Messages in this thread | | | Subject | Re: [PATCH v2 6/7] powerpc/secvar: Extend sysfs to include config vars | From | Andrew Donnellan <> | Date | Thu, 05 Jan 2023 18:28:16 +1100 |
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On Fri, 2022-12-30 at 15:20 +1100, Russell Currey wrote: > 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>
Minor comments below, but regardless:
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
> --- > I played around with adding an API call to facilitate a more generic > key/value interface for config variables and it seemed like > unnecessary > complexity. I think this is cleaner. If there was ever a secvar > interface other than sysfs we'd have to rework it, though.
I concur, this can be dealt with if/when the secvar interface is exposed by some other means than sysfs.
> > arch/powerpc/include/asm/secvar.h | 3 +++ > arch/powerpc/kernel/secvar-sysfs.c | 40 ++++++++++++++++++++++++++-- > -- > 2 files changed, 38 insertions(+), 5 deletions(-) > > 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) { } > > #endif > > diff --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, > + };
I was slightly concerned that you're putting this on the stack, but it doesn't appear that sysfs_create_group() keeps any references to the group around after it creates all the files, so I think this is fine.
> + > + 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");
This file defines pr_fmt, so the secvar: prefix here can go away, though I notice that is the case for all the existing prints in this function too.
> + 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");
Same comment as above
> + goto err; > + } > } > > secvar_sysfs_load(); > > return 0; > +err: > + kobject_put(secvar_kobj); > + return rc; > } > > late_initcall(secvar_sysfs_init);
-- Andrew Donnellan OzLabs, ADL Canberra ajd@linux.ibm.com IBM Australia Limited
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