From 3417f33e762bf7d4277031a655e3ad07e73ce0be Mon Sep 17 00:00:00 2001 From: George Sapountzis Date: Tue, 24 Oct 2006 12:03:04 -0700 Subject: drm: add flag for mapping PCI DMA buffers read-only. 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 --- drivers/char/drm/drm.h | 3 ++- drivers/char/drm/drmP.h | 3 ++- drivers/char/drm/drm_bufs.c | 10 +++++++--- drivers/char/drm/drm_vm.c | 16 ++++++++++++++++ 4 files changed, 27 insertions(+), 5 deletions(-) (limited to 'drivers') diff --git a/drivers/char/drm/drm.h b/drivers/char/drm/drm.h index 3f28a1551621..8db9041e306c 100644 --- a/drivers/char/drm/drm.h +++ b/drivers/char/drm/drm.h @@ -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 diff --git a/drivers/char/drm/drmP.h b/drivers/char/drm/drmP.h index 2f18329c5eb8..0bbb04f2390f 100644 --- a/drivers/char/drm/drmP.h +++ b/drivers/char/drm/drmP.h @@ -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; diff --git a/drivers/char/drm/drm_bufs.c b/drivers/char/drm/drm_bufs.c index 6eafff13dab6..9f65f5697ba8 100644 --- a/drivers/char/drm/drm_bufs.c +++ b/drivers/char/drm/drm_bufs.c @@ -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) diff --git a/drivers/char/drm/drm_vm.c b/drivers/char/drm/drm_vm.c index b40ae438f531..74686e9a2d34 100644 --- a/drivers/char/drm/drm_vm.c +++ b/drivers/char/drm/drm_vm.c @@ -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 */ -- cgit v1.2.2