Sync to v4.15-rc3 for security subsystem developers to work against.

1 files changed, 22 insertions, 2 deletions

diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
index 4bfad9f6dc9f..76c0b0ca9388 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 from above */
 		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 +234,20 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
 	 */
 	cxl_ctx_get();
 
+	/*
+	 * A 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.
+	 *
+	 * The barrier should really be mb(), since it involves a
+	 * device. However, it's only useful when we have local
+	 * vs. global TLBIs, i.e SMP=y. So keep smp_mb().
+	 */
+	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 +258,8 @@ 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;
 	}