The base firmware and an FDPIC module disagree about what a function
pointer is. Firmware is not built FDPIC, so to it a pointer is a code
address and it branches there. A module passes the address of a two word
descriptor instead, because its code and data are placed independently and
a bare code address would leave the callee unable to find its own data. A
firmware routine that takes a callback therefore branches into the
module's data segment and faults.
So the ten entry points that can be handed a callback by a module resolve
the descriptor before storing or branching to it: qsort, bsearch,
pthread_create, signal, sigaction, task_create and task_create_with_stack,
task_spawn, pthread_once, scandir, and mq_notify and timer_create with
SIGEV_THREAD.
Which one resolves matters as much as that one does. Resolving twice would
take an already resolved code address for a descriptor and read two words
from the instruction stream, so each pointer is resolved exactly once, at
the outermost point that sees it. signal() passes its argument through
untouched because sigaction() and then nxsig_action() will resolve it,
which covers a module calling sigaction() directly as well. qsort() is
split so that the public entry resolves and the recursive implementation
does not. scandir() resolves its filter but not its comparison function,
which it hands to qsort().
Whether a caller is a module at all is asked of the PIC base register,
which up_initial_state() sets only for a task that has a D-Space. A plain
kernel task therefore reads zero and is left alone.
SIGEV_THREAD is the case the register cannot answer, because the callback
runs later on a work queue worker that carries no module's base at all.
The base is captured instead when the notification is registered, in the
module's own context, and installed around the call.
All of it is behind CONFIG_FDPIC, which defaults off. Built for
mps3-an547:picostest both ways; with it off the entry points compile to
what they were.
Assisted-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>
Most tools used for compliance and SBOM generation use SPDX identifiers
This change brings us a step closer to an easy SBOM generation.
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
1. remove descript management in mqueue, save code size
2. use i_ops instead of i_mqueue to remove the dup logic
Change-Id: Ie88960e50ddcae9c87977c9ad65a45297c663291
Signed-off-by: ligd <liguiding1@xiaomi.com>
PR #488 introduced an error in a file license header in file sched/mqueue/mqueue.h. This commit fixe that error and in the course of doing that, changing the license header to the standard Apache 2.0 header. I am the author and copyright hold of all modified files.
sched/mqueue/mq_notify.c: Fix - only part of struct copied to internal structure
As source adress the adress of the struct member sigev_value was used,
and it is not located the start of the struct.
This leads to invalid data being copied to internal structure.
Both source and destination should be of type struct sigevent* .
Approved-by: GregoryN <gnutt@nuttx.org>
Change all calls to mq_receive() and mq_timedreceive() in the OS to calls to nxmq_receive() and nxmq_timedreceive(), making appropriate changes for differences in return values.
sched/mqueue: Add nxmq_receive() and mxmq_timedreceive() which are functionally equivalent to the standard mq_receive and mq_timedreceive() except that (1) they do not create cancellation points, and (2) the do not modify the application's errno variable.
