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-rw-r--r--drivers/char/hw_random/core.c108
-rw-r--r--drivers/char/hw_random/virtio-rng.c78
2 files changed, 92 insertions, 94 deletions
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 1573aebd54b..8b7d56a0fe3 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -52,7 +52,9 @@
static struct hwrng *current_rng;
static LIST_HEAD(rng_list);
static DEFINE_MUTEX(rng_mutex);
-
+static int data_avail;
+static u8 rng_buffer[SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES]
+ __cacheline_aligned;
static inline int hwrng_init(struct hwrng *rng)
{
@@ -67,19 +69,6 @@ static inline void hwrng_cleanup(struct hwrng *rng)
rng->cleanup(rng);
}
-static inline int hwrng_data_present(struct hwrng *rng, int wait)
-{
- if (!rng->data_present)
- return 1;
- return rng->data_present(rng, wait);
-}
-
-static inline int hwrng_data_read(struct hwrng *rng, u32 *data)
-{
- return rng->data_read(rng, data);
-}
-
-
static int rng_dev_open(struct inode *inode, struct file *filp)
{
/* enforce read-only access to this chrdev */
@@ -91,54 +80,87 @@ static int rng_dev_open(struct inode *inode, struct file *filp)
return 0;
}
+static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
+ int wait) {
+ int present;
+
+ if (rng->read)
+ return rng->read(rng, (void *)buffer, size, wait);
+
+ if (rng->data_present)
+ present = rng->data_present(rng, wait);
+ else
+ present = 1;
+
+ if (present)
+ return rng->data_read(rng, (u32 *)buffer);
+
+ return 0;
+}
+
static ssize_t rng_dev_read(struct file *filp, char __user *buf,
size_t size, loff_t *offp)
{
- u32 data;
ssize_t ret = 0;
int err = 0;
- int bytes_read;
+ int bytes_read, len;
while (size) {
- err = -ERESTARTSYS;
- if (mutex_lock_interruptible(&rng_mutex))
+ if (mutex_lock_interruptible(&rng_mutex)) {
+ err = -ERESTARTSYS;
goto out;
+ }
+
if (!current_rng) {
- mutex_unlock(&rng_mutex);
err = -ENODEV;
- goto out;
+ goto out_unlock;
}
- bytes_read = 0;
- if (hwrng_data_present(current_rng,
- !(filp->f_flags & O_NONBLOCK)))
- bytes_read = hwrng_data_read(current_rng, &data);
- mutex_unlock(&rng_mutex);
-
- err = -EAGAIN;
- if (!bytes_read && (filp->f_flags & O_NONBLOCK))
- goto out;
- if (bytes_read < 0) {
- err = bytes_read;
- goto out;
+ if (!data_avail) {
+ bytes_read = rng_get_data(current_rng, rng_buffer,
+ sizeof(rng_buffer),
+ !(filp->f_flags & O_NONBLOCK));
+ if (bytes_read < 0) {
+ err = bytes_read;
+ goto out_unlock;
+ }
+ data_avail = bytes_read;
}
- err = -EFAULT;
- while (bytes_read && size) {
- if (put_user((u8)data, buf++))
- goto out;
- size--;
- ret++;
- bytes_read--;
- data >>= 8;
+ if (!data_avail) {
+ if (filp->f_flags & O_NONBLOCK) {
+ err = -EAGAIN;
+ goto out_unlock;
+ }
+ } else {
+ len = data_avail;
+ if (len > size)
+ len = size;
+
+ data_avail -= len;
+
+ if (copy_to_user(buf + ret, rng_buffer + data_avail,
+ len)) {
+ err = -EFAULT;
+ goto out_unlock;
+ }
+
+ size -= len;
+ ret += len;
}
+ mutex_unlock(&rng_mutex);
+
if (need_resched())
schedule_timeout_interruptible(1);
- err = -ERESTARTSYS;
- if (signal_pending(current))
+
+ if (signal_pending(current)) {
+ err = -ERESTARTSYS;
goto out;
+ }
}
+out_unlock:
+ mutex_unlock(&rng_mutex);
out:
return ret ? : err;
}
@@ -280,7 +302,7 @@ int hwrng_register(struct hwrng *rng)
struct hwrng *old_rng, *tmp;
if (rng->name == NULL ||
- rng->data_read == NULL)
+ (rng->data_read == NULL && rng->read == NULL))
goto out;
mutex_lock(&rng_mutex);
diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
index 915157fcff9..bdaef8e9402 100644
--- a/drivers/char/hw_random/virtio-rng.c
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -16,6 +16,7 @@
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
+
#include <linux/err.h>
#include <linux/hw_random.h>
#include <linux/scatterlist.h>
@@ -23,78 +24,64 @@
#include <linux/virtio.h>
#include <linux/virtio_rng.h>
-/* The host will fill any buffer we give it with sweet, sweet randomness. We
- * give it 64 bytes at a time, and the hwrng framework takes it 4 bytes at a
- * time. */
-#define RANDOM_DATA_SIZE 64
-
static struct virtqueue *vq;
-static u32 *random_data;
-static unsigned int data_left;
+static unsigned int data_avail;
static DECLARE_COMPLETION(have_data);
+static bool busy;
static void random_recv_done(struct virtqueue *vq)
{
- unsigned int len;
-
/* We can get spurious callbacks, e.g. shared IRQs + virtio_pci. */
- if (!vq->vq_ops->get_buf(vq, &len))
+ if (!vq->vq_ops->get_buf(vq, &data_avail))
return;
- data_left += len;
complete(&have_data);
}
-static void register_buffer(void)
+/* The host will fill any buffer we give it with sweet, sweet randomness. */
+static void register_buffer(u8 *buf, size_t size)
{
struct scatterlist sg;
- sg_init_one(&sg, random_data+data_left, RANDOM_DATA_SIZE-data_left);
+ sg_init_one(&sg, buf, size);
+
/* There should always be room for one buffer. */
- if (vq->vq_ops->add_buf(vq, &sg, 0, 1, random_data) < 0)
+ if (vq->vq_ops->add_buf(vq, &sg, 0, 1, buf) < 0)
BUG();
+
vq->vq_ops->kick(vq);
}
-/* At least we don't udelay() in a loop like some other drivers. */
-static int virtio_data_present(struct hwrng *rng, int wait)
+static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait)
{
- if (data_left >= sizeof(u32))
- return 1;
-again:
+ if (!busy) {
+ busy = true;
+ init_completion(&have_data);
+ register_buffer(buf, size);
+ }
+
if (!wait)
return 0;
wait_for_completion(&have_data);
- /* Not enough? Re-register. */
- if (unlikely(data_left < sizeof(u32))) {
- register_buffer();
- goto again;
- }
+ busy = false;
- return 1;
+ return data_avail;
}
-/* virtio_data_present() must have succeeded before this is called. */
-static int virtio_data_read(struct hwrng *rng, u32 *data)
+static void virtio_cleanup(struct hwrng *rng)
{
- BUG_ON(data_left < sizeof(u32));
- data_left -= sizeof(u32);
- *data = random_data[data_left / 4];
-
- if (data_left < sizeof(u32)) {
- init_completion(&have_data);
- register_buffer();
- }
- return sizeof(*data);
+ if (busy)
+ wait_for_completion(&have_data);
}
+
static struct hwrng virtio_hwrng = {
- .name = "virtio",
- .data_present = virtio_data_present,
- .data_read = virtio_data_read,
+ .name = "virtio",
+ .cleanup = virtio_cleanup,
+ .read = virtio_read,
};
static int virtrng_probe(struct virtio_device *vdev)
@@ -112,7 +99,6 @@ static int virtrng_probe(struct virtio_device *vdev)
return err;
}
- register_buffer();
return 0;
}
@@ -138,21 +124,11 @@ static struct virtio_driver virtio_rng = {
static int __init init(void)
{
- int err;
-
- random_data = kmalloc(RANDOM_DATA_SIZE, GFP_KERNEL);
- if (!random_data)
- return -ENOMEM;
-
- err = register_virtio_driver(&virtio_rng);
- if (err)
- kfree(random_data);
- return err;
+ return register_virtio_driver(&virtio_rng);
}
static void __exit fini(void)
{
- kfree(random_data);
unregister_virtio_driver(&virtio_rng);
}
module_init(init);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-17 16:09:19 +0000