linux-kernel - Re: [PATCH v10 11/15] platform/x86: dell-smbios-smm: test for WSMT

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Date:   Thu, 19 Oct 2017 20:09:26 +0200
From:   Pali Rohár <pali.rohar@...il.com>
To:     Mario Limonciello <mario.limonciello@...l.com>
Cc:     dvhart@...radead.org, Andy Shevchenko <andy.shevchenko@...il.com>,
        LKML <linux-kernel@...r.kernel.org>,
        platform-driver-x86@...r.kernel.org,
        Andy Lutomirski <luto@...nel.org>, quasisec@...gle.com,
        rjw@...ysocki.net, mjg59@...gle.com, hch@....de,
        Greg KH <greg@...ah.com>, Alan Cox <gnomes@...rguk.ukuu.org.uk>
Subject: Re: [PATCH v10 11/15] platform/x86: dell-smbios-smm: test for WSMT

On Thursday 19 October 2017 12:50:14 Mario Limonciello wrote:
> +/* When enabled this indicates that SMM won't work */
> +static bool test_wsmt_enabled(void)
> +{
> +	struct calling_interface_token *token;
> +
> +	/* if token doesn't exist, SMM will work */
> +	token = dell_smbios_find_token(WSMT_EN_TOKEN);
> +	if (!token)
> +		return false;
> +
> +	/* if token exists, try to access over SMM */
> +	buffer->class = CLASS_TOKEN_READ;
> +	buffer->select = SELECT_TOKEN_STD;
> +	memset(buffer, 0, sizeof(struct calling_interface_buffer));
> +	buffer->input[0] = token->location;
> +	dell_smbios_smm_call(buffer);
> +
> +	/* if lookup failed, we know WSMT was enabled */
> +	if (buffer->output[0] != 0)
> +		return true;
> +
> +	/* query token status if it didn't fail */
> +	return (buffer->output[1] == token->value);
> +}
> +
>  static int __init dell_smbios_smm_init(void)
>  {
>  	int ret;
> @@ -115,6 +140,13 @@ static int __init dell_smbios_smm_init(void)
>  
>  	dmi_walk(find_cmd_address, NULL);
>  
> +	ret = test_wsmt_enabled();

ret is int, but test_wsmt_enabled() returns bool.

-- 
Pali Rohár
pali.rohar@...il.com