Op 09-05-13 09:33, Inki Dae schreef: > Hi all, > > This post introduces a new helper framework based on dma fence. And the > purpose of this post is to collect other opinions and advices before RFC > posting. > > First of all, this helper framework, called fence helper, is in progress > yet so might not have enough comments in codes and also might need to be > more cleaned up. Moreover, we might be missing some parts of the dma fence. > However, I'd like to say that all things mentioned below has been tested > with Linux platform and worked well. > .... > > And tutorial for user process. > just before cpu access > struct dma_buf_fence *df; > > df->type = DMA_BUF_ACCESS_READ or DMA_BUF_ACCESS_WRITE; > ioctl(fd, DMA_BUF_GET_FENCE, &df); > > after memset or memcpy > ioctl(fd, DMA_BUF_PUT_FENCE, &df); NAK. Userspace doesn't need to trigger fences. It can do a buffer idle wait, and postpone submitting new commands until after it's done using the buffer. Kernel space doesn't need the root hole you created by giving a dereferencing a pointer passed from userspace. Your next exercise should be to write a security exploit from the api you created here. It's the only way to learn how to write safe code. Hint: df.ctx = mmap(..); ~Maarten -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
