Messages in this thread | | | From | Sumit Garg <> | Date | Mon, 14 Mar 2022 14:33:26 +0530 | Subject | Re: [PATCH 2/3] optee: add FF-A capability OPTEE_FFA_SEC_CAP_ARG_OFFSET |
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On Wed, 2 Mar 2022 at 01:18, Jens Wiklander <jens.wiklander@linaro.org> wrote: > > Adds the secure capability OPTEE_FFA_SEC_CAP_ARG_OFFSET to indicate that > OP-TEE with FF-A can support an argument struct at a non-zero offset into > a passed shared memory object. >
It isn't clear to me why FF-A ABI requires this capability. shm->offset should be honoured by default, if it isn't then it's a bug. AFAIK, FF-A is currently still in its early stages so it shouldn't be that hard to fix bugs in the ABI.
-Sumit
> Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org> > --- > drivers/tee/optee/ffa_abi.c | 17 +++++++++++++++-- > drivers/tee/optee/optee_ffa.h | 12 +++++++++++- > 2 files changed, 26 insertions(+), 3 deletions(-) > > diff --git a/drivers/tee/optee/ffa_abi.c b/drivers/tee/optee/ffa_abi.c > index 7686f7020616..cc863aaefcd9 100644 > --- a/drivers/tee/optee/ffa_abi.c > +++ b/drivers/tee/optee/ffa_abi.c > @@ -615,12 +615,21 @@ static int optee_ffa_do_call_with_arg(struct tee_context *ctx, > .data0 = OPTEE_FFA_YIELDING_CALL_WITH_ARG, > .data1 = (u32)shm->sec_world_id, > .data2 = (u32)(shm->sec_world_id >> 32), > - .data3 = shm->offset, > + .data3 = 0, > }; > struct optee_msg_arg *arg; > unsigned int rpc_arg_offs; > struct optee_msg_arg *rpc_arg; > > + /* > + * The shared memory object has to start on a page when passed as > + * an argument struct. This is also what the shm pool allocator > + * returns, but check this before calling secure world to catch > + * eventual errors early in case something changes. > + */ > + if (shm->offset) > + return -EINVAL; > + > arg = tee_shm_get_va(shm, 0); > if (IS_ERR(arg)) > return PTR_ERR(arg); > @@ -678,6 +687,7 @@ static bool optee_ffa_api_is_compatbile(struct ffa_device *ffa_dev, > > static bool optee_ffa_exchange_caps(struct ffa_device *ffa_dev, > const struct ffa_dev_ops *ops, > + u32 *sec_caps, > unsigned int *rpc_param_count) > { > struct ffa_send_direct_data data = { OPTEE_FFA_EXCHANGE_CAPABILITIES }; > @@ -694,6 +704,7 @@ static bool optee_ffa_exchange_caps(struct ffa_device *ffa_dev, > } > > *rpc_param_count = (u8)data.data1; > + *sec_caps = data.data2; > > return true; > } > @@ -777,6 +788,7 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev) > struct tee_device *teedev; > struct tee_context *ctx; > struct optee *optee; > + u32 sec_caps; > int rc; > > ffa_ops = ffa_dev_ops_get(ffa_dev); > @@ -788,7 +800,8 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev) > if (!optee_ffa_api_is_compatbile(ffa_dev, ffa_ops)) > return -EINVAL; > > - if (!optee_ffa_exchange_caps(ffa_dev, ffa_ops, &rpc_param_count)) > + if (!optee_ffa_exchange_caps(ffa_dev, ffa_ops, &sec_caps, > + &rpc_param_count)) > return -EINVAL; > > optee = kzalloc(sizeof(*optee), GFP_KERNEL); > diff --git a/drivers/tee/optee/optee_ffa.h b/drivers/tee/optee/optee_ffa.h > index ee3a03fc392c..97266243deaa 100644 > --- a/drivers/tee/optee/optee_ffa.h > +++ b/drivers/tee/optee/optee_ffa.h > @@ -81,8 +81,16 @@ > * as the second MSG arg struct for > * OPTEE_FFA_YIELDING_CALL_WITH_ARG. > * Bit[31:8]: Reserved (MBZ) > - * w5-w7: Note used (MBZ) > + * w5: Bitfield of secure world capabilities OPTEE_FFA_SEC_CAP_* below, > + * unused bits MBZ. > + * w6-w7: Not used (MBZ) > + */ > +/* > + * Secure world supports giving an offset into the argument shared memory > + * object, see also OPTEE_FFA_YIELDING_CALL_WITH_ARG > */ > +#define OPTEE_FFA_SEC_CAP_ARG_OFFSET BIT(0) > + > #define OPTEE_FFA_EXCHANGE_CAPABILITIES OPTEE_FFA_BLOCKING_CALL(2) > > /* > @@ -112,6 +120,8 @@ > * OPTEE_MSG_GET_ARG_SIZE(num_params) follows a struct optee_msg_arg > * for RPC, this struct has reserved space for the number of RPC > * parameters as returned by OPTEE_FFA_EXCHANGE_CAPABILITIES. > + * MBZ unless the bit OPTEE_FFA_SEC_CAP_ARG_OFFSET is received with > + * OPTEE_FFA_EXCHANGE_CAPABILITIES. > * w7: Not used (MBZ) > * Resume from RPC. Register usage: > * w3: Service ID, OPTEE_FFA_YIELDING_CALL_RESUME > -- > 2.31.1 >
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