Subject: Re: [PATCH V2 35/68] powerpc/mm: Abstraction for switch_mmu_context

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Thu, 28 Apr 2016 11:43:23 +0530

"Aneesh Kumar K.V" <[email-masked]> writes:

How we swith mmu context differ between hash and radix. For hash we need
to switch the slb details and for radix we need to switch PID SPR.

> Signed-off-by: Aneesh Kumar K.V <[email-masked]>
> ---
>  arch/powerpc/include/asm/mmu_context.h | 25 +++++++++++++------------
>  arch/powerpc/kernel/swsusp.c           |  2 +-
>  arch/powerpc/mm/mmu_context_nohash.c   |  3 ++-
>  drivers/cpufreq/pmac32-cpufreq.c       |  2 +-
>  drivers/macintosh/via-pmu.c            |  4 ++--
>  5 files changed, 19 insertions(+), 17 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
> index 878c27771717..0dd522ff4559 100644
> --- a/arch/powerpc/include/asm/mmu_context.h
> +++ b/arch/powerpc/include/asm/mmu_context.h
> @@ -33,16 +33,23 @@ extern long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
>  extern long mm_iommu_mapped_inc(struct mm_iommu_table_group_mem_t *mem);
>  extern void mm_iommu_mapped_dec(struct mm_iommu_table_group_mem_t *mem);
>  #endif
> -
> -extern void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next);
>  extern void switch_slb(struct task_struct *tsk, struct mm_struct *mm);
>  extern void set_context(unsigned long id, pgd_t *pgd);
>
>  #ifdef CONFIG_PPC_BOOK3S_64
> +static inline void switch_mmu_context(struct mm_struct *prev,
> +				      struct mm_struct *next,
> +				      struct task_struct *tsk)
> +{
> +	return switch_slb(tsk, next);
> +}
> +
>  extern int __init_new_context(void);
>  extern void __destroy_context(int context_id);
>  static inline void mmu_context_init(void) { }
>  #else
> +extern void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,
> +			       struct task_struct *tsk);
>  extern unsigned long __init_new_context(void);
>  extern void __destroy_context(unsigned long context_id);
>  extern void mmu_context_init(void);
> @@ -88,17 +95,11 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
>  	if (cpu_has_feature(CPU_FTR_ALTIVEC))
>  		asm volatile ("dssall");
>  #endif /* CONFIG_ALTIVEC */
> -
> -	/* The actual HW switching method differs between the various
> -	 * sub architectures.
> +	/*
> +	 * The actual HW switching method differs between the various
> +	 * sub architectures. Out of line for now
>  	 */
> -#ifdef CONFIG_PPC_STD_MMU_64
> -	switch_slb(tsk, next);
> -#else
> -	/* Out of line for now */
> -	switch_mmu_context(prev, next);
> -#endif
> -
> +	switch_mmu_context(prev, next, tsk);
>  }
>
>  #define deactivate_mm(tsk,mm)	do { } while (0)
> diff --git a/arch/powerpc/kernel/swsusp.c b/arch/powerpc/kernel/swsusp.c
> index 6669b1752512..6ae9bd5086a4 100644
> --- a/arch/powerpc/kernel/swsusp.c
> +++ b/arch/powerpc/kernel/swsusp.c
> @@ -31,6 +31,6 @@ void save_processor_state(void)
>  void restore_processor_state(void)
>  {
>  #ifdef CONFIG_PPC32
> -	switch_mmu_context(current->active_mm, current->active_mm);
> +	switch_mmu_context(current->active_mm, current->active_mm, NULL);
>  #endif
>  }
> diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c
> index 986afbc22c76..a36c43a27893 100644
> --- a/arch/powerpc/mm/mmu_context_nohash.c
> +++ b/arch/powerpc/mm/mmu_context_nohash.c
> @@ -226,7 +226,8 @@ static void context_check_map(void)
>  static void context_check_map(void) { }
>  #endif
>
> -void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
> +void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,
> +			struct task_struct *tsk)
>  {
>  	unsigned int i, id, cpu = smp_processor_id();
>  	unsigned long *map;
> diff --git a/drivers/cpufreq/pmac32-cpufreq.c b/drivers/cpufreq/pmac32-cpufreq.c
> index 1f49d97a70ea..bde503c66945 100644
> --- a/drivers/cpufreq/pmac32-cpufreq.c
> +++ b/drivers/cpufreq/pmac32-cpufreq.c
> @@ -298,7 +298,7 @@ static int pmu_set_cpu_speed(int low_speed)
>   		_set_L3CR(save_l3cr);
>
>  	/* Restore userland MMU context */
> -	switch_mmu_context(NULL, current->active_mm);
> +	switch_mmu_context(NULL, current->active_mm, NULL);
>
>  #ifdef DEBUG_FREQ
>  	printk(KERN_DEBUG "HID1, after: %x\n", mfspr(SPRN_HID1));
> diff --git a/drivers/macintosh/via-pmu.c b/drivers/macintosh/via-pmu.c
> index 01ee736fe0ef..f8b6d1403c16 100644
> --- a/drivers/macintosh/via-pmu.c
> +++ b/drivers/macintosh/via-pmu.c
> @@ -1851,7 +1851,7 @@ static int powerbook_sleep_grackle(void)
>   		_set_L2CR(save_l2cr);
>  	
>  	/* Restore userland MMU context */
> -	switch_mmu_context(NULL, current->active_mm);
> +	switch_mmu_context(NULL, current->active_mm, NULL);
>
>  	/* Power things up */
>  	pmu_unlock();
> @@ -1940,7 +1940,7 @@ powerbook_sleep_Core99(void)
>   		_set_L3CR(save_l3cr);
>  	
>  	/* Restore userland MMU context */
> -	switch_mmu_context(NULL, current->active_mm);
> +	switch_mmu_context(NULL, current->active_mm, NULL);
>
>  	/* Tell PMU we are ready */
>  	pmu_unlock();
> -- 
> 2.5.0