Re: [RESEND PATCH 4/8] mfd: cros_ec: Use a zero-length array for command data

Gwendal Grignou
2015-04-24T20:30:12Z

On Mon, Apr 6, 2015 at 9:15 AM, Javier Martinez Canillas
<javier.martinez@collabora.co.uk> wrote:
> Commit 1b84f2a4cd4a ("mfd: cros_ec: Use fixed size arrays to transfer
> data with the EC") modified the struct cros_ec_command fields to not
> use pointers for the input and output buffers and use fixed length
> arrays instead.
>
> This change was made because the cros_ec ioctl API uses that struct
> cros_ec_command to allow user-space to send commands to the EC and
> to get data from the EC. So using pointers made the API not 64-bit
> safe. Unfortunately this approach was not flexible enough for all
> the use-cases since there may be a need to send larger commands
> on newer versions of the EC command protocol.
>
> So to avoid to choose a constant length that it may be too big for
> most commands and thus wasting memory and CPU cycles on copy from
> and to user-space or having a size that is too small for some big
> commands, use a zero-length array that is both 64-bit safe and
> flexible. The same buffer is used for both output and input data
> so the maximum of these values should be used to allocate it.
>
> Suggested-by: Gwendal Grignou <gwendal@chromium.org>
> Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
> ---
> drivers/i2c/busses/i2c-cros-ec-tunnel.c | 44 ++++++---
> drivers/input/keyboard/cros_ec_keyb.c | 27 ++++--
> drivers/mfd/cros_ec.c | 26 +++--
> drivers/mfd/cros_ec_i2c.c | 4 +-
> drivers/mfd/cros_ec_spi.c | 2 +-
> drivers/platform/chrome/cros_ec_dev.c | 49 ++++++----
> drivers/platform/chrome/cros_ec_lightbar.c | 151 +++++++++++++++++++----------
> drivers/platform/chrome/cros_ec_lpc.c | 8 +-
> drivers/platform/chrome/cros_ec_sysfs.c | 149 +++++++++++++++++-----------
> include/linux/mfd/cros_ec.h | 6 +-
> 10 files changed, 297 insertions(+), 169 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-cros-ec-tunnel.c b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
> index fa8dedd8c3a2..4139ede8e6ed 100644
> --- a/drivers/i2c/busses/i2c-cros-ec-tunnel.c
> +++ b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
> @@ -183,7 +183,7 @@ static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
> int request_len;
> int response_len;
> int result;
> - struct cros_ec_command msg = { };
> + struct cros_ec_command *msg;
>
> request_len = ec_i2c_count_message(i2c_msgs, num);
> if (request_len < 0) {
> @@ -198,25 +198,39 @@ static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
> return response_len;
> }
>
> - result = ec_i2c_construct_message(msg.outdata, i2c_msgs, num, bus_num);
> - if (result)
> - return result;
> + msg = kzalloc(sizeof(*msg) + max(request_len, response_len),
> + GFP_KERNEL);
> + if (!msg)
> + return -ENOMEM;
>
> - msg.version = 0;
> - msg.command = EC_CMD_I2C_PASSTHRU;
> - msg.outsize = request_len;
> - msg.insize = response_len;
> + result = ec_i2c_construct_message(msg->data, i2c_msgs, num, bus_num);
> + if (result) {
> + dev_err(dev, "Error constructing EC i2c message %d\n", result);
> + goto exit;
> + }
>
> - result = cros_ec_cmd_xfer(bus->ec, &msg);
> - if (result < 0)
> - return result;
> + msg->version = 0;
> + msg->command = EC_CMD_I2C_PASSTHRU;
> + msg->outsize = request_len;
> + msg->insize = response_len;
>
> - result = ec_i2c_parse_response(msg.indata, i2c_msgs, &num);
> - if (result < 0)
> - return result;
> + result = cros_ec_cmd_xfer(bus->ec, msg);
> + if (result < 0) {
> + dev_err(dev, "Error transferring EC i2c message %d\n", result);
> + goto exit;
> + }
> +
> + result = ec_i2c_parse_response(msg->data, i2c_msgs, &num);
> + if (result < 0) {
> + dev_err(dev, "Error parsing EC i2c message %d\n", result);
> + goto exit;
> + }
>
> /* Indicate success by saying how many messages were sent */
> - return num;
> + result = num;
> +exit:
> + kfree(msg);
> + return result;
> }
>
> static u32 ec_i2c_functionality(struct i2c_adapter *adap)
> diff --git a/drivers/input/keyboard/cros_ec_keyb.c b/drivers/input/keyboard/cros_ec_keyb.c
> index 769f8f7f62b7..df12cf15b306 100644
> --- a/drivers/input/keyboard/cros_ec_keyb.c
> +++ b/drivers/input/keyboard/cros_ec_keyb.c
> @@ -148,19 +148,26 @@ static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
>
> static int cros_ec_keyb_get_state(struct cros_ec_keyb *ckdev, uint8_t *kb_state)
> {
> - int ret;
> - struct cros_ec_command msg = {
> - .command = EC_CMD_MKBP_STATE,
> - .insize = ckdev->cols,
> - };
> + int ret = 0;
> + struct cros_ec_command *msg;
>
> - ret = cros_ec_cmd_xfer(ckdev->ec, &msg);
> - if (ret < 0)
> - return ret;
> + msg = kzalloc(sizeof(*msg) + ckdev->cols, GFP_KERNEL);
> + if (!msg)
> + return -ENOMEM;
>
> - memcpy(kb_state, msg.indata, ckdev->cols);
> + msg->command = EC_CMD_MKBP_STATE;
> + msg->insize = ckdev->cols;
>
> - return 0;
> + ret = cros_ec_cmd_xfer(ckdev->ec, msg);
> + if (ret < 0) {
> + dev_err(ckdev->dev, "Error transferring EC message %d\n", ret);
> + goto exit;
> + }
> +
> + memcpy(kb_state, msg->data, ckdev->cols);
> +exit:
> + kfree(msg);
> + return ret;
> }
>
> static irqreturn_t cros_ec_keyb_irq(int irq, void *data)
> diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
> index 8aa83b91e25c..c532dbca7404 100644
> --- a/drivers/mfd/cros_ec.c
> +++ b/drivers/mfd/cros_ec.c
> @@ -41,7 +41,7 @@ int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
> out[2] = msg->outsize;
> csum = out[0] + out[1] + out[2];
> for (i = 0; i < msg->outsize; i++)
> - csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->outdata[i];
> + csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
> out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = (uint8_t)(csum & 0xff);
>
> return EC_MSG_TX_PROTO_BYTES + msg->outsize;
> @@ -75,11 +75,18 @@ int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
> ret = ec_dev->cmd_xfer(ec_dev, msg);
> if (msg->result == EC_RES_IN_PROGRESS) {
> int i;
> - struct cros_ec_command status_msg = { };
> + struct cros_ec_command *status_msg;
> struct ec_response_get_comms_status *status;
>
> - status_msg.command = EC_CMD_GET_COMMS_STATUS;
> - status_msg.insize = sizeof(*status);
> + status_msg = kzalloc(sizeof(*status_msg) + sizeof(*status),
> + GFP_KERNEL);
> + if (!status_msg) {
> + ret = -ENOMEM;
> + goto exit;
> + }
> +
> + status_msg->command = EC_CMD_GET_COMMS_STATUS;
> + status_msg->insize = sizeof(*status);
>
> /*
> * Query the EC's status until it's no longer busy or
> @@ -88,20 +95,23 @@ int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
> for (i = 0; i < EC_COMMAND_RETRIES; i++) {
> usleep_range(10000, 11000);
>
> - ret = ec_dev->cmd_xfer(ec_dev, &status_msg);
> + ret = ec_dev->cmd_xfer(ec_dev, status_msg);
> if (ret < 0)
> break;
>
> - msg->result = status_msg.result;
> - if (status_msg.result != EC_RES_SUCCESS)
> + msg->result = status_msg->result;
> + if (status_msg->result != EC_RES_SUCCESS)
> break;
>
> status = (struct ec_response_get_comms_status *)
> - status_msg.indata;
> + status_msg->data;
> if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
> break;
> }
> +
> + kfree(status_msg);
> }
> +exit:
> mutex_unlock(&ec_dev->lock);
>
> return ret;
> diff --git a/drivers/mfd/cros_ec_i2c.c b/drivers/mfd/cros_ec_i2c.c
> index 82b4d6148698..fbf7819f5de5 100644
> --- a/drivers/mfd/cros_ec_i2c.c
> +++ b/drivers/mfd/cros_ec_i2c.c
> @@ -76,7 +76,7 @@ static int cros_ec_cmd_xfer_i2c(struct cros_ec_device *ec_dev,
> /* copy message payload and compute checksum */
> sum = out_buf[0] + out_buf[1] + out_buf[2];
> for (i = 0; i < msg->outsize; i++) {
> - out_buf[3 + i] = msg->outdata[i];
> + out_buf[3 + i] = msg->data[i];
> sum += out_buf[3 + i];
> }
> out_buf[3 + msg->outsize] = sum;
> @@ -109,7 +109,7 @@ static int cros_ec_cmd_xfer_i2c(struct cros_ec_device *ec_dev,
> /* copy response packet payload and compute checksum */
> sum = in_buf[0] + in_buf[1];
> for (i = 0; i < len; i++) {
> - msg->indata[i] = in_buf[2 + i];
> + msg->data[i] = in_buf[2 + i];
> sum += in_buf[2 + i];
> }
> dev_dbg(ec_dev->dev, "packet: %*ph, sum = %02x\n",
> diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c
> index 27bd52e5e8b7..573730fec947 100644
> --- a/drivers/mfd/cros_ec_spi.c
> +++ b/drivers/mfd/cros_ec_spi.c
> @@ -299,7 +299,7 @@ static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
> for (i = 0; i < len; i++) {
> sum += ptr[i + 2];
> if (ec_msg->insize)
> - ec_msg->indata[i] = ptr[i + 2];
> + ec_msg->data[i] = ptr[i + 2];
> }
> sum &= 0xff;
>
> diff --git a/drivers/platform/chrome/cros_ec_dev.c b/drivers/platform/chrome/cros_ec_dev.c
> index 6090d0b2826f..e7e50f18097f 100644
> --- a/drivers/platform/chrome/cros_ec_dev.c
> +++ b/drivers/platform/chrome/cros_ec_dev.c
> @@ -20,6 +20,7 @@
> #include <linux/fs.h>
> #include <linux/module.h>
> #include <linux/platform_device.h>
> +#include <linux/slab.h>
> #include <linux/uaccess.h>
>
> #include "cros_ec_dev.h"
> @@ -36,28 +37,30 @@ static int ec_get_version(struct cros_ec_device *ec, char *str, int maxlen)
> static const char * const current_image_name[] = {
> "unknown", "read-only", "read-write", "invalid",
> };
> - struct cros_ec_command msg = {
> - .version = 0,
> - .command = EC_CMD_GET_VERSION,
> - .outdata = { 0 },
> - .outsize = 0,
> - .indata = { 0 },
> - .insize = sizeof(*resp),
> - };
> + struct cros_ec_command *msg;
> int ret;
>
> - ret = cros_ec_cmd_xfer(ec, &msg);
> + msg = kzalloc(sizeof(*msg) + sizeof(*resp), GFP_KERNEL);
> + if (!msg)
> + return -ENOMEM;
> +
> + msg->version = 0;
> + msg->command = EC_CMD_GET_VERSION;
> + msg->insize = sizeof(*resp);
> +
> + ret = cros_ec_cmd_xfer(ec, msg);
> if (ret < 0)
> - return ret;
> + goto exit;
>
> - if (msg.result != EC_RES_SUCCESS) {
> + if (msg->result != EC_RES_SUCCESS) {
> snprintf(str, maxlen,
> "%s\nUnknown EC version: EC returned %d\n",
> - CROS_EC_DEV_VERSION, msg.result);
> - return 0;
> + CROS_EC_DEV_VERSION, msg->result);
> + ret = -EINVAL;
> + goto exit;
> }
>
> - resp = (struct ec_response_get_version *)msg.indata;
> + resp = (struct ec_response_get_version *)msg->data;
> if (resp->current_image >= ARRAY_SIZE(current_image_name))
> resp->current_image = 3; /* invalid */
>
> @@ -65,6 +68,8 @@ static int ec_get_version(struct cros_ec_device *ec, char *str, int maxlen)
> resp->version_string_ro, resp->version_string_rw,
> current_image_name[resp->current_image]);
>
> +exit:
> + kfree(msg);
> return 0;
> }
>
> @@ -110,17 +115,25 @@ static ssize_t ec_device_read(struct file *filp, char __user *buffer,
> static long ec_device_ioctl_xcmd(struct cros_ec_device *ec, void __user *arg)
> {
> long ret;
> - struct cros_ec_command s_cmd = { };
> + int len;
> + struct cros_ec_command *u_cmd = arg;
> + struct cros_ec_command *s_cmd;
> +
> + len = max(u_cmd->outsize, u_cmd->insize);
It does not work, u_cmd is not accessible yet. You should do:
struct cros_ec_command u_cmd;
if (copy_from_user(&u_cmd, arg, sizeof(u_cmd)))
return -EFAULT;
len = max(u_cmd.outsize, u_cmd.insize);

> +
> + s_cmd = kzalloc(sizeof(*s_cmd) + len, GFP_KERNEL);
> + if (!s_cmd)
> + return -ENOMEM;
>
> - if (copy_from_user(&s_cmd, arg, sizeof(s_cmd)))
> + if (copy_from_user(s_cmd, arg, sizeof(*s_cmd) + len))
sizeof(*s_cmd) + u_cmd.outsize is good enough.
> return -EFAULT;
>
> - ret = cros_ec_cmd_xfer(ec, &s_cmd);
> + ret = cros_ec_cmd_xfer(ec, s_cmd);
> /* Only copy data to userland if data was received. */
> if (ret < 0)
> return ret;
>
> - if (copy_to_user(arg, &s_cmd, sizeof(s_cmd)))
> + if (copy_to_user(arg, s_cmd, sizeof(*s_cmd) + len))
sizeof(*s_cmd) + min(ret, u_cmd.insize) is safer
> return -EFAULT;
>
> return 0;
I missed this one earlier. Tools expect the number of byte read, so it should be
return ret;

> diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c
> index b4ff47a9069a..8ffec6649ead 100644
> --- a/drivers/platform/chrome/cros_ec_lightbar.c
> +++ b/drivers/platform/chrome/cros_ec_lightbar.c
> @@ -31,6 +31,7 @@
> #include <linux/sched.h>
> #include <linux/types.h>
> #include <linux/uaccess.h>
> +#include <linux/slab.h>
>
> #include "cros_ec_dev.h"
>
> @@ -91,54 +92,78 @@ out:
> return ret;
> }
>
> -#define INIT_MSG(P, R) { \
> - .command = EC_CMD_LIGHTBAR_CMD, \
> - .outsize = sizeof(*P), \
> - .insize = sizeof(*R), \
> - }
> +static struct cros_ec_command *alloc_command_msg(void)
> +{
> + struct cros_ec_command *msg;
> + int len;
> +
> + len = max(sizeof(struct ec_params_lightbar),
> + sizeof(struct ec_response_lightbar));
> +
> + msg = kzalloc(sizeof(*msg) + len, GFP_KERNEL);
> + if (!msg)
> + return NULL;
> +
> + msg->command = EC_CMD_LIGHTBAR_CMD;
> + msg->outsize = sizeof(struct ec_params_lightbar);
> + msg->insize = sizeof(struct ec_response_lightbar);
> +
> + return msg;
> +}
>
> static int get_lightbar_version(struct cros_ec_device *ec,
> uint32_t *ver_ptr, uint32_t *flg_ptr)
> {
> struct ec_params_lightbar *param;
> struct ec_response_lightbar *resp;
> - struct cros_ec_command msg = INIT_MSG(param, resp);
> + struct cros_ec_command *msg;
> int ret;
>
> - param = (struct ec_params_lightbar *)msg.outdata;
> - param->cmd = LIGHTBAR_CMD_VERSION;
> - ret = cros_ec_cmd_xfer(ec, &msg);
> - if (ret < 0)
> + msg = alloc_command_msg();
> + if (!msg)
> return 0;
>
> - switch (msg.result) {
> + param = (struct ec_params_lightbar *)msg->data;
> + param->cmd = LIGHTBAR_CMD_VERSION;
> + ret = cros_ec_cmd_xfer(ec, msg);
> + if (ret < 0) {
> + ret = 0;
> + goto exit;
> + }
> +
> + switch (msg->result) {
> case EC_RES_INVALID_PARAM:
> /* Pixel had no version command. */
> if (ver_ptr)
> *ver_ptr = 0;
> if (flg_ptr)
> *flg_ptr = 0;
> - return 1;
> + ret = 1;
> + goto exit;
>
> case EC_RES_SUCCESS:
> - resp = (struct ec_response_lightbar *)msg.indata;
> + resp = (struct ec_response_lightbar *)msg->data;
>
> /* Future devices w/lightbars should implement this command */
> if (ver_ptr)
> *ver_ptr = resp->version.num;
> if (flg_ptr)
> *flg_ptr = resp->version.flags;
> - return 1;
> + ret = 1;
> + goto exit;
> }
>
> /* Anything else (ie, EC_RES_INVALID_COMMAND) - no lightbar */
> - return 0;
> + ret = 0;
> +exit:
> + kfree(msg);
> + return ret;
> }
>
> static ssize_t version_show(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> - uint32_t version, flags;
> + uint32_t version = 0, flags = 0;
> struct cros_ec_device *ec = dev_get_drvdata(dev);
> int ret;
>
> @@ -158,8 +183,7 @@ static ssize_t brightness_store(struct device *dev,
> const char *buf, size_t count)
> {
> struct ec_params_lightbar *param;
> - struct ec_response_lightbar *resp;
> - struct cros_ec_command msg = INIT_MSG(param, resp);
> + struct cros_ec_command *msg;
> int ret;
> unsigned int val;
> struct cros_ec_device *ec = dev_get_drvdata(dev);
> @@ -167,21 +191,30 @@ static ssize_t brightness_store(struct device *dev,
> if (kstrtouint(buf, 0, &val))
> return -EINVAL;
>
> - param = (struct ec_params_lightbar *)msg.outdata;
> + msg = alloc_command_msg();
> + if (!msg)
> + return -ENOMEM;
> +
> + param = (struct ec_params_lightbar *)msg->data;
> param->cmd = LIGHTBAR_CMD_BRIGHTNESS;
> param->brightness.num = val;
> ret = lb_throttle();
> if (ret)
> - return ret;
> + goto exit;
>
> - ret = cros_ec_cmd_xfer(ec, &msg);
> + ret = cros_ec_cmd_xfer(ec, msg);
> if (ret < 0)
> - return ret;
> + goto exit;
>
> - if (msg.result != EC_RES_SUCCESS)
> - return -EINVAL;
> + if (msg->result != EC_RES_SUCCESS) {
> + ret = -EINVAL;
> + goto exit;
> + }
>
> - return count;
> + ret = count;
> +exit:
> + kfree(msg);
> + return ret;
> }
>
>
> @@ -196,12 +229,15 @@ static ssize_t led_rgb_store(struct device *dev, struct device_attribute *attr,
> const char *buf, size_t count)
> {
> struct ec_params_lightbar *param;
> - struct ec_response_lightbar *resp;
> - struct cros_ec_command msg = INIT_MSG(param, resp);
> + struct cros_ec_command *msg;
> struct cros_ec_device *ec = dev_get_drvdata(dev);
> unsigned int val[4];
> int ret, i = 0, j = 0, ok = 0;
>
> + msg = alloc_command_msg();
> + if (!msg)
> + return -ENOMEM;
> +
> do {
> /* Skip any whitespace */
> while (*buf && isspace(*buf))
> @@ -215,7 +251,7 @@ static ssize_t led_rgb_store(struct device *dev, struct device_attribute *attr,
> return -EINVAL;
>
> if (i == 4) {
> - param = (struct ec_params_lightbar *)msg.outdata;
> + param = (struct ec_params_lightbar *)msg->data;
> param->cmd = LIGHTBAR_CMD_RGB;
> param->rgb.led = val[0];
> param->rgb.red = val[1];
> @@ -231,12 +267,14 @@ static ssize_t led_rgb_store(struct device *dev, struct device_attribute *attr,
> return ret;
> }
>
> - ret = cros_ec_cmd_xfer(ec, &msg);
> + ret = cros_ec_cmd_xfer(ec, msg);
> if (ret < 0)
> - return ret;
> + goto exit;
>
> - if (msg.result != EC_RES_SUCCESS)
> - return -EINVAL;
> + if (msg->result != EC_RES_SUCCESS) {
> + ret = -EINVAL;
> + goto exit;
> + }
>
> i = 0;
> ok = 1;
> @@ -248,6 +286,8 @@ static ssize_t led_rgb_store(struct device *dev, struct device_attribute *attr,
>
> } while (*buf);
>
> +exit:
> + kfree(msg);
> return (ok && i == 0) ? count : -EINVAL;
> }
>
> @@ -261,42 +301,55 @@ static ssize_t sequence_show(struct device *dev,
> {
> struct ec_params_lightbar *param;
> struct ec_response_lightbar *resp;
> - struct cros_ec_command msg = INIT_MSG(param, resp);
> + struct cros_ec_command *msg;
> int ret;
> struct cros_ec_device *ec = dev_get_drvdata(dev);
>
> - param = (struct ec_params_lightbar *)msg.outdata;
> + msg = alloc_command_msg();
> + if (!msg)
> + return -ENOMEM;
> +
> + param = (struct ec_params_lightbar *)msg->data;
> param->cmd = LIGHTBAR_CMD_GET_SEQ;
> ret = lb_throttle();
> if (ret)
> - return ret;
> + goto exit;
>
> - ret = cros_ec_cmd_xfer(ec, &msg);
> + ret = cros_ec_cmd_xfer(ec, msg);
> if (ret < 0)
> - return ret;
> + goto exit;
>
> - if (msg.result != EC_RES_SUCCESS)
> - return scnprintf(buf, PAGE_SIZE,
> - "ERROR: EC returned %d\n", msg.result);
> + if (msg->result != EC_RES_SUCCESS) {
> + ret = scnprintf(buf, PAGE_SIZE,
> + "ERROR: EC returned %d\n", msg->result);
> + goto exit;
> + }
>
> - resp = (struct ec_response_lightbar *)msg.indata;
> + resp = (struct ec_response_lightbar *)msg->data;
> if (resp->get_seq.num >= ARRAY_SIZE(seqname))
> - return scnprintf(buf, PAGE_SIZE, "%d\n", resp->get_seq.num);
> + ret = scnprintf(buf, PAGE_SIZE, "%d\n", resp->get_seq.num);
> else
> - return scnprintf(buf, PAGE_SIZE, "%s\n",
> - seqname[resp->get_seq.num]);
> + ret = scnprintf(buf, PAGE_SIZE, "%s\n",
> + seqname[resp->get_seq.num]);
> +
> +exit:
> + kfree(msg);
> + return ret;
> }
>
> static ssize_t sequence_store(struct device *dev, struct device_attribute *attr,
> const char *buf, size_t count)
> {
> struct ec_params_lightbar *param;
> - struct ec_response_lightbar *resp;
> - struct cros_ec_command msg = INIT_MSG(param, resp);
> + struct cros_ec_command *msg;
> unsigned int num;
> int ret, len;
> struct cros_ec_device *ec = dev_get_drvdata(dev);
>
> + msg = alloc_command_msg();
> + if (!msg)
> + return -ENOMEM;
> +
> for (len = 0; len < count; len++)
> if (!isalnum(buf[len]))
> break;
> @@ -311,18 +364,18 @@ static ssize_t sequence_store(struct device *dev, struct device_attribute *attr,
> return ret;
> }
>
> - param = (struct ec_params_lightbar *)msg.outdata;
> + param = (struct ec_params_lightbar *)msg->data;
> param->cmd = LIGHTBAR_CMD_SEQ;
> param->seq.num = num;
> ret = lb_throttle();
> if (ret)
> return ret;
>
> - ret = cros_ec_cmd_xfer(ec, &msg);
> + ret = cros_ec_cmd_xfer(ec, msg);
> if (ret < 0)
> return ret;
>
> - if (msg.result != EC_RES_SUCCESS)
> + if (msg->result != EC_RES_SUCCESS)
> return -EINVAL;
>
> return count;
> diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
> index 3a675817c95d..32b1df29fc58 100644
> --- a/drivers/platform/chrome/cros_ec_lpc.c
> +++ b/drivers/platform/chrome/cros_ec_lpc.c
> @@ -73,8 +73,8 @@ static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec,
>
> /* Copy data and update checksum */
> for (i = 0; i < msg->outsize; i++) {
> - outb(msg->outdata[i], EC_LPC_ADDR_HOST_PARAM + i);
> - csum += msg->outdata[i];
> + outb(msg->data[i], EC_LPC_ADDR_HOST_PARAM + i);
> + csum += msg->data[i];
> }
>
> /* Finalize checksum and write args */
> @@ -119,8 +119,8 @@ static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec,
>
> /* Read response and update checksum */
> for (i = 0; i < args.data_size; i++) {
> - msg->indata[i] = inb(EC_LPC_ADDR_HOST_PARAM + i);
> - csum += msg->indata[i];
> + msg->data[i] = inb(EC_LPC_ADDR_HOST_PARAM + i);
> + csum += msg->data[i];
> }
>
> /* Verify checksum */
> diff --git a/drivers/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c
> index fb62ab6cc659..6f309f2b4efb 100644
> --- a/drivers/platform/chrome/cros_ec_sysfs.c
> +++ b/drivers/platform/chrome/cros_ec_sysfs.c
> @@ -29,6 +29,7 @@
> #include <linux/module.h>
> #include <linux/platform_device.h>
> #include <linux/printk.h>
> +#include <linux/slab.h>
> #include <linux/stat.h>
> #include <linux/types.h>
> #include <linux/uaccess.h>
> @@ -66,14 +67,19 @@ static ssize_t store_ec_reboot(struct device *dev,
> {"hibernate", EC_REBOOT_HIBERNATE, 0},
> {"at-shutdown", -1, EC_REBOOT_FLAG_ON_AP_SHUTDOWN},
> };
> - struct cros_ec_command msg = { 0 };
> - struct ec_params_reboot_ec *param =
> - (struct ec_params_reboot_ec *)msg.outdata;
> + struct cros_ec_command *msg;
> + struct ec_params_reboot_ec *param;
> int got_cmd = 0, offset = 0;
> int i;
> int ret;
> struct cros_ec_device *ec = dev_get_drvdata(dev);
>
> + msg = kzalloc(sizeof(*msg) + sizeof(*param), GFP_KERNEL);
> + if (!msg)
> + return -ENOMEM;
> +
> + param = (struct ec_params_reboot_ec *)msg->data;
> +
> param->flags = 0;
> while (1) {
> /* Find word to start scanning */
> @@ -100,19 +106,25 @@ static ssize_t store_ec_reboot(struct device *dev,
> offset++;
> }
>
> - if (!got_cmd)
> - return -EINVAL;
> + if (!got_cmd) {
> + count = -EINVAL;
> + goto exit;
> + }
>
> - msg.command = EC_CMD_REBOOT_EC;
> - msg.outsize = sizeof(param);
> - ret = cros_ec_cmd_xfer(ec, &msg);
> - if (ret < 0)
> - return ret;
> - if (msg.result != EC_RES_SUCCESS) {
> - dev_dbg(ec->dev, "EC result %d\n", msg.result);
> - return -EINVAL;
> + msg->command = EC_CMD_REBOOT_EC;
> + msg->outsize = sizeof(*param);
> + ret = cros_ec_cmd_xfer(ec, msg);
> + if (ret < 0) {
> + count = ret;
> + goto exit;
> + }
> + if (msg->result != EC_RES_SUCCESS) {
> + dev_err(ec->dev, "EC result %d\n", msg->result);
> + count = -EINVAL;
> }
>
> +exit:
> + kfree(msg);
> return count;
> }
>
> @@ -123,22 +135,30 @@ static ssize_t show_ec_version(struct device *dev,
> struct ec_response_get_version *r_ver;
> struct ec_response_get_chip_info *r_chip;
> struct ec_response_board_version *r_board;
> - struct cros_ec_command msg = { 0 };
> + struct cros_ec_command *msg;
> int ret;
> int count = 0;
> struct cros_ec_device *ec = dev_get_drvdata(dev);
>
> + msg = kzalloc(sizeof(*msg) + EC_HOST_PARAM_SIZE, GFP_KERNEL);
> + if (!msg)
> + return -ENOMEM;
> +
> /* Get versions. RW may change. */
> - msg.command = EC_CMD_GET_VERSION;
> - msg.insize = sizeof(*r_ver);
> - ret = cros_ec_cmd_xfer(ec, &msg);
> - if (ret < 0)
> - return ret;
> - if (msg.result != EC_RES_SUCCESS)
> - return scnprintf(buf, PAGE_SIZE,
> - "ERROR: EC returned %d\n", msg.result);
> + msg->command = EC_CMD_GET_VERSION;
> + msg->insize = sizeof(*r_ver);
> + ret = cros_ec_cmd_xfer(ec, msg);
> + if (ret < 0) {
> + count = ret;
> + goto exit;
> + }
> + if (msg->result != EC_RES_SUCCESS) {
> + count = scnprintf(buf, PAGE_SIZE,
> + "ERROR: EC returned %d\n", msg->result);
> + goto exit;
> + }
>
> - r_ver = (struct ec_response_get_version *)msg.indata;
> + r_ver = (struct ec_response_get_version *)msg->data;
> /* Strings should be null-terminated, but let's be sure. */
> r_ver->version_string_ro[sizeof(r_ver->version_string_ro) - 1] = '\0';
> r_ver->version_string_rw[sizeof(r_ver->version_string_rw) - 1] = '\0';
> @@ -152,33 +172,33 @@ static ssize_t show_ec_version(struct device *dev,
> image_names[r_ver->current_image] : "?"));
>
> /* Get build info. */
> - msg.command = EC_CMD_GET_BUILD_INFO;
> - msg.insize = sizeof(msg.indata);
> - ret = cros_ec_cmd_xfer(ec, &msg);
> + msg->command = EC_CMD_GET_BUILD_INFO;
> + msg->insize = EC_HOST_PARAM_SIZE;
> + ret = cros_ec_cmd_xfer(ec, msg);
> if (ret < 0)
> count += scnprintf(buf + count, PAGE_SIZE - count,
> "Build info: XFER ERROR %d\n", ret);
> - else if (msg.result != EC_RES_SUCCESS)
> + else if (msg->result != EC_RES_SUCCESS)
> count += scnprintf(buf + count, PAGE_SIZE - count,
> - "Build info: EC error %d\n", msg.result);
> + "Build info: EC error %d\n", msg->result);
> else {
> - msg.indata[sizeof(msg.indata) - 1] = '\0';
> + msg->data[sizeof(msg->data) - 1] = '\0';
> count += scnprintf(buf + count, PAGE_SIZE - count,
> - "Build info: %s\n", msg.indata);
> + "Build info: %s\n", msg->data);
> }
>
> /* Get chip info. */
> - msg.command = EC_CMD_GET_CHIP_INFO;
> - msg.insize = sizeof(*r_chip);
> - ret = cros_ec_cmd_xfer(ec, &msg);
> + msg->command = EC_CMD_GET_CHIP_INFO;
> + msg->insize = sizeof(*r_chip);
> + ret = cros_ec_cmd_xfer(ec, msg);
> if (ret < 0)
> count += scnprintf(buf + count, PAGE_SIZE - count,
> "Chip info: XFER ERROR %d\n", ret);
> - else if (msg.result != EC_RES_SUCCESS)
> + else if (msg->result != EC_RES_SUCCESS)
> count += scnprintf(buf + count, PAGE_SIZE - count,
> - "Chip info: EC error %d\n", msg.result);
> + "Chip info: EC error %d\n", msg->result);
> else {
> - r_chip = (struct ec_response_get_chip_info *)msg.indata;
> + r_chip = (struct ec_response_get_chip_info *)msg->data;
>
> r_chip->vendor[sizeof(r_chip->vendor) - 1] = '\0';
> r_chip->name[sizeof(r_chip->name) - 1] = '\0';
> @@ -192,23 +212,25 @@ static ssize_t show_ec_version(struct device *dev,
> }
>
> /* Get board version */
> - msg.command = EC_CMD_GET_BOARD_VERSION;
> - msg.insize = sizeof(*r_board);
> - ret = cros_ec_cmd_xfer(ec, &msg);
> + msg->command = EC_CMD_GET_BOARD_VERSION;
> + msg->insize = sizeof(*r_board);
> + ret = cros_ec_cmd_xfer(ec, msg);
> if (ret < 0)
> count += scnprintf(buf + count, PAGE_SIZE - count,
> "Board version: XFER ERROR %d\n", ret);
> - else if (msg.result != EC_RES_SUCCESS)
> + else if (msg->result != EC_RES_SUCCESS)
> count += scnprintf(buf + count, PAGE_SIZE - count,
> - "Board version: EC error %d\n", msg.result);
> + "Board version: EC error %d\n", msg->result);
> else {
> - r_board = (struct ec_response_board_version *)msg.indata;
> + r_board = (struct ec_response_board_version *)msg->data;
>
> count += scnprintf(buf + count, PAGE_SIZE - count,
> "Board version: %d\n",
> r_board->board_version);
> }
>
> +exit:
> + kfree(msg);
> return count;
> }
>
> @@ -216,27 +238,37 @@ static ssize_t show_ec_flashinfo(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> struct ec_response_flash_info *resp;
> - struct cros_ec_command msg = { 0 };
> + struct cros_ec_command *msg;
> int ret;
> struct cros_ec_device *ec = dev_get_drvdata(dev);
>
> + msg = kzalloc(sizeof(*msg) + sizeof(*resp), GFP_KERNEL);
> + if (!msg)
> + return -ENOMEM;
> +
> /* The flash info shouldn't ever change, but ask each time anyway. */
> - msg.command = EC_CMD_FLASH_INFO;
> - msg.insize = sizeof(*resp);
> - ret = cros_ec_cmd_xfer(ec, &msg);
> + msg->command = EC_CMD_FLASH_INFO;
> + msg->insize = sizeof(*resp);
> + ret = cros_ec_cmd_xfer(ec, msg);
> if (ret < 0)
> - return ret;
> - if (msg.result != EC_RES_SUCCESS)
> - return scnprintf(buf, PAGE_SIZE,
> - "ERROR: EC returned %d\n", msg.result);
> -
> - resp = (struct ec_response_flash_info *)msg.indata;
> -
> - return scnprintf(buf, PAGE_SIZE,
> - "FlashSize %d\nWriteSize %d\n"
> - "EraseSize %d\nProtectSize %d\n",
> - resp->flash_size, resp->write_block_size,
> - resp->erase_block_size, resp->protect_block_size);
> + goto exit;
> + if (msg->result != EC_RES_SUCCESS) {
> + ret = scnprintf(buf, PAGE_SIZE,
> + "ERROR: EC returned %d\n", msg->result);
> + goto exit;
> + }
> +
> + resp = (struct ec_response_flash_info *)msg->data;
> +
> + ret = scnprintf(buf, PAGE_SIZE,
> + "FlashSize %d\nWriteSize %d\n"
> + "EraseSize %d\nProtectSize %d\n",
> + resp->flash_size, resp->write_block_size,
> + resp->erase_block_size, resp->protect_block_size);
> +
> +exit:
> + kfree(msg);
> + return ret;
> }
>
> /* Module initialization */
> @@ -269,3 +301,4 @@ void ec_dev_sysfs_remove(struct cros_ec_device *ec)
> {
> sysfs_remove_group(&ec->vdev->kobj, &ec_attr_group);
> }
> +
> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> index 14cf522123dd..7eee38abd02a 100644
> --- a/include/linux/mfd/cros_ec.h
> +++ b/include/linux/mfd/cros_ec.h
> @@ -42,8 +42,7 @@ enum {
> * @outsize: Outgoing length in bytes
> * @insize: Max number of bytes to accept from EC
> * @result: EC's response to the command (separate from communication failure)
> - * @outdata: Outgoing data to EC
> - * @indata: Where to put the incoming data from EC
> + * @data: Where to put the incoming data from EC and outgoing data to EC
> */
> struct cros_ec_command {
> uint32_t version;
> @@ -51,8 +50,7 @@ struct cros_ec_command {
> uint32_t outsize;
> uint32_t insize;
> uint32_t result;
> - uint8_t outdata[EC_PROTO2_MAX_PARAM_SIZE];
> - uint8_t indata[EC_PROTO2_MAX_PARAM_SIZE];
> + uint8_t data[0];
> };
>
> /**
> --
> 2.1.4
>