linux-kernel - Re: [PATCH v11 6/7] ACPI/IORT: Stub out ACS functions when CONFIG

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20181218115959.GA9090@e107981-ln.cambridge.arm.com>
Date:   Tue, 18 Dec 2018 12:00:07 +0000
From:   Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:     Sinan Kaya <okaya@...nel.org>
Cc:     linux-acpi@...r.kernel.org, Hanjun Guo <hanjun.guo@...aro.org>,
        Sudeep Holla <sudeep.holla@....com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v11 6/7] ACPI/IORT: Stub out ACS functions when
 CONFIG_PCI is not set

On Tue, Dec 18, 2018 at 02:56:05AM +0000, Sinan Kaya wrote:
> Remove PCI dependent code out of iort.c when CONFIG_PCI is not defined.
> A quick search reveals the following functions:
> 1. pci_request_acs()
> 2. pci_domain_nr()
> 3. pci_is_root_bus()
> 4. to_pci_dev()
> 
> Both pci_domain_nr() and pci_is_root_bus() are defined in linux/pci.h.
> pci_domain_nr() is a stub function when CONFIG_PCI is not set and
> pci_is_root_bus() just returns a reference to a structure member which
> is still valid without CONFIG_PCI set.
> 
> to_pci_dev() is a macro that expands to container_of.
> 
> pci_request_acs() is the only code that gets pulled in from drivers/pci/*.c

I am not a big fan of these assumptions but we can stub all code
relying on those behind the CONFIG_PCI guard later, which would result
in cleaner code too.

> 
> Signed-off-by: Sinan Kaya <okaya@...nel.org>
> ---
>  drivers/acpi/arm64/iort.c | 21 ++++++++++++++-------
>  1 file changed, 14 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> index 70f4e80b9246..beb7e4c05bf5 100644
> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -1435,8 +1435,14 @@ static int __init iort_add_platform_device(struct acpi_iort_node *node,
>  	return ret;
>  }
>  
> -static bool __init iort_enable_acs(struct acpi_iort_node *iort_node)
> +#ifdef CONFIG_PCI
> +static void __init iort_enable_acs(struct acpi_iort_node *iort_node)
>  {
> +	static bool acs_enabled __initdata;
> +
> +	if (acs_enabled)
> +		return;
> +
>  	if (iort_node->type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX) {
>  		struct acpi_iort_node *parent;
>  		struct acpi_iort_id_mapping *map;
> @@ -1458,13 +1464,16 @@ static bool __init iort_enable_acs(struct acpi_iort_node *iort_node)
>  			if ((parent->type == ACPI_IORT_NODE_SMMU) ||
>  				(parent->type == ACPI_IORT_NODE_SMMU_V3)) {
>  				pci_request_acs();
> -				return true;
> +				acs_enabled = true;
> +				return;
>  			}
>  		}
>  	}
> -
> -	return false;
> +	return;

Remove this return;

With that updated:

Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@....com>

>  }
> +#else
> +static inline void iort_enable_acs(struct acpi_iort_node *iort_node) { }
> +#endif
>  
>  static void __init iort_init_platform_devices(void)
>  {
> @@ -1472,7 +1481,6 @@ static void __init iort_init_platform_devices(void)
>  	struct acpi_table_iort *iort;
>  	struct fwnode_handle *fwnode;
>  	int i, ret;
> -	bool acs_enabled = false;
>  	const struct iort_dev_config *ops;
>  
>  	/*
> @@ -1493,8 +1501,7 @@ static void __init iort_init_platform_devices(void)
>  			return;
>  		}
>  
> -		if (!acs_enabled)
> -			acs_enabled = iort_enable_acs(iort_node);
> +		iort_enable_acs(iort_node);
>  
>  		ops = iort_get_dev_cfg(iort_node);
>  		if (ops) {
> -- 
> 2.19.0
>