From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Frediano Ziglio" , "Takashi Iwai" , "Stefano Panella" Date: Sun, 29 Dec 2013 03:08:44 +0100 Message-ID: Subject: [PATCH 3.2 130/185] ALSA: memalloc.h - fix wrong truncation of dma_addr_t In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.2.54-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Stefano Panella commit 932e9dec380c67ec15ac3eb073bb55797d8b4801 upstream. When running a 32bit kernel the hda_intel driver is still reporting a 64bit dma_mask if the HW supports it. =46romsound/pci/hda/hda_intel.c: /* allow 64bit DMA address if supported by H/W */ if ((gcap & ICH6_GCAP_64OK) && !pci_set_dma_mask(pci, DMA_BIT_MASK(64))) pci_set_consistent_dma_mask(pci, DMA_BIT_MASK(64)); else { pci_set_dma_mask(pci, DMA_BIT_MASK(32)); pci_set_consistent_dma_mask(pci, DMA_BIT_MASK(32)); } which means when there is a call to dma_alloc_coherent from snd_malloc_dev_pages a machine address bigger than 32bit can be returned. This can be true in particular if running the 32bit kernel as a pv dom0 under the Xen Hypervisor or PAE on bare metal. The problem is that when calling setup_bdle to program the BLE the dma_addr_t returned from the dma_alloc_coherent is wrongly truncated from snd_sgbuf_get_addr if running a 32bit kernel: static inline dma_addr_t snd_sgbuf_get_addr(struct snd_dma_buffer *dmab, size_t offset) { struct snd_sg_buf *sgbuf = dmab->private_data; dma_addr_t addr = sgbuf->table[offset >> PAGE_SHIFT].addr; addr &= PAGE_MASK; return addr + offset % PAGE_SIZE; } where PAGE_MASK in a 32bit kernel is zeroing the upper 32bit af addr. Without this patch the HW will fetch the 32bit truncated address, which is not the one obtained from dma_alloc_coherent and will result to a non working audio but can corrupt host memory at a random location. The current patch apply to v3.13-rc3-74-g6c843f5 Signed-off-by: Stefano Panella Reviewed-by: Frediano Ziglio Signed-off-by: Takashi Iwai Signed-off-by: Ben Hutchings --- include/sound/memalloc.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/sound/memalloc.h +++ b/include/sound/memalloc.h @@ -101,7 +101,7 @@ static inline unsigned int snd_sgbuf_ali static inline dma_addr_t snd_sgbuf_get_addr(struct snd_sg_buf *sgbuf, size_t offset) { dma_addr_t addr = sgbuf->table[offset >> PAGE_SHIFT].addr; - addr &= PAGE_MASK; + addr &= ~((dma_addr_t)PAGE_SIZE - 1); return addr + offset % PAGE_SIZE; }