Re: [PATCH v5 10/25] powerpc/secvar: Extend sysfs to include config vars

Stefan Berger
2023-01-31T15:49:54Z

On 1/31/23 01:39, Andrew Donnellan wrote:
> From: Russell Currey <ruscur@russell.cc>
>
> The forthcoming pseries consumer of the secvar API wants to expose a
> number of config variables. Allowing secvar implementations to provide
> their own sysfs attributes makes it easy for consumers to expose what
> they need to.
>
> This is not being used by the OPAL secvar implementation at present, and
> the config directory will not be created if no attributes are set.
>
> Signed-off-by: Russell Currey <ruscur@russell.cc>
> Co-developed-by: Andrew Donnellan <ajd@linux.ibm.com>
> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>

Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>

>
> ---
>
> v3: Remove unnecessary "secvar:" prefix from error messages (ajd)
>
> Merge config attributes into secvar_operations (mpe)
> ---
> arch/powerpc/include/asm/secvar.h | 2 ++
> arch/powerpc/kernel/secvar-sysfs.c | 33 +++++++++++++++++++++++++-----
> 2 files changed, 30 insertions(+), 5 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/secvar.h b/arch/powerpc/include/asm/secvar.h
> index bf396215903d..011a53a8076c 100644
> --- a/arch/powerpc/include/asm/secvar.h
> +++ b/arch/powerpc/include/asm/secvar.h
> @@ -10,6 +10,7 @@
>
> #include <linux/types.h>
> #include <linux/errno.h>
> +#include <linux/sysfs.h>
>
> extern const struct secvar_operations *secvar_ops;
>
> @@ -19,6 +20,7 @@ struct secvar_operations {
> int (*set)(const char *key, u64 key_len, u8 *data, u64 data_size);
> ssize_t (*format)(char *buf, size_t bufsize);
> int (*max_size)(u64 *max_size);
> + const struct attribute **config_attrs;
> };
>
> #ifdef CONFIG_PPC_SECURE_BOOT
> diff --git a/arch/powerpc/kernel/secvar-sysfs.c b/arch/powerpc/kernel/secvar-sysfs.c
> index 8f3deff94009..7df32be86507 100644
> --- a/arch/powerpc/kernel/secvar-sysfs.c
> +++ b/arch/powerpc/kernel/secvar-sysfs.c
> @@ -144,6 +144,19 @@ static int update_kobj_size(void)
> return 0;
> }
>
> +static int secvar_sysfs_config(struct kobject *kobj)
> +{
> + struct attribute_group config_group = {
> + .name = "config",
> + .attrs = (struct attribute **)secvar_ops->config_attrs,
> + };
> +
> + if (secvar_ops->config_attrs)
> + return sysfs_create_group(kobj, &config_group);
> +
> + return 0;
> +}
> +
> static int secvar_sysfs_load(void)
> {
> struct kobject *kobj;
> @@ -208,26 +221,36 @@ static int secvar_sysfs_init(void)
>
> rc = sysfs_create_file(secvar_kobj, &format_attr.attr);
> if (rc) {
> - kobject_put(secvar_kobj);
> - return -ENOMEM;
> + pr_err("Failed to create format object\n");
> + rc = -ENOMEM;
> + goto err;
> }
>
> secvar_kset = kset_create_and_add("vars", NULL, secvar_kobj);
> if (!secvar_kset) {
> pr_err("sysfs kobject registration failed\n");
> - kobject_put(secvar_kobj);
> - return -ENOMEM;
> + rc = -ENOMEM;
> + goto err;
> }
>
> rc = update_kobj_size();
> if (rc) {
> pr_err("Cannot read the size of the attribute\n");
> - return rc;
> + goto err;
> + }
> +
> + rc = secvar_sysfs_config(secvar_kobj);
> + if (rc) {
> + pr_err("Failed to create config directory\n");
> + goto err;
> }
>
> secvar_sysfs_load();
>
> return 0;
> +err:
> + kobject_put(secvar_kobj);
> + return rc;
> }
>
> late_initcall(secvar_sysfs_init);