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Merge branch 'for-next/mitigations' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux into for-next/core

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Esse commit está contido em:
Will Deacon
2019-05-01 15:34:56 +01:00
pai 9431ac2bf6 4ad499c942
commit 50abbe1962
13 arquivos alterados com 325 adições e 97 exclusões
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243
arch/arm64/kernel/cpu_errata.c
Ver arquivo

@@ -19,6 +19,7 @@
#include <linux/arm-smccc.h>
#include <linux/psci.h>
#include <linux/types.h>
#include <linux/cpu.h>
#include <asm/cpu.h>
#include <asm/cputype.h>
#include <asm/cpufeature.h>
@@ -109,7 +110,6 @@ cpu_enable_trap_ctr_access(const struct arm64_cpu_capabilities *__unused)
atomic_t arm64_el2_vector_last_slot = ATOMIC_INIT(-1);
#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
#include <asm/mmu_context.h>
#include <asm/cacheflush.h>
@@ -131,9 +131,9 @@ static void __copy_hyp_vect_bpi(int slot, const char *hyp_vecs_start,
__flush_icache_range((uintptr_t)dst, (uintptr_t)dst + SZ_2K);
}
static void __install_bp_hardening_cb(bp_hardening_cb_t fn,
const char *hyp_vecs_start,
const char *hyp_vecs_end)
static void install_bp_hardening_cb(bp_hardening_cb_t fn,
const char *hyp_vecs_start,
const char *hyp_vecs_end)
{
static DEFINE_RAW_SPINLOCK(bp_lock);
int cpu, slot = -1;
@@ -169,7 +169,7 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn,
#define __smccc_workaround_1_smc_start NULL
#define __smccc_workaround_1_smc_end NULL
static void __install_bp_hardening_cb(bp_hardening_cb_t fn,
static void install_bp_hardening_cb(bp_hardening_cb_t fn,
const char *hyp_vecs_start,
const char *hyp_vecs_end)
{
@@ -177,23 +177,6 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn,
}
#endif /* CONFIG_KVM_INDIRECT_VECTORS */
static void install_bp_hardening_cb(const struct arm64_cpu_capabilities *entry,
bp_hardening_cb_t fn,
const char *hyp_vecs_start,
const char *hyp_vecs_end)
{
u64 pfr0;
if (!entry->matches(entry, SCOPE_LOCAL_CPU))
return;
pfr0 = read_cpuid(ID_AA64PFR0_EL1);
if (cpuid_feature_extract_unsigned_field(pfr0, ID_AA64PFR0_CSV2_SHIFT))
return;
__install_bp_hardening_cb(fn, hyp_vecs_start, hyp_vecs_end);
}
#include <uapi/linux/psci.h>
#include <linux/arm-smccc.h>
#include <linux/psci.h>
@@ -220,60 +203,83 @@ static void qcom_link_stack_sanitization(void)
: "=&r" (tmp));
}
static void
enable_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry)
static bool __nospectre_v2;
static int __init parse_nospectre_v2(char *str)
{
__nospectre_v2 = true;
return 0;
}
early_param("nospectre_v2", parse_nospectre_v2);
/*
* -1: No workaround
* 0: No workaround required
* 1: Workaround installed
*/
static int detect_harden_bp_fw(void)
{
bp_hardening_cb_t cb;
void *smccc_start, *smccc_end;
struct arm_smccc_res res;
u32 midr = read_cpuid_id();
if (!entry->matches(entry, SCOPE_LOCAL_CPU))
return;
if (psci_ops.smccc_version == SMCCC_VERSION_1_0)
return;
return -1;
switch (psci_ops.conduit) {
case PSCI_CONDUIT_HVC:
arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
ARM_SMCCC_ARCH_WORKAROUND_1, &res);
if ((int)res.a0 < 0)
return;
cb = call_hvc_arch_workaround_1;
/* This is a guest, no need to patch KVM vectors */
smccc_start = NULL;
smccc_end = NULL;
switch ((int)res.a0) {
case 1:
/* Firmware says we're just fine */
return 0;
case 0:
cb = call_hvc_arch_workaround_1;
/* This is a guest, no need to patch KVM vectors */
smccc_start = NULL;
smccc_end = NULL;
break;
default:
return -1;
}
break;
case PSCI_CONDUIT_SMC:
arm_smccc_1_1_smc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
ARM_SMCCC_ARCH_WORKAROUND_1, &res);
if ((int)res.a0 < 0)
return;
cb = call_smc_arch_workaround_1;
smccc_start = __smccc_workaround_1_smc_start;
smccc_end = __smccc_workaround_1_smc_end;
switch ((int)res.a0) {
case 1:
/* Firmware says we're just fine */
return 0;
case 0:
cb = call_smc_arch_workaround_1;
smccc_start = __smccc_workaround_1_smc_start;
smccc_end = __smccc_workaround_1_smc_end;
break;
default:
return -1;
}
break;
default:
return;
return -1;
}
if (((midr & MIDR_CPU_MODEL_MASK) == MIDR_QCOM_FALKOR) ||
((midr & MIDR_CPU_MODEL_MASK) == MIDR_QCOM_FALKOR_V1))
cb = qcom_link_stack_sanitization;
install_bp_hardening_cb(entry, cb, smccc_start, smccc_end);
if (IS_ENABLED(CONFIG_HARDEN_BRANCH_PREDICTOR))
install_bp_hardening_cb(cb, smccc_start, smccc_end);
return;
return 1;
}
#endif /* CONFIG_HARDEN_BRANCH_PREDICTOR */
#ifdef CONFIG_ARM64_SSBD
DEFINE_PER_CPU_READ_MOSTLY(u64, arm64_ssbd_callback_required);
int ssbd_state __read_mostly = ARM64_SSBD_KERNEL;
static bool __ssb_safe = true;
static const struct ssbd_options {
const char *str;
@@ -343,6 +349,11 @@ void __init arm64_enable_wa2_handling(struct alt_instr *alt,
void arm64_set_ssbd_mitigation(bool state)
{
if (!IS_ENABLED(CONFIG_ARM64_SSBD)) {
pr_info_once("SSBD disabled by kernel configuration\n");
return;
}
if (this_cpu_has_cap(ARM64_SSBS)) {
if (state)
asm volatile(SET_PSTATE_SSBS(0));
@@ -372,16 +383,28 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
struct arm_smccc_res res;
bool required = true;
s32 val;
bool this_cpu_safe = false;
WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible());
if (cpu_mitigations_off())
ssbd_state = ARM64_SSBD_FORCE_DISABLE;
/* delay setting __ssb_safe until we get a firmware response */
if (is_midr_in_range_list(read_cpuid_id(), entry->midr_range_list))
this_cpu_safe = true;
if (this_cpu_has_cap(ARM64_SSBS)) {
if (!this_cpu_safe)
__ssb_safe = false;
required = false;
goto out_printmsg;
}
if (psci_ops.smccc_version == SMCCC_VERSION_1_0) {
ssbd_state = ARM64_SSBD_UNKNOWN;
if (!this_cpu_safe)
__ssb_safe = false;
return false;
}
@@ -398,6 +421,8 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
default:
ssbd_state = ARM64_SSBD_UNKNOWN;
if (!this_cpu_safe)
__ssb_safe = false;
return false;
}
@@ -406,14 +431,18 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
switch (val) {
case SMCCC_RET_NOT_SUPPORTED:
ssbd_state = ARM64_SSBD_UNKNOWN;
if (!this_cpu_safe)
__ssb_safe = false;
return false;
/* machines with mixed mitigation requirements must not return this */
case SMCCC_RET_NOT_REQUIRED:
pr_info_once("%s mitigation not required\n", entry->desc);
ssbd_state = ARM64_SSBD_MITIGATED;
return false;
case SMCCC_RET_SUCCESS:
__ssb_safe = false;
required = true;
break;
@@ -423,6 +452,8 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
default:
WARN_ON(1);
if (!this_cpu_safe)
__ssb_safe = false;
return false;
}
@@ -462,7 +493,14 @@ out_printmsg:
return required;
}
#endif /* CONFIG_ARM64_SSBD */
/* known invulnerable cores */
static const struct midr_range arm64_ssb_cpus[] = {
MIDR_ALL_VERSIONS(MIDR_CORTEX_A35),
MIDR_ALL_VERSIONS(MIDR_CORTEX_A53),
MIDR_ALL_VERSIONS(MIDR_CORTEX_A55),
{},
};
static void __maybe_unused
cpu_enable_cache_maint_trap(const struct arm64_cpu_capabilities *__unused)
@@ -507,26 +545,67 @@ cpu_enable_cache_maint_trap(const struct arm64_cpu_capabilities *__unused)
.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, \
CAP_MIDR_RANGE_LIST(midr_list)
#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
/* Track overall mitigation state. We are only mitigated if all cores are ok */
static bool __hardenbp_enab = true;
static bool __spectrev2_safe = true;
/*
* List of CPUs where we need to issue a psci call to
* harden the branch predictor.
* List of CPUs that do not need any Spectre-v2 mitigation at all.
*/
static const struct midr_range arm64_bp_harden_smccc_cpus[] = {
MIDR_ALL_VERSIONS(MIDR_CORTEX_A57),
MIDR_ALL_VERSIONS(MIDR_CORTEX_A72),
MIDR_ALL_VERSIONS(MIDR_CORTEX_A73),
MIDR_ALL_VERSIONS(MIDR_CORTEX_A75),
MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2),
MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR_V1),
MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR),
MIDR_ALL_VERSIONS(MIDR_NVIDIA_DENVER),
{},
static const struct midr_range spectre_v2_safe_list[] = {
MIDR_ALL_VERSIONS(MIDR_CORTEX_A35),
MIDR_ALL_VERSIONS(MIDR_CORTEX_A53),
MIDR_ALL_VERSIONS(MIDR_CORTEX_A55),
{ /* sentinel */ }
};
#endif
/*
* Track overall bp hardening for all heterogeneous cores in the machine.
* We are only considered "safe" if all booted cores are known safe.
*/
static bool __maybe_unused
check_branch_predictor(const struct arm64_cpu_capabilities *entry, int scope)
{
int need_wa;
WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible());
/* If the CPU has CSV2 set, we're safe */
if (cpuid_feature_extract_unsigned_field(read_cpuid(ID_AA64PFR0_EL1),
ID_AA64PFR0_CSV2_SHIFT))
return false;
/* Alternatively, we have a list of unaffected CPUs */
if (is_midr_in_range_list(read_cpuid_id(), spectre_v2_safe_list))
return false;
/* Fallback to firmware detection */
need_wa = detect_harden_bp_fw();
if (!need_wa)
return false;
__spectrev2_safe = false;
if (!IS_ENABLED(CONFIG_HARDEN_BRANCH_PREDICTOR)) {
pr_warn_once("spectrev2 mitigation disabled by kernel configuration\n");
__hardenbp_enab = false;
return false;
}
/* forced off */
if (__nospectre_v2 || cpu_mitigations_off()) {
pr_info_once("spectrev2 mitigation disabled by command line option\n");
__hardenbp_enab = false;
return false;
}
if (need_wa < 0) {
pr_warn_once("ARM_SMCCC_ARCH_WORKAROUND_1 missing from firmware\n");
__hardenbp_enab = false;
}
return (need_wa > 0);
}
#ifdef CONFIG_HARDEN_EL2_VECTORS
@@ -701,13 +780,11 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
ERRATA_MIDR_ALL_VERSIONS(MIDR_CORTEX_A73),
},
#endif
#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
{
.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
.cpu_enable = enable_smccc_arch_workaround_1,
ERRATA_MIDR_RANGE_LIST(arm64_bp_harden_smccc_cpus),
.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM,
.matches = check_branch_predictor,
},
#endif
#ifdef CONFIG_HARDEN_EL2_VECTORS
{
.desc = "EL2 vector hardening",
@@ -715,14 +792,13 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
ERRATA_MIDR_RANGE_LIST(arm64_harden_el2_vectors),
},
#endif
#ifdef CONFIG_ARM64_SSBD
{
.desc = "Speculative Store Bypass Disable",
.capability = ARM64_SSBD,
.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM,
.matches = has_ssbd_mitigation,
.midr_range_list = arm64_ssb_cpus,
},
#endif
#ifdef CONFIG_ARM64_ERRATUM_1188873
{
/* Cortex-A76 r0p0 to r2p0 */
@@ -742,3 +818,38 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
{
}
};
ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr,
char *buf)
{
return sprintf(buf, "Mitigation: __user pointer sanitization\n");
}
ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr,
char *buf)
{
if (__spectrev2_safe)
return sprintf(buf, "Not affected\n");
if (__hardenbp_enab)
return sprintf(buf, "Mitigation: Branch predictor hardening\n");
return sprintf(buf, "Vulnerable\n");
}
ssize_t cpu_show_spec_store_bypass(struct device *dev,
struct device_attribute *attr, char *buf)
{
if (__ssb_safe)
return sprintf(buf, "Not affected\n");
switch (ssbd_state) {
case ARM64_SSBD_KERNEL:
case ARM64_SSBD_FORCE_ENABLE:
if (IS_ENABLED(CONFIG_ARM64_SSBD))
return sprintf(buf,
"Mitigation: Speculative Store Bypass disabled via prctl\n");
}
return sprintf(buf, "Vulnerable\n");
}

66
arch/arm64/kernel/cpufeature.c
Ver arquivo

@@ -25,6 +25,7 @@
#include <linux/stop_machine.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/cpu.h>
#include <asm/cpu.h>
#include <asm/cpufeature.h>
#include <asm/cpu_ops.h>
@@ -956,7 +957,7 @@ has_useable_cnp(const struct arm64_cpu_capabilities *entry, int scope)
return has_cpuid_feature(entry, scope);
}
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
static bool __meltdown_safe = true;
static int __kpti_forced; /* 0: not forced, >0: forced on, <0: forced off */
static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
@@ -975,7 +976,17 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
MIDR_ALL_VERSIONS(MIDR_HISI_TSV110),
{ /* sentinel */ }
};
char const *str = "command line option";
char const *str = "kpti command line option";
bool meltdown_safe;
meltdown_safe = is_midr_in_range_list(read_cpuid_id(), kpti_safe_list);
/* Defer to CPU feature registers */
if (has_cpuid_feature(entry, scope))
meltdown_safe = true;
if (!meltdown_safe)
__meltdown_safe = false;
/*
* For reasons that aren't entirely clear, enabling KPTI on Cavium
@@ -987,6 +998,24 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
__kpti_forced = -1;
}
/* Useful for KASLR robustness */
if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_offset() > 0) {
if (!__kpti_forced) {
str = "KASLR";
__kpti_forced = 1;
}
}
if (cpu_mitigations_off() && !__kpti_forced) {
str = "mitigations=off";
__kpti_forced = -1;
}
if (!IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0)) {
pr_info_once("kernel page table isolation disabled by kernel configuration\n");
return false;
}
/* Forced? */
if (__kpti_forced) {
pr_info_once("kernel page table isolation forced %s by %s\n",
@@ -994,18 +1023,10 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
return __kpti_forced > 0;
}
/* Useful for KASLR robustness */
if (IS_ENABLED(CONFIG_RANDOMIZE_BASE))
return kaslr_offset() > 0;
/* Don't force KPTI for CPUs that are not vulnerable */
if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list))
return false;
/* Defer to CPU feature registers */
return !has_cpuid_feature(entry, scope);
return !meltdown_safe;
}
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
static void
kpti_install_ng_mappings(const struct arm64_cpu_capabilities *__unused)
{
@@ -1035,6 +1056,12 @@ kpti_install_ng_mappings(const struct arm64_cpu_capabilities *__unused)
return;
}
#else
static void
kpti_install_ng_mappings(const struct arm64_cpu_capabilities *__unused)
{
}
#endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */
static int __init parse_kpti(char *str)
{
@@ -1048,7 +1075,6 @@ static int __init parse_kpti(char *str)
return 0;
}
early_param("kpti", parse_kpti);
#endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */
#ifdef CONFIG_ARM64_HW_AFDBM
static inline void __cpu_enable_hw_dbm(void)
@@ -1315,7 +1341,6 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.field_pos = ID_AA64PFR0_EL0_SHIFT,
.min_field_value = ID_AA64PFR0_EL0_32BIT_64BIT,
},
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
{
.desc = "Kernel page table isolation (KPTI)",
.capability = ARM64_UNMAP_KERNEL_AT_EL0,
@@ -1331,7 +1356,6 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.matches = unmap_kernel_at_el0,
.cpu_enable = kpti_install_ng_mappings,
},
#endif
{
/* FP/SIMD is not implemented */
.capability = ARM64_HAS_NO_FPSIMD,
@@ -2156,3 +2180,15 @@ static int __init enable_mrs_emulation(void)
}
core_initcall(enable_mrs_emulation);
ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr,
char *buf)
{
if (__meltdown_safe)
return sprintf(buf, "Not affected\n");
if (arm64_kernel_unmapped_at_el0())
return sprintf(buf, "Mitigation: PTI\n");
return sprintf(buf, "Vulnerable\n");
}