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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>
This commit is contained in:
Catalin Marinas 2011-11-28 15:59:10 +00:00
parent 7fec1b57b8
commit e323969ccd
2 changed files with 1 additions and 18 deletions
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7
arch/arm/include/asm/mmu_context.h
View File

@ -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));

12
arch/arm/mm/context.c
View File

@ -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;