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-rw-r--r--arch/x86/kernel/cpu/bugs.c75
-rw-r--r--arch/x86/kernel/cpu/common.c44
-rw-r--r--arch/x86/kernel/head64.c2
-rw-r--r--arch/x86/kernel/pmem.c7
-rw-r--r--arch/x86/kernel/unwind_orc.c15
5 files changed, 122 insertions, 21 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 058e92b93..501d09d59 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -396,7 +396,8 @@ static void __init mmio_select_mitigation(void)
u64 ia32_cap;
if (!boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA) ||
- cpu_mitigations_off()) {
+ boot_cpu_has_bug(X86_BUG_MMIO_UNKNOWN) ||
+ cpu_mitigations_off()) {
mmio_mitigation = MMIO_MITIGATION_OFF;
return;
}
@@ -501,6 +502,8 @@ out:
pr_info("TAA: %s\n", taa_strings[taa_mitigation]);
if (boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA))
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");
}
static void __init md_clear_select_mitigation(void)
@@ -1043,6 +1046,49 @@ static enum spectre_v2_mitigation __init spectre_v2_select_retpoline(void)
return SPECTRE_V2_RETPOLINE;
}
+static void __init spectre_v2_determine_rsb_fill_type_at_vmexit(enum spectre_v2_mitigation mode)
+{
+ /*
+ * Similar to context switches, there are two types of RSB attacks
+ * after VM exit:
+ *
+ * 1) RSB underflow
+ *
+ * 2) Poisoned RSB entry
+ *
+ * When retpoline is enabled, both are mitigated by filling/clearing
+ * the RSB.
+ *
+ * When IBRS is enabled, while #1 would be mitigated by the IBRS branch
+ * prediction isolation protections, RSB still needs to be cleared
+ * because of #2. Note that SMEP provides no protection here, unlike
+ * user-space-poisoned RSB entries.
+ *
+ * eIBRS should protect against RSB poisoning, but if the EIBRS_PBRSB
+ * bug is present then a LITE version of RSB protection is required,
+ * just a single call needs to retire before a RET is executed.
+ */
+ switch (mode) {
+ case SPECTRE_V2_NONE:
+ /* These modes already fill RSB at vmexit */
+ case SPECTRE_V2_LFENCE:
+ case SPECTRE_V2_RETPOLINE:
+ case SPECTRE_V2_EIBRS_RETPOLINE:
+ return;
+
+ case SPECTRE_V2_EIBRS_LFENCE:
+ case SPECTRE_V2_EIBRS:
+ if (boot_cpu_has_bug(X86_BUG_EIBRS_PBRSB)) {
+ setup_force_cpu_cap(X86_FEATURE_RSB_VMEXIT_LITE);
+ pr_info("Spectre v2 / PBRSB-eIBRS: Retire a single CALL on VMEXIT\n");
+ }
+ return;
+ }
+
+ pr_warn_once("Unknown Spectre v2 mode, disabling RSB mitigation at VM exit");
+ dump_stack();
+}
+
static void __init spectre_v2_select_mitigation(void)
{
enum spectre_v2_mitigation_cmd cmd = spectre_v2_parse_cmdline();
@@ -1135,6 +1181,8 @@ static void __init spectre_v2_select_mitigation(void)
setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW);
pr_info("Spectre v2 / SpectreRSB mitigation: Filling RSB on context switch\n");
+ spectre_v2_determine_rsb_fill_type_at_vmexit(mode);
+
/*
* Retpoline means the kernel is safe because it has no indirect
* branches. Enhanced IBRS protects firmware too, so, enable restricted
@@ -1823,6 +1871,9 @@ static ssize_t tsx_async_abort_show_state(char *buf)
static ssize_t mmio_stale_data_show_state(char *buf)
{
+ if (boot_cpu_has_bug(X86_BUG_MMIO_UNKNOWN))
+ return sysfs_emit(buf, "Unknown: No mitigations\n");
+
if (mmio_mitigation == MMIO_MITIGATION_OFF)
return sysfs_emit(buf, "%s\n", mmio_strings[mmio_mitigation]);
@@ -1867,6 +1918,19 @@ static char *ibpb_state(void)
return "";
}
+static char *pbrsb_eibrs_state(void)
+{
+ if (boot_cpu_has_bug(X86_BUG_EIBRS_PBRSB)) {
+ if (boot_cpu_has(X86_FEATURE_RSB_VMEXIT_LITE) ||
+ boot_cpu_has(X86_FEATURE_RETPOLINE))
+ return ", PBRSB-eIBRS: SW sequence";
+ else
+ return ", PBRSB-eIBRS: Vulnerable";
+ } else {
+ return ", PBRSB-eIBRS: Not affected";
+ }
+}
+
static ssize_t spectre_v2_show_state(char *buf)
{
if (spectre_v2_enabled == SPECTRE_V2_LFENCE)
@@ -1879,12 +1943,13 @@ static ssize_t spectre_v2_show_state(char *buf)
spectre_v2_enabled == SPECTRE_V2_EIBRS_LFENCE)
return sprintf(buf, "Vulnerable: eIBRS+LFENCE with unprivileged eBPF and SMT\n");
- return sprintf(buf, "%s%s%s%s%s%s\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());
}
@@ -1936,6 +2001,7 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr
return srbds_show_state(buf);
case X86_BUG_MMIO_STALE_DATA:
+ case X86_BUG_MMIO_UNKNOWN:
return mmio_stale_data_show_state(buf);
default:
@@ -1992,6 +2058,9 @@ ssize_t cpu_show_srbds(struct device *dev, struct device_attribute *attr, char *
ssize_t cpu_show_mmio_stale_data(struct device *dev, struct device_attribute *attr, char *buf)
{
- return cpu_show_common(dev, attr, buf, X86_BUG_MMIO_STALE_DATA);
+ if (boot_cpu_has_bug(X86_BUG_MMIO_UNKNOWN))
+ return cpu_show_common(dev, attr, buf, X86_BUG_MMIO_UNKNOWN);
+ else
+ return cpu_show_common(dev, attr, buf, X86_BUG_MMIO_STALE_DATA);
}
#endif
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 389d11b2c..653ced7cb 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -954,6 +954,8 @@ static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
#define MSBDS_ONLY BIT(5)
#define NO_SWAPGS BIT(6)
#define NO_ITLB_MULTIHIT BIT(7)
+#define NO_EIBRS_PBRSB BIT(8)
+#define NO_MMIO BIT(9)
#define VULNWL(_vendor, _family, _model, _whitelist) \
{ X86_VENDOR_##_vendor, _family, _model, X86_FEATURE_ANY, _whitelist }
@@ -971,6 +973,11 @@ static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = {
VULNWL(NSC, 5, X86_MODEL_ANY, NO_SPECULATION),
/* Intel Family 6 */
+ VULNWL_INTEL(TIGERLAKE, NO_MMIO),
+ VULNWL_INTEL(TIGERLAKE_L, NO_MMIO),
+ VULNWL_INTEL(ALDERLAKE, NO_MMIO),
+ VULNWL_INTEL(ALDERLAKE_L, NO_MMIO),
+
VULNWL_INTEL(ATOM_SALTWELL, NO_SPECULATION | NO_ITLB_MULTIHIT),
VULNWL_INTEL(ATOM_SALTWELL_TABLET, NO_SPECULATION | NO_ITLB_MULTIHIT),
VULNWL_INTEL(ATOM_SALTWELL_MID, NO_SPECULATION | NO_ITLB_MULTIHIT),
@@ -988,9 +995,9 @@ static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = {
VULNWL_INTEL(ATOM_AIRMONT_MID, NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT),
- VULNWL_INTEL(ATOM_GOLDMONT, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT),
- VULNWL_INTEL(ATOM_GOLDMONT_X, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT),
- VULNWL_INTEL(ATOM_GOLDMONT_PLUS, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT),
+ VULNWL_INTEL(ATOM_GOLDMONT, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
+ VULNWL_INTEL(ATOM_GOLDMONT_X, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
+ VULNWL_INTEL(ATOM_GOLDMONT_PLUS, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO | NO_EIBRS_PBRSB),
/*
* Technically, swapgs isn't serializing on AMD (despite it previously
@@ -1000,16 +1007,18 @@ static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = {
* good enough for our purposes.
*/
- VULNWL_INTEL(ATOM_TREMONT_X, NO_ITLB_MULTIHIT),
+ VULNWL_INTEL(ATOM_TREMONT, NO_EIBRS_PBRSB),
+ VULNWL_INTEL(ATOM_TREMONT_L, NO_EIBRS_PBRSB),
+ VULNWL_INTEL(ATOM_TREMONT_X, NO_ITLB_MULTIHIT | NO_EIBRS_PBRSB),
/* AMD Family 0xf - 0x12 */
- VULNWL_AMD(0x0f, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT),
- VULNWL_AMD(0x10, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT),
- VULNWL_AMD(0x11, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT),
- VULNWL_AMD(0x12, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT),
+ VULNWL_AMD(0x0f, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
+ VULNWL_AMD(0x10, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
+ VULNWL_AMD(0x11, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
+ VULNWL_AMD(0x12, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
/* FAMILY_ANY must be last, otherwise 0x0f - 0x12 matches won't work */
- VULNWL_AMD(X86_FAMILY_ANY, NO_MELTDOWN | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT),
+ VULNWL_AMD(X86_FAMILY_ANY, NO_MELTDOWN | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
{}
};
@@ -1149,10 +1158,21 @@ static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c)
* Affected CPU list is generally enough to enumerate the vulnerability,
* but for virtualization case check for ARCH_CAP MSR bits also, VMM may
* not want the guest to enumerate the bug.
+ *
+ * Set X86_BUG_MMIO_UNKNOWN for CPUs that are neither in the blacklist,
+ * nor in the whitelist and also don't enumerate MSR ARCH_CAP MMIO bits.
*/
- if (cpu_matches(cpu_vuln_blacklist, MMIO) &&
- !arch_cap_mmio_immune(ia32_cap))
- setup_force_cpu_bug(X86_BUG_MMIO_STALE_DATA);
+ if (!arch_cap_mmio_immune(ia32_cap)) {
+ if (cpu_matches(cpu_vuln_blacklist, MMIO))
+ setup_force_cpu_bug(X86_BUG_MMIO_STALE_DATA);
+ else if (!cpu_matches(cpu_vuln_whitelist, NO_MMIO))
+ setup_force_cpu_bug(X86_BUG_MMIO_UNKNOWN);
+ }
+
+ if (cpu_has(c, X86_FEATURE_IBRS_ENHANCED) &&
+ !cpu_matches(cpu_vuln_whitelist, NO_EIBRS_PBRSB) &&
+ !(ia32_cap & ARCH_CAP_PBRSB_NO))
+ setup_force_cpu_bug(X86_BUG_EIBRS_PBRSB);
if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN))
return;
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 88dc38b4a..90c2613af 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -383,6 +383,8 @@ static void __init clear_bss(void)
{
memset(__bss_start, 0,
(unsigned long) __bss_stop - (unsigned long) __bss_start);
+ memset(__brk_base, 0,
+ (unsigned long) __brk_limit - (unsigned long) __brk_base);
}
static unsigned long get_cmd_line_ptr(void)
diff --git a/arch/x86/kernel/pmem.c b/arch/x86/kernel/pmem.c
index 6b07faaa1..23154d24b 100644
--- a/arch/x86/kernel/pmem.c
+++ b/arch/x86/kernel/pmem.c
@@ -27,6 +27,11 @@ static __init int register_e820_pmem(void)
* simply here to trigger the module to load on demand.
*/
pdev = platform_device_alloc("e820_pmem", -1);
- return platform_device_add(pdev);
+
+ rc = platform_device_add(pdev);
+ if (rc)
+ platform_device_put(pdev);
+
+ return rc;
}
device_initcall(register_e820_pmem);
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index 4f17c1c94..5c48d2c4c 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -89,22 +89,27 @@ static struct orc_entry *orc_find(unsigned long ip);
static struct orc_entry *orc_ftrace_find(unsigned long ip)
{
struct ftrace_ops *ops;
- unsigned long caller;
+ unsigned long tramp_addr, offset;
ops = ftrace_ops_trampoline(ip);
if (!ops)
return NULL;
+ /* Set tramp_addr to the start of the code copied by the trampoline */
if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
- caller = (unsigned long)ftrace_regs_call;
+ tramp_addr = (unsigned long)ftrace_regs_caller;
else
- caller = (unsigned long)ftrace_call;
+ tramp_addr = (unsigned long)ftrace_caller;
+
+ /* Now place tramp_addr to the location within the trampoline ip is at */
+ offset = ip - ops->trampoline;
+ tramp_addr += offset;
/* Prevent unlikely recursion */
- if (ip == caller)
+ if (ip == tramp_addr)
return NULL;
- return orc_find(caller);
+ return orc_find(tramp_addr);
}
#else
static struct orc_entry *orc_ftrace_find(unsigned long ip)
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-24 06:54:32 +0000