RE: [PATCH v6 4/5] scsi: ufs: add program_key() variant op

[Avri Altman <Avri.Altman@wdc.com>]

 
> 
> From: Eric Biggers <ebiggers@google.com>
> 
> On Snapdragon SoCs, the Linux kernel isn't permitted to directly access
> the standard UFS crypto configuration registers.  Instead, programming
> and evicting keys must be done through vendor-specific SMC calls.
> 
> To support this hardware, add a ->program_key() method to
> 'struct ufs_hba_variant_ops'.  This allows overriding the UFS standard
> key programming / eviction procedure.
> 
> Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>


> ---
>  drivers/scsi/ufs/ufshcd-crypto.c | 27 +++++++++++++++++----------
>  drivers/scsi/ufs/ufshcd.h        |  3 +++
>  2 files changed, 20 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufshcd-crypto.c b/drivers/scsi/ufs/ufshcd-crypto.c
> index 98ff87c38aa7..d2edbd960ebf 100644
> --- a/drivers/scsi/ufs/ufshcd-crypto.c
> +++ b/drivers/scsi/ufs/ufshcd-crypto.c
> @@ -17,14 +17,20 @@ static const struct ufs_crypto_alg_entry {
>         },
>  };
> 
> -static void ufshcd_program_key(struct ufs_hba *hba,
> -                              const union ufs_crypto_cfg_entry *cfg,
> -                              int slot)
> +static int ufshcd_program_key(struct ufs_hba *hba,
> +                             const union ufs_crypto_cfg_entry *cfg, int slot)
>  {
>         int i;
>         u32 slot_offset = hba->crypto_cfg_register + slot * sizeof(*cfg);
> +       int err = 0;
> 
>         ufshcd_hold(hba, false);
> +
> +       if (hba->vops && hba->vops->program_key) {
> +               err = hba->vops->program_key(hba, cfg, slot);
> +               goto out;
> +       }
> +
>         /* Ensure that CFGE is cleared before programming the key */
>         ufshcd_writel(hba, 0, slot_offset + 16 * sizeof(cfg->reg_val[0]));
>         for (i = 0; i < 16; i++) {
> @@ -37,7 +43,9 @@ static void ufshcd_program_key(struct ufs_hba *hba,
>         /* Dword 16 must be written last */
>         ufshcd_writel(hba, le32_to_cpu(cfg->reg_val[16]),
>                       slot_offset + 16 * sizeof(cfg->reg_val[0]));
> +out:
>         ufshcd_release(hba);
> +       return err;
>  }
> 
>  static int ufshcd_crypto_keyslot_program(struct blk_keyslot_manager *ksm,
> @@ -52,6 +60,7 @@ static int ufshcd_crypto_keyslot_program(struct
> blk_keyslot_manager *ksm,
>         int i;
>         int cap_idx = -1;
>         union ufs_crypto_cfg_entry cfg = { 0 };
> +       int err;
> 
>         BUILD_BUG_ON(UFS_CRYPTO_KEY_SIZE_INVALID != 0);
>         for (i = 0; i < hba->crypto_capabilities.num_crypto_cap; i++) {
> @@ -79,13 +88,13 @@ static int ufshcd_crypto_keyslot_program(struct
> blk_keyslot_manager *ksm,
>                 memcpy(cfg.crypto_key, key->raw, key->size);
>         }
> 
> -       ufshcd_program_key(hba, &cfg, slot);
> +       err = ufshcd_program_key(hba, &cfg, slot);
> 
>         memzero_explicit(&cfg, sizeof(cfg));
> -       return 0;
> +       return err;
>  }
> 
> -static void ufshcd_clear_keyslot(struct ufs_hba *hba, int slot)
> +static int ufshcd_clear_keyslot(struct ufs_hba *hba, int slot)
>  {
>         /*
>          * Clear the crypto cfg on the device. Clearing CFGE
> @@ -93,7 +102,7 @@ static void ufshcd_clear_keyslot(struct ufs_hba *hba,
> int slot)
>          */
>         union ufs_crypto_cfg_entry cfg = { 0 };
> 
> -       ufshcd_program_key(hba, &cfg, slot);
> +       return ufshcd_program_key(hba, &cfg, slot);
>  }
> 
>  static int ufshcd_crypto_keyslot_evict(struct blk_keyslot_manager *ksm,
> @@ -102,9 +111,7 @@ static int ufshcd_crypto_keyslot_evict(struct
> blk_keyslot_manager *ksm,
>  {
>         struct ufs_hba *hba = container_of(ksm, struct ufs_hba, ksm);
> 
> -       ufshcd_clear_keyslot(hba, slot);
> -
> -       return 0;
> +       return ufshcd_clear_keyslot(hba, slot);
>  }
> 
>  bool ufshcd_crypto_enable(struct ufs_hba *hba)
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> index 656c0691c858..b2ef18f1b746 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -281,6 +281,7 @@ struct ufs_pwr_mode_info {
>   * @dbg_register_dump: used to dump controller debug information
>   * @phy_initialization: used to initialize phys
>   * @device_reset: called to issue a reset pulse on the UFS device
> + * @program_key: program or evict an inline encryption key
>   */
>  struct ufs_hba_variant_ops {
>         const char *name;
> @@ -314,6 +315,8 @@ struct ufs_hba_variant_ops {
>         void    (*config_scaling_param)(struct ufs_hba *hba,
>                                         struct devfreq_dev_profile *profile,
>                                         void *data);
> +       int     (*program_key)(struct ufs_hba *hba,
> +                              const union ufs_crypto_cfg_entry *cfg, int slot);
>  };
> 
>  /* clock gating state  */
> --
> 2.27.0