[alsa-devel] [PATCH 01/11] ASoC: SOF: Add Sound Open Firmware driver core

[Pierre-Louis Bossart]

we seem to have a new 0-day report with randconfig related to the 
page/sgbuffer management. Not sure why it wasn't seen before, I've 
already fixed quite a few exotic configurations for non-Intel targets.

sound/soc/sof/core.c: In function 'snd_sof_create_page_table':
sound/soc/sof/core.c:201:10: error: implicit declaration of function 
'snd_sgbuf_aligned_pages' [-Werror=implicit-function-declaration]
   pages = snd_sgbuf_aligned_pages(size);
           ^
Looking at the code:
> +static inline unsigned int sof_get_pages(size_t size)
> +{
> +	return (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
> +}
this inline doesn't seem to be used but duplicates the code from

static inline unsigned int snd_sgbuf_aligned_pages(size_t size)
{
     return (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
}

which is used below
> +int snd_sof_create_page_table(struct snd_sof_dev *sdev,
> +			      struct snd_dma_buffer *dmab,
> +			      unsigned char *page_table, size_t size)
> +{
> +	int i, pages;
> +
> +	pages = snd_sgbuf_aligned_pages(size);
this code doesn't compile unless CONFIG_SND_DMA_SGBUF is defined (it is 
set for the intel-specific code but not for the SOF core). We can fix 
this in different ways
0. require SND_CMD_SGBUF for the core - likely not desirable
1. use sof_get_pages()
2. change include/sound/memalloc.h to make sure this 
snd_sgbuf_aligned_pages() inline is available whether 
CONFIG_SND_DMA_SGBUF is defined or not - maybe making sure while we are 
at it that the malloc and free functions are empty static inlines?

Thoughts?
Thanks
-Pierre

> +
> +	dev_dbg(sdev->dev, "generating page table for %p size 0x%zx pages %d\n",
> +		dmab->area, size, pages);
> +
> +	for (i = 0; i < pages; i++) {
> +		u32 idx = (((i << 2) + i)) >> 1;
> +		u32 pfn = snd_sgbuf_get_addr(dmab, i * PAGE_SIZE) >> PAGE_SHIFT;
> +		u32 *pg_table;
> +
> +		dev_dbg(sdev->dev, "pfn i %i idx %d pfn %x\n", i, idx, pfn);
> +
> +		pg_table = (u32 *)(page_table + idx);
> +
> +		if (i & 1)
> +			*pg_table |= (pfn << 4);
> +		else
> +			*pg_table |= pfn;
> +	}
> +
> +	return pages;
> +}