aarch64: mmu: apply domain switching on all CPUs if SMP

It is apparently possible for one CPU to change the memory domain
of a thread already being executed on another CPU.

All CPUs must ensure they're using the appropriate mapping after a
thread is newly added to a domain.

Signed-off-by: Nicolas Pitre <[email protected]>

Author: Nicolas Pitre

arch/arm/core/aarch64/mmu/arm_mmu.c

@@ -989,15 +989,21 @@ void arch_mem_domain_thread_add(struct k_thread *thread)
 	}
 
 	thread->arch.ptables = domain_ptables;
+	if (thread == _current) {
+		if (!is_ptable_active(domain_ptables)) {
+			z_arm64_swap_ptables(thread);
+		}
+	} else {
+#ifdef CONFIG_SMP
+		/* the thread could be running on another CPU right now */
+		arch_sched_ipi();
+#endif
+	}
 
 	if (is_migration) {
 		reset_map(old_ptables, __func__, thread->stack_info.start,
 				thread->stack_info.size);
 	}
-
-	if (thread == _current && !is_ptable_active(domain_ptables)) {
-		z_arm64_swap_ptables(thread);
-	}
 }
 
 void arch_mem_domain_thread_remove(struct k_thread *thread)
@@ -1026,8 +1032,6 @@ void z_arm64_swap_ptables(struct k_thread *incoming)
 
 	if (!is_ptable_active(ptables)) {
 		z_arm64_set_ttbr0((uintptr_t)ptables->base_xlat_table);
-	} else {
-		invalidate_tlb_all();
 	}
 }
 

arch/arm/core/aarch64/smp.c

@@ -98,6 +98,14 @@ void sched_ipi_handler(const void *unused)
 {
 	ARG_UNUSED(unused);
 
+#ifdef CONFIG_USERSPACE
+	/*
+	 * Make sure a domain switch by another CPU is effective on this CPU.
+	 * This is a no-op if the page table is already the right one.
+	 */
+	z_arm64_swap_ptables(_current);
+#endif
+
 	z_sched_ipi();
 }