[PATCH v7 1/3 RESEND] block:sed-opal: SED Opal keystore

[Nick Desaulniers]

On Wed, Sep 13, 2023 at 9:56 AM Nathan Chancellor <nathan at kernel.org> wrote:
>
> Hi Greg,
>
> On Fri, Sep 08, 2023 at 10:30:54AM -0500, gjoyce at linux.vnet.ibm.com wrote:
> > From: Greg Joyce <gjoyce at linux.vnet.ibm.com>
> >
> > Add read and write functions that allow SED Opal keys to stored
> > in a permanent keystore.
> >
> > Signed-off-by: Greg Joyce <gjoyce at linux.vnet.ibm.com>
> > Reviewed-by: Jonathan Derrick <jonathan.derrick at linux.dev>
> > ---
> >  block/Makefile               |  2 +-
> >  block/sed-opal-key.c         | 24 ++++++++++++++++++++++++
> >  include/linux/sed-opal-key.h | 15 +++++++++++++++
> >  3 files changed, 40 insertions(+), 1 deletion(-)
> >  create mode 100644 block/sed-opal-key.c
> >  create mode 100644 include/linux/sed-opal-key.h
> >
> > diff --git a/block/Makefile b/block/Makefile
> > index 46ada9dc8bbf..ea07d80402a6 100644
> > --- a/block/Makefile
> > +++ b/block/Makefile
> > @@ -34,7 +34,7 @@ obj-$(CONFIG_BLK_DEV_ZONED) += blk-zoned.o
> >  obj-$(CONFIG_BLK_WBT)                += blk-wbt.o
> >  obj-$(CONFIG_BLK_DEBUG_FS)   += blk-mq-debugfs.o
> >  obj-$(CONFIG_BLK_DEBUG_FS_ZONED)+= blk-mq-debugfs-zoned.o
> > -obj-$(CONFIG_BLK_SED_OPAL)   += sed-opal.o
> > +obj-$(CONFIG_BLK_SED_OPAL)   += sed-opal.o sed-opal-key.o
> >  obj-$(CONFIG_BLK_PM)         += blk-pm.o
> >  obj-$(CONFIG_BLK_INLINE_ENCRYPTION)  += blk-crypto.o blk-crypto-profile.o \
> >                                          blk-crypto-sysfs.o
> > diff --git a/block/sed-opal-key.c b/block/sed-opal-key.c
> > new file mode 100644
> > index 000000000000..16f380164c44
> > --- /dev/null
> > +++ b/block/sed-opal-key.c
> > @@ -0,0 +1,24 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * SED key operations.
> > + *
> > + * Copyright (C) 2022 IBM Corporation
> > + *
> > + * These are the accessor functions (read/write) for SED Opal
> > + * keys. Specific keystores can provide overrides.
> > + *
> > + */
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/errno.h>
> > +#include <linux/sed-opal-key.h>
> > +
> > +int __weak sed_read_key(char *keyname, char *key, u_int *keylen)
> > +{
> > +     return -EOPNOTSUPP;
> > +}
> > +
> > +int __weak sed_write_key(char *keyname, char *key, u_int keylen)
> > +{
> > +     return -EOPNOTSUPP;
> > +}
>
> This change causes a build failure for certain clang configurations due
> to an unfortunate issue [1] with recordmcount, clang's integrated
> assembler, and object files that contain a section with only weak
> functions/symbols (in this case, the .text section in sed-opal-key.c),
> resulting in
>
>   Cannot find symbol for section 2: .text.
>   block/sed-opal-key.o: failed
>
> when building this file.

The definitions in
block/sed-opal-key.c
should be deleted. Instead, in
include/linux/sed-opal-key.h
CONFIG_PSERIES_PLPKS_SED should be used to define static inline
versions when CONFIG_PSERIES_PLPKS_SED is not defined.

#ifdef CONFIG_PSERIES_PLPKS_SED
int sed_read_key(char *keyname, char *key, u_int *keylen);
int sed_write_key(char *keyname, char *key, u_int keylen);
#else
static inline
int sed_read_key(char *keyname, char *key, u_int *keylen) {
  return -EOPNOTSUPP;
}
static inline
int sed_write_key(char *keyname, char *key, u_int keylen);
  return -EOPNOTSUPP;
}
#endif

>
> Is there any real reason to have a separate translation unit for these
> two functions versus just having them living in sed-opal.c? Those two
> object files share the same Kconfig dependency. I am happy to send a
> patch if that is an acceptable approach.
>
> [1]: https://github.com/ClangBuiltLinux/linux/issues/981
>
> Cheers,
> Nathan
>


-- 
Thanks,
~Nick Desaulniers