Commit d82158fa authored by Will Deacon's avatar Will Deacon Committed by Peter Zijlstra
Browse files

arm64: Implement task_cpu_possible_mask() 



Provide an implementation of task_cpu_possible_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: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210730112443.23245-11-will@kernel.org
parent c94d89fa

arch/arm64/include/asm/mmu_context.h

+13 −0
Original line number Diff line number Diff line
@@ -231,6 +231,19 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next, 
	update_saved_ttbr0(tsk, next);

}



static inline const struct cpumask *

task_cpu_possible_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 task_cpu_possible_mask	task_cpu_possible_mask



void verify_cpu_asid_bits(void);

void post_ttbr_update_workaround(void);