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authorLinus Torvalds <torvalds@linux-foundation.org>2024-09-16 06:48:38 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2024-09-16 06:48:38 +0200
commit963d0d60d690ce2525a8fbcc0a63c4ae22f4670c (patch)
treefa7c29a9f09847ad131a62c4930eb760a086cb87 /arch/x86/kernel
parentd580d74ea2836edbbd49cd791eb5d0acad7b14aa (diff)
parent1dbb6b1495d472806fef1f4c94f5b3e4c89a3c1d (diff)
Merge tag 'x86_bugs_for_v6.12_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 hw mitigation updates from Borislav Petkov: - Add CONFIG_ option for every hw CPU mitigation. The intent is to support configurations and scenarios where the mitigations code is irrelevant - Other small fixlets and improvements * tag 'x86_bugs_for_v6.12_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/bugs: Fix handling when SRSO mitigation is disabled x86/bugs: Add missing NO_SSB flag Documentation/srso: Document a method for checking safe RET operates properly x86/bugs: Add a separate config for GDS x86/bugs: Remove GDS Force Kconfig option x86/bugs: Add a separate config for SSB x86/bugs: Add a separate config for Spectre V2 x86/bugs: Add a separate config for SRBDS x86/bugs: Add a separate config for Spectre v1 x86/bugs: Add a separate config for RETBLEED x86/bugs: Add a separate config for L1TF x86/bugs: Add a separate config for MMIO Stable Data x86/bugs: Add a separate config for TAA x86/bugs: Add a separate config for MDS
Diffstat (limited to 'arch/x86/kernel')
-rw-r--r--arch/x86/kernel/cpu/bugs.c60
-rw-r--r--arch/x86/kernel/cpu/common.c4
2 files changed, 33 insertions, 31 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 45675da354f3..d1915427b4ff 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -233,7 +233,8 @@ static void x86_amd_ssb_disable(void)
#define pr_fmt(fmt) "MDS: " fmt
/* Default mitigation for MDS-affected CPUs */
-static enum mds_mitigations mds_mitigation __ro_after_init = MDS_MITIGATION_FULL;
+static enum mds_mitigations mds_mitigation __ro_after_init =
+ IS_ENABLED(CONFIG_MITIGATION_MDS) ? MDS_MITIGATION_FULL : MDS_MITIGATION_OFF;
static bool mds_nosmt __ro_after_init = false;
static const char * const mds_strings[] = {
@@ -293,7 +294,8 @@ enum taa_mitigations {
};
/* Default mitigation for TAA-affected CPUs */
-static enum taa_mitigations taa_mitigation __ro_after_init = TAA_MITIGATION_VERW;
+static enum taa_mitigations taa_mitigation __ro_after_init =
+ IS_ENABLED(CONFIG_MITIGATION_TAA) ? TAA_MITIGATION_VERW : TAA_MITIGATION_OFF;
static bool taa_nosmt __ro_after_init;
static const char * const taa_strings[] = {
@@ -391,7 +393,8 @@ enum mmio_mitigations {
};
/* Default mitigation for Processor MMIO Stale Data vulnerabilities */
-static enum mmio_mitigations mmio_mitigation __ro_after_init = MMIO_MITIGATION_VERW;
+static enum mmio_mitigations mmio_mitigation __ro_after_init =
+ IS_ENABLED(CONFIG_MITIGATION_MMIO_STALE_DATA) ? MMIO_MITIGATION_VERW : MMIO_MITIGATION_OFF;
static bool mmio_nosmt __ro_after_init = false;
static const char * const mmio_strings[] = {
@@ -605,7 +608,8 @@ enum srbds_mitigations {
SRBDS_MITIGATION_HYPERVISOR,
};
-static enum srbds_mitigations srbds_mitigation __ro_after_init = SRBDS_MITIGATION_FULL;
+static enum srbds_mitigations srbds_mitigation __ro_after_init =
+ IS_ENABLED(CONFIG_MITIGATION_SRBDS) ? SRBDS_MITIGATION_FULL : SRBDS_MITIGATION_OFF;
static const char * const srbds_strings[] = {
[SRBDS_MITIGATION_OFF] = "Vulnerable",
@@ -731,11 +735,8 @@ enum gds_mitigations {
GDS_MITIGATION_HYPERVISOR,
};
-#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;
-#endif
+static enum gds_mitigations gds_mitigation __ro_after_init =
+ IS_ENABLED(CONFIG_MITIGATION_GDS) ? GDS_MITIGATION_FULL : GDS_MITIGATION_OFF;
static const char * const gds_strings[] = {
[GDS_MITIGATION_OFF] = "Vulnerable",
@@ -871,7 +872,8 @@ enum spectre_v1_mitigation {
};
static enum spectre_v1_mitigation spectre_v1_mitigation __ro_after_init =
- SPECTRE_V1_MITIGATION_AUTO;
+ IS_ENABLED(CONFIG_MITIGATION_SPECTRE_V1) ?
+ SPECTRE_V1_MITIGATION_AUTO : SPECTRE_V1_MITIGATION_NONE;
static const char * const spectre_v1_strings[] = {
[SPECTRE_V1_MITIGATION_NONE] = "Vulnerable: __user pointer sanitization and usercopy barriers only; no swapgs barriers",
@@ -986,7 +988,7 @@ static const char * const retbleed_strings[] = {
static enum retbleed_mitigation retbleed_mitigation __ro_after_init =
RETBLEED_MITIGATION_NONE;
static enum retbleed_mitigation_cmd retbleed_cmd __ro_after_init =
- RETBLEED_CMD_AUTO;
+ IS_ENABLED(CONFIG_MITIGATION_RETBLEED) ? RETBLEED_CMD_AUTO : RETBLEED_CMD_OFF;
static int __ro_after_init retbleed_nosmt = false;
@@ -1447,17 +1449,18 @@ static void __init spec_v2_print_cond(const char *reason, bool secure)
static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
{
- enum spectre_v2_mitigation_cmd cmd = SPECTRE_V2_CMD_AUTO;
+ enum spectre_v2_mitigation_cmd cmd;
char arg[20];
int ret, i;
+ cmd = IS_ENABLED(CONFIG_MITIGATION_SPECTRE_V2) ? SPECTRE_V2_CMD_AUTO : SPECTRE_V2_CMD_NONE;
if (cmdline_find_option_bool(boot_command_line, "nospectre_v2") ||
cpu_mitigations_off())
return SPECTRE_V2_CMD_NONE;
ret = cmdline_find_option(boot_command_line, "spectre_v2", arg, sizeof(arg));
if (ret < 0)
- return SPECTRE_V2_CMD_AUTO;
+ return cmd;
for (i = 0; i < ARRAY_SIZE(mitigation_options); i++) {
if (!match_option(arg, ret, mitigation_options[i].option))
@@ -1467,8 +1470,8 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
}
if (i >= ARRAY_SIZE(mitigation_options)) {
- pr_err("unknown option (%s). Switching to AUTO select\n", arg);
- return SPECTRE_V2_CMD_AUTO;
+ pr_err("unknown option (%s). Switching to default mode\n", arg);
+ return cmd;
}
if ((cmd == SPECTRE_V2_CMD_RETPOLINE ||
@@ -2021,10 +2024,12 @@ static const struct {
static enum ssb_mitigation_cmd __init ssb_parse_cmdline(void)
{
- enum ssb_mitigation_cmd cmd = SPEC_STORE_BYPASS_CMD_AUTO;
+ enum ssb_mitigation_cmd cmd;
char arg[20];
int ret, i;
+ cmd = IS_ENABLED(CONFIG_MITIGATION_SSB) ?
+ SPEC_STORE_BYPASS_CMD_AUTO : SPEC_STORE_BYPASS_CMD_NONE;
if (cmdline_find_option_bool(boot_command_line, "nospec_store_bypass_disable") ||
cpu_mitigations_off()) {
return SPEC_STORE_BYPASS_CMD_NONE;
@@ -2032,7 +2037,7 @@ static enum ssb_mitigation_cmd __init ssb_parse_cmdline(void)
ret = cmdline_find_option(boot_command_line, "spec_store_bypass_disable",
arg, sizeof(arg));
if (ret < 0)
- return SPEC_STORE_BYPASS_CMD_AUTO;
+ return cmd;
for (i = 0; i < ARRAY_SIZE(ssb_mitigation_options); i++) {
if (!match_option(arg, ret, ssb_mitigation_options[i].option))
@@ -2043,8 +2048,8 @@ static enum ssb_mitigation_cmd __init ssb_parse_cmdline(void)
}
if (i >= ARRAY_SIZE(ssb_mitigation_options)) {
- pr_err("unknown option (%s). Switching to AUTO select\n", arg);
- return SPEC_STORE_BYPASS_CMD_AUTO;
+ pr_err("unknown option (%s). Switching to default mode\n", arg);
+ return cmd;
}
}
@@ -2371,7 +2376,8 @@ EXPORT_SYMBOL_GPL(itlb_multihit_kvm_mitigation);
#define pr_fmt(fmt) "L1TF: " fmt
/* Default mitigation for L1TF-affected CPUs */
-enum l1tf_mitigations l1tf_mitigation __ro_after_init = L1TF_MITIGATION_FLUSH;
+enum l1tf_mitigations l1tf_mitigation __ro_after_init =
+ IS_ENABLED(CONFIG_MITIGATION_L1TF) ? L1TF_MITIGATION_FLUSH : L1TF_MITIGATION_OFF;
#if IS_ENABLED(CONFIG_KVM_INTEL)
EXPORT_SYMBOL_GPL(l1tf_mitigation);
#endif
@@ -2551,10 +2557,9 @@ static void __init srso_select_mitigation(void)
{
bool has_microcode = boot_cpu_has(X86_FEATURE_IBPB_BRTYPE);
- if (cpu_mitigations_off())
- return;
-
- if (!boot_cpu_has_bug(X86_BUG_SRSO)) {
+ if (!boot_cpu_has_bug(X86_BUG_SRSO) ||
+ cpu_mitigations_off() ||
+ srso_cmd == SRSO_CMD_OFF) {
if (boot_cpu_has(X86_FEATURE_SBPB))
x86_pred_cmd = PRED_CMD_SBPB;
return;
@@ -2585,11 +2590,6 @@ static void __init srso_select_mitigation(void)
}
switch (srso_cmd) {
- case SRSO_CMD_OFF:
- if (boot_cpu_has(X86_FEATURE_SBPB))
- x86_pred_cmd = PRED_CMD_SBPB;
- return;
-
case SRSO_CMD_MICROCODE:
if (has_microcode) {
srso_mitigation = SRSO_MITIGATION_MICROCODE;
@@ -2643,6 +2643,8 @@ static void __init srso_select_mitigation(void)
pr_err("WARNING: kernel not compiled with MITIGATION_SRSO.\n");
}
break;
+ default:
+ break;
}
out:
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index d4e539d4e158..be307c9ef263 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1165,8 +1165,8 @@ static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = {
VULNWL_INTEL(INTEL_CORE_YONAH, NO_SSB),
- VULNWL_INTEL(INTEL_ATOM_AIRMONT_MID, NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT),
- VULNWL_INTEL(INTEL_ATOM_AIRMONT_NP, NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT),
+ VULNWL_INTEL(INTEL_ATOM_AIRMONT_MID, NO_SSB | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | MSBDS_ONLY),
+ VULNWL_INTEL(INTEL_ATOM_AIRMONT_NP, NO_SSB | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT),
VULNWL_INTEL(INTEL_ATOM_GOLDMONT, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
VULNWL_INTEL(INTEL_ATOM_GOLDMONT_D, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),