diff options
| -rw-r--r-- | arch/arm/include/asm/mmu.h | 2 | ||||
| -rw-r--r-- | arch/arm/include/asm/mmu_context.h | 72 | ||||
| -rw-r--r-- | arch/arm/include/asm/thread_info.h | 1 | ||||
| -rw-r--r-- | arch/arm/mm/context.c | 4 | ||||
| -rw-r--r-- | arch/arm/mm/proc-v7-2level.S | 3 |
5 files changed, 61 insertions, 21 deletions
diff --git a/arch/arm/include/asm/mmu.h b/arch/arm/include/asm/mmu.h index b8e580a297e4..20b43d6f23b3 100644 --- a/arch/arm/include/asm/mmu.h +++ b/arch/arm/include/asm/mmu.h @@ -39,6 +39,8 @@ typedef struct { * so enable interrupts over the context switch to avoid high * latency. */ +#ifndef CONFIG_CPU_HAS_ASID #define __ARCH_WANT_INTERRUPTS_ON_CTXSW +#endif #endif diff --git a/arch/arm/include/asm/mmu_context.h b/arch/arm/include/asm/mmu_context.h index a0b3cac0547c..94e265cb5146 100644 --- a/arch/arm/include/asm/mmu_context.h +++ b/arch/arm/include/asm/mmu_context.h @@ -49,39 +49,80 @@ DECLARE_PER_CPU(struct mm_struct *, current_mm); void __init_new_context(struct task_struct *tsk, struct mm_struct *mm); void __new_context(struct mm_struct *mm); +void cpu_set_reserved_ttbr0(void); -static inline void check_context(struct mm_struct *mm) +static inline void switch_new_context(struct mm_struct *mm) { - /* - * This code is executed with interrupts enabled. Therefore, - * mm->context.id cannot be updated to the latest ASID version - * on a different CPU (and condition below not triggered) - * without first getting an IPI to reset the context. The - * alternative is to take a read_lock on mm->context.id_lock - * (after changing its type to rwlock_t). - */ - if (unlikely((mm->context.id ^ cpu_last_asid) >> ASID_BITS)) - __new_context(mm); + unsigned long flags; + __new_context(mm); + + local_irq_save(flags); + cpu_switch_mm(mm->pgd, mm); + local_irq_restore(flags); +} + +static inline void check_and_switch_context(struct mm_struct *mm, + struct task_struct *tsk) +{ if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq)) __check_kvm_seq(mm); + + /* + * Required during context switch to avoid speculative page table + * walking with the wrong TTBR. + */ + cpu_set_reserved_ttbr0(); + + if (!((mm->context.id ^ cpu_last_asid) >> ASID_BITS)) + /* + * The ASID is from the current generation, just switch to the + * new pgd. This condition is only true for calls from + * context_switch() and interrupts are already disabled. + */ + cpu_switch_mm(mm->pgd, mm); + else if (irqs_disabled()) + /* + * Defer the new ASID allocation until after the context + * switch critical region since __new_context() cannot be + * called with interrupts disabled (it sends IPIs). + */ + set_ti_thread_flag(task_thread_info(tsk), TIF_SWITCH_MM); + else + /* + * That is a direct call to switch_mm() or activate_mm() with + * interrupts enabled and a new context. + */ + switch_new_context(mm); } #define init_new_context(tsk,mm) (__init_new_context(tsk,mm),0) -#else +#define finish_arch_post_lock_switch \ + finish_arch_post_lock_switch +static inline void finish_arch_post_lock_switch(void) +{ + if (test_and_clear_thread_flag(TIF_SWITCH_MM)) + switch_new_context(current->mm); +} -static inline void check_context(struct mm_struct *mm) +#else /* !CONFIG_CPU_HAS_ASID */ + +static inline void check_and_switch_context(struct mm_struct *mm, + struct task_struct *tsk) { #ifdef CONFIG_MMU if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq)) __check_kvm_seq(mm); + cpu_switch_mm(mm->pgd, mm); #endif } #define init_new_context(tsk,mm) 0 -#endif +#define finish_arch_post_lock_switch() do { } while (0) + +#endif /* CONFIG_CPU_HAS_ASID */ #define destroy_context(mm) do { } while(0) @@ -123,8 +164,7 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next, struct mm_struct **crt_mm = &per_cpu(current_mm, cpu); *crt_mm = next; #endif - check_context(next); - cpu_switch_mm(next->pgd, next); + check_and_switch_context(next, tsk); if (cache_is_vivt()) cpumask_clear_cpu(cpu, mm_cpumask(prev)); } diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h index d4c24d412a8d..9e13e33ec746 100644 --- a/arch/arm/include/asm/thread_info.h +++ b/arch/arm/include/asm/thread_info.h @@ -146,6 +146,7 @@ extern void vfp_flush_hwstate(struct thread_info *); #define TIF_MEMDIE 18 /* is terminating due to OOM killer */ #define TIF_RESTORE_SIGMASK 20 #define TIF_SECCOMP 21 +#define TIF_SWITCH_MM 22 /* deferred switch_mm */ #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c index aaa291fc072e..06a2e7ce23c3 100644 --- a/arch/arm/mm/context.c +++ b/arch/arm/mm/context.c @@ -23,7 +23,7 @@ DEFINE_PER_CPU(struct mm_struct *, current_mm); #endif #ifdef CONFIG_ARM_LPAE -static void cpu_set_reserved_ttbr0(void) +void cpu_set_reserved_ttbr0(void) { unsigned long ttbl = __pa(swapper_pg_dir); unsigned long ttbh = 0; @@ -39,7 +39,7 @@ static void cpu_set_reserved_ttbr0(void) isb(); } #else -static void cpu_set_reserved_ttbr0(void) +void cpu_set_reserved_ttbr0(void) { u32 ttb; /* Copy TTBR1 into TTBR0 */ diff --git a/arch/arm/mm/proc-v7-2level.S b/arch/arm/mm/proc-v7-2level.S index 72270482a922..42ac069c8012 100644 --- a/arch/arm/mm/proc-v7-2level.S +++ b/arch/arm/mm/proc-v7-2level.S @@ -46,9 +46,6 @@ ENTRY(cpu_v7_switch_mm) #ifdef CONFIG_ARM_ERRATA_430973 mcr p15, 0, r2, c7, c5, 6 @ flush BTAC/BTB #endif - mrc p15, 0, r2, c2, c0, 1 @ load TTB 1 - mcr p15, 0, r2, c2, c0, 0 @ into TTB 0 - isb #ifdef CONFIG_ARM_ERRATA_754322 dsb #endif |