From 10ebd8556b7990499c896a550e3d416b444211e6 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Fri, 10 May 2024 02:23:07 +0000
Subject: [PATCH] add led
---
kernel/drivers/char/hw_random/virtio-rng.c | 104 ++++++++++++++++++++++++++++++++++------------------
1 files changed, 68 insertions(+), 36 deletions(-)
diff --git a/kernel/drivers/char/hw_random/virtio-rng.c b/kernel/drivers/char/hw_random/virtio-rng.c
index 7abd604..3a194eb 100644
--- a/kernel/drivers/char/hw_random/virtio-rng.c
+++ b/kernel/drivers/char/hw_random/virtio-rng.c
@@ -1,22 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Randomness driver for virtio
* Copyright (C) 2007, 2008 Rusty Russell IBM Corporation
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
+#include <asm/barrier.h>
#include <linux/err.h>
#include <linux/hw_random.h>
#include <linux/scatterlist.h>
@@ -24,77 +12,118 @@
#include <linux/virtio.h>
#include <linux/virtio_rng.h>
#include <linux/module.h>
+#include <linux/slab.h>
static DEFINE_IDA(rng_index_ida);
struct virtrng_info {
struct hwrng hwrng;
struct virtqueue *vq;
- struct completion have_data;
char name[25];
- unsigned int data_avail;
int index;
- bool busy;
bool hwrng_register_done;
bool hwrng_removed;
+ /* data transfer */
+ struct completion have_data;
+ unsigned int data_avail;
+ unsigned int data_idx;
+ /* minimal size returned by rng_buffer_size() */
+#if SMP_CACHE_BYTES < 32
+ u8 data[32];
+#else
+ u8 data[SMP_CACHE_BYTES];
+#endif
};
static void random_recv_done(struct virtqueue *vq)
{
struct virtrng_info *vi = vq->vdev->priv;
+ unsigned int len;
/* We can get spurious callbacks, e.g. shared IRQs + virtio_pci. */
- if (!virtqueue_get_buf(vi->vq, &vi->data_avail))
+ if (!virtqueue_get_buf(vi->vq, &len))
return;
+ smp_store_release(&vi->data_avail, len);
complete(&vi->have_data);
}
-/* The host will fill any buffer we give it with sweet, sweet randomness. */
-static void register_buffer(struct virtrng_info *vi, u8 *buf, size_t size)
+static void request_entropy(struct virtrng_info *vi)
{
struct scatterlist sg;
- sg_init_one(&sg, buf, size);
+ reinit_completion(&vi->have_data);
+ vi->data_idx = 0;
+
+ sg_init_one(&sg, vi->data, sizeof(vi->data));
/* There should always be room for one buffer. */
- virtqueue_add_inbuf(vi->vq, &sg, 1, buf, GFP_KERNEL);
+ virtqueue_add_inbuf(vi->vq, &sg, 1, vi->data, GFP_KERNEL);
virtqueue_kick(vi->vq);
+}
+
+static unsigned int copy_data(struct virtrng_info *vi, void *buf,
+ unsigned int size)
+{
+ size = min_t(unsigned int, size, vi->data_avail);
+ memcpy(buf, vi->data + vi->data_idx, size);
+ vi->data_idx += size;
+ vi->data_avail -= size;
+ if (vi->data_avail == 0)
+ request_entropy(vi);
+ return size;
}
static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait)
{
int ret;
struct virtrng_info *vi = (struct virtrng_info *)rng->priv;
+ unsigned int chunk;
+ size_t read;
if (vi->hwrng_removed)
return -ENODEV;
- if (!vi->busy) {
- vi->busy = true;
- reinit_completion(&vi->have_data);
- register_buffer(vi, buf, size);
+ read = 0;
+
+ /* copy available data */
+ if (smp_load_acquire(&vi->data_avail)) {
+ chunk = copy_data(vi, buf, size);
+ size -= chunk;
+ read += chunk;
}
if (!wait)
- return 0;
+ return read;
- ret = wait_for_completion_killable(&vi->have_data);
- if (ret < 0)
- return ret;
+ /* We have already copied available entropy,
+ * so either size is 0 or data_avail is 0
+ */
+ while (size != 0) {
+ /* data_avail is 0 but a request is pending */
+ ret = wait_for_completion_killable(&vi->have_data);
+ if (ret < 0)
+ return ret;
+ /* if vi->data_avail is 0, we have been interrupted
+ * by a cleanup, but buffer stays in the queue
+ */
+ if (vi->data_avail == 0)
+ return read;
- vi->busy = false;
+ chunk = copy_data(vi, buf + read, size);
+ size -= chunk;
+ read += chunk;
+ }
- return vi->data_avail;
+ return read;
}
static void virtio_cleanup(struct hwrng *rng)
{
struct virtrng_info *vi = (struct virtrng_info *)rng->priv;
- if (vi->busy)
- wait_for_completion(&vi->have_data);
+ complete(&vi->have_data);
}
static int probe_common(struct virtio_device *vdev)
@@ -130,6 +159,9 @@
goto err_find;
}
+ /* we always have a pending entropy request */
+ request_entropy(vi);
+
return 0;
err_find:
@@ -145,9 +177,9 @@
vi->hwrng_removed = true;
vi->data_avail = 0;
+ vi->data_idx = 0;
complete(&vi->have_data);
vdev->config->reset(vdev);
- vi->busy = false;
if (vi->hwrng_register_done)
hwrng_unregister(&vi->hwrng);
vdev->config->del_vqs(vdev);
@@ -207,7 +239,7 @@
}
#endif
-static struct virtio_device_id id_table[] = {
+static const struct virtio_device_id id_table[] = {
{ VIRTIO_ID_RNG, VIRTIO_DEV_ANY_ID },
{ 0 },
};
--
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