Messages in this thread |  | | Subject | Re: [PATCH v2 5/7] ocxl: Expose the thread_id needed for wait on p9 | From | Frederic Barrat <> | Date | Mon, 7 May 2018 20:08:35 +0200 |
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Le 18/04/2018 à 03:08, Alastair D'Silva a écrit : > From: Alastair D'Silva <alastair@d-silva.org> > > In order to successfully issue as_notify, an AFU needs to know the TID > to notify, which in turn means that this information should be > available in userspace so it can be communicated to the AFU. > > Signed-off-by: Alastair D'Silva <alastair@d-silva.org> > --- > drivers/misc/ocxl/context.c | 5 +++- > drivers/misc/ocxl/file.c | 53 +++++++++++++++++++++++++++++++++++++++ > drivers/misc/ocxl/link.c | 36 ++++++++++++++++++++++++++ > drivers/misc/ocxl/ocxl_internal.h | 1 + > include/misc/ocxl.h | 9 +++++++ > include/uapi/misc/ocxl.h | 10 ++++++++ > 6 files changed, 113 insertions(+), 1 deletion(-) > > diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c > index 909e8807824a..95f74623113e 100644 > --- a/drivers/misc/ocxl/context.c > +++ b/drivers/misc/ocxl/context.c > @@ -34,6 +34,8 @@ int ocxl_context_init(struct ocxl_context *ctx, struct ocxl_afu *afu, > mutex_init(&ctx->xsl_error_lock); > mutex_init(&ctx->irq_lock); > idr_init(&ctx->irq_idr); > + ctx->tidr = 0; > + > /* > * Keep a reference on the AFU to make sure it's valid for the > * duration of the life of the context > @@ -65,6 +67,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr) > { > int rc; > > + // Locks both status & tidr > mutex_lock(&ctx->status_mutex); > if (ctx->status != OPENED) { > rc = -EIO; > @@ -72,7 +75,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr) > } > > rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid, > - current->mm->context.id, 0, amr, current->mm, > + current->mm->context.id, ctx->tidr, amr, current->mm, > xsl_fault_error, ctx); > if (rc) > goto out; > diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c > index 038509e5d031..eb409a469f21 100644 > --- a/drivers/misc/ocxl/file.c > +++ b/drivers/misc/ocxl/file.c > @@ -5,6 +5,8 @@ > #include <linux/sched/signal.h> > #include <linux/uaccess.h> > #include <uapi/misc/ocxl.h> > +#include <asm/reg.h> > +#include <asm/switch_to.h> > #include "ocxl_internal.h" > > > @@ -123,11 +125,55 @@ static long afu_ioctl_get_metadata(struct ocxl_context *ctx, > return 0; > } > > +#ifdef CONFIG_PPC64 > +static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx, > + struct ocxl_ioctl_p9_wait __user *uarg) > +{ > + struct ocxl_ioctl_p9_wait arg; > + > + memset(&arg, 0, sizeof(arg)); > + > + if (cpu_has_feature(CPU_FTR_P9_TIDR)) { > + enum ocxl_context_status status; > + > + // Locks both status & tidr > + mutex_lock(&ctx->status_mutex); > + if (!ctx->tidr) { > + if (set_thread_tidr(current)) > + return -ENOENT; > + > + ctx->tidr = current->thread.tidr; > + }
Now that we don't have the TIDR limit problem, I'm wondering if we cannot relax our rule a bit and have: - first thread to enable will become the default thread and update the Process element - any subsequent enable would just allocate the TIDR for the calling thread.
That way, more than one thread could be used for 'wait'. Thoughts?
Fred
> + > + status = ctx->status; > + mutex_unlock(&ctx->status_mutex); > + > + if (status == ATTACHED) { > + int rc; > + struct link *link = ctx->afu->fn->link; > + > + rc = ocxl_link_update_pe(link, ctx->pasid, ctx->tidr); > + if (rc) > + return rc; > + } > + > + arg.thread_id = ctx->tidr; > + } else > + return -ENOENT; > + > + if (copy_to_user(uarg, &arg, sizeof(arg))) > + return -EFAULT; > + > + return 0; > +} > +#endif > + > #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" : \ > x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" : \ > x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" : \ > x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" : \ > x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \ > + x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" : \ > "UNKNOWN") > > static long afu_ioctl(struct file *file, unsigned int cmd, > @@ -186,6 +232,13 @@ static long afu_ioctl(struct file *file, unsigned int cmd, > (struct ocxl_ioctl_metadata __user *) args); > break; > > +#ifdef CONFIG_PPC64 > + case OCXL_IOCTL_ENABLE_P9_WAIT: > + rc = afu_ioctl_enable_p9_wait(ctx, > + (struct ocxl_ioctl_p9_wait __user *) args); > + break; > +#endif > + > default: > rc = -EINVAL; > } > diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c > index 656e8610eec2..88876ae8f330 100644 > --- a/drivers/misc/ocxl/link.c > +++ b/drivers/misc/ocxl/link.c > @@ -544,6 +544,42 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32 pidr, u32 tidr, > } > EXPORT_SYMBOL_GPL(ocxl_link_add_pe); > > +int ocxl_link_update_pe(void *link_handle, int pasid, __u16 tid) > +{ > + struct link *link = (struct link *) link_handle; > + struct spa *spa = link->spa; > + struct ocxl_process_element *pe; > + int pe_handle, rc; > + > + if (pasid > SPA_PASID_MAX) > + return -EINVAL; > + > + pe_handle = pasid & SPA_PE_MASK; > + pe = spa->spa_mem + pe_handle; > + > + mutex_lock(&spa->spa_lock); > + > + pe->tid = tid; > + > + /* > + * The barrier makes sure the PE is updated > + * before we clear the NPU context cache below, so that the > + * old PE cannot be reloaded erroneously. > + */ > + mb(); > + > + /* > + * hook to platform code > + * On powerpc, the entry needs to be cleared from the context > + * cache of the NPU. > + */ > + rc = pnv_ocxl_spa_remove_pe_from_cache(link->platform_data, pe_handle); > + WARN_ON(rc); > + > + mutex_unlock(&spa->spa_lock); > + return rc; > +} > + > int ocxl_link_remove_pe(void *link_handle, int pasid) > { > struct link *link = (struct link *) link_handle; > diff --git a/drivers/misc/ocxl/ocxl_internal.h b/drivers/misc/ocxl/ocxl_internal.h > index 5d421824afd9..6c6d4e61888e 100644 > --- a/drivers/misc/ocxl/ocxl_internal.h > +++ b/drivers/misc/ocxl/ocxl_internal.h > @@ -77,6 +77,7 @@ struct ocxl_context { > struct ocxl_xsl_error xsl_error; > struct mutex irq_lock; > struct idr irq_idr; > + __u16 tidr; // Thread ID used for P9 wait implementation > }; > > struct ocxl_process_element { > diff --git a/include/misc/ocxl.h b/include/misc/ocxl.h > index 51ccf76db293..9ff6ddc28e22 100644 > --- a/include/misc/ocxl.h > +++ b/include/misc/ocxl.h > @@ -188,6 +188,15 @@ extern int ocxl_link_add_pe(void *link_handle, int pasid, u32 pidr, u32 tidr, > void (*xsl_err_cb)(void *data, u64 addr, u64 dsisr), > void *xsl_err_data); > > +/** > + * Update values within a Process Element > + * > + * link_handle: the link handle associated with the process element > + * pasid: the PASID for the AFU context > + * tid: the new thread id for the process element > + */ > +extern int ocxl_link_update_pe(void *link_handle, int pasid, __u16 tid); > + > /* > * Remove a Process Element from the Shared Process Area for a link > */ > diff --git a/include/uapi/misc/ocxl.h b/include/uapi/misc/ocxl.h > index 0af83d80fb3e..8d2748e69c84 100644 > --- a/include/uapi/misc/ocxl.h > +++ b/include/uapi/misc/ocxl.h > @@ -48,6 +48,15 @@ struct ocxl_ioctl_metadata { > __u64 reserved[13]; // Total of 16*u64 > }; > > +struct ocxl_ioctl_p9_wait { > + __u16 thread_id; // The thread ID required to wake this thread > + __u16 reserved1; > + __u32 reserved2; > + __u64 reserved3[3]; > +}; > + > +}; > + > struct ocxl_ioctl_irq_fd { > __u64 irq_offset; > __s32 eventfd; > @@ -62,5 +71,6 @@ struct ocxl_ioctl_irq_fd { > #define OCXL_IOCTL_IRQ_FREE _IOW(OCXL_MAGIC, 0x12, __u64) > #define OCXL_IOCTL_IRQ_SET_FD _IOW(OCXL_MAGIC, 0x13, struct ocxl_ioctl_irq_fd) > #define OCXL_IOCTL_GET_METADATA _IOR(OCXL_MAGIC, 0x14, struct ocxl_ioctl_metadata) > +#define OCXL_IOCTL_ENABLE_P9_WAIT _IOR(OCXL_MAGIC, 0x15, struct ocxl_ioctl_p9_wait) > > #endif /* _UAPI_MISC_OCXL_H */ >
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