linux/arch/arm/mm/proc-v7-bugs.c
Dmitry Osipenko e4ced82deb ARM: 9213/1: Print message about disabled Spectre workarounds only once
Print the message about disabled Spectre workarounds only once. The
message is printed each time CPU goes out from idling state on NVIDIA
Tegra boards, causing storm in KMSG that makes system unusable.

Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-07-06 22:44:49 +01:00

298 lines
6.6 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/arm-smccc.h>
#include <linux/kernel.h>
#include <linux/smp.h>
#include <asm/cp15.h>
#include <asm/cputype.h>
#include <asm/proc-fns.h>
#include <asm/spectre.h>
#include <asm/system_misc.h>
#ifdef CONFIG_ARM_PSCI
static int __maybe_unused spectre_v2_get_cpu_fw_mitigation_state(void)
{
struct arm_smccc_res res;
arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
ARM_SMCCC_ARCH_WORKAROUND_1, &res);
switch ((int)res.a0) {
case SMCCC_RET_SUCCESS:
return SPECTRE_MITIGATED;
case SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED:
return SPECTRE_UNAFFECTED;
default:
return SPECTRE_VULNERABLE;
}
}
#else
static int __maybe_unused spectre_v2_get_cpu_fw_mitigation_state(void)
{
return SPECTRE_VULNERABLE;
}
#endif
#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
DEFINE_PER_CPU(harden_branch_predictor_fn_t, harden_branch_predictor_fn);
extern void cpu_v7_iciallu_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm);
extern void cpu_v7_bpiall_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm);
extern void cpu_v7_smc_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm);
extern void cpu_v7_hvc_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm);
static void harden_branch_predictor_bpiall(void)
{
write_sysreg(0, BPIALL);
}
static void harden_branch_predictor_iciallu(void)
{
write_sysreg(0, ICIALLU);
}
static void __maybe_unused call_smc_arch_workaround_1(void)
{
arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL);
}
static void __maybe_unused call_hvc_arch_workaround_1(void)
{
arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL);
}
static unsigned int spectre_v2_install_workaround(unsigned int method)
{
const char *spectre_v2_method = NULL;
int cpu = smp_processor_id();
if (per_cpu(harden_branch_predictor_fn, cpu))
return SPECTRE_MITIGATED;
switch (method) {
case SPECTRE_V2_METHOD_BPIALL:
per_cpu(harden_branch_predictor_fn, cpu) =
harden_branch_predictor_bpiall;
spectre_v2_method = "BPIALL";
break;
case SPECTRE_V2_METHOD_ICIALLU:
per_cpu(harden_branch_predictor_fn, cpu) =
harden_branch_predictor_iciallu;
spectre_v2_method = "ICIALLU";
break;
case SPECTRE_V2_METHOD_HVC:
per_cpu(harden_branch_predictor_fn, cpu) =
call_hvc_arch_workaround_1;
cpu_do_switch_mm = cpu_v7_hvc_switch_mm;
spectre_v2_method = "hypervisor";
break;
case SPECTRE_V2_METHOD_SMC:
per_cpu(harden_branch_predictor_fn, cpu) =
call_smc_arch_workaround_1;
cpu_do_switch_mm = cpu_v7_smc_switch_mm;
spectre_v2_method = "firmware";
break;
}
if (spectre_v2_method)
pr_info("CPU%u: Spectre v2: using %s workaround\n",
smp_processor_id(), spectre_v2_method);
return SPECTRE_MITIGATED;
}
#else
static unsigned int spectre_v2_install_workaround(unsigned int method)
{
pr_info_once("Spectre V2: workarounds disabled by configuration\n");
return SPECTRE_VULNERABLE;
}
#endif
static void cpu_v7_spectre_v2_init(void)
{
unsigned int state, method = 0;
switch (read_cpuid_part()) {
case ARM_CPU_PART_CORTEX_A8:
case ARM_CPU_PART_CORTEX_A9:
case ARM_CPU_PART_CORTEX_A12:
case ARM_CPU_PART_CORTEX_A17:
case ARM_CPU_PART_CORTEX_A73:
case ARM_CPU_PART_CORTEX_A75:
state = SPECTRE_MITIGATED;
method = SPECTRE_V2_METHOD_BPIALL;
break;
case ARM_CPU_PART_CORTEX_A15:
case ARM_CPU_PART_BRAHMA_B15:
state = SPECTRE_MITIGATED;
method = SPECTRE_V2_METHOD_ICIALLU;
break;
case ARM_CPU_PART_BRAHMA_B53:
/* Requires no workaround */
state = SPECTRE_UNAFFECTED;
break;
default:
/* Other ARM CPUs require no workaround */
if (read_cpuid_implementor() == ARM_CPU_IMP_ARM) {
state = SPECTRE_UNAFFECTED;
break;
}
fallthrough;
/* Cortex A57/A72 require firmware workaround */
case ARM_CPU_PART_CORTEX_A57:
case ARM_CPU_PART_CORTEX_A72:
state = spectre_v2_get_cpu_fw_mitigation_state();
if (state != SPECTRE_MITIGATED)
break;
switch (arm_smccc_1_1_get_conduit()) {
case SMCCC_CONDUIT_HVC:
method = SPECTRE_V2_METHOD_HVC;
break;
case SMCCC_CONDUIT_SMC:
method = SPECTRE_V2_METHOD_SMC;
break;
default:
state = SPECTRE_VULNERABLE;
break;
}
}
if (state == SPECTRE_MITIGATED)
state = spectre_v2_install_workaround(method);
spectre_v2_update_state(state, method);
}
#ifdef CONFIG_HARDEN_BRANCH_HISTORY
static int spectre_bhb_method;
static const char *spectre_bhb_method_name(int method)
{
switch (method) {
case SPECTRE_V2_METHOD_LOOP8:
return "loop";
case SPECTRE_V2_METHOD_BPIALL:
return "BPIALL";
default:
return "unknown";
}
}
static int spectre_bhb_install_workaround(int method)
{
if (spectre_bhb_method != method) {
if (spectre_bhb_method) {
pr_err("CPU%u: Spectre BHB: method disagreement, system vulnerable\n",
smp_processor_id());
return SPECTRE_VULNERABLE;
}
if (spectre_bhb_update_vectors(method) == SPECTRE_VULNERABLE)
return SPECTRE_VULNERABLE;
spectre_bhb_method = method;
pr_info("CPU%u: Spectre BHB: enabling %s workaround for all CPUs\n",
smp_processor_id(), spectre_bhb_method_name(method));
}
return SPECTRE_MITIGATED;
}
#else
static int spectre_bhb_install_workaround(int method)
{
return SPECTRE_VULNERABLE;
}
#endif
static void cpu_v7_spectre_bhb_init(void)
{
unsigned int state, method = 0;
switch (read_cpuid_part()) {
case ARM_CPU_PART_CORTEX_A15:
case ARM_CPU_PART_BRAHMA_B15:
case ARM_CPU_PART_CORTEX_A57:
case ARM_CPU_PART_CORTEX_A72:
state = SPECTRE_MITIGATED;
method = SPECTRE_V2_METHOD_LOOP8;
break;
case ARM_CPU_PART_CORTEX_A73:
case ARM_CPU_PART_CORTEX_A75:
state = SPECTRE_MITIGATED;
method = SPECTRE_V2_METHOD_BPIALL;
break;
default:
state = SPECTRE_UNAFFECTED;
break;
}
if (state == SPECTRE_MITIGATED)
state = spectre_bhb_install_workaround(method);
spectre_v2_update_state(state, method);
}
static __maybe_unused bool cpu_v7_check_auxcr_set(bool *warned,
u32 mask, const char *msg)
{
u32 aux_cr;
asm("mrc p15, 0, %0, c1, c0, 1" : "=r" (aux_cr));
if ((aux_cr & mask) != mask) {
if (!*warned)
pr_err("CPU%u: %s", smp_processor_id(), msg);
*warned = true;
return false;
}
return true;
}
static DEFINE_PER_CPU(bool, spectre_warned);
static bool check_spectre_auxcr(bool *warned, u32 bit)
{
return IS_ENABLED(CONFIG_HARDEN_BRANCH_PREDICTOR) &&
cpu_v7_check_auxcr_set(warned, bit,
"Spectre v2: firmware did not set auxiliary control register IBE bit, system vulnerable\n");
}
void cpu_v7_ca8_ibe(void)
{
if (check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(6)))
cpu_v7_spectre_v2_init();
}
void cpu_v7_ca15_ibe(void)
{
if (check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(0)))
cpu_v7_spectre_v2_init();
cpu_v7_spectre_bhb_init();
}
void cpu_v7_bugs_init(void)
{
cpu_v7_spectre_v2_init();
cpu_v7_spectre_bhb_init();
}