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powerpc: Account mm_cpumask and active_cpus in init_mm

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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: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230524060821.148015-2-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2023-05-24 16:08:18 +10:00 committed by Michael Ellerman
parent ab48181791
commit c3c2e93753
3 changed files with 18 additions and 1 deletions
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6
arch/powerpc/kernel/setup-common.c
View File

@ -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();

12
arch/powerpc/kernel/smp.c
View File

@ -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);
}

1
arch/powerpc/mm/mmu_context.c
View File

@ -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);