[PATCH 2/2] cxl: Enable global TLBIs for cxl contexts
Benjamin Herrenschmidt
benh at kernel.crashing.org
Mon Aug 28 22:03:03 AEST 2017
On Mon, 2017-08-28 at 10:47 +0200, Frederic Barrat wrote:
>
>
> Signed-off-by: Frederic Barrat <fbarrat at linux.vnet.ibm.com>
> diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
> index 309592589e30..6447c0df7ec4 100644
> --- a/arch/powerpc/include/asm/mmu_context.h
> +++ b/arch/powerpc/include/asm/mmu_context.h
> @@ -77,6 +77,41 @@ extern void switch_cop(struct mm_struct *next);
> extern int use_cop(unsigned long acop, struct mm_struct *mm);
> extern void drop_cop(unsigned long acop, struct mm_struct *mm);
>
> +#ifdef CONFIG_PPC_BOOK3S_64
> +static inline void inc_mm_active_cpus(struct mm_struct *mm)
> +{
> + atomic_inc(&mm->context.active_cpus);
> +}
> +
> +static inline void dec_mm_active_cpus(struct mm_struct *mm)
> +{
> + atomic_dec(&mm->context.active_cpus);
> +}
> +
> +static inline void mm_context_add_copro(struct mm_struct *mm)
> +{
> + inc_mm_active_cpus(mm);
> +}
> +
> +static inline void mm_context_remove_copro(struct mm_struct *mm)
> +{
> + /*
> + * Need to broadcast a global flush of the full mm before
> + * decrementing active_cpus count, as the next TLBI may be
> + * local and the nMMU and/or PSL need to be cleaned up.
> + * Should be rare enough so that it's acceptable.
> + */
> + flush_tlb_mm(mm);
> + dec_mm_active_cpus(mm);
> +}
You probably need to kill the pwc too. With my recent optimizations
flush_tlb_mm won't do that anymore. You need a bigger hammer (I don't
have the code at hand right now to tell you what exactly :-) Basically
something that does a RIC_FLUSH_ALL.
> +#else
> +static inline void inc_mm_active_cpus(struct mm_struct *mm) { }
> +static inline void dec_mm_active_cpus(struct mm_struct *mm) { }
> +static inline void mm_context_add_copro(struct mm_struct *mm) { }
> +static inline void mm_context_remove_copro(struct mm_struct *mm) { }
> +#endif
> +
> +
> extern void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
> struct task_struct *tsk);
>
> diff --git a/arch/powerpc/mm/mmu_context.c b/arch/powerpc/mm/mmu_context.c
> index 0f613bc63c50..d60a62bf4fc7 100644
> --- a/arch/powerpc/mm/mmu_context.c
> +++ b/arch/powerpc/mm/mmu_context.c
> @@ -34,15 +34,6 @@ static inline void switch_mm_pgdir(struct task_struct *tsk,
> struct mm_struct *mm) { }
> #endif
>
> -#ifdef CONFIG_PPC_BOOK3S_64
> -static inline void inc_mm_active_cpus(struct mm_struct *mm)
> -{
> - atomic_inc(&mm->context.active_cpus);
> -}
> -#else
> -static inline void inc_mm_active_cpus(struct mm_struct *mm) { }
> -#endif
> -
> void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
> struct task_struct *tsk)
> {
> diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
> index e0dfd1eadd70..33daf33e0e05 100644
> --- a/drivers/misc/cxl/api.c
> +++ b/drivers/misc/cxl/api.c
> @@ -15,6 +15,7 @@
> #include <linux/module.h>
> #include <linux/mount.h>
> #include <linux/sched/mm.h>
> +#include <linux/mmu_context.h>
>
> #include "cxl.h"
>
> @@ -332,8 +333,11 @@ int cxl_start_context(struct cxl_context *ctx, u64 wed,
> cxl_context_mm_count_get(ctx);
>
> /* decrement the use count */
> - if (ctx->mm)
> + if (ctx->mm) {
> mmput(ctx->mm);
> + /* make TLBIs for this context global */
> + mm_context_add_copro(ctx->mm);
> + }
> }
>
> /*
> @@ -342,13 +346,25 @@ int cxl_start_context(struct cxl_context *ctx, u64 wed,
> */
> cxl_ctx_get();
>
> + /*
> + * Barrier is needed to make sure all TLBIs are global before
> + * we attach and the context starts being used by the adapter.
> + *
> + * Needed after mm_context_add_copro() for radix and
> + * cxl_ctx_get() for hash/p8
> + */
> + smp_mb();
> +
> if ((rc = cxl_ops->attach_process(ctx, kernel, wed, 0))) {
> put_pid(ctx->pid);
> ctx->pid = NULL;
> cxl_adapter_context_put(ctx->afu->adapter);
> cxl_ctx_put();
> - if (task)
> + if (task) {
> cxl_context_mm_count_put(ctx);
> + if (ctx->mm)
> + mm_context_remove_copro(ctx->mm);
> + }
> goto out;
> }
>
> diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c
> index 8c32040b9c09..12a41b2753f0 100644
> --- a/drivers/misc/cxl/context.c
> +++ b/drivers/misc/cxl/context.c
> @@ -18,6 +18,7 @@
> #include <linux/slab.h>
> #include <linux/idr.h>
> #include <linux/sched/mm.h>
> +#include <linux/mmu_context.h>
> #include <asm/cputable.h>
> #include <asm/current.h>
> #include <asm/copro.h>
> @@ -267,6 +268,8 @@ int __detach_context(struct cxl_context *ctx)
>
> /* Decrease the mm count on the context */
> cxl_context_mm_count_put(ctx);
> + if (ctx->mm)
> + mm_context_remove_copro(ctx->mm);
> ctx->mm = NULL;
>
> return 0;
> diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
> index b76a491a485d..411e83cbbd82 100644
> --- a/drivers/misc/cxl/file.c
> +++ b/drivers/misc/cxl/file.c
> @@ -19,6 +19,7 @@
> #include <linux/mm.h>
> #include <linux/slab.h>
> #include <linux/sched/mm.h>
> +#include <linux/mmu_context.h>
> #include <asm/cputable.h>
> #include <asm/current.h>
> #include <asm/copro.h>
> @@ -220,9 +221,12 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
> /* ensure this mm_struct can't be freed */
> cxl_context_mm_count_get(ctx);
>
> - /* decrement the use count */
> - if (ctx->mm)
> + if (ctx->mm) {
> + /* decrement the use count */
> mmput(ctx->mm);
> + /* make TLBIs for this context global */
> + mm_context_add_copro(ctx->mm);
> + }
>
> /*
> * Increment driver use count. Enables global TLBIs for hash
> @@ -230,6 +234,15 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
> */
> cxl_ctx_get();
>
> + /*
> + * Barrier is needed to make sure all TLBIs are global before
> + * we attach and the context starts being used by the adapter.
> + *
> + * Needed after mm_context_add_copro() for radix and
> + * cxl_ctx_get() for hash/p8
> + */
> + smp_mb();
> +
> trace_cxl_attach(ctx, work.work_element_descriptor, work.num_interrupts, amr);
>
> if ((rc = cxl_ops->attach_process(ctx, false, work.work_element_descriptor,
> @@ -240,6 +253,8 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
> ctx->pid = NULL;
> cxl_ctx_put();
> cxl_context_mm_count_put(ctx);
> + if (ctx->mm)
> + mm_context_remove_copro(ctx->mm);
> goto out;
> }
>
More information about the Linuxppc-dev
mailing list