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SDEI: Allow platforms to define explicit events 

The current macros only allow to define dynamic and statically-bound
SDEI events. However, there ought be a mechanism to define SDEI events
that are explicitly dispatched; i.e., events that are dispatched as a
result of a previous secure interrupt or other exception

This patch introduces SDEI_EXPLICIT_EVENT() macro to define an explicit
event. They must be placed under private mappings. Only the priority
flags are allowed to be additionally specified.

Documentation updated.

Change-Id: I2e12f5571381195d6234c9dfbd5904608ad41db3
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>
This commit is contained in:
Jeenu Viswambharan 2018-01-17 12:30:11 +00:00
parent 6d769420b0
commit af2c9ecdf1
5 changed files with 64 additions and 17 deletions
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33
docs/sdei.rst
View File

@ -48,8 +48,10 @@ execute the registered handler [10]. The client terminates its execution with
original EL2 execution [13]. Note that the SDEI interrupt remains active until
the client handler completes, at which point EL3 does EOI [12].
SDEI events can be explicitly dispatched in response to other asynchronous
exceptions. See `Explicit dispatch of events`_.
Other than events bound to interrupts (as depicted in the sequence above, SDEI
events can be explicitly dispatched in response to other exceptions, for
example, upon receiving an *SError* or *Synchronous External Abort*. See
`Explicit dispatch of events`_.
The remainder of this document only discusses the design and implementation of
SDEI dispatcher in TF-A, and assumes that the reader is familiar with the SDEI
@ -71,7 +73,8 @@ event descriptors. Both macros take 3 arguments:
- The event number: this must be a positive 32-bit integer.
- The interrupt number the event is bound to:
- For an event that has a backing interrupt, the interrupt number the event is
bound to:
- If it's not applicable to an event, this shall be left as ``0``.
@ -82,6 +85,17 @@ event descriptors. Both macros take 3 arguments:
To define event 0, the macro ``SDEI_DEFINE_EVENT_0()`` should be used. This
macro takes only one parameter: an SGI number to signal other PEs.
To define an event that's meant to be `explicitly dispatched`__ (i.e., not as a
result of receiving an SDEI interrupt), the macro ``SDEI_EXPLICIT_EVENT()``
should be used. It accepts two parameters:
.. __: `Explicit dispatch of events`_
- The event number (as above);
- Event priority: ``SDEI_MAPF_CRITICAL`` or ``SDEI_MAPF_NORMAL``, as described
below.
Once the event descriptor arrays are defined, they should be exported to the
SDEI dispatcher using the ``REGISTER_SDEI_MAP()`` macro, passing it the pointers
to the private and shared event descriptor arrays, respectively. Note that the
@ -99,6 +113,8 @@ Regarding event descriptors:
- Must be bound to a Secure SGI on the platform.
- Explicit events should only be used in the private array.
- Statically bound shared and private interrupts must be bound to shared and
private interrupts on the platform, respectively. See the section on
`interrupt configuration`__.
@ -132,8 +148,10 @@ Event flags describe the properties of the event. They are bit maps that can be
- ``SDEI_MAPF_BOUND``: Marks the event as statically bound to an interrupt.
These events cannot be re-bound at runtime.
- ``SDEI_MAPF_NORMAL``: Marks the event as having *Normal* priority. This is
the default priority.
- ``SDEI_MAPF_CRITICAL``: Marks the event as having *Critical* priority.
Without this flag, the event is assumed to have *Normal* priority.
Event definition example
------------------------
@ -150,6 +168,10 @@ Event definition example
/* Dynamic private events */
SDEI_PRIVATE_EVENT(100, SDEI_DYN_IRQ, SDEI_MAPF_DYNAMIC),
SDEI_PRIVATE_EVENT(101, SDEI_DYN_IRQ, SDEI_MAPF_DYNAMIC)
/* Events for explicit dispatch */
SDEI_EXPLICIT_EVENT(2000, SDEI_MAPF_NORMAL);
SDEI_EXPLICIT_EVENT(2000, SDEI_MAPF_CRITICAL);
};
/* Shared event mappings */
@ -258,7 +280,8 @@ event to be dispatched:
- Event 0 can't be dispatched.
- The event must neither be a dynamic event nor be bound to an interrupt.
- The event must be declared using the ``SDEI_EXPLICIT_EVENT()`` macro
described above.
- The event must be private to the PE.

9
include/services/sdei.h
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
* Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@ -52,6 +52,7 @@
#define _SDEI_MAPF_SIGNALABLE_SHIFT 3
#define _SDEI_MAPF_PRIVATE_SHIFT 4
#define _SDEI_MAPF_CRITICAL_SHIFT 5
#define _SDEI_MAPF_EXPLICIT_SHIFT 6
/* SDEI event 0 */
#define SDEI_EVENT_0 0
@ -81,9 +82,12 @@
*/
#define SDEI_MAPF_DYNAMIC BIT(_SDEI_MAPF_DYNAMIC_SHIFT)
#define SDEI_MAPF_BOUND BIT(_SDEI_MAPF_BOUND_SHIFT)
#define SDEI_MAPF_EXPLICIT BIT(_SDEI_MAPF_EXPLICIT_SHIFT)
#define SDEI_MAPF_SIGNALABLE BIT(_SDEI_MAPF_SIGNALABLE_SHIFT)
#define SDEI_MAPF_PRIVATE BIT(_SDEI_MAPF_PRIVATE_SHIFT)
#define SDEI_MAPF_NORMAL 0
#define SDEI_MAPF_CRITICAL BIT(_SDEI_MAPF_CRITICAL_SHIFT)
/* Indices of private and shared mappings */
@ -114,6 +118,9 @@
#define SDEI_DEFINE_EVENT_0(_intr) \
SDEI_PRIVATE_EVENT(SDEI_EVENT_0, _intr, SDEI_MAPF_SIGNALABLE)
#define SDEI_EXPLICIT_EVENT(_event, _pri) \
SDEI_EVENT_MAP(_event, 0, _pri | SDEI_MAPF_EXPLICIT | SDEI_MAPF_PRIVATE)
/*
* Declare shared and private entries for each core. Also declare a global
* structure containing private and share entries.

11
services/std_svc/sdei/sdei_intr_mgmt.c
View File

@ -520,15 +520,8 @@ int sdei_dispatch_event(int ev_num, unsigned int preempted_sec_state)
if (!map)
return -1;
/*
* Statically-bound or dynamic maps are dispatched only as a result of
* interrupt, and not upon explicit request.
*/
if (is_map_dynamic(map) || is_map_bound(map))
return -1;
/* The event must be private */
if (is_event_shared(map))
/* Only explicit events can be dispatched */
if (!is_map_explicit(map))
return -1;
/* Examine state of dispatch stack */

21
services/std_svc/sdei/sdei_main.c
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
* Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@ -111,6 +111,9 @@ void sdei_class_init(sdei_class_t class)
/* No shared mapping should have signalable property */
assert(!is_event_signalable(map));
/* Shared mappings can't be explicit */
assert(!is_map_explicit(map));
#endif
/* Skip initializing the wrong priority */
@ -162,6 +165,16 @@ void sdei_class_init(sdei_class_t class)
/* Make sure it's a private event */
assert(is_event_private(map));
/*
* Other than priority, explicit events can only have explicit
* and private flags set.
*/
if (is_map_explicit(map)) {
assert((map->map_flags | SDEI_MAPF_CRITICAL) ==
(SDEI_MAPF_EXPLICIT | SDEI_MAPF_PRIVATE
| SDEI_MAPF_CRITICAL));
}
#endif
/* Skip initializing the wrong priority */
@ -174,6 +187,12 @@ void sdei_class_init(sdei_class_t class)
assert(map->intr == SDEI_DYN_IRQ);
assert(is_event_normal(map));
num_dyn_priv_slots++;
} else if (is_map_explicit(map)) {
/*
* Explicit mappings don't have a backing
* SDEI interrupt, but verify that anyway.
*/
assert(map->intr == SDEI_DYN_IRQ);
} else {
/*
* Private mappings must be bound to private

7
services/std_svc/sdei/sdei_private.h
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
* Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@ -137,6 +137,11 @@ static inline void set_map_bound(sdei_ev_map_t *map)
map->map_flags |= BIT(_SDEI_MAPF_BOUND_SHIFT);
}
static inline int is_map_explicit(sdei_ev_map_t *map)
{
return ((map->map_flags & BIT(_SDEI_MAPF_EXPLICIT_SHIFT)) != 0);
}
static inline void clr_map_bound(sdei_ev_map_t *map)
{
map->map_flags &= ~(BIT(_SDEI_MAPF_BOUND_SHIFT));