linux-kernel - Re: [PATCH v9 1/8] powerpc: detect the secure boot mode of the system

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Message-ID: <b0282ef2-f75c-a139-9991-01eba15adb22@linux.microsoft.com>
Date:   Thu, 24 Oct 2019 10:26:47 -0700
From:   Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>
To:     Nayna Jain <nayna@...ux.ibm.com>, linuxppc-dev@...abs.org,
        linux-efi@...r.kernel.org, linux-integrity@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Jeremy Kerr <jk@...abs.org>,
        Matthew Garret <matthew.garret@...ula.com>,
        Mimi Zohar <zohar@...ux.ibm.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Claudio Carvalho <cclaudio@...ux.ibm.com>,
        George Wilson <gcwilson@...ux.ibm.com>,
        Elaine Palmer <erpalmer@...ibm.com>,
        Eric Ricther <erichte@...ux.ibm.com>,
        Oliver O'Halloran <oohall@...il.com>,
        Prakhar Srivastava <prsriva02@...il.com>
Subject: Re: [PATCH v9 1/8] powerpc: detect the secure boot mode of the system

On 10/23/2019 8:47 PM, Nayna Jain wrote:
> This patch defines a function to detect the secure boot state of a
> PowerNV system.

> +bool is_ppc_secureboot_enabled(void)
> +{
> +	struct device_node *node;
> +	bool enabled = false;
> +
> +	node = of_find_compatible_node(NULL, NULL, "ibm,secvar-v1");
> +	if (!of_device_is_available(node)) {
> +		pr_err("Cannot find secure variable node in device tree; failing to secure state\n");
> +		goto out;

Related to "goto out;" above:

Would of_find_compatible_node return NULL if the given node is not found?

If of_device_is_available returns false (say, because node is NULL or it 
does not find the specified node) would it be correct to call of_node_put?

> +
> +out:
> +	of_node_put(node);

  -lakshmi