[V6] cxl: Add support for ASB_Notify on POWER9

Message ID 1515513430-23959-1-git-send-email-clombard@linux.vnet.ibm.com
State Superseded
Headers show
Series
  • [V6] cxl: Add support for ASB_Notify on POWER9
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Commit Message

christophe lombard Jan. 9, 2018, 3:57 p.m.
The POWER9 core supports a new feature: ASB_Notify which requires the
support of the Special Purpose Register: TIDR.

The ASB_Notify command, generated by the AFU, will attempt to
wake-up the host thread identified by the particular LPID:PID:TID.

This patch assign a unique TIDR (thread id) for the current thread which
will be used in the process element entry.

Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com>
Reviewed-by: Philippe Bergheaud <felix@linux.vnet.ibm.com>

---
Changelog[v6]
 - Rebased to latest upstream.
 - Updated the ioctl interface.
 - Removed the updated ptrace.
 - Assigned a unique TIDR for the current thread at a lower level.

Changelog[v5]
 - Rebased to latest upstream.
 - Updated the ioctl interface.
 - Returned the tid in the ioctl structure.

Changelog[v4]
 - Rebased to latest upstream.
 - Updated the ioctl interface.
 - Removed the field tid in the context structure.

Changelog[v3]
 - Rebased to latest upstream.
 - Updated attr->tid field in cxllib_get_PE_attributes().

Changelog[v2]
 - Rebased to latest upstream.
 - Updated the ioctl interface.
 - Added a checking to allow updating the TIDR if a P9 chip is present.
---
 arch/powerpc/kernel/process.c |  1 +
 drivers/misc/cxl/context.c    |  1 +
 drivers/misc/cxl/cxl.h        |  3 +++
 drivers/misc/cxl/cxllib.c     |  3 ++-
 drivers/misc/cxl/file.c       | 10 +++++++++-
 drivers/misc/cxl/native.c     | 13 ++++++++++++-
 include/uapi/misc/cxl.h       | 10 ++++++----
 7 files changed, 34 insertions(+), 7 deletions(-)

Comments

Frederic Barrat Jan. 10, 2018, 1:44 p.m. | #1
Hi Christophe,


Couple of comments about file.c, the rest of the patch looks ok to me.


> @@ -193,6 +194,7 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
>   		amr = work.amr & mfspr(SPRN_UAMOR);
> 
>   	ctx->mmio_err_ff = !!(work.flags & CXL_START_WORK_ERR_FF);
> +	ctx->wflags = work.flags;


I would prefer to add a	boolean "need to allocate a TID" to the context 
instead of saving the full user land flags, that seems more in-line with 
the existing code.


>   	/*
>   	 * Increment the mapped context count for adapter. This also checks
> @@ -263,6 +265,12 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
>   		goto out;
>   	}
> 
> +	if (work.flags & CXL_START_WORK_TID) {
> +		work.tid = ctx->tidr;
> +		if (copy_to_user(uwork, &work, sizeof(work)))
> +			return -EFAULT;
> +	}
> +

In case of error writing the TID value to user space, we still need to 
release the mutex and mark the context as STARTED.

   Fred


>   	ctx->status = STARTED;
>   	rc = 0;
>   out:
> diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c
> index 02b6b45..0cccf27 100644
> --- a/drivers/misc/cxl/native.c
> +++ b/drivers/misc/cxl/native.c
> @@ -16,6 +16,7 @@
>   #include <linux/uaccess.h>
>   #include <linux/delay.h>
>   #include <asm/synch.h>
> +#include <asm/switch_to.h>
>   #include <misc/cxl-base.h>
> 
>   #include "cxl.h"
> @@ -655,6 +656,7 @@ static void update_ivtes_directed(struct cxl_context *ctx)
>   static int process_element_entry_psl9(struct cxl_context *ctx, u64 wed, u64 amr)
>   {
>   	u32 pid;
> +	int rc;
> 
>   	cxl_assign_psn_space(ctx);
> 
> @@ -673,7 +675,16 @@ static int process_element_entry_psl9(struct cxl_context *ctx, u64 wed, u64 amr)
>   		pid = ctx->mm->context.id;
>   	}
> 
> -	ctx->elem->common.tid = 0;
> +	/* Assign a unique TIDR (thread id) for the current thread */
> +	if (!(ctx->tidr) && (ctx->wflags & CXL_START_WORK_TID)) {
> +		rc = set_thread_tidr(current);
> +		if (rc)
> +			return -ENODEV;
> +		ctx->tidr = current->thread.tidr;
> +		pr_devel("%s: current tidr: %d\n", __func__, ctx->tidr);
> +	}
> +
> +	ctx->elem->common.tid = cpu_to_be32(ctx->tidr);
>   	ctx->elem->common.pid = cpu_to_be32(pid);
> 
>   	ctx->elem->sr = cpu_to_be64(calculate_sr(ctx));
> diff --git a/include/uapi/misc/cxl.h b/include/uapi/misc/cxl.h
> index 49e8fd0..56376d3 100644
> --- a/include/uapi/misc/cxl.h
> +++ b/include/uapi/misc/cxl.h
> @@ -20,20 +20,22 @@ struct cxl_ioctl_start_work {
>   	__u64 work_element_descriptor;
>   	__u64 amr;
>   	__s16 num_interrupts;
> -	__s16 reserved1;
> -	__s32 reserved2;
> +	__u16 tid;
> +	__s32 reserved1;
> +	__u64 reserved2;
>   	__u64 reserved3;
>   	__u64 reserved4;
>   	__u64 reserved5;
> -	__u64 reserved6;
>   };
> 
>   #define CXL_START_WORK_AMR		0x0000000000000001ULL
>   #define CXL_START_WORK_NUM_IRQS		0x0000000000000002ULL
>   #define CXL_START_WORK_ERR_FF		0x0000000000000004ULL
> +#define CXL_START_WORK_TID		0x0000000000000008ULL
>   #define CXL_START_WORK_ALL		(CXL_START_WORK_AMR |\
>   					 CXL_START_WORK_NUM_IRQS |\
> -					 CXL_START_WORK_ERR_FF)
> +					 CXL_START_WORK_ERR_FF |\
> +					 CXL_START_WORK_TID)
> 
> 
>   /* Possible modes that an afu can be in */
>

Patch

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 72be0c3..1dc39dd 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1589,6 +1589,7 @@  int set_thread_tidr(struct task_struct *t)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(set_thread_tidr);
 
 #endif /* CONFIG_PPC64 */
 
diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c
index 12a41b2..9a1c6b9 100644
--- a/drivers/misc/cxl/context.c
+++ b/drivers/misc/cxl/context.c
@@ -45,6 +45,7 @@  int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master)
 	ctx->pid = NULL; /* Set in start work ioctl */
 	mutex_init(&ctx->mapping_lock);
 	ctx->mapping = NULL;
+	ctx->tidr = 0;
 
 	if (cxl_is_power8()) {
 		spin_lock_init(&ctx->sste_lock);
diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
index e46a406..86ae215 100644
--- a/drivers/misc/cxl/cxl.h
+++ b/drivers/misc/cxl/cxl.h
@@ -630,6 +630,9 @@  struct cxl_context {
 	struct list_head extra_irq_contexts;
 
 	struct mm_struct *mm;
+
+	u16 tidr;
+	u64 wflags;
 };
 
 struct cxl_irq_info;
diff --git a/drivers/misc/cxl/cxllib.c b/drivers/misc/cxl/cxllib.c
index dc9bc18..30ccba4 100644
--- a/drivers/misc/cxl/cxllib.c
+++ b/drivers/misc/cxl/cxllib.c
@@ -199,10 +199,11 @@  int cxllib_get_PE_attributes(struct task_struct *task,
 		 */
 		attr->pid = mm->context.id;
 		mmput(mm);
+		attr->tid = task->thread.tidr;
 	} else {
 		attr->pid = 0;
+		attr->tid = 0;
 	}
-	attr->tid = 0;
 	return 0;
 }
 EXPORT_SYMBOL_GPL(cxllib_get_PE_attributes);
diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
index 76c0b0c..e28aefb 100644
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -173,7 +173,7 @@  static long afu_ioctl_start_work(struct cxl_context *ctx,
 	 * flags are set it's invalid
 	 */
 	if (work.reserved1 || work.reserved2 || work.reserved3 ||
-	    work.reserved4 || work.reserved5 || work.reserved6 ||
+	    work.reserved4 || work.reserved5 ||
 	    (work.flags & ~CXL_START_WORK_ALL)) {
 		rc = -EINVAL;
 		goto out;
@@ -186,6 +186,7 @@  static long afu_ioctl_start_work(struct cxl_context *ctx,
 		rc =  -EINVAL;
 		goto out;
 	}
+
 	if ((rc = afu_register_irqs(ctx, work.num_interrupts)))
 		goto out;
 
@@ -193,6 +194,7 @@  static long afu_ioctl_start_work(struct cxl_context *ctx,
 		amr = work.amr & mfspr(SPRN_UAMOR);
 
 	ctx->mmio_err_ff = !!(work.flags & CXL_START_WORK_ERR_FF);
+	ctx->wflags = work.flags;
 
 	/*
 	 * Increment the mapped context count for adapter. This also checks
@@ -263,6 +265,12 @@  static long afu_ioctl_start_work(struct cxl_context *ctx,
 		goto out;
 	}
 
+	if (work.flags & CXL_START_WORK_TID) {
+		work.tid = ctx->tidr;
+		if (copy_to_user(uwork, &work, sizeof(work)))
+			return -EFAULT;
+	}
+
 	ctx->status = STARTED;
 	rc = 0;
 out:
diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c
index 02b6b45..0cccf27 100644
--- a/drivers/misc/cxl/native.c
+++ b/drivers/misc/cxl/native.c
@@ -16,6 +16,7 @@ 
 #include <linux/uaccess.h>
 #include <linux/delay.h>
 #include <asm/synch.h>
+#include <asm/switch_to.h>
 #include <misc/cxl-base.h>
 
 #include "cxl.h"
@@ -655,6 +656,7 @@  static void update_ivtes_directed(struct cxl_context *ctx)
 static int process_element_entry_psl9(struct cxl_context *ctx, u64 wed, u64 amr)
 {
 	u32 pid;
+	int rc;
 
 	cxl_assign_psn_space(ctx);
 
@@ -673,7 +675,16 @@  static int process_element_entry_psl9(struct cxl_context *ctx, u64 wed, u64 amr)
 		pid = ctx->mm->context.id;
 	}
 
-	ctx->elem->common.tid = 0;
+	/* Assign a unique TIDR (thread id) for the current thread */
+	if (!(ctx->tidr) && (ctx->wflags & CXL_START_WORK_TID)) {
+		rc = set_thread_tidr(current);
+		if (rc)
+			return -ENODEV;
+		ctx->tidr = current->thread.tidr;
+		pr_devel("%s: current tidr: %d\n", __func__, ctx->tidr);
+	}
+
+	ctx->elem->common.tid = cpu_to_be32(ctx->tidr);
 	ctx->elem->common.pid = cpu_to_be32(pid);
 
 	ctx->elem->sr = cpu_to_be64(calculate_sr(ctx));
diff --git a/include/uapi/misc/cxl.h b/include/uapi/misc/cxl.h
index 49e8fd0..56376d3 100644
--- a/include/uapi/misc/cxl.h
+++ b/include/uapi/misc/cxl.h
@@ -20,20 +20,22 @@  struct cxl_ioctl_start_work {
 	__u64 work_element_descriptor;
 	__u64 amr;
 	__s16 num_interrupts;
-	__s16 reserved1;
-	__s32 reserved2;
+	__u16 tid;
+	__s32 reserved1;
+	__u64 reserved2;
 	__u64 reserved3;
 	__u64 reserved4;
 	__u64 reserved5;
-	__u64 reserved6;
 };
 
 #define CXL_START_WORK_AMR		0x0000000000000001ULL
 #define CXL_START_WORK_NUM_IRQS		0x0000000000000002ULL
 #define CXL_START_WORK_ERR_FF		0x0000000000000004ULL
+#define CXL_START_WORK_TID		0x0000000000000008ULL
 #define CXL_START_WORK_ALL		(CXL_START_WORK_AMR |\
 					 CXL_START_WORK_NUM_IRQS |\
-					 CXL_START_WORK_ERR_FF)
+					 CXL_START_WORK_ERR_FF |\
+					 CXL_START_WORK_TID)
 
 
 /* Possible modes that an afu can be in */