATURE_L1TF_PTEINV))
@@ -2364,7 +2371,7 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr
break;
}
- return sprintf(buf, "Vulnerable\n");
+ return sysfs_emit(buf, "Vulnerable\n");
}
ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-06-19 01:13:22 +0000