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fault mmaped area upon rtdm_mmap_to_user.

PATCH In review Gilles Chanteperdrix 2 participants 2 messages Nov 15, 2008 – Nov 16, 2008

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Gilles Chanteperdrix

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#0 lore raw

PATCH 1/1 fault mmaped area upon rtdm_mmap_to_user.

Hi Jan,

I have just commited a modification of the nucleus heap which allows faulting newly mapped pages. However, I noticed that we should modify rtdm_mmap_to_user as in the attached patch.

At this chance, I also noticed that there is no way to ask for uncached memory to rtdm_mmap_to_user, how do you think we should change rtdm_mmap_to_user to allow this?

Regards.

skins/rtdm/drvlib.c +17 -6
Index: ksrc/skins/rtdm/drvlib.c
===================================================================
@@ -1781,6 +1781,7 @@ static int rtdm_mmap_buffer(struct file
 {
 	struct rtdm_mmap_data *mmap_data = filp->private_data;
 	unsigned long vaddr, paddr, maddr, size;
+	int ret;
 
 	vma->vm_ops = mmap_data->vm_ops;
 	vma->vm_private_data = mmap_data->vm_private_data;

@@ -1810,15 +1811,25 @@ static int rtdm_mmap_buffer(struct file
 			vaddr += PAGE_SIZE;
 			mapped_size += PAGE_SIZE;
 		}
-		return 0;
+#ifdef xnarch_fault_range
+		xnarch_fault_range(vma);
+#endif /* xnarch_fault_range */
+		ret = 0;
 	} else
 #endif /* CONFIG_MMU */
 	if (mmap_data->src_paddr)
-	  	return xnarch_remap_io_page_range(filp, vma, maddr, paddr,
-						  size, PAGE_SHARED);
-	else
-		return xnarch_remap_kmem_page_range(vma, maddr, paddr,
-						    size, PAGE_SHARED);
+	  	ret = xnarch_remap_io_page_range(filp, vma, maddr, paddr,
+						 size, PAGE_SHARED);
+	else {
+		ret = xnarch_remap_kmem_page_range(vma, maddr, paddr,
+						   size, PAGE_SHARED);
+#ifdef xnarch_fault_range
+		if (!ret)
+			xnarch_fault_range(vma);
+#endif /* xnarch_fault_range */
+	}
+
+	return ret;
 }
 
 static struct file_operations rtdm_mmap_fops = {
Signature · 1 line
					    Gilles.
#1 lore raw
Quoted 5 lines · Gilles Chanteperdrix

Hi Jan,

I have just commited a modification of the nucleus heap which allows faulting newly mapped pages. However, I noticed that we should modify rtdm_mmap_to_user as in the attached patch.

No general concerns, please just provide an empty xnarch_fault_range as default to avoid the #ifdefs. Is this an ARM-only issue?

Quoted 4 lines

At this chance, I also noticed that there is no way to ask for uncached memory to rtdm_mmap_to_user, how do you think we should change rtdm_mmap_to_user to allow this?

Look like we would have to introduce a 'flags' argument to rtdm_mmap_to_user. That's 2.5 material, where we'll change a few RTDM APIs anyway.

Jan

Quoted 49 lines

Regards.

Index: ksrc/skins/rtdm/drvlib.c
===================================================================

skins/rtdm/drvlib.c +17 -6
@@ -1781,6 +1781,7 @@ static int rtdm_mmap_buffer(struct file
 {
 	struct rtdm_mmap_data *mmap_data = filp->private_data;
 	unsigned long vaddr, paddr, maddr, size;
+	int ret;
 
 	vma->vm_ops = mmap_data->vm_ops;
 	vma->vm_private_data = mmap_data->vm_private_data;

@@ -1810,15 +1811,25 @@ static int rtdm_mmap_buffer(struct file
 			vaddr += PAGE_SIZE;
 			mapped_size += PAGE_SIZE;
 		}
-		return 0;
+#ifdef xnarch_fault_range
+		xnarch_fault_range(vma);
+#endif /* xnarch_fault_range */
+		ret = 0;
 	} else
 #endif /* CONFIG_MMU */
 	if (mmap_data->src_paddr)
-	  	return xnarch_remap_io_page_range(filp, vma, maddr, paddr,
-						  size, PAGE_SHARED);
-	else
-		return xnarch_remap_kmem_page_range(vma, maddr, paddr,
-						    size, PAGE_SHARED);
+	  	ret = xnarch_remap_io_page_range(filp, vma, maddr, paddr,
+						 size, PAGE_SHARED);
+	else {
+		ret = xnarch_remap_kmem_page_range(vma, maddr, paddr,
+						   size, PAGE_SHARED);
+#ifdef xnarch_fault_range
+		if (!ret)
+			xnarch_fault_range(vma);
+#endif /* xnarch_fault_range */
+	}
+
+	return ret;
 }
 
 static struct file_operations rtdm_mmap_fops = {