patacongo opened a new pull request #1328:
URL: https://github.com/apache/incubator-nuttx/pull/1328
## Summary
1. A user-space shim is needed to catch any return from a pthead main
function and to automatically call pthread_exit() from user space.
Rename pthread_create() in sched/pthread/pthread_create.c to
nx_pthread_create(). Add one new parameter: The address of the user-space
pthread startup function. Instead of calling the pthread main entry (directly
or indirectly), pthread_start() would call the pthread startup function,
passing it the real address of the pthread main function.
The call to pthread_exist would be removed from pthread_startup() and move
into a new function in user space.
2. Add libs/libc/pthread/lib_pthread_start.c that would contain two trivial
functions:
static void pthread_startup(pthread_startroutine_t startroutine,
pthread_addr_t arg)
{
pthread_exit(startroutine(arg));
}
int pthread_create(FAR pthread_t *thread, FAR const pthread_attr_t *attr,
pthread_startroutine_t startroutine, pthread_addr_t
arg)
{
return nx_pthread_create(pthread_startup, thread, attr, startroutine,
arg);
}
Still to do:
a. Modifiy up_pthread_start so that it takes three parameters: startup,
entry, and arg.
b. Remove pthread_startup function pointer from struct userspace_s; it is no
longer needed.
c. Modify how pthread is started in pthread_start() (and
up_pthread_startup()) so that the startup function is called with the entry and
arg paramgers.
d. Remove call to pthread_exit() from pthread_start()
e. Rename pthread_exit() to nx_pthread_exit(). Remove logic that calls
pthread_cleanup() functions.
f. Make nx_pthread_exit() a system call.
g. Create libc/pthread/pthread_exit() that contains only i) the logic that
calls the pthread_cleanup functions, and ii) calls the nx_pthread_exit() system
call.
h. Extend TLS and pthread-specific data function so that the destructor is
retained in TLS
i. Extend pthread_exit() so that it also calls the pthread-specific data
destructors from user-space.
## Impact
This PR would effect all logic that uses pthread and, hence, must be well
verified before merging.
## Testing
Most testing is performed with sim:ostest which exercises pthread logic
pretty well.
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