1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/arm-smccc.h>
3 #include <linux/kernel.h>
7 #include <asm/cputype.h>
8 #include <asm/proc-fns.h>
9 #include <asm/system_misc.h>
11 #ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
12 DEFINE_PER_CPU(harden_branch_predictor_fn_t, harden_branch_predictor_fn);
14 extern void cpu_v7_iciallu_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm);
15 extern void cpu_v7_bpiall_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm);
16 extern void cpu_v7_smc_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm);
17 extern void cpu_v7_hvc_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm);
19 static void harden_branch_predictor_bpiall(void)
21 write_sysreg(0, BPIALL);
24 static void harden_branch_predictor_iciallu(void)
26 write_sysreg(0, ICIALLU);
29 static void __maybe_unused call_smc_arch_workaround_1(void)
31 arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL);
34 static void __maybe_unused call_hvc_arch_workaround_1(void)
36 arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL);
39 static void cpu_v7_spectre_init(void)
41 const char *spectre_v2_method = NULL;
42 int cpu = smp_processor_id();
44 if (per_cpu(harden_branch_predictor_fn, cpu))
47 switch (read_cpuid_part()) {
48 case ARM_CPU_PART_CORTEX_A8:
49 case ARM_CPU_PART_CORTEX_A9:
50 case ARM_CPU_PART_CORTEX_A12:
51 case ARM_CPU_PART_CORTEX_A17:
52 case ARM_CPU_PART_CORTEX_A73:
53 case ARM_CPU_PART_CORTEX_A75:
54 per_cpu(harden_branch_predictor_fn, cpu) =
55 harden_branch_predictor_bpiall;
56 spectre_v2_method = "BPIALL";
59 case ARM_CPU_PART_CORTEX_A15:
60 case ARM_CPU_PART_BRAHMA_B15:
61 per_cpu(harden_branch_predictor_fn, cpu) =
62 harden_branch_predictor_iciallu;
63 spectre_v2_method = "ICIALLU";
66 #ifdef CONFIG_ARM_PSCI
68 /* Other ARM CPUs require no workaround */
69 if (read_cpuid_implementor() == ARM_CPU_IMP_ARM)
72 /* Cortex A57/A72 require firmware workaround */
73 case ARM_CPU_PART_CORTEX_A57:
74 case ARM_CPU_PART_CORTEX_A72: {
75 struct arm_smccc_res res;
77 arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
78 ARM_SMCCC_ARCH_WORKAROUND_1, &res);
82 switch (arm_smccc_1_1_get_conduit()) {
83 case SMCCC_CONDUIT_HVC:
84 per_cpu(harden_branch_predictor_fn, cpu) =
85 call_hvc_arch_workaround_1;
86 cpu_do_switch_mm = cpu_v7_hvc_switch_mm;
87 spectre_v2_method = "hypervisor";
90 case SMCCC_CONDUIT_SMC:
91 per_cpu(harden_branch_predictor_fn, cpu) =
92 call_smc_arch_workaround_1;
93 cpu_do_switch_mm = cpu_v7_smc_switch_mm;
94 spectre_v2_method = "firmware";
104 if (spectre_v2_method)
105 pr_info("CPU%u: Spectre v2: using %s workaround\n",
106 smp_processor_id(), spectre_v2_method);
109 static void cpu_v7_spectre_init(void)
114 static __maybe_unused bool cpu_v7_check_auxcr_set(bool *warned,
115 u32 mask, const char *msg)
119 asm("mrc p15, 0, %0, c1, c0, 1" : "=r" (aux_cr));
121 if ((aux_cr & mask) != mask) {
123 pr_err("CPU%u: %s", smp_processor_id(), msg);
130 static DEFINE_PER_CPU(bool, spectre_warned);
132 static bool check_spectre_auxcr(bool *warned, u32 bit)
134 return IS_ENABLED(CONFIG_HARDEN_BRANCH_PREDICTOR) &&
135 cpu_v7_check_auxcr_set(warned, bit,
136 "Spectre v2: firmware did not set auxiliary control register IBE bit, system vulnerable\n");
139 void cpu_v7_ca8_ibe(void)
141 if (check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(6)))
142 cpu_v7_spectre_init();
145 void cpu_v7_ca15_ibe(void)
147 if (check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(0)))
148 cpu_v7_spectre_init();
151 void cpu_v7_bugs_init(void)
153 cpu_v7_spectre_init();