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>

1 files changed, 1 insertions, 11 deletions

diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c
index 06a2e7ce23c..806cc4f6351 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 @@ static void reset_context(void *info)
 {
         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;