Warn at error level if the context switching function is not what we
are expecting. This can happen with big.Little systems, which we
currently do not support.
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
---
arch/arm/mm/proc-v7-bugs.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c
index 5e50b0d9354c..615ff233641d 100644
--- a/arch/arm/mm/proc-v7-bugs.c
+++ b/arch/arm/mm/proc-v7-bugs.c
@@ -12,6 +12,8 @@
#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);
@@ -52,6 +54,8 @@ static void cpu_v7_spectre_init(void)
case ARM_CPU_PART_CORTEX_A17:
case ARM_CPU_PART_CORTEX_A73:
case ARM_CPU_PART_CORTEX_A75:
+ if (processor.switch_mm != cpu_v7_bpiall_switch_mm)
+ goto bl_error;
per_cpu(harden_branch_predictor_fn, cpu) =
harden_branch_predictor_bpiall;
spectre_v2_method = "BPIALL";
@@ -59,6 +63,8 @@ static void cpu_v7_spectre_init(void)
case ARM_CPU_PART_CORTEX_A15:
case ARM_CPU_PART_BRAHMA_B15:
+ if (processor.switch_mm != cpu_v7_iciallu_switch_mm)
+ goto bl_error;
per_cpu(harden_branch_predictor_fn, cpu) =
harden_branch_predictor_iciallu;
spectre_v2_method = "ICIALLU";
@@ -84,6 +90,8 @@ static void cpu_v7_spectre_init(void)
ARM_SMCCC_ARCH_WORKAROUND_1, &res);
if ((int)res.a0 != 0)
break;
+ if (processor.switch_mm != cpu_v7_hvc_switch_mm && cpu)
+ goto bl_error;
per_cpu(harden_branch_predictor_fn, cpu) =
call_hvc_arch_workaround_1;
processor.switch_mm = cpu_v7_hvc_switch_mm;
@@ -95,6 +103,8 @@ static void cpu_v7_spectre_init(void)
ARM_SMCCC_ARCH_WORKAROUND_1, &res);
if ((int)res.a0 != 0)
break;
+ if (processor.switch_mm != cpu_v7_smc_switch_mm && cpu)
+ goto bl_error;
per_cpu(harden_branch_predictor_fn, cpu) =
call_smc_arch_workaround_1;
processor.switch_mm = cpu_v7_smc_switch_mm;
@@ -111,6 +121,11 @@ static void cpu_v7_spectre_init(void)
if (spectre_v2_method)
pr_info("CPU%u: Spectre v2: using %s workaround\n",
smp_processor_id(), spectre_v2_method);
+ return;
+
+bl_error:
+ pr_err("CPU%u: Spectre v2: incorrect context switching function, system vulnerable\n",
+ cpu);
}
#else
static void cpu_v7_spectre_init(void)
--
2.7.4
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