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Commit e323969c authored by Catalin Marinas's avatar Catalin Marinas
Browse files

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: default avatarWill Deacon <will.deacon@arm.com>
Tested-by: default avatarWill Deacon <will.deacon@arm.com>
Reviewed-by: default avatarFrank Rowand <frank.rowand@am.sony.com>
Tested-by: default avatarMarc Zyngier <Marc.Zyngier@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 7fec1b57

arch/arm/include/asm/mmu_context.h

+0 −7
Original line number Diff line number Diff line
@@ -43,9 +43,6 @@ void __check_kvm_seq(struct mm_struct *mm); 
#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 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next, 
		__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));

arch/arm/mm/context.c

+1 −11
Original line number Diff line number Diff line
@@ -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;