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/*
* Copyright (c) 2015, Linaro Limited
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include "optee_private.h"
void optee_supp_init(struct optee_supp *supp)
{
memset(supp, 0, sizeof(*supp));
mutex_init(&supp->thrd_mutex);
mutex_init(&supp->supp_mutex);
init_completion(&supp->data_to_supp);
init_completion(&supp->data_from_supp);
}
void optee_supp_uninit(struct optee_supp *supp)
{
mutex_destroy(&supp->thrd_mutex);
mutex_destroy(&supp->supp_mutex);
}
u32 optee_supp_thrd_req(struct tee_context *ctx, u32 func, size_t num_params,
struct tee_param *param)
{
struct optee *optee = tee_get_drvdata(ctx->teedev);
struct optee_supp *supp = &optee->supp;
u32 ret;
/*
* Other threads blocks here until we've copied our answer from
* supplicant.
*/
mutex_lock(&supp->thrd_mutex);
/*
* We have exclusive access now since the supplicant at this
* point is either doing a
* wait_for_completion_interruptible(data_to_supp) or is in
* userspace still about to do the ioctl() to enter
* optee_supp_read() below.
*/
supp->func = func;
supp->num_params = num_params;
supp->param = param;
supp->req_posted = true;
/* Let supplicant get the data */
complete(&supp->data_to_supp);
/*
* Wait for supplicant to process and return result, once we've
* returned from wait_for_completion(data_from_supp) we have
* exclusive access again.
*/
wait_for_completion(&supp->data_from_supp);
ret = supp->ret;
supp->param = NULL;
supp->req_posted = false;
/* We're done, let someone else talk to the supplicant now. */
mutex_unlock(&supp->thrd_mutex);
return ret;
}
int optee_supp_recv(struct tee_context *ctx, u32 *func, u32 *num_params,
struct tee_param *param)
{
struct tee_device *teedev = ctx->teedev;
struct optee *optee = tee_get_drvdata(teedev);
struct optee_supp *supp = &optee->supp;
int rc;
/*
* In case two supplicants or two threads in one supplicant is
* calling this function simultaneously we need to protect the
* data with a mutex which we'll release before returning.
*/
mutex_lock(&supp->supp_mutex);
if (supp->supp_next_send) {
/*
* optee_supp_recv() has been called again without
* a optee_supp_send() in between. Supplicant has
* probably been restarted before it was able to
* write back last result. Abort last request and
* wait for a new.
*/
if (supp->req_posted) {
supp->ret = TEEC_ERROR_COMMUNICATION;
supp->supp_next_send = false;
complete(&supp->data_from_supp);
}
}
/*
* This is where supplicant will be hanging most of the
* time, let's make this interruptable so we can easily
* restart supplicant if needed.
*/
if (wait_for_completion_interruptible(&supp->data_to_supp)) {
rc = -ERESTARTSYS;
goto out;
}
/* We have exlusive access to the data */
if (*num_params < supp->num_params) {
/*
* Not enough room for parameters, tell supplicant
* it failed and abort last request.
*/
supp->ret = TEEC_ERROR_COMMUNICATION;
rc = -EINVAL;
complete(&supp->data_from_supp);
goto out;
}
*func = supp->func;
*num_params = supp->num_params;
memcpy(param, supp->param,
sizeof(struct tee_param) * supp->num_params);
/* Allow optee_supp_send() below to do its work */
supp->supp_next_send = true;
rc = 0;
out:
mutex_unlock(&supp->supp_mutex);
return rc;
}
int optee_supp_send(struct tee_context *ctx, u32 ret, u32 num_params,
struct tee_param *param)
{
struct tee_device *teedev = ctx->teedev;
struct optee *optee = tee_get_drvdata(teedev);
struct optee_supp *supp = &optee->supp;
size_t n;
int rc = 0;
/*
* We still have exclusive access to the data since that's how we
* left it when returning from optee_supp_read().
*/
/* See comment on mutex in optee_supp_read() above */
mutex_lock(&supp->supp_mutex);
if (!supp->supp_next_send) {
/*
* Something strange is going on, supplicant shouldn't
* enter optee_supp_send() in this state
*/
rc = -ENOENT;
goto out;
}
if (num_params != supp->num_params) {
/*
* Something is wrong, let supplicant restart. Next call to
* optee_supp_recv() will give an error to the requesting
* thread and release it.
*/
rc = -EINVAL;
goto out;
}
/* Update out and in/out parameters */
for (n = 0; n < num_params; n++) {
struct tee_param *p = supp->param + n;
switch (p->attr) {
case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT:
case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
p->u.value.a = param[n].u.value.a;
p->u.value.b = param[n].u.value.b;
p->u.value.c = param[n].u.value.c;
break;
case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
p->u.memref.size = param[n].u.memref.size;
break;
default:
break;
}
}
supp->ret = ret;
/* Allow optee_supp_recv() above to do its work */
supp->supp_next_send = false;
/* Let the requesting thread continue */
complete(&supp->data_from_supp);
out:
mutex_unlock(&supp->supp_mutex);
return rc;
}
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