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Diffstat (limited to 'arch/x86/kernel/cpu/bugs.c')
-rw-r--r--arch/x86/kernel/cpu/bugs.c157
1 files changed, 121 insertions, 36 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index bb0ab8466b91..e7ba936d798b 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -56,7 +56,7 @@ EXPORT_SYMBOL_GPL(x86_spec_ctrl_base);
/* The current value of the SPEC_CTRL MSR with task-specific bits set */
DEFINE_PER_CPU(u64, x86_spec_ctrl_current);
-EXPORT_SYMBOL_GPL(x86_spec_ctrl_current);
+EXPORT_PER_CPU_SYMBOL_GPL(x86_spec_ctrl_current);
u64 x86_pred_cmd __ro_after_init = PRED_CMD_IBPB;
EXPORT_SYMBOL_GPL(x86_pred_cmd);
@@ -111,9 +111,6 @@ DEFINE_STATIC_KEY_FALSE(switch_mm_cond_ibpb);
/* Control unconditional IBPB in switch_mm() */
DEFINE_STATIC_KEY_FALSE(switch_mm_always_ibpb);
-/* Control MDS CPU buffer clear before returning to user space */
-DEFINE_STATIC_KEY_FALSE(mds_user_clear);
-EXPORT_SYMBOL_GPL(mds_user_clear);
/* Control MDS CPU buffer clear before idling (halt, mwait) */
DEFINE_STATIC_KEY_FALSE(mds_idle_clear);
EXPORT_SYMBOL_GPL(mds_idle_clear);
@@ -252,7 +249,7 @@ static void __init mds_select_mitigation(void)
if (!boot_cpu_has(X86_FEATURE_MD_CLEAR))
mds_mitigation = MDS_MITIGATION_VMWERV;
- static_branch_enable(&mds_user_clear);
+ setup_force_cpu_cap(X86_FEATURE_CLEAR_CPU_BUF);
if (!boot_cpu_has(X86_BUG_MSBDS_ONLY) &&
(mds_nosmt || cpu_mitigations_auto_nosmt()))
@@ -356,7 +353,7 @@ static void __init taa_select_mitigation(void)
* For guests that can't determine whether the correct microcode is
* present on host, enable the mitigation for UCODE_NEEDED as well.
*/
- static_branch_enable(&mds_user_clear);
+ setup_force_cpu_cap(X86_FEATURE_CLEAR_CPU_BUF);
if (taa_nosmt || cpu_mitigations_auto_nosmt())
cpu_smt_disable(false);
@@ -424,7 +421,14 @@ static void __init mmio_select_mitigation(void)
*/
if (boot_cpu_has_bug(X86_BUG_MDS) || (boot_cpu_has_bug(X86_BUG_TAA) &&
boot_cpu_has(X86_FEATURE_RTM)))
- static_branch_enable(&mds_user_clear);
+ setup_force_cpu_cap(X86_FEATURE_CLEAR_CPU_BUF);
+
+ /*
+ * X86_FEATURE_CLEAR_CPU_BUF could be enabled by other VERW based
+ * mitigations, disable KVM-only mitigation in that case.
+ */
+ if (boot_cpu_has(X86_FEATURE_CLEAR_CPU_BUF))
+ static_branch_disable(&mmio_stale_data_clear);
else
static_branch_enable(&mmio_stale_data_clear);
@@ -477,6 +481,57 @@ static int __init mmio_stale_data_parse_cmdline(char *str)
early_param("mmio_stale_data", mmio_stale_data_parse_cmdline);
#undef pr_fmt
+#define pr_fmt(fmt) "Register File Data Sampling: " fmt
+
+enum rfds_mitigations {
+ RFDS_MITIGATION_OFF,
+ RFDS_MITIGATION_VERW,
+ RFDS_MITIGATION_UCODE_NEEDED,
+};
+
+/* Default mitigation for Register File Data Sampling */
+static enum rfds_mitigations rfds_mitigation __ro_after_init =
+ IS_ENABLED(CONFIG_MITIGATION_RFDS) ? RFDS_MITIGATION_VERW : RFDS_MITIGATION_OFF;
+
+static const char * const rfds_strings[] = {
+ [RFDS_MITIGATION_OFF] = "Vulnerable",
+ [RFDS_MITIGATION_VERW] = "Mitigation: Clear Register File",
+ [RFDS_MITIGATION_UCODE_NEEDED] = "Vulnerable: No microcode",
+};
+
+static void __init rfds_select_mitigation(void)
+{
+ if (!boot_cpu_has_bug(X86_BUG_RFDS) || cpu_mitigations_off()) {
+ rfds_mitigation = RFDS_MITIGATION_OFF;
+ return;
+ }
+ if (rfds_mitigation == RFDS_MITIGATION_OFF)
+ return;
+
+ if (x86_read_arch_cap_msr() & ARCH_CAP_RFDS_CLEAR)
+ setup_force_cpu_cap(X86_FEATURE_CLEAR_CPU_BUF);
+ else
+ rfds_mitigation = RFDS_MITIGATION_UCODE_NEEDED;
+}
+
+static __init int rfds_parse_cmdline(char *str)
+{
+ if (!str)
+ return -EINVAL;
+
+ if (!boot_cpu_has_bug(X86_BUG_RFDS))
+ return 0;
+
+ if (!strcmp(str, "off"))
+ rfds_mitigation = RFDS_MITIGATION_OFF;
+ else if (!strcmp(str, "on"))
+ rfds_mitigation = RFDS_MITIGATION_VERW;
+
+ return 0;
+}
+early_param("reg_file_data_sampling", rfds_parse_cmdline);
+
+#undef pr_fmt
#define pr_fmt(fmt) "" fmt
static void __init md_clear_update_mitigation(void)
@@ -484,12 +539,12 @@ static void __init md_clear_update_mitigation(void)
if (cpu_mitigations_off())
return;
- if (!static_key_enabled(&mds_user_clear))
+ if (!boot_cpu_has(X86_FEATURE_CLEAR_CPU_BUF))
goto out;
/*
- * mds_user_clear is now enabled. Update MDS, TAA and MMIO Stale Data
- * mitigation, if necessary.
+ * X86_FEATURE_CLEAR_CPU_BUF is now enabled. Update MDS, TAA and MMIO
+ * Stale Data mitigation, if necessary.
*/
if (mds_mitigation == MDS_MITIGATION_OFF &&
boot_cpu_has_bug(X86_BUG_MDS)) {
@@ -501,11 +556,19 @@ static void __init md_clear_update_mitigation(void)
taa_mitigation = TAA_MITIGATION_VERW;
taa_select_mitigation();
}
- if (mmio_mitigation == MMIO_MITIGATION_OFF &&
- boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA)) {
+ /*
+ * MMIO_MITIGATION_OFF is not checked here so that mmio_stale_data_clear
+ * gets updated correctly as per X86_FEATURE_CLEAR_CPU_BUF state.
+ */
+ if (boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA)) {
mmio_mitigation = MMIO_MITIGATION_VERW;
mmio_select_mitigation();
}
+ if (rfds_mitigation == RFDS_MITIGATION_OFF &&
+ boot_cpu_has_bug(X86_BUG_RFDS)) {
+ rfds_mitigation = RFDS_MITIGATION_VERW;
+ rfds_select_mitigation();
+ }
out:
if (boot_cpu_has_bug(X86_BUG_MDS))
pr_info("MDS: %s\n", mds_strings[mds_mitigation]);
@@ -515,6 +578,8 @@ out:
pr_info("MMIO Stale Data: %s\n", mmio_strings[mmio_mitigation]);
else if (boot_cpu_has_bug(X86_BUG_MMIO_UNKNOWN))
pr_info("MMIO Stale Data: Unknown: No mitigations\n");
+ if (boot_cpu_has_bug(X86_BUG_RFDS))
+ pr_info("Register File Data Sampling: %s\n", rfds_strings[rfds_mitigation]);
}
static void __init md_clear_select_mitigation(void)
@@ -522,11 +587,12 @@ static void __init md_clear_select_mitigation(void)
mds_select_mitigation();
taa_select_mitigation();
mmio_select_mitigation();
+ rfds_select_mitigation();
/*
- * As MDS, TAA and MMIO Stale Data mitigations are inter-related, update
- * and print their mitigation after MDS, TAA and MMIO Stale Data
- * mitigation selection is done.
+ * As these mitigations are inter-related and rely on VERW instruction
+ * to clear the microarchitural buffers, update and print their status
+ * after mitigation selection is done for each of these vulnerabilities.
*/
md_clear_update_mitigation();
}
@@ -671,7 +737,7 @@ enum gds_mitigations {
GDS_MITIGATION_HYPERVISOR,
};
-#if IS_ENABLED(CONFIG_GDS_FORCE_MITIGATION)
+#if IS_ENABLED(CONFIG_MITIGATION_GDS_FORCE)
static enum gds_mitigations gds_mitigation __ro_after_init = GDS_MITIGATION_FORCE;
#else
static enum gds_mitigations gds_mitigation __ro_after_init = GDS_MITIGATION_FULL;
@@ -982,10 +1048,10 @@ static void __init retbleed_select_mitigation(void)
return;
case RETBLEED_CMD_UNRET:
- if (IS_ENABLED(CONFIG_CPU_UNRET_ENTRY)) {
+ if (IS_ENABLED(CONFIG_MITIGATION_UNRET_ENTRY)) {
retbleed_mitigation = RETBLEED_MITIGATION_UNRET;
} else {
- pr_err("WARNING: kernel not compiled with CPU_UNRET_ENTRY.\n");
+ pr_err("WARNING: kernel not compiled with MITIGATION_UNRET_ENTRY.\n");
goto do_cmd_auto;
}
break;
@@ -994,24 +1060,24 @@ static void __init retbleed_select_mitigation(void)
if (!boot_cpu_has(X86_FEATURE_IBPB)) {
pr_err("WARNING: CPU does not support IBPB.\n");
goto do_cmd_auto;
- } else if (IS_ENABLED(CONFIG_CPU_IBPB_ENTRY)) {
+ } else if (IS_ENABLED(CONFIG_MITIGATION_IBPB_ENTRY)) {
retbleed_mitigation = RETBLEED_MITIGATION_IBPB;
} else {
- pr_err("WARNING: kernel not compiled with CPU_IBPB_ENTRY.\n");
+ pr_err("WARNING: kernel not compiled with MITIGATION_IBPB_ENTRY.\n");
goto do_cmd_auto;
}
break;
case RETBLEED_CMD_STUFF:
- if (IS_ENABLED(CONFIG_CALL_DEPTH_TRACKING) &&
+ if (IS_ENABLED(CONFIG_MITIGATION_CALL_DEPTH_TRACKING) &&
spectre_v2_enabled == SPECTRE_V2_RETPOLINE) {
retbleed_mitigation = RETBLEED_MITIGATION_STUFF;
} else {
- if (IS_ENABLED(CONFIG_CALL_DEPTH_TRACKING))
+ if (IS_ENABLED(CONFIG_MITIGATION_CALL_DEPTH_TRACKING))
pr_err("WARNING: retbleed=stuff depends on spectre_v2=retpoline\n");
else
- pr_err("WARNING: kernel not compiled with CALL_DEPTH_TRACKING.\n");
+ pr_err("WARNING: kernel not compiled with MITIGATION_CALL_DEPTH_TRACKING.\n");
goto do_cmd_auto;
}
@@ -1021,9 +1087,10 @@ do_cmd_auto:
case RETBLEED_CMD_AUTO:
if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
- if (IS_ENABLED(CONFIG_CPU_UNRET_ENTRY))
+ if (IS_ENABLED(CONFIG_MITIGATION_UNRET_ENTRY))
retbleed_mitigation = RETBLEED_MITIGATION_UNRET;
- else if (IS_ENABLED(CONFIG_CPU_IBPB_ENTRY) && boot_cpu_has(X86_FEATURE_IBPB))
+ else if (IS_ENABLED(CONFIG_MITIGATION_IBPB_ENTRY) &&
+ boot_cpu_has(X86_FEATURE_IBPB))
retbleed_mitigation = RETBLEED_MITIGATION_IBPB;
}
@@ -1102,7 +1169,7 @@ static enum spectre_v2_user_mitigation spectre_v2_user_stibp __ro_after_init =
static enum spectre_v2_user_mitigation spectre_v2_user_ibpb __ro_after_init =
SPECTRE_V2_USER_NONE;
-#ifdef CONFIG_RETPOLINE
+#ifdef CONFIG_MITIGATION_RETPOLINE
static bool spectre_v2_bad_module;
bool retpoline_module_ok(bool has_retpoline)
@@ -1415,7 +1482,7 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
cmd == SPECTRE_V2_CMD_RETPOLINE_GENERIC ||
cmd == SPECTRE_V2_CMD_EIBRS_LFENCE ||
cmd == SPECTRE_V2_CMD_EIBRS_RETPOLINE) &&
- !IS_ENABLED(CONFIG_RETPOLINE)) {
+ !IS_ENABLED(CONFIG_MITIGATION_RETPOLINE)) {
pr_err("%s selected but not compiled in. Switching to AUTO select\n",
mitigation_options[i].option);
return SPECTRE_V2_CMD_AUTO;
@@ -1438,7 +1505,7 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
return SPECTRE_V2_CMD_AUTO;
}
- if (cmd == SPECTRE_V2_CMD_IBRS && !IS_ENABLED(CONFIG_CPU_IBRS_ENTRY)) {
+ if (cmd == SPECTRE_V2_CMD_IBRS && !IS_ENABLED(CONFIG_MITIGATION_IBRS_ENTRY)) {
pr_err("%s selected but not compiled in. Switching to AUTO select\n",
mitigation_options[i].option);
return SPECTRE_V2_CMD_AUTO;
@@ -1469,7 +1536,7 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
static enum spectre_v2_mitigation __init spectre_v2_select_retpoline(void)
{
- if (!IS_ENABLED(CONFIG_RETPOLINE)) {
+ if (!IS_ENABLED(CONFIG_MITIGATION_RETPOLINE)) {
pr_err("Kernel not compiled with retpoline; no mitigation available!");
return SPECTRE_V2_NONE;
}
@@ -1564,7 +1631,7 @@ static void __init spectre_v2_select_mitigation(void)
break;
}
- if (IS_ENABLED(CONFIG_CPU_IBRS_ENTRY) &&
+ if (IS_ENABLED(CONFIG_MITIGATION_IBRS_ENTRY) &&
boot_cpu_has_bug(X86_BUG_RETBLEED) &&
retbleed_cmd != RETBLEED_CMD_OFF &&
retbleed_cmd != RETBLEED_CMD_STUFF &&
@@ -2457,7 +2524,7 @@ static void __init srso_select_mitigation(void)
break;
case SRSO_CMD_SAFE_RET:
- if (IS_ENABLED(CONFIG_CPU_SRSO)) {
+ if (IS_ENABLED(CONFIG_MITIGATION_SRSO)) {
/*
* Enable the return thunk for generated code
* like ftrace, static_call, etc.
@@ -2477,29 +2544,29 @@ static void __init srso_select_mitigation(void)
else
srso_mitigation = SRSO_MITIGATION_SAFE_RET_UCODE_NEEDED;
} else {
- pr_err("WARNING: kernel not compiled with CPU_SRSO.\n");
+ pr_err("WARNING: kernel not compiled with MITIGATION_SRSO.\n");
}
break;
case SRSO_CMD_IBPB:
- if (IS_ENABLED(CONFIG_CPU_IBPB_ENTRY)) {
+ if (IS_ENABLED(CONFIG_MITIGATION_IBPB_ENTRY)) {
if (has_microcode) {
setup_force_cpu_cap(X86_FEATURE_ENTRY_IBPB);
srso_mitigation = SRSO_MITIGATION_IBPB;
}
} else {
- pr_err("WARNING: kernel not compiled with CPU_IBPB_ENTRY.\n");
+ pr_err("WARNING: kernel not compiled with MITIGATION_IBPB_ENTRY.\n");
}
break;
case SRSO_CMD_IBPB_ON_VMEXIT:
- if (IS_ENABLED(CONFIG_CPU_SRSO)) {
+ if (IS_ENABLED(CONFIG_MITIGATION_SRSO)) {
if (!boot_cpu_has(X86_FEATURE_ENTRY_IBPB) && has_microcode) {
setup_force_cpu_cap(X86_FEATURE_IBPB_ON_VMEXIT);
srso_mitigation = SRSO_MITIGATION_IBPB_ON_VMEXIT;
}
} else {
- pr_err("WARNING: kernel not compiled with CPU_SRSO.\n");
+ pr_err("WARNING: kernel not compiled with MITIGATION_SRSO.\n");
}
break;
}
@@ -2615,6 +2682,11 @@ static ssize_t mmio_stale_data_show_state(char *buf)
sched_smt_active() ? "vulnerable" : "disabled");
}
+static ssize_t rfds_show_state(char *buf)
+{
+ return sysfs_emit(buf, "%s\n", rfds_strings[rfds_mitigation]);
+}
+
static char *stibp_state(void)
{
if (spectre_v2_in_eibrs_mode(spectre_v2_enabled) &&
@@ -2774,6 +2846,9 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr
case X86_BUG_GDS:
return gds_show_state(buf);
+ case X86_BUG_RFDS:
+ return rfds_show_state(buf);
+
default:
break;
}
@@ -2848,4 +2923,14 @@ ssize_t cpu_show_gds(struct device *dev, struct device_attribute *attr, char *bu
{
return cpu_show_common(dev, attr, buf, X86_BUG_GDS);
}
+
+ssize_t cpu_show_reg_file_data_sampling(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ return cpu_show_common(dev, attr, buf, X86_BUG_RFDS);
+}
#endif
+
+void __warn_thunk(void)
+{
+ WARN_ONCE(1, "Unpatched return thunk in use. This should not happen!\n");
+}
generated by cgit v1.2.3 (git 2.39.0) at 2024-09-29 13:20:20 +0300