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drm: add flag for mapping PCI DMA buffers read-only.

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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.

Signed-off-by: Dave Airlie <airlied@linux.ie>
This commit is contained in:
George Sapountzis 2006-10-24 12:03:04 -07:00 committed by airlied
parent 5c2df2bfb1
commit 3417f33e76
4 changed files with 27 additions and 5 deletions
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3
drivers/char/drm/drm.h
View File

@ -356,7 +356,8 @@ typedef struct drm_buf_desc {
_DRM_PAGE_ALIGN = 0x01, /**< Align on page boundaries for DMA */
_DRM_AGP_BUFFER = 0x02, /**< Buffer is in AGP space */
_DRM_SG_BUFFER = 0x04, /**< Scatter/gather memory buffer */
_DRM_FB_BUFFER = 0x08 /**< Buffer is in frame buffer */
_DRM_FB_BUFFER = 0x08, /**< Buffer is in frame buffer */
_DRM_PCI_BUFFER_RO = 0x10 /**< Map PCI DMA buffer read-only */
} flags;
unsigned long agp_start; /**<
* Start address of where the AGP buffers are

3
drivers/char/drm/drmP.h
View File

@ -431,7 +431,8 @@ 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;

10
drivers/char/drm/drm_bufs.c
View File

@ -887,6 +887,9 @@ 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;
@ -1471,9 +1474,10 @@ 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)

16
drivers/char/drm/drm_vm.c
View File

@ -473,6 +473,22 @@ 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;
vma->vm_flags |= VM_RESERVED; /* Don't swap */