ARM: Remove current_mm per-cpu variable
The current_mm variable was used to store the new mm between the
switch_mm() and switch_to() calls where an IPI to reset the context
could have set the wrong mm. Since the interrupts are disabled during
context switch, there is no need for this variable, current->active_mm
already points to the current mm when interrupts are re-enabled.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Tested-by: Marc Zyngier <Marc.Zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm/include/asm/mmu_context.h b/arch/arm/include/asm/mmu_context.h
index 94e265c..8da4b9c 100644
--- a/arch/arm/include/asm/mmu_context.h
+++ b/arch/arm/include/asm/mmu_context.h
@@ -43,9 +43,6 @@
#define ASID_FIRST_VERSION (1 << ASID_BITS)
extern unsigned int cpu_last_asid;
-#ifdef CONFIG_SMP
-DECLARE_PER_CPU(struct mm_struct *, current_mm);
-#endif
void __init_new_context(struct task_struct *tsk, struct mm_struct *mm);
void __new_context(struct mm_struct *mm);
@@ -160,10 +157,6 @@
__flush_icache_all();
#endif
if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) {
-#ifdef CONFIG_SMP
- struct mm_struct **crt_mm = &per_cpu(current_mm, cpu);
- *crt_mm = next;
-#endif
check_and_switch_context(next, tsk);
if (cache_is_vivt())
cpumask_clear_cpu(cpu, mm_cpumask(prev));
diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c
index 06a2e7c..806cc4f 100644
--- a/arch/arm/mm/context.c
+++ b/arch/arm/mm/context.c
@@ -18,9 +18,6 @@
static DEFINE_RAW_SPINLOCK(cpu_asid_lock);
unsigned int cpu_last_asid = ASID_FIRST_VERSION;
-#ifdef CONFIG_SMP
-DEFINE_PER_CPU(struct mm_struct *, current_mm);
-#endif
#ifdef CONFIG_ARM_LPAE
void cpu_set_reserved_ttbr0(void)
@@ -108,14 +105,7 @@
{
unsigned int asid;
unsigned int cpu = smp_processor_id();
- struct mm_struct *mm = per_cpu(current_mm, cpu);
-
- /*
- * Check if a current_mm was set on this CPU as it might still
- * be in the early booting stages and using the reserved ASID.
- */
- if (!mm)
- return;
+ struct mm_struct *mm = current->active_mm;
smp_rmb();
asid = cpu_last_asid + cpu + 1;