Re: [PATCH v2] ath10k: support firmware crash-by-assert

[Ben Greear <greearb@candelatech.com>]

On 09/10/2014 08:59 AM, Kalle Valo wrote:
> From: Ben Greear <greearb@candelatech.com>
>
> 10.1 firmware does not have an official way to
> cause assert on purpose, but it can be done with
> carefully crafted WMI command.  This is a different
> kind of crash from the 'hard' crash, which is
> a bad memory dereference.
>
> Different crashes decode in different manners, so
> this will help the crash-report testing as well as
> offer better ways to test firmware failure and
> recovery.
>
> kvalo: move the wmi command creation to debug.c, modify
> the info print

This looks fine to me.  I have not tested this version.

Thanks,
Ben

>
> Signed-off-by: Ben Greear <greearb@candelatech.com>
> Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
> ---
>   drivers/net/wireless/ath/ath10k/debug.c |   28 +++++++++++++++++++++++++++-
>   1 file changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/ath/ath10k/debug.c b/drivers/net/wireless/ath/ath10k/debug.c
> index f948a4d8ee59..c5d01058c2a3 100644
> --- a/drivers/net/wireless/ath/ath10k/debug.c
> +++ b/drivers/net/wireless/ath/ath10k/debug.c
> @@ -565,6 +565,26 @@ static const struct file_operations fops_fw_stats = {
>   	.llseek = default_llseek,
>   };
>
> +/* This is a clean assert crash in firmware. */
> +static int ath10k_debug_fw_assert(struct ath10k *ar)
> +{
> +	struct wmi_vdev_install_key_cmd *cmd;
> +	struct sk_buff *skb;
> +
> +	skb = ath10k_wmi_alloc_skb(ar, sizeof(*cmd) + 16);
> +	if (!skb)
> +		return -ENOMEM;
> +
> +	cmd = (struct wmi_vdev_install_key_cmd *)skb->data;
> +	memset(cmd, 0, sizeof(*cmd));
> +
> +	/* big enough number so that firmware asserts */
> +	cmd->vdev_id = __cpu_to_le32(0x7ffe);
> +
> +	return ath10k_wmi_cmd_send(ar, skb,
> +				   ar->wmi.cmd->vdev_install_key_cmdid);
> +}
> +
>   static ssize_t ath10k_read_simulate_fw_crash(struct file *file,
>   					     char __user *user_buf,
>   					     size_t count, loff_t *ppos)
> @@ -574,7 +594,10 @@ static ssize_t ath10k_read_simulate_fw_crash(struct file *file,
>   			   " WMI_FORCE_FW_HANG_ASSERT to firmware if FW"
>   			   " supports that command.\n `hard` - this will send"
>   			   " to firmware command with illegal parameters"
> -			   " causing firmware crash.\n";
> +			   " causing firmware crash.\n"
> +			   "`assert` - this will send special illegal parameter"
> +			   " to firmware to cause assert failure"
> +			   " and crash.\n";
>
>   	return simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));
>   }
> @@ -623,6 +646,9 @@ static ssize_t ath10k_write_simulate_fw_crash(struct file *file,
>   		 */
>   		ret = ath10k_wmi_vdev_set_param(ar, 0x7fff,
>   					ar->wmi.vdev_param->rts_threshold, 0);
> +	} else if (!strcmp(buf, "assert")) {
> +		ath10k_info(ar, "simulating firmware assert crash\n");
> +		ret = ath10k_debug_fw_assert(ar);
>   	} else {
>   		ret = -EINVAL;
>   		goto exit;
>
> --
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-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com