[U-Boot] [PATCH 5/9] [v3] lib/rsa: Modify rsa to use DM driver if available

[Ruchika Gupta <ruchika.gupta@freescale.com>]

Resending as the message bounced from u-boot mailing list.

Hi Simon,

> -----Original Message-----
> From: sjg at google.com [mailto:sjg at google.com] On Behalf Of Simon Glass
> Sent: Wednesday, December 24, 2014 6:19 AM
> To: Gupta Ruchika-R66431
> Cc: U-Boot Mailing List; Sun York-R58495
> Subject: Re: [PATCH 5/9] [v3] lib/rsa: Modify rsa to use DM driver if
> available
>
> Hi Ruchika,
>
> On 23 December 2014 at 04:32, Ruchika Gupta
> <ruchika.gupta@freescale.com>
> wrote:
> > Modify rsa_verify to use the rsa driver of DM library available.The
> > tools and the configurations which don't use Driver Model, will
> > continue to use the same RSA sw library. The software implementation
> > of RSA Modular Exponentation is now compiled if RSA_MOD_EXP_SW is selected.
> >
> > Kconfig options are also added for rsa library.
> >
> > Signed-off-by: Ruchika Gupta <ruchika.gupta@freescale.com>
> > CC: Simon Glass <sjg@chromium.org>
> > ---
> > Changes in v3:
> > New patch
> >
> >  include/configs/am335x_evm.h |  1 +
> >  lib/Kconfig                  |  6 +-----
> >  lib/rsa/Kconfig              | 31 +++++++++++++++++++++++++++++++
> >  lib/rsa/Makefile             |  3 ++-
> >  lib/rsa/rsa-verify.c         | 18 ++++++++++++++++++
> >  5 files changed, 53 insertions(+), 6 deletions(-)  create mode
> > 100644 lib/rsa/Kconfig
> >
> > diff --git a/include/configs/am335x_evm.h
> > b/include/configs/am335x_evm.h index cc36985..aa79841 100644
> > --- a/include/configs/am335x_evm.h
> > +++ b/include/configs/am335x_evm.h
> > @@ -25,6 +25,7 @@
> >  # ifdef CONFIG_ENABLE_VBOOT
> >  # define CONFIG_FIT_SIGNATURE
> >  # define CONFIG_RSA
> > +# define CONFIG_RSA_MOD_EXP_SW
>
> This should go in am335x_boneblack_vboot_defconfig I think.

I didn?t move it in the defconfig as it was conditionally defined under CONFIG_ENABLE_VBOOT

>
> >  # endif
> >  #endif
> >
> > diff --git a/lib/Kconfig b/lib/Kconfig index 602dd37..a1f30a2 100644
> > --- a/lib/Kconfig
> > +++ b/lib/Kconfig
> > @@ -27,10 +27,6 @@ config SYS_HZ
> >           get_timer() must operate in milliseconds and this option must be
> >           set to 1000.
> >
> > -config RSA
> > -       bool "Use RSA Library"
> > -       help
> > -         RSA support.This enables the RSA algorithm used for FIT image
> > -         verification in U-Boot.
> > +source lib/rsa/Kconfig
> >
> >  endmenu
> > diff --git a/lib/rsa/Kconfig b/lib/rsa/Kconfig new file mode 100644
> > index 0000000..8f9aa44
> > --- /dev/null
> > +++ b/lib/rsa/Kconfig
> > @@ -0,0 +1,31 @@
> > +config RSA
> > +       bool "Use RSA Library"
> > +       select RSA_MOD_EXP_SW if !DM
> > +       select DM_RSA if DM
> > +       help
> > +         RSA support.This enables the RSA algorithm used for FIT image
> > +         verification in U-Boot.
> > +         See doc/uImage.FIT/signature.txt for more details.
> > +
> > +if RSA && DM_RSA
> > +
> > +config RSA_SW
> > +       bool "User driver Model for RSA Modular Exponentiation in software"
> > +       depends on DM && DM_RSA && RSA
> > +       select RSA_MOD_EXP_SW
> > +       default y
> > +       help
> > +         Enables driver for modular exponentiation in software.
> > +This is a
> RSA
> > +         algorithm used in FIT image verification. It required RSA Key as
> > +         input.
> > +         See doc/uImage.FIT/signature.txt for more details.
> > +
> > +endif
> > +
> > +config RSA_MOD_EXP_SW
> > +       bool
> > +       default n
> > +       help
> > +         Library for SW implementation of RSA Modular Exponentiation. This
> > +         library is used by the mkimage tool(not selected through
> > +this
> option)
> > +         as well as by the RSA driver model with SW implementation.
> > diff --git a/lib/rsa/Makefile b/lib/rsa/Makefile index
> > cc25b3c..ccc6060 100644
> > --- a/lib/rsa/Makefile
> > +++ b/lib/rsa/Makefile
> > @@ -7,4 +7,5 @@
> >  # SPDX-License-Identifier:     GPL-2.0+
> >  #
> >
> > -obj-$(CONFIG_FIT_SIGNATURE) += rsa-verify.o rsa-checksum.o
> > rsa-mod-exp.o
> > +obj-$(CONFIG_FIT_SIGNATURE) += rsa-verify.o rsa-checksum.o
> > +obj-$(CONFIG_RSA_MOD_EXP_SW) += rsa-mod-exp.o
> > diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c index
> > f8bc086..27f10ef 100644
> > --- a/lib/rsa/rsa-verify.c
> > +++ b/lib/rsa/rsa-verify.c
> > @@ -12,6 +12,7 @@
> >  #include <asm/errno.h>
> >  #include <asm/types.h>
> >  #include <asm/unaligned.h>
> > +#include <dm.h>
> >  #else
> >  #include "fdt_host.h"
> >  #include "mkimage.h"
> > @@ -43,6 +44,9 @@ static int rsa_verify_key(struct key_prop *prop,
> > const
> uint8_t *sig,
> >         const uint8_t *padding;
> >         int pad_len;
> >         int ret;
> > +#if defined(CONFIG_DM_RSA) && !defined(USE_HOSTCC)
> > +       struct udevice *rsa_dev;
> > +#endif
> >
> >         if (!prop || !sig || !hash || !algo)
> >                 return -EIO;
> > @@ -63,11 +67,25 @@ static int rsa_verify_key(struct key_prop *prop,
> > const uint8_t *sig,
> >
> >         uint8_t buf[sig_len];
> >
> > +#if defined(CONFIG_DM_RSA) && !defined(USE_HOSTCC)
> > +       ret = uclass_get_device(UCLASS_RSA, 0, &rsa_dev);
> > +       if (!ret) {
> > +               ret = rsa_mod_exp(rsa_dev, sig, sig_len, prop, buf);
> > +               if (ret) {
> > +                       debug("Error in Modular exponentation\n");
> > +                       return ret;
> > +               }
> > +       } else {
> > +               printf("RSA: Can't find Mod Exp implemnetation\n");
> > +               return -EINVAL;
> > +       }
> > +#else
> >         ret = rsa_mod_exp_sw(sig, sig_len, prop, buf);
> >         if (ret) {
> >                 debug("Error in Modular exponentation\n");
> >                 return ret;
> >         }
> > +#endif
>
> This should use the uclass regardless I think. The software
> implementation should just be a driver like the hardware implementation.

I have already added software implementation as a driver in the previous patch. I have kept it here for the tools (mkimage) and the platforms which don?t use CONFIG_DM by default.

>
> >
> >         padding = algo->rsa_padding;
> >         pad_len = algo->pad_len - algo->checksum_len;
> > --
> > 1.8.1.4
> >
>
> Regards,
> Simon

Regards,
Ruchika