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/drmP.h     |  3 ++-
 linux-core/drm_bufs.c | 10 +++++++---
 linux-core/drm_vm.c   | 16 ++++++++++++++++
 3 files changed, 25 insertions(+), 4 deletions(-)

(limited to 'linux-core')

diff --git a/linux-core/drmP.h b/linux-core/drmP.h
index 5c9644e0..2bbec70c 100644
--- a/linux-core/drmP.h
+++ b/linux-core/drmP.h
@@ -449,7 +449,8 @@ typedef struct drm_device_dma {
 	enum {
 		_DRM_DMA_USE_AGP = 0x01,
 		_DRM_DMA_USE_SG = 0x02,
-		_DRM_DMA_USE_FB = 0x04
+		_DRM_DMA_USE_FB = 0x04,
+		_DRM_DMA_USE_PCI_RO = 0x08
 	} flags;
 
 } drm_device_dma_t;
diff --git a/linux-core/drm_bufs.c b/linux-core/drm_bufs.c
index abd7c829..a2a3dbf7 100644
--- a/linux-core/drm_bufs.c
+++ b/linux-core/drm_bufs.c
@@ -942,6 +942,9 @@ int drm_addbufs_pci(drm_device_t * dev, drm_buf_desc_t * request)
 	request->count = entry->buf_count;
 	request->size = size;
 
+	if (request->flags & _DRM_PCI_BUFFER_RO)
+		dma->flags = _DRM_DMA_USE_PCI_RO;
+
 	atomic_dec(&dev->buf_alloc);
 	return 0;
 
@@ -1528,9 +1531,10 @@ int drm_freebufs(struct inode *inode, struct file *filp,
  * \param arg pointer to a drm_buf_map structure.
  * \return zero on success or a negative number on failure.
  *
- * Maps the AGP or SG buffer region with do_mmap(), and copies information
- * about each buffer into user space. The PCI buffers are already mapped on the
- * addbufs_pci() call.
+ * Maps the AGP, SG or PCI buffer region with do_mmap(), and copies information
+ * about each buffer into user space. For PCI buffers, it calls do_mmap() with
+ * offset equal to 0, which drm_mmap() interpretes as PCI buffers and calls
+ * drm_mmap_dma().
  */
 int drm_mapbufs(struct inode *inode, struct file *filp,
 		unsigned int cmd, unsigned long arg)
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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