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ARM: 7769/1: Cortex-A15: fix erratum 798181 implementation

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Looking into the active_asids array is not enough, as we also need
to look into the reserved_asids array (they both represent processes
that are currently running).

Also, not holding the ASID allocator lock is racy, as another CPU
could schedule that process and trigger a rollover, making the erratum
workaround miss an IPI.

Exposing this outside of context.c is a little ugly on the side, so
let's define a new entry point that the erratum workaround can call
to obtain the cpumask.

Cc: <stable@vger.kernel.org> # 3.9
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Marc Zyngier
2013-06-21 12:07:27 +01:00
committed by Russell King
parent b8e4a4740f
commit 0d0752bca1
3 changed files with 39 additions and 18 deletions
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29
arch/arm/mm/context.c
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@@ -45,10 +45,37 @@ static DEFINE_RAW_SPINLOCK(cpu_asid_lock);
static atomic64_t asid_generation = ATOMIC64_INIT(ASID_FIRST_VERSION);
static DECLARE_BITMAP(asid_map, NUM_USER_ASIDS);
DEFINE_PER_CPU(atomic64_t, active_asids);
static DEFINE_PER_CPU(atomic64_t, active_asids);
static DEFINE_PER_CPU(u64, reserved_asids);
static cpumask_t tlb_flush_pending;
#ifdef CONFIG_ARM_ERRATA_798181
void a15_erratum_get_cpumask(int this_cpu, struct mm_struct *mm,
cpumask_t *mask)
{
int cpu;
unsigned long flags;
u64 context_id, asid;
raw_spin_lock_irqsave(&cpu_asid_lock, flags);
context_id = mm->context.id.counter;
for_each_online_cpu(cpu) {
if (cpu == this_cpu)
continue;
/*
* We only need to send an IPI if the other CPUs are
* running the same ASID as the one being invalidated.
*/
asid = per_cpu(active_asids, cpu).counter;
if (asid == 0)
asid = per_cpu(reserved_asids, cpu);
if (context_id == asid)
cpumask_set_cpu(cpu, mask);
}
raw_spin_unlock_irqrestore(&cpu_asid_lock, flags);
}
#endif
#ifdef CONFIG_ARM_LPAE
static void cpu_set_reserved_ttbr0(void)
{