Commit c3c2e937 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc: Account mm_cpumask and active_cpus in init_mm 



init_mm mm_cpumask and context.active_cpus is not maintained at boot
and hotplug. This seems to be harmless because init_mm does not have a
userspace and so never gets user TLBs flushed, but it looks odd and it
prevents some sanity checks being added.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230524060821.148015-2-npiggin@gmail.com
parent ab481817

arch/powerpc/kernel/setup-common.c

+5 −1
Original line number Diff line number Diff line
@@ -969,8 +969,12 @@ void __init setup_arch(char **cmdline_p) 
	klp_init_thread_info(&init_task);



	setup_initial_init_mm(_stext, _etext, _edata, _end);



	/* sched_init() does the mmgrab(&init_mm) for the primary CPU */

	VM_WARN_ON(cpumask_test_cpu(smp_processor_id(), mm_cpumask(&init_mm)));

	cpumask_set_cpu(smp_processor_id(), mm_cpumask(&init_mm));

	inc_mm_active_cpus(&init_mm);

	mm_iommu_init(&init_mm);



	irqstack_early_init();

	exc_lvl_early_init();

	emergency_stack_init();

arch/powerpc/kernel/smp.c

+12 −0
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ 
#include <asm/smp.h>

#include <asm/time.h>

#include <asm/machdep.h>

#include <asm/mmu_context.h>

#include <asm/cputhreads.h>

#include <asm/cputable.h>

#include <asm/mpic.h>
@@ -1616,6 +1617,9 @@ void start_secondary(void *unused) 


	mmgrab_lazy_tlb(&init_mm);

	current->active_mm = &init_mm;

	VM_WARN_ON(cpumask_test_cpu(smp_processor_id(), mm_cpumask(&init_mm)));

	cpumask_set_cpu(cpu, mm_cpumask(&init_mm));

	inc_mm_active_cpus(&init_mm);



	smp_store_cpu_info(cpu);

	set_dec(tb_ticks_per_jiffy);
@@ -1751,6 +1755,14 @@ int __cpu_disable(void) 


void __cpu_die(unsigned int cpu)

{

	/*

	 * This could perhaps be a generic call in idlea_task_dead(), but

	 * that requires testing from all archs, so first put it here to

	 */

	VM_WARN_ON_ONCE(!cpumask_test_cpu(cpu, mm_cpumask(&init_mm)));

	dec_mm_active_cpus(&init_mm);

	cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));



	if (smp_ops->cpu_die)

		smp_ops->cpu_die(cpu);

}

arch/powerpc/mm/mmu_context.c

+1 −0
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, 


	/* Mark this context has been used on the new CPU */

	if (!cpumask_test_cpu(smp_processor_id(), mm_cpumask(next))) {

		VM_WARN_ON_ONCE(next == &init_mm);

		cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));

		inc_mm_active_cpus(next);