From f3deef730d52c94ce21ada7e4ceb63aa28a8601b Mon Sep 17 00:00:00 2001
From: George Sapountzis <gsap7@yahoo.gr>
Date: Mon, 2 Oct 2006 05:46:42 +0300
Subject: Bug 6242: [mach64] Use private DMA buffers, part #3.

Add DRM_PCI_BUFFER_RO flag for mapping PCI DMA buffer read-only. An additional
flag is needed, since PCI DMA buffers do not have an associated map.
---
 linux-core/drm_vm.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

(limited to 'linux-core/drm_vm.c')

diff --git a/linux-core/drm_vm.c b/linux-core/drm_vm.c
index 9672269a..adff7d1a 100644
--- a/linux-core/drm_vm.c
+++ b/linux-core/drm_vm.c
@@ -506,6 +506,22 @@ static int drm_mmap_dma(struct file *filp, struct vm_area_struct *vma)
 	}
 	unlock_kernel();
 
+	if (!capable(CAP_SYS_ADMIN) &&
+	    (dma->flags & _DRM_DMA_USE_PCI_RO)) {
+		vma->vm_flags &= ~(VM_WRITE | VM_MAYWRITE);
+#if defined(__i386__) || defined(__x86_64__)
+		pgprot_val(vma->vm_page_prot) &= ~_PAGE_RW;
+#else
+		/* Ye gads this is ugly.  With more thought
+		   we could move this up higher and use
+		   `protection_map' instead.  */
+		vma->vm_page_prot =
+		    __pgprot(pte_val
+			     (pte_wrprotect
+			      (__pte(pgprot_val(vma->vm_page_prot)))));
+#endif
+	}
+
 	vma->vm_ops = &drm_vm_dma_ops;
 
 #if LINUX_VERSION_CODE <= 0x02040e	/* KERNEL_VERSION(2,4,14) */
-- 
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