WSL2-Linux-Kernel/drivers/firmware/arm_scmi/mailbox.c

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5.1 KiB
C
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// SPDX-License-Identifier: GPL-2.0
/*
* System Control and Management Interface (SCMI) Message Mailbox Transport
* driver.
*
* Copyright (C) 2019 ARM Ltd.
*/
#include <linux/err.h>
#include <linux/device.h>
#include <linux/mailbox_client.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/slab.h>
#include "common.h"
/**
* struct scmi_mailbox - Structure representing a SCMI mailbox transport
*
* @cl: Mailbox Client
* @chan: Transmit/Receive mailbox channel
* @cinfo: SCMI channel info
* @shmem: Transmit/Receive shared memory area
*/
struct scmi_mailbox {
struct mbox_client cl;
struct mbox_chan *chan;
struct scmi_chan_info *cinfo;
struct scmi_shared_mem __iomem *shmem;
};
#define client_to_scmi_mailbox(c) container_of(c, struct scmi_mailbox, cl)
static void tx_prepare(struct mbox_client *cl, void *m)
{
struct scmi_mailbox *smbox = client_to_scmi_mailbox(cl);
shmem_tx_prepare(smbox->shmem, m);
}
static void rx_callback(struct mbox_client *cl, void *m)
{
struct scmi_mailbox *smbox = client_to_scmi_mailbox(cl);
scmi_rx_callback(smbox->cinfo, shmem_read_header(smbox->shmem), NULL);
}
static bool mailbox_chan_available(struct device *dev, int idx)
{
return !of_parse_phandle_with_args(dev->of_node, "mboxes",
"#mbox-cells", idx, NULL);
}
static int mailbox_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
bool tx)
{
const char *desc = tx ? "Tx" : "Rx";
struct device *cdev = cinfo->dev;
struct scmi_mailbox *smbox;
struct device_node *shmem;
int ret, idx = tx ? 0 : 1;
struct mbox_client *cl;
resource_size_t size;
struct resource res;
smbox = devm_kzalloc(dev, sizeof(*smbox), GFP_KERNEL);
if (!smbox)
return -ENOMEM;
shmem = of_parse_phandle(cdev->of_node, "shmem", idx);
if (!of_device_is_compatible(shmem, "arm,scmi-shmem"))
return -ENXIO;
ret = of_address_to_resource(shmem, 0, &res);
of_node_put(shmem);
if (ret) {
dev_err(cdev, "failed to get SCMI %s shared memory\n", desc);
return ret;
}
size = resource_size(&res);
smbox->shmem = devm_ioremap(dev, res.start, size);
if (!smbox->shmem) {
dev_err(dev, "failed to ioremap SCMI %s shared memory\n", desc);
return -EADDRNOTAVAIL;
}
cl = &smbox->cl;
cl->dev = cdev;
cl->tx_prepare = tx ? tx_prepare : NULL;
cl->rx_callback = rx_callback;
cl->tx_block = false;
cl->knows_txdone = tx;
smbox->chan = mbox_request_channel(cl, tx ? 0 : 1);
if (IS_ERR(smbox->chan)) {
ret = PTR_ERR(smbox->chan);
if (ret != -EPROBE_DEFER)
dev_err(cdev, "failed to request SCMI %s mailbox\n",
tx ? "Tx" : "Rx");
return ret;
}
cinfo->transport_info = smbox;
smbox->cinfo = cinfo;
return 0;
}
static int mailbox_chan_free(int id, void *p, void *data)
{
struct scmi_chan_info *cinfo = p;
struct scmi_mailbox *smbox = cinfo->transport_info;
firmware: arm_scmi: Fix NULL pointer dereference in mailbox_chan_free scmi_mailbox is obtained from cinfo->transport_info and the first call to mailbox_chan_free frees the channel and sets cinfo->transport_info to NULL. Care is taken to check for non NULL smbox->chan but smbox can itself be NULL. Fix it by checking for it without which, kernel crashes with below NULL pointer dereference and eventually kernel panic. Unable to handle kernel NULL pointer dereference at virtual address 0000000000000038 Modules linked in: scmi_module(-) Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Sep 2 2020 pstate: 80000005 (Nzcv daif -PAN -UAO BTYPE=--) pc : mailbox_chan_free+0x2c/0x70 [scmi_module] lr : idr_for_each+0x6c/0xf8 Call trace: mailbox_chan_free+0x2c/0x70 [scmi_module] idr_for_each+0x6c/0xf8 scmi_remove+0xa8/0xf0 [scmi_module] platform_drv_remove+0x34/0x58 device_release_driver_internal+0x118/0x1f0 driver_detach+0x58/0xe8 bus_remove_driver+0x64/0xe0 driver_unregister+0x38/0x68 platform_driver_unregister+0x1c/0x28 scmi_driver_exit+0x38/0x44 [scmi_module] ---[ end trace 17bde19f50436de9 ]--- Kernel panic - not syncing: Fatal exception SMP: stopping secondary CPUs Kernel Offset: 0x1d0000 from 0xffff800010000000 PHYS_OFFSET: 0x80000000 CPU features: 0x0240022,25806004 Memory Limit: none ---[ end Kernel panic - not syncing: Fatal exception ]--- Link: https://lore.kernel.org/r/20200908112611.31515-1-sudeep.holla@arm.com Fixes: 5c8a47a5a91d ("firmware: arm_scmi: Make scmi core independent of the transport type") Cc: Cristian Marussi <cristian.marussi@arm.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Tested-by: Cristian Marussi <cristian.marussi@arm.com> Reviewed-by: Cristian Marussi <cristian.marussi@arm.com> Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
2020-09-08 14:26:11 +03:00
if (smbox && !IS_ERR(smbox->chan)) {
mbox_free_channel(smbox->chan);
cinfo->transport_info = NULL;
smbox->chan = NULL;
smbox->cinfo = NULL;
}
scmi_free_channel(cinfo, data, id);
return 0;
}
static int mailbox_send_message(struct scmi_chan_info *cinfo,
struct scmi_xfer *xfer)
{
struct scmi_mailbox *smbox = cinfo->transport_info;
int ret;
ret = mbox_send_message(smbox->chan, xfer);
/* mbox_send_message returns non-negative value on success, so reset */
if (ret > 0)
ret = 0;
return ret;
}
static void mailbox_mark_txdone(struct scmi_chan_info *cinfo, int ret)
{
struct scmi_mailbox *smbox = cinfo->transport_info;
/*
* NOTE: we might prefer not to need the mailbox ticker to manage the
* transfer queueing since the protocol layer queues things by itself.
* Unfortunately, we have to kick the mailbox framework after we have
* received our message.
*/
mbox_client_txdone(smbox->chan, ret);
}
static void mailbox_fetch_response(struct scmi_chan_info *cinfo,
struct scmi_xfer *xfer)
{
struct scmi_mailbox *smbox = cinfo->transport_info;
shmem_fetch_response(smbox->shmem, xfer);
}
static void mailbox_fetch_notification(struct scmi_chan_info *cinfo,
size_t max_len, struct scmi_xfer *xfer)
{
struct scmi_mailbox *smbox = cinfo->transport_info;
shmem_fetch_notification(smbox->shmem, max_len, xfer);
}
static void mailbox_clear_channel(struct scmi_chan_info *cinfo)
{
struct scmi_mailbox *smbox = cinfo->transport_info;
shmem_clear_channel(smbox->shmem);
}
static bool
mailbox_poll_done(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer)
{
struct scmi_mailbox *smbox = cinfo->transport_info;
return shmem_poll_done(smbox->shmem, xfer);
}
static const struct scmi_transport_ops scmi_mailbox_ops = {
.chan_available = mailbox_chan_available,
.chan_setup = mailbox_chan_setup,
.chan_free = mailbox_chan_free,
.send_message = mailbox_send_message,
.mark_txdone = mailbox_mark_txdone,
.fetch_response = mailbox_fetch_response,
.fetch_notification = mailbox_fetch_notification,
.clear_channel = mailbox_clear_channel,
.poll_done = mailbox_poll_done,
};
const struct scmi_desc scmi_mailbox_desc = {
.ops = &scmi_mailbox_ops,
.max_rx_timeout_ms = 30, /* We may increase this if required */
.max_msg = 20, /* Limited by MBOX_TX_QUEUE_LEN */
.max_msg_size = 128,
};