[PATCH 2/7] ocxl: Allow external drivers to use OpenCAPI contexts

["Alastair D'Silva" <alastair@au1.ibm.com>]

From: Alastair D'Silva <alastair@d-silva.org>

Most OpenCAPI operations require a valid context, so
exposing these functions to external drivers is necessary.

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
---
 drivers/misc/ocxl/context.c       |  9 +++++--
 drivers/misc/ocxl/file.c          |  2 +-
 drivers/misc/ocxl/ocxl_internal.h |  6 -----
 include/misc/ocxl.h               | 44 +++++++++++++++++++++++++++++++
 4 files changed, 52 insertions(+), 9 deletions(-)

diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
index 3498a0199bde..1534b56f1db1 100644
--- a/drivers/misc/ocxl/context.c
+++ b/drivers/misc/ocxl/context.c
@@ -8,6 +8,7 @@ struct ocxl_context *ocxl_context_alloc(void)
 {
 	return kzalloc(sizeof(struct ocxl_context), GFP_KERNEL);
 }
+EXPORT_SYMBOL_GPL(ocxl_context_alloc);
 
 int ocxl_context_init(struct ocxl_context *ctx, struct ocxl_afu *afu,
 		struct address_space *mapping)
@@ -43,6 +44,7 @@ int ocxl_context_init(struct ocxl_context *ctx, struct ocxl_afu *afu,
 	ocxl_afu_get(afu);
 	return 0;
 }
+EXPORT_SYMBOL_GPL(ocxl_context_init);
 
 /*
  * Callback for when a translation fault triggers an error
@@ -63,7 +65,7 @@ static void xsl_fault_error(void *data, u64 addr, u64 dsisr)
 	wake_up_all(&ctx->events_wq);
 }
 
-int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
+int ocxl_context_attach(struct ocxl_context *ctx, u64 amr, struct mm_struct *mm)
 {
 	int rc;
 
@@ -75,7 +77,7 @@ 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, ctx->tidr, amr, current->mm,
+			mm->context.id, ctx->tidr, amr, mm,
 			xsl_fault_error, ctx);
 	if (rc)
 		goto out;
@@ -85,6 +87,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
 	mutex_unlock(&ctx->status_mutex);
 	return rc;
 }
+EXPORT_SYMBOL_GPL(ocxl_context_attach);
 
 static vm_fault_t map_afu_irq(struct vm_area_struct *vma, unsigned long address,
 		u64 offset, struct ocxl_context *ctx)
@@ -243,6 +246,7 @@ int ocxl_context_detach(struct ocxl_context *ctx)
 	}
 	return 0;
 }
+EXPORT_SYMBOL_GPL(ocxl_context_detach);
 
 void ocxl_context_detach_all(struct ocxl_afu *afu)
 {
@@ -280,3 +284,4 @@ void ocxl_context_free(struct ocxl_context *ctx)
 	ocxl_afu_put(ctx->afu);
 	kfree(ctx);
 }
+EXPORT_SYMBOL_GPL(ocxl_context_free);
diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index 16eb8a60d5c7..865b3d176431 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -100,7 +100,7 @@ static long afu_ioctl_attach(struct ocxl_context *ctx,
 		return -EINVAL;
 
 	amr = arg.amr & mfspr(SPRN_UAMOR);
-	rc = ocxl_context_attach(ctx, amr);
+	rc = ocxl_context_attach(ctx, amr, current->mm);
 	return rc;
 }
 
diff --git a/drivers/misc/ocxl/ocxl_internal.h b/drivers/misc/ocxl/ocxl_internal.h
index 06fd98c989c8..779d15ef60b5 100644
--- a/drivers/misc/ocxl/ocxl_internal.h
+++ b/drivers/misc/ocxl/ocxl_internal.h
@@ -130,15 +130,9 @@ int ocxl_config_check_afu_index(struct pci_dev *dev,
  */
 int ocxl_link_update_pe(void *link_handle, int pasid, __u16 tid);
 
-struct ocxl_context *ocxl_context_alloc(void);
-int ocxl_context_init(struct ocxl_context *ctx, struct ocxl_afu *afu,
-			struct address_space *mapping);
-int ocxl_context_attach(struct ocxl_context *ctx, u64 amr);
 int ocxl_context_mmap(struct ocxl_context *ctx,
 			struct vm_area_struct *vma);
-int ocxl_context_detach(struct ocxl_context *ctx);
 void ocxl_context_detach_all(struct ocxl_afu *afu);
-void ocxl_context_free(struct ocxl_context *ctx);
 
 int ocxl_sysfs_add_afu(struct ocxl_afu *afu);
 void ocxl_sysfs_remove_afu(struct ocxl_afu *afu);
diff --git a/include/misc/ocxl.h b/include/misc/ocxl.h
index 3b320c39f0af..ebbfe83cd5a6 100644
--- a/include/misc/ocxl.h
+++ b/include/misc/ocxl.h
@@ -51,6 +51,7 @@ struct ocxl_fn_config {
 
 // These are opaque outside the ocxl driver
 struct ocxl_afu;
+struct ocxl_context;
 
 enum ocxl_endian {
 	OCXL_BIG_ENDIAN = 0,    /**< AFU data is big-endian */
@@ -58,6 +59,49 @@ enum ocxl_endian {
 	OCXL_HOST_ENDIAN = 2,   /**< AFU data is the same endianness as the host */
 };
 
+/**
+ * Allocate space for a new OpenCAPI context
+ *
+ * Returns NULL on failure
+ */
+struct ocxl_context *ocxl_context_alloc(void);
+
+/**
+ * Initialize an OpenCAPI context
+ *
+ * @ctx: The OpenCAPI context to initialize
+ * @afu: The AFU the context belongs to
+ * @mapping: The mapping to unmap when the context is closed (may be NULL)
+ */
+int ocxl_context_init(struct ocxl_context *ctx, struct ocxl_afu *afu,
+			struct address_space *mapping);
+
+/**
+ * Free an OpenCAPI context
+ *
+ * @ctx: The OpenCAPI context to free
+ */
+void ocxl_context_free(struct ocxl_context *ctx);
+
+/**
+ * Grant access to an MM to an OpenCAPI context
+ * @ctx: The OpenCAPI context to attach
+ * @amr: The value of the AMR register to restrict access
+ * @mm: The mm to attach to the context
+ *
+ * Returns 0 on success, negative on failure
+ */
+int ocxl_context_attach(struct ocxl_context *ctx, u64 amr,
+				struct mm_struct *mm);
+
+/**
+ * Detach an MM from an OpenCAPI context
+ * @ctx: The OpenCAPI context to attach
+ *
+ * Returns 0 on success, negative on failure
+ */
+int ocxl_context_detach(struct ocxl_context *ctx);
+
 /**
  * Read a 32 bit value from global MMIO
  *
-- 
2.20.1