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[Modifications] drivers: stm32_etzpc: new driver to use firewall API
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Remove check_memory_access() as there is no use for it and the
implementation was incorrect

Modify stm32_etzpc_configure() so that the DECPROT macro is reused as the
access-controllers second parameter.

Modify stm32_etzpc_check_access() to take into account the new format of
the second parameter and to correct the checking rules.

Add etzpc_decprot_strings that is embedded when TRACE_LEVEL >= TRACE_DEBUG
to print clear about the attributes of the firewall configuration.

Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com>
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@GseoC
GseoC committed May 7, 2024
1 parent 721a3a8 commit bf12ebf
Showing 1 changed file with 43 additions and 55 deletions.
98 changes: 43 additions & 55 deletions core/drivers/firewall/stm32_etzpc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -118,6 +118,15 @@ struct etzpc_device {
unsigned int lock;
};

#if TRACE_LEVEL >= TRACE_DEBUG
static const char *const etzpc_decprot_strings[] = {
"ETZPC_DECPROT_S_RW",
"ETZPC_DECPROT_NS_R_S_W",
"ETZPC_DECPROT_MCU_ISOLATION",
"ETZPC_DECPROT_NS_RW",
};
#endif

static uint32_t etzpc_lock(struct etzpc_device *dev)
{
return may_spin_lock(&dev->lock);
Expand Down Expand Up @@ -170,7 +179,8 @@ static void etzpc_do_configure_decprot(struct etzpc_device *etzpc_dev,

assert(valid_decprot_id(etzpc_dev, decprot_id));

FMSG("ID : %"PRIu32", CONF %d", decprot_id, attr);
DMSG("ID : %"PRIu32", CONF %s", decprot_id,
etzpc_decprot_strings[attr]);

exceptions = etzpc_lock(etzpc_dev);

Expand Down Expand Up @@ -344,18 +354,33 @@ static TEE_Result stm32_etzpc_check_access(struct firewall_query *firewall)
* Peripheral configuration, we assume the configuration is as
* follows:
* firewall->args[0]: Firewall ID
* firewall->args[1]: tzpc_decprot_attributes to check
* firewall->args[1]: DECPROT macro to extract etzpc_decprot_attributes
* from
*/
if (firewall->args[1] >= ETZPC_DECPROT_MAX)
return TEE_ERROR_BAD_PARAMETERS;
id = firewall->args[0];
attr_req = firewall->args[1];
attr_req = etzpc_binding2decprot((firewall->args[1] >>
ETZPC_MODE_SHIFT) & ETZPC_MODE_MASK);

if (id < etzpc_dev->ddata->num_per_sec) {
attr = etzpc_do_get_decprot(etzpc_dev, id);
DMSG("Check access %"PRIu32" - attr %d - requested %d", id,
attr, attr_req);
if (attr == attr_req)
DMSG("Check access %"PRIu32" - attr %s - requested %s", id,
etzpc_decprot_strings[attr],
etzpc_decprot_strings[attr_req]);

/*
* Access authorized if the attributes requested match the
* current configuration, or if the requester is secure and
* the device is not MCU isolated, or if the requester is
* non-secure and the device is not MCU isolated and not secure
*/
if (attr == attr_req ||
((attr_req == ETZPC_DECPROT_S_RW ||
attr_req == ETZPC_DECPROT_NS_R_S_W) && attr !=
ETZPC_DECPROT_MCU_ISOLATION) ||
((attr_req == ETZPC_DECPROT_NS_RW ||
attr_req == ETZPC_DECPROT_NS_R_S_W) && attr !=
ETZPC_DECPROT_MCU_ISOLATION && attr !=
ETZPC_DECPROT_S_RW))
return TEE_SUCCESS;
else
return TEE_ERROR_ACCESS_DENIED;
Expand Down Expand Up @@ -386,47 +411,6 @@ static TEE_Result stm32_etzpc_acquire_access(struct firewall_query *firewall)
return TEE_SUCCESS;
}

static TEE_Result
stm32_etzpc_check_memory_access(struct firewall_query *firewall, paddr_t paddr,
size_t size, bool read, bool write)
{
struct etzpc_device *etzpc_dev = firewall->firewall_ctrl->priv;
enum etzpc_decprot_attributes attr_req = ETZPC_DECPROT_MAX;
paddr_t tzma_base = 0;
size_t tzma_size = 0;
size_t prot_size = 0;
uint32_t id = 0;

if (!firewall || firewall->arg_count != 2)
return TEE_ERROR_BAD_PARAMETERS;

id = firewall->args[0];
attr_req = firewall->args[1];
if (!(id == ETZPC_TZMA0_ID || id == ETZPC_TZMA1_ID))
return TEE_ERROR_BAD_PARAMETERS;

tzma_base = id == ETZPC_TZMA0_ID ? ROM_BASE : SYSRAM_BASE;
tzma_size = id == ETZPC_TZMA0_ID ? ROM_SIZE : SYSRAM_SIZE;
prot_size = etzpc_do_get_tzma(etzpc_dev, id == ETZPC_TZMA0_ID ? 0 : 1) *
SMALL_PAGE_SIZE;

DMSG("Checking access for TZMA%u, secured from %"PRIxPA" to %"PRIxPA,
id == ETZPC_TZMA0_ID ? 0 : 1, tzma_base, tzma_base + prot_size);

if (core_is_buffer_inside(paddr, size, tzma_base, prot_size) &&
(attr_req == ETZPC_DECPROT_S_RW ||
(attr_req == ETZPC_DECPROT_NS_R_S_W && write)))
return TEE_SUCCESS;

if (core_is_buffer_inside(paddr, size, tzma_base + prot_size,
tzma_size - prot_size) &&
(attr_req == ETZPC_DECPROT_NS_RW ||
(attr_req == ETZPC_DECPROT_NS_R_S_W && read)))
return TEE_SUCCESS;

return TEE_ERROR_ACCESS_DENIED;
}

static TEE_Result
stm32_etzpc_acquire_memory_access(struct firewall_query *firewall,
paddr_t paddr, size_t size,
Expand Down Expand Up @@ -472,24 +456,27 @@ static TEE_Result stm32_etzpc_configure(struct firewall_query *firewall)
FMSG("Setting firewall configuration for peripheral ID: %u", id);

if (id < etzpc_dev->ddata->num_per_sec) {
uint32_t mode = 0;

/*
* Peripheral configuration, we assume the configuration is as
* follows:
* firewall->args[0]: Firewall ID
* firewall->args[1]: One of etzpc_decprot_attributes
* firewall->args[1]: Firewall configuration to apply
*/

attr = firewall->args[1];

if (firewall->args[1] >= ETZPC_DECPROT_MAX)
return TEE_ERROR_BAD_PARAMETERS;
mode = (firewall->args[1] >> ETZPC_MODE_SHIFT) &
ETZPC_MODE_MASK;
attr = etzpc_binding2decprot(mode);

if (is_decprot_locked(etzpc_dev, id)) {
EMSG("Peripheral configuration locked");
return TEE_ERROR_ACCESS_DENIED;
}

etzpc_do_configure_decprot(etzpc_dev, id, attr);
if (firewall->args[1] & ETZPC_LOCK_MASK)
etzpc_do_lock_decprot(etzpc_dev, id);

return TEE_SUCCESS;
} else if (id == ETZPC_TZMA0_ID || id == ETZPC_TZMA1_ID) {
Expand Down Expand Up @@ -518,6 +505,8 @@ static TEE_Result stm32_etzpc_configure(struct firewall_query *firewall)
return TEE_ERROR_BAD_PARAMETERS;
}

assert(IS_ALIGNED(firewall->args[1], SMALL_PAGE_SIZE));

if (is_tzma_locked(etzpc_dev, tzma_id)) {
EMSG("TZMA configuration locked");
return TEE_ERROR_ACCESS_DENIED;
Expand Down Expand Up @@ -659,7 +648,6 @@ static const struct firewall_controller_ops firewall_ops = {
.set_conf = stm32_etzpc_configure,
.check_access = stm32_etzpc_check_access,
.acquire_access = stm32_etzpc_acquire_access,
.check_memory_access = stm32_etzpc_check_memory_access,
.acquire_memory_access = stm32_etzpc_acquire_memory_access,
};

Expand Down

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