On 24-06-14, Sascha Hauer wrote: > On Thu, Jun 13, 2024 at 03:09:40PM +0200, Marco Felsch wrote: > > Add an helper to revoke an i.MX SRK key. At the moment the helper > > supprts i.MX8M devices only, but adding support for other SoCs can be > > done easily by providing the .revoke_key() hook. > > > > Signed-off-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx> > > --- > > drivers/hab/hab.c | 45 ++++++++++++++++++++++++++++++++ > > include/hab.h | 6 +++++ > > include/mach/imx/ocotp-fusemap.h | 1 + > > 3 files changed, 52 insertions(+) > > > > diff --git a/drivers/hab/hab.c b/drivers/hab/hab.c > > index 28a091841a69..e21a3c3acf81 100644 > > --- a/drivers/hab/hab.c > > +++ b/drivers/hab/hab.c > > @@ -231,6 +231,27 @@ static int imx8m_hab_device_locked_down_ocotp(void) > > return v; > > } > > > > +static int imx8m_hab_revoke_key_ocotp(unsigned key_idx) > > +{ > > + int ret; > > + > > + /* Prohibit revocation of last possible key */ > > + if (key_idx >= 4) > > + return -EINVAL; > > + > > + ret = imx_ocotp_srk_revoke_locked(); > > + if (ret < 0) > > + return ret; > > + > > + /* Return -EINVAL in case the SRK_REVOKE write is locked */ > > + if (ret == 1) > > + return -EINVAL; > > + > > + ret = imx_ocotp_write_field(MX8M_OCOTP_SRK_REVOKE, BIT(key_idx)); > > + > > + return ret; > > +} > > + > > struct imx_hab_ops { > > int (*write_srk_hash)(const u8 *srk, unsigned flags); > > int (*read_srk_hash)(u8 *srk); > > @@ -238,6 +259,7 @@ struct imx_hab_ops { > > int (*lockdown_device)(unsigned flags); > > int (*device_locked_down)(void); > > int (*print_status)(void); > > + int (*revoke_key)(unsigned key_idx); > > }; > > > > static struct imx_hab_ops imx_hab_ops_iim = { > > @@ -265,6 +287,7 @@ static struct imx_hab_ops imx8m_hab_ops_ocotp = { > > .device_locked_down = imx8m_hab_device_locked_down_ocotp, > > .permanent_write_enable = imx_hab_permanent_write_enable_ocotp, > > .print_status = imx8m_hab_print_status, > > + .revoke_key = imx8m_hab_revoke_key_ocotp, > > }; > > > > static int imx_ahab_write_srk_hash(const u8 *__newsrk, unsigned flags) > > @@ -536,3 +559,25 @@ static int init_imx_hab_print_status(void) > > return 0; > > } > > postmmu_initcall(init_imx_hab_print_status); > > + > > +int imx_hab_revoke_key(unsigned key_idx, unsigned flags) > > Are you anticipating more flags? If not, should we better use a boolean > flag for now? I followed the actual concept of having separate flags but to answer you question, no I don't anticipate more flags. > Otherwise it's not really clear which of the IMX_SRK_* flags is used by > which function. I added the documentation above the flag like the previous flags did. But you're right in the end it is all about permanent write en-/disable so this could be covered in just one flag. Regards, Marco > Sascha > > > > +{ > > + struct imx_hab_ops *ops = imx_get_hab_ops(); > > + int ret; > > + > > + if (!ops || !ops->revoke_key) > > + return -ENOSYS; > > + > > + if (flags & IMX_SRK_REVOKE_KEY_PERMANENT) { > > + ret = ops->permanent_write_enable(1); > > + if (ret) > > + return ret; > > + } > > + > > + ret = ops->revoke_key(key_idx); > > + > > + if (flags & IMX_SRK_REVOKE_KEY_PERMANENT) > > + ops->permanent_write_enable(0); > > + > > + return ret; > > +} > > diff --git a/include/hab.h b/include/hab.h > > index 2cef3841d149..fd32bff15ef8 100644 > > --- a/include/hab.h > > +++ b/include/hab.h > > @@ -42,6 +42,11 @@ static inline int habv4_get_state(void) > > * fuses so that the key hash can not be modified. > > */ > > #define IMX_SRK_HASH_WRITE_LOCK BIT(2) > > +/* > > + * Revoke the SRK key permanently, without the flag only shadow registers are > > + * written. > > + */ > > +#define IMX_SRK_REVOKE_KEY_PERMANENT BIT(3) > > > > bool imx_hab_srk_hash_valid(const void *buf); > > int imx_hab_write_srk_hash(const void *buf, unsigned flags); > > @@ -51,5 +56,6 @@ int imx_hab_read_srk_hash(void *buf); > > int imx_hab_lockdown_device(unsigned flags); > > int imx_hab_device_locked_down(void); > > int imx_hab_print_status(void); > > +int imx_hab_revoke_key(unsigned key_idx, unsigned flags); > > > > #endif /* __HABV4_H */ > > diff --git a/include/mach/imx/ocotp-fusemap.h b/include/mach/imx/ocotp-fusemap.h > > index c4f94e61e8f8..e6fa96b40ba9 100644 > > --- a/include/mach/imx/ocotp-fusemap.h > > +++ b/include/mach/imx/ocotp-fusemap.h > > @@ -57,5 +57,6 @@ > > #define MX8M_OCOTP_SRK_LOCK (OCOTP_WORD(0x400) | OCOTP_BIT(9) | OCOTP_WIDTH(1)) > > #define MX8M_OCOTP_SEC_CONFIG_1 (OCOTP_WORD(0x470) | OCOTP_BIT(25) | OCOTP_WIDTH(1)) > > #define MX8MQ_OCOTP_DIR_BT_DIS (OCOTP_WORD(0x470) | OCOTP_BIT(27) | OCOTP_WIDTH(1)) > > +#define MX8M_OCOTP_SRK_REVOKE (OCOTP_WORD(0x670) | OCOTP_BIT(0) | OCOTP_WIDTH(4)) > > > > #endif /* __MACH_IMX_OCOTP_FUSEMAP_H */ > > -- > > 2.39.2 > > > > > > > > -- > Pengutronix e.K. | | > Steuerwalder Str. 21 | http://www.pengutronix.de/ | > 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | >