Provide an implementation of arch_cpu_allowed_mask() so that we can prevent 64-bit-only cores being added to the 'cpus_mask' for compat tasks on systems with mismatched 32-bit support at EL0,
Signed-off-by: Will Deacon <[email protected]> --- arch/arm64/include/asm/mmu_context.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h index 0672236e1aea..54fc469e7db9 100644 --- a/arch/arm64/include/asm/mmu_context.h +++ b/arch/arm64/include/asm/mmu_context.h @@ -251,6 +251,18 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next, #define deactivate_mm(tsk,mm) do { } while (0) #define activate_mm(prev,next) switch_mm(prev, next, current) +static inline const struct cpumask *arch_cpu_allowed_mask(struct task_struct *p) +{ + if (!static_branch_unlikely(&arm64_mismatched_32bit_el0)) + return cpu_possible_mask; + + if (!is_compat_thread(task_thread_info(p))) + return cpu_possible_mask; + + return system_32bit_el0_cpumask(); +} +#define arch_cpu_allowed_mask arch_cpu_allowed_mask + void verify_cpu_asid_bits(void); void post_ttbr_update_workaround(void); -- 2.29.2.299.gdc1121823c-goog
