ps3fb: fix possible overlap of GPU command buffer and frame buffer

ps3fb: In the case of non-fullscreen video modes, there was a partial overlap
of the GPU command buffer and the frame buffer. Fix and cleanup various issues
with overlap and alignment:
  - Move the GPU command buffer from the beginning to the end of video memory
  - Exclude the GPU command buffer from the actual frame buffer memory
  - Align the start of the virtual frame buffer to PAGE_SIZE instead of to 64
    KiB, and don't waste memory if it's already aligned (for fullscreen modes)
  - Take into account the alignment when checking memory requirements and
    maximum number of frames
  - Make sure fb_fix_screeninfo.smem_start always points to the virtual frame
    buffer start, so we don't have to compensate for that in ps3fb_mmap()

Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 39 insertions, 27 deletions

diff --git a/drivers/video/ps3fb.c b/drivers/video/ps3fb.c
index 4885978dd5be..8bbe479f73f7 100644
--- a/drivers/video/ps3fb.c
+++ b/drivers/video/ps3fb.c
@@ -52,7 +52,7 @@
 #define L1GPU_DISPLAY_SYNC_VSYNC                2
 
 #define DDR_SIZE                                (0)     /* used no ddr */
-#define GPU_OFFSET                              (64 * 1024)
+#define GPU_CMD_BUF_SIZE                        (64 * 1024)
 #define GPU_IOIF                                (0x0d000000UL)
 
 #define PS3FB_FULL_MODE_BIT                     0x80
@@ -117,6 +117,7 @@ struct ps3fb_priv {
 
         u64 context_handle, memory_handle;
         void *xdr_ea;
+        size_t xdr_size;
         struct gpu_driver_info *dinfo;
         u32 res_index;
 
@@ -280,9 +281,20 @@ static const struct fb_videomode ps3fb_modedb[] = {
 #define Y_OFF(i)        (ps3fb_res[i].yoff)     /* top/bottom margin (pixel) */
 #define WIDTH(i)        (ps3fb_res[i].xres)     /* width of FB */
 #define HEIGHT(i)       (ps3fb_res[i].yres)     /* height of FB */
-#define BPP     4               /* number of bytes per pixel */
-#define VP_OFF(i)       (WIDTH(i) * Y_OFF(i) * BPP + X_OFF(i) * BPP)
-#define FB_OFF(i)       (GPU_OFFSET - VP_OFF(i) % GPU_OFFSET)
+#define BPP             4                       /* number of bytes per pixel */
+
+/* Start of the virtual frame buffer (relative to fullscreen ) */
+#define VP_OFF(i)       ((WIDTH(i) * Y_OFF(i) + X_OFF(i)) * BPP)
+
+/*
+ * Start of the virtual frame buffer (relative to start of video memory)
+ * This is PAGE_SIZE aligned for easier mmap()
+ */
+#define VFB_OFF(i)      PAGE_ALIGN(VP_OFF(i))
+
+/* Start of the fullscreen frame buffer (relative to start of video memory) */
+#define FB_OFF(i)       (-VP_OFF(i) & ~PAGE_MASK)
+
 
 static int ps3fb_mode;
 module_param(ps3fb_mode, int, 0);
@@ -517,7 +529,8 @@ static int ps3fb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
 
         /* Memory limit */
         i = ps3fb_get_res_table(var->xres, var->yres, mode);
-        if (ps3fb_res[i].xres*ps3fb_res[i].yres*BPP > ps3fb_videomemory.size) {
+        if (ps3fb_res[i].xres*ps3fb_res[i].yres*BPP >
+            ps3fb.xdr_size - VFB_OFF(i)) {
                 dev_dbg(info->device, "Not enough memory\n");
                 return -ENOMEM;
         }
@@ -549,12 +562,13 @@ static int ps3fb_set_par(struct fb_info *info)
         i = ps3fb_get_res_table(info->var.xres, info->var.yres, mode);
         ps3fb.res_index = i;
 
-        offset = FB_OFF(i) + VP_OFF(i);
-        info->fix.smem_len = ps3fb_videomemory.size - offset;
+        offset = VFB_OFF(i);
+        info->fix.smem_start = virt_to_abs(ps3fb.xdr_ea) + offset;
+        info->fix.smem_len = ps3fb.xdr_size - offset;
         info->screen_base = (char __iomem *)ps3fb.xdr_ea + offset;
-        memset(ps3fb.xdr_ea, 0, ps3fb_videomemory.size);
+        memset(ps3fb.xdr_ea, 0, ps3fb.xdr_size);
 
-        ps3fb.num_frames = ps3fb_videomemory.size/
+        ps3fb.num_frames = info->fix.smem_len/
                            (ps3fb_res[i].xres*ps3fb_res[i].yres*BPP);
 
         /* Keep the special bits we cannot set using fb_var_screeninfo */
@@ -596,18 +610,13 @@ static int ps3fb_setcolreg(unsigned int regno, unsigned int red,
 static int ps3fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
 {
         unsigned long size, offset;
-        int i;
-
-        i = ps3fb_get_res_table(info->var.xres, info->var.yres, ps3fb_mode);
-        if (i == -1)
-                return -EINVAL;
 
         size = vma->vm_end - vma->vm_start;
         offset = vma->vm_pgoff << PAGE_SHIFT;
         if (offset + size > info->fix.smem_len)
                 return -EINVAL;
 
-        offset += info->fix.smem_start + FB_OFF(i) + VP_OFF(i);
+        offset += info->fix.smem_start;
         if (remap_pfn_range(vma, vma->vm_start, offset >> PAGE_SHIFT,
                             size, vma->vm_page_prot))
                 return -EAGAIN;
@@ -899,8 +908,9 @@ static int ps3fb_xdr_settings(u64 xdr_lpar, struct device *dev)
 
         status = lv1_gpu_context_attribute(ps3fb.context_handle,
                                            L1GPU_CONTEXT_ATTRIBUTE_FB_SETUP,
-                                           xdr_lpar, ps3fb_videomemory.size,
-                                           GPU_IOIF, 0);
+                                           xdr_lpar + ps3fb.xdr_size,
+                                           GPU_CMD_BUF_SIZE,
+                                           GPU_IOIF + ps3fb.xdr_size, 0);
         if (status) {
                 dev_err(dev,
                         "%s: lv1_gpu_context_attribute FB_SETUP failed: %d\n",
@@ -1038,29 +1048,31 @@ static int __devinit ps3fb_probe(struct ps3_system_bus_device *dev)
         if (retval)
                 goto err_iounmap_dinfo;
 
-        /* xdr frame buffer */
+        /* XDR frame buffer */
         ps3fb.xdr_ea = ps3fb_videomemory.address;
         xdr_lpar = ps3_mm_phys_to_lpar(__pa(ps3fb.xdr_ea));
+
+        /* Clear memory to prevent kernel info leakage into userspace */
+        memset(ps3fb.xdr_ea, 0, ps3fb_videomemory.size);
+
+        /* The GPU command buffer is at the end of video memory */
+        ps3fb.xdr_size = ps3fb_videomemory.size - GPU_CMD_BUF_SIZE;
+
         retval = ps3fb_xdr_settings(xdr_lpar, &dev->core);
         if (retval)
                 goto err_free_irq;
 
-        /*
-         * ps3fb must clear memory to prevent kernel info
-         * leakage into userspace
-         */
-        memset(ps3fb.xdr_ea, 0, ps3fb_videomemory.size);
         info = framebuffer_alloc(sizeof(u32) * 16, &dev->core);
         if (!info)
                 goto err_free_irq;
 
-        offset = FB_OFF(ps3fb.res_index) + VP_OFF(ps3fb.res_index);
+        offset = VFB_OFF(ps3fb.res_index);
         info->screen_base = (char __iomem *)ps3fb.xdr_ea + offset;
         info->fbops = &ps3fb_ops;
 
         info->fix = ps3fb_fix;
-        info->fix.smem_start = virt_to_abs(ps3fb.xdr_ea);
-        info->fix.smem_len = ps3fb_videomemory.size - offset;
+        info->fix.smem_start = virt_to_abs(ps3fb.xdr_ea) + offset;
+        info->fix.smem_len = ps3fb.xdr_size - offset;
         info->pseudo_palette = info->par;
         info->par = NULL;
         info->flags = FBINFO_DEFAULT | FBINFO_READS_FAST;
@@ -1086,7 +1098,7 @@ static int __devinit ps3fb_probe(struct ps3_system_bus_device *dev)
 
         dev_info(info->device, "%s %s, using %lu KiB of video memory\n",
                  dev_driver_string(info->dev), info->dev->bus_id,
-                 ps3fb_videomemory.size >> 10);
+                 ps3fb.xdr_size >> 10);
 
         task = kthread_run(ps3fbd, info, DEVICE_NAME);
         if (IS_ERR(task)) {