[PATCH 3/5] ALSA: emu10k1: add optional debug printouts with DMA addresses

[PATCH 3/5] ALSA: emu10k1: add optional debug printouts with DMA addresses

[Maciej S. Szmigiero]

When we get a IOMMU page fault for a emu10k1 device it is very hard to
discover which of chip many DMA allocations triggered it (since on a IOMMU
system the DMA address space is often very different from the CPU one).
Let's add optional debug printouts providing this information.

These debug printouts are only enabled on an explicit request via the
kernel dynamic debug mechanism.

Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
---
 sound/pci/emu10k1/emu10k1_main.c |  8 ++++++++
 sound/pci/emu10k1/memory.c       | 11 +++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/sound/pci/emu10k1/emu10k1_main.c b/sound/pci/emu10k1/emu10k1_main.c
index 11e868f569d6..8decd2a7a404 100644
--- a/sound/pci/emu10k1/emu10k1_main.c
+++ b/sound/pci/emu10k1/emu10k1_main.c
@@ -1898,6 +1898,9 @@ int snd_emu10k1_create(struct snd_card *card,
 		err = -ENOMEM;
 		goto error;
 	}
+	dev_dbg(card->dev, "page table address range is %.8lx:%.8lx\n",
+		(unsigned long)emu->ptb_pages.addr,
+		(unsigned long)(emu->ptb_pages.addr + emu->ptb_pages.bytes));
 
 	emu->page_ptr_table = vmalloc(emu->max_cache_pages * sizeof(void *));
 	emu->page_addr_table = vmalloc(emu->max_cache_pages *
@@ -1912,6 +1915,11 @@ int snd_emu10k1_create(struct snd_card *card,
 		err = -ENOMEM;
 		goto error;
 	}
+	dev_dbg(card->dev, "silent page range is %.8lx:%.8lx\n",
+		(unsigned long)emu->silent_page.addr,
+		(unsigned long)(emu->silent_page.addr +
+				emu->silent_page.bytes));
+
 	emu->memhdr = snd_util_memhdr_new(emu->max_cache_pages * PAGE_SIZE);
 	if (emu->memhdr == NULL) {
 		err = -ENOMEM;
diff --git a/sound/pci/emu10k1/memory.c b/sound/pci/emu10k1/memory.c
index eaa61024ac7f..39afe199e1c7 100644
--- a/sound/pci/emu10k1/memory.c
+++ b/sound/pci/emu10k1/memory.c
@@ -35,6 +35,8 @@
  */
 #define __set_ptb_entry(emu,page,addr) \
 	(((u32 *)(emu)->ptb_pages.area)[page] = cpu_to_le32(((addr) << (emu->address_mode)) | (page)))
+#define __get_ptb_entry(emu, page) \
+	(le32_to_cpu(((u32 *)(emu)->ptb_pages.area)[page]))
 
 #define UNIT_PAGES		(PAGE_SIZE / EMUPAGESIZE)
 #define MAX_ALIGN_PAGES0		(MAXPAGES0 / UNIT_PAGES)
@@ -44,7 +46,7 @@
 /* get offset address from aligned page */
 #define aligned_page_offset(page)	((page) << PAGE_SHIFT)
 
-#if PAGE_SIZE == 4096
+#if PAGE_SIZE == 4096 && !IS_ENABLED(CONFIG_DYNAMIC_DEBUG)
 /* page size == EMUPAGESIZE */
 /* fill PTB entrie(s) corresponding to page with addr */
 #define set_ptb_entry(emu,page,addr)	__set_ptb_entry(emu,page,addr)
@@ -58,6 +60,8 @@ static inline void set_ptb_entry(struct snd_emu10k1 *emu, int page, dma_addr_t a
 	page *= UNIT_PAGES;
 	for (i = 0; i < UNIT_PAGES; i++, page++) {
 		__set_ptb_entry(emu, page, addr);
+		dev_dbg(emu->card->dev, "mapped page %d to entry %.8x\n", page,
+			(unsigned int)__get_ptb_entry(emu, page));
 		addr += EMUPAGESIZE;
 	}
 }
@@ -65,9 +69,12 @@ static inline void set_silent_ptb(struct snd_emu10k1 *emu, int page)
 {
 	int i;
 	page *= UNIT_PAGES;
-	for (i = 0; i < UNIT_PAGES; i++, page++)
+	for (i = 0; i < UNIT_PAGES; i++, page++) {
 		/* do not increment ptr */
 		__set_ptb_entry(emu, page, emu->silent_page.addr);
+		dev_dbg(emu->card->dev, "mapped silent page %d to entry %.8x\n",
+			page, (unsigned int)__get_ptb_entry(emu, page));
+	}
 }
 #endif /* PAGE_SIZE */
 

Re: [PATCH 3/5] ALSA: emu10k1: add optional debug printouts with DMA addresses

[kbuild test robot]

Hi Maciej,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on sound/for-next]
[also build test WARNING on v4.15-rc8 next-20180119]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Maciej-S-Szmigiero/ALSA-emu10k1-remove-reserved_page/20180122-022950
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git for-next
reproduce:
        # apt-get install sparse
        make ARCH=x86_64 allmodconfig
        make C=1 CF=-D__CHECK_ENDIAN__


sparse warnings: (new ones prefixed by >>)

   sound/pci/emu10k1/memory.c:62:17: sparse: incorrect type in assignment (different base types) @@ expected unsigned int <noident> @@ got ed int <noident> @@
   sound/pci/emu10k1/memory.c:62:17: expected unsigned int <noident>
   sound/pci/emu10k1/memory.c:62:17: got restricted __le32 <noident>
>> sound/pci/emu10k1/memory.c:63:17: sparse: cast to restricted __le32
   sound/pci/emu10k1/memory.c:74:17: sparse: incorrect type in assignment (different base types) @@ expected unsigned int <noident> @@ got ed int <noident> @@
   sound/pci/emu10k1/memory.c:74:17: expected unsigned int <noident>
   sound/pci/emu10k1/memory.c:74:17: got restricted __le32 <noident>
   sound/pci/emu10k1/memory.c:75:17: sparse: cast to restricted __le32

vim +63 sound/pci/emu10k1/memory.c

    48	
    49	#if PAGE_SIZE == 4096 && !IS_ENABLED(CONFIG_DYNAMIC_DEBUG)
    50	/* page size == EMUPAGESIZE */
    51	/* fill PTB entrie(s) corresponding to page with addr */
    52	#define set_ptb_entry(emu,page,addr)	__set_ptb_entry(emu,page,addr)
    53	/* fill PTB entrie(s) corresponding to page with silence pointer */
    54	#define set_silent_ptb(emu,page)	__set_ptb_entry(emu,page,emu->silent_page.addr)
    55	#else
    56	/* fill PTB entries -- we need to fill UNIT_PAGES entries */
    57	static inline void set_ptb_entry(struct snd_emu10k1 *emu, int page, dma_addr_t addr)
    58	{
    59		int i;
    60		page *= UNIT_PAGES;
    61		for (i = 0; i < UNIT_PAGES; i++, page++) {
  > 62			__set_ptb_entry(emu, page, addr);
  > 63			dev_dbg(emu->card->dev, "mapped page %d to entry %.8x\n", page,
    64				(unsigned int)__get_ptb_entry(emu, page));
    65			addr += EMUPAGESIZE;
    66		}
    67	}
    68	static inline void set_silent_ptb(struct snd_emu10k1 *emu, int page)
    69	{
    70		int i;
    71		page *= UNIT_PAGES;
    72		for (i = 0; i < UNIT_PAGES; i++, page++) {
    73			/* do not increment ptr */
    74			__set_ptb_entry(emu, page, emu->silent_page.addr);
    75			dev_dbg(emu->card->dev, "mapped silent page %d to entry %.8x\n",
    76				page, (unsigned int)__get_ptb_entry(emu, page));
    77		}
    78	}
    79	#endif /* PAGE_SIZE */
    80	
    81	

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