This patch allocates a few pages and performs an ioread8_rep() from the bus
address, which are then copied to userspace. This fixes the sparse warning:
drivers/staging/goldfish/goldfish_audio.c:136:43: warning: incorrect type in argument 2 (different address spaces)
drivers/staging/goldfish/goldfish_audio.c:136:43: expected void const *from
drivers/staging/goldfish/goldfish_audio.c:136:43: got char [noderef] <asn:2>*read_buffer
which was a result of performing a copy_to_user() directly from the bus address
to the userspace, which can be unsafe across some architectures.
Signed-off-by: James A Shackleford <shack@xxxxxxxxx>
---
drivers/staging/goldfish/goldfish_audio.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/goldfish/goldfish_audio.c b/drivers/staging/goldfish/goldfish_audio.c
index a166424..535ed20 100644
--- a/drivers/staging/goldfish/goldfish_audio.c
+++ b/drivers/staging/goldfish/goldfish_audio.c
@@ -118,10 +118,17 @@ static ssize_t goldfish_audio_read(struct file *fp, char __user *buf,
struct goldfish_audio *data = fp->private_data;
int length;
int result = 0;
+ unsigned int order;
+ void *read_buffer;
if (!data->read_supported)
return -ENODEV;
+ order = get_order(READ_BUFFER_SIZE);
+ read_buffer = (void *)__get_free_pages(GFP_KERNEL, order);
+ if (!read_buffer)
+ return -ENOMEM;
+
while (count > 0) {
length = (count > READ_BUFFER_SIZE ? READ_BUFFER_SIZE : count);
AUDIO_WRITE(data, AUDIO_START_READ, length);
@@ -129,17 +136,21 @@ static ssize_t goldfish_audio_read(struct file *fp, char __user *buf,
wait_event_interruptible(data->wait,
(data->buffer_status & AUDIO_INT_READ_BUFFER_FULL));
- length = AUDIO_READ(data,
- AUDIO_READ_BUFFER_AVAILABLE);
+ length = AUDIO_READ(data, AUDIO_READ_BUFFER_AVAILABLE);
/* copy data to user space */
- if (copy_to_user(buf, data->read_buffer, length))
- return -EFAULT;
+ ioread8_rep(data->read_buffer, read_buffer, length);
+ if (copy_to_user(buf, read_buffer, length)) {
+ result = -EFAULT;
+ goto error;
+ }
result += length;
buf += length;
count -= length;
}
+error:
+ __free_pages(read_buffer, order);
return result;
}
--
1.7.9.5
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