Re: [PATCH v7 08/17] cryptodisk: Add macro GRUB_TYPE_BITS() to replace some literals

[Patrick Steinhardt]

On Fri, Dec 04, 2020 at 10:43:37AM -0600, Glenn Washburn wrote:
> The new macro GRUB_TYPE_BITS(type) returns the number of bits allocated for
> type.
> 
> Signed-off-by: Glenn Washburn <development@efficientek.com>

Reviewed-by: Patrick Steinhardt <ps@pks.im>

> ---
>  grub-core/disk/cryptodisk.c | 7 ++++---
>  include/grub/types.h        | 2 ++
>  2 files changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c
> index 473c93976..0e955a020 100644
> --- a/grub-core/disk/cryptodisk.c
> +++ b/grub-core/disk/cryptodisk.c
> @@ -281,20 +281,21 @@ grub_cryptodisk_endecrypt (struct grub_cryptodisk *dev,
>         }
>         break;
>       case GRUB_CRYPTODISK_MODE_IV_PLAIN64:
> -       iv[1] = grub_cpu_to_le32 (sector >> 32);
> +       iv[1] = grub_cpu_to_le32 (sector >> GRUB_TYPE_BITS (iv[0]));
>         /* FALLTHROUGH */
>       case GRUB_CRYPTODISK_MODE_IV_PLAIN:
>         iv[0] = grub_cpu_to_le32 (sector & 0xFFFFFFFF);
>         break;
>       case GRUB_CRYPTODISK_MODE_IV_BYTECOUNT64:
> -       iv[1] = grub_cpu_to_le32 (sector >> (32 - dev->log_sector_size));
> +       iv[1] = grub_cpu_to_le32 (sector >> (GRUB_TYPE_BITS (iv[1])
> +                                            - dev->log_sector_size));
>         iv[0] = grub_cpu_to_le32 ((sector << dev->log_sector_size)
>                                   & 0xFFFFFFFF);
>         break;
>       case GRUB_CRYPTODISK_MODE_IV_BENBI:
>         {
>           grub_uint64_t num = (sector << dev->benbi_log) + 1;
> -         iv[sz - 2] = grub_cpu_to_be32 (num >> 32);
> +         iv[sz - 2] = grub_cpu_to_be32 (num >> GRUB_TYPE_BITS (iv[0]));
>           iv[sz - 1] = grub_cpu_to_be32 (num & 0xFFFFFFFF);
>         }
>         break;
> diff --git a/include/grub/types.h b/include/grub/types.h
> index f22055f98..9989e3a16 100644
> --- a/include/grub/types.h
> +++ b/include/grub/types.h
> @@ -80,6 +80,8 @@
>  # define GRUB_CHAR_BIT       __CHAR_BIT__
>  #endif
>  
> +#define GRUB_TYPE_BITS(type) (sizeof(type) * GRUB_CHAR_BIT)
> +
>  /* Define various wide integers.  */
>  typedef signed char          grub_int8_t;
>  typedef short                        grub_int16_t;
> -- 
> 2.27.0
>

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