Re: [PATCH v2 6/7] powerpc/secvar: Extend sysfs to include config vars
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2023-01-06 04:15:55
Also in:
lkml
Russell Currey [off-list ref] writes:
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.
Would it be slightly cleaner if the attributes were just a member of secvar_operations? That would avoid the need for some of the separate handling of the ops and the attributes. I know "ops" implies it's only methods, but I think that's not a big problem. The power_pmu struct does something similar, where it combines ops and attributes. cheers
quoted hunk ↗ jump to hunk
diff --git a/arch/powerpc/include/asm/secvar.h b/arch/powerpc/include/asm/secvar.h index 92d2c051918b..250e7066b6da 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;@@ -27,10 +28,12 @@ struct secvar_operations { #ifdef CONFIG_PPC_SECURE_BOOT extern void set_secvar_ops(const struct secvar_operations *ops); +extern void set_secvar_config_attrs(const struct attribute **attrs); #else static inline void set_secvar_ops(const struct secvar_operations *ops) { } +static inline void set_secvar_config_attrs(const struct attribute **attrs) { } #endifdiff --git a/arch/powerpc/kernel/secvar-sysfs.c b/arch/powerpc/kernel/secvar-sysfs.c index aa1daec480e1..ad1e1d72d2ae 100644 --- a/arch/powerpc/kernel/secvar-sysfs.c +++ b/arch/powerpc/kernel/secvar-sysfs.c@@ -15,9 +15,17 @@ #define NAME_MAX_SIZE 1024 +const struct attribute **secvar_config_attrs __ro_after_init = NULL; + static struct kobject *secvar_kobj; static struct kset *secvar_kset; +void set_secvar_config_attrs(const struct attribute **attrs) +{ + WARN_ON_ONCE(secvar_config_attrs); + secvar_config_attrs = attrs; +} + static ssize_t format_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) {@@ -134,6 +142,16 @@ 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_config_attrs, + }; + + return sysfs_create_group(kobj, &config_group); +} + static int secvar_sysfs_load(void) { char *name;@@ -196,26 +214,38 @@ 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("secvar: 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("secvar: 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; + } + + if (secvar_config_attrs) { + rc = secvar_sysfs_config(secvar_kobj); + if (rc) { + pr_err("secvar: 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);-- 2.38.1