[PATCH v8 03/27] lib: Adapt digest header files to MbedTLS

[Raymond Mao]

Hi Tom,

On Wed, 9 Oct 2024 at 10:38, Tom Rini <trini at konsulko.com> wrote:

> On Thu, Oct 03, 2024 at 02:50:16PM -0700, Raymond Mao wrote:
>
> > Adapt digest header files to support both original libs and MbedTLS
> > by switching on/off MBEDTLS_LIB_CRYPTO.
> > Introduce <alg>_LEGACY kconfig for legacy hash implementations.
> > sha256.o should depend on SHA256 kconfig only but not SUPPORT_EMMC_RPMB,
> > SHA256 should be selected when SUPPORT_EMMC_RPMB is enabled instead.
> >
> > `IS_ENABLED` or `CONFIG_IS_ENABLED` is not applicable here, since
> > including <linux/kconfig.h> causes undefined reference on schedule()
> > with sandbox build, as <linux/kconfig.h> includes <generated/autoconf.h>
> > which enables `CONFIG_HW_WATCHDOG` and `CONFIG_WATCHDOG` but no
> schedule()
> > are defined in sandbox build,
> > Thus we use `#if defined(CONFIG_MBEDTLS_LIB_CRYPTO)` instead.
> >
> > Signed-off-by: Raymond Mao <raymond.mao at linaro.org>
> > Reviewed-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
>
> There's three platforms where we see something like:
>        arm: (for 1/1 boards) all +5651.0 data +112.0 rodata +139.0 text
> +5400.0
>             o4-imx6ull-nano: all +5651 data +112 rodata +139 text +5400
>                u-boot: add: 23/0, grow: 1/0 bytes: 1172/0 (1172)
>                  function                                   old     new
>  delta
>                  hash_command                               108     296
> +188
>                  sha1_finish                                  -     156
> +156
>                  static.sha1_update                           -     114
> +114
>                  hash_algo                                    -     112
> +112
>                  sha1_padding                                 -      64
>  +64
>                  hash_lookup_algo                             -      60
>  +60
>                  sha1_starts                                  -      52
>  +52
>                  crc16_ccitt_wd_buf                           -      36
>  +36
>                  sha256_csum_wd                               -      34
>  +34
>                  sha1_csum_wd                                 -      34
>  +34
>                  hash_finish_sha256                           -      34
>  +34
>                  hash_finish_sha1                             -      34
>  +34
>                  crc32_wd_buf                                 -      34
>  +34
>                  hash_finish_crc32                            -      28
>  +28
>                  hash_finish_crc16_ccitt                      -      28
>  +28
>                  hash_init_sha256                             -      22
>  +22
>                  hash_init_sha1                               -      22
>  +22
>                  hash_update_crc32                            -      20
>  +20
>                  hash_update_crc16_ccitt                      -      20
>  +20
>                  hash_init_crc32                              -      20
>  +20
>                  hash_init_crc16_ccitt                        -      20
>  +20
>                  hash_update_sha256                           -      16
>  +16
>                  hash_update_sha1                             -      16
>  +16
>                  sha1_update                                  -       8
>   +8
>
> This is because:
> > diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
> > index 982e84dc3bc..5d7fd904950 100644
> > --- a/drivers/mmc/Kconfig
> > +++ b/drivers/mmc/Kconfig
> > @@ -119,6 +119,7 @@ config MMC_HW_PARTITIONING
> >  config SUPPORT_EMMC_RPMB
> >       bool "Support eMMC replay protected memory block (RPMB)"
> >       imply CMD_MMC_RPMB
> > +     select SHA256
> >       help
> >         Enable support for reading, writing and programming the
> >         key for the Replay Protection Memory Block partition in eMMC.
>
> Wasn't true / required before now, no hashing algorithms were enabled.
> This was fine because:
> [snip]
> > diff --git a/lib/Makefile b/lib/Makefile
> > index c4950b78a29..33755778283 100644
> > --- a/lib/Makefile
> > +++ b/lib/Makefile
> > @@ -50,7 +50,6 @@ obj-$(CONFIG_XXHASH) += xxhash.o
> >  obj-y += net_utils.o
> >  obj-$(CONFIG_PHYSMEM) += physmem.o
> >  obj-y += rc4.o
> > -obj-$(CONFIG_SUPPORT_EMMC_RPMB) += sha256.o
> >  obj-$(CONFIG_RBTREE) += rbtree.o
> >  obj-$(CONFIG_BITREVERSE) += bitrev.o
> >  obj-y += list_sort.o
>
> Got us the library access without bringing in everything else. And since
> two of the platforms that are hitting this now are "nano" this is an
> important thing to figure out how to continue to support. If there's
> just no way around it, we can likely live with the size increase, but
> I'd like to see this looked in to specifically first, thanks!
>
> To address this, I think there are two options.
1. Introduce SUPPORT_EMMC_RPMB into the MbedTLS sub makefile.
2. Make MBEDTLS_LIB_CRYPTO depends on !SUPPORT_EMMC_RPMB.
1) looks to be ugly, I prefer 2) if you agree.

Regards,
Raymond