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mirror of https://github.com/RIOT-OS/RIOT.git synced 2025-12-16 18:13:49 +01:00

cpu/native: restructure CPU

This commit is contained in:
carl 2025-03-07 14:37:57 +01:00
parent 9c96c18566
commit ccc97b0018

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@ -50,7 +50,7 @@ static ucontext_t _end_context;
*/ */
void thread_print_stack(void) void thread_print_stack(void)
{ {
CPU_DEBUG("thread_print_stack\n"); DEBUG_CPU("thread_print_stack\n");
return; return;
} }
@ -66,6 +66,161 @@ void native_breakpoint(void)
raise(SIGTRAP); raise(SIGTRAP);
} }
/* ========================================= */
/* ISR -> user switch function */
void _isr_switch_to_user(void) {
DEBUG_CPU("... ISR: switching to user thread, calling setcontext(PID %" PRIkernel_pid ")\n\n", thread_getpid());
ucontext_t *context = _native_user_context();
_native_interrupts_enabled = true;
/* Get PC/LR. This is where we will resume execution on the userspace thread. */
_native_user_fptr = (uintptr_t)_context_get_fptr(context);
/* Now we want to go to _native_isr_leave before resuming execution at _native_user_fptr. */
_context_set_fptr(context, (uintptr_t)_native_isr_leave);
if (setcontext(context) == -1) {
err(EXIT_FAILURE, "_isr_schedule_and_switch: setcontext");
}
errx(EXIT_FAILURE, "2 this should have never been reached!!");
}
/* ========================================= */
void _isr_context_switch_exit(void)
{
DEBUG_CPU("_isr_schedule_and_switch\n");
/* Schedule thread job if no active thread */
if (((sched_context_switch_request == 1) || (thread_get_active() == NULL))
&& IS_USED(MODULE_CORE_THREAD)) {
/* Schedule active thread */
sched_run();
}
/* Switch to active userspace thread */
_isr_switch_to_user();
}
/* ^
* |
* |
* cpu_switch_context_exit continues
* in ISR context in _isr_context_switch_exit
*/
void cpu_switch_context_exit(void)
{
# ifdef NATIVE_AUTO_EXIT
if (sched_num_threads <= 1) {
extern unsigned _native_retval;
DEBUG_CPU("cpu_switch_context_exit: last task has ended. exiting.\n");
real_exit(_native_retval);
}
# endif
if (_native_in_isr == 0) {
/* Disable interrupts while switching */
irq_disable();
_native_in_isr = 1;
_native_isr_context_make(_isr_context_switch_exit);
if (setcontext(_native_isr_context) == -1) {
err(EXIT_FAILURE, "cpu_switch_context_exit: setcontext");
}
errx(EXIT_FAILURE, "1 this should have never been reached!!");
}
else {
_isr_context_switch_exit();
}
errx(EXIT_FAILURE, "3 this should have never been reached!!");
}
/* ========================================= */
void _isr_thread_yield(void)
{
DEBUG_CPU("... ISR: switched to ISR context, scheduling\n");
if (_native_pending_signals > 0) {
DEBUG_CPU("... ISR: pending signals, handling signals\n\n");
_native_call_sig_handlers_and_switch();
}
if (!IS_USED(MODULE_CORE_THREAD)) {
return;
}
/* Set active thread */
sched_run();
/* Switch to active userspace thread */
_isr_switch_to_user();
}
/* ^
* |
* |
* thread_yield_higher continues
* in ISR context in _isr_thread_yield
*/
void thread_yield_higher(void)
{
sched_context_switch_request = 1;
if (_native_in_isr == 0 && _native_interrupts_enabled) {
DEBUG_CPU("yielding higher priority thread, switching to ISR context ...\n");
_native_in_isr = 1;
irq_disable();
/* Create the ISR context, will execute isr_thread_yield */
_native_isr_context_make(_isr_thread_yield);
if (swapcontext(_native_user_context(), _native_isr_context) == -1) {
err(EXIT_FAILURE, "thread_yield_higher: swapcontext");
}
irq_enable();
}
}
/* ========================================= */
void native_cpu_init(void)
{
if (getcontext(&_end_context) == -1) {
err(EXIT_FAILURE, "native_cpu_init: getcontext");
}
/* The _end_context allows RIOT to execute code after a thread task func returns.
* This works as follows (explanation based on libplatform)
* - In thread_stack_init, we call makecontext with the thread task func
* and uc_link = _end_context.
* - makecontext modifies the ucontext so that _ctx_start (in the libc/libplatform impl)
* is called when setcontext is executed. The thread task func resides in a register.
* - When the thread is started using setcontext, _ctx_start branches and links to the
* the task func. After the task func returns, _ctx_start would normally call exit.
* However, if _end_context is set, it calls setcontext on th bespoke _end_context.
*/
_end_context.uc_stack.ss_sp = malloc(SIGSTKSZ);
expect(_end_context.uc_stack.ss_sp != NULL);
_end_context.uc_stack.ss_size = SIGSTKSZ;
_end_context.uc_stack.ss_flags = 0;
makecontext(&_end_context, sched_task_exit, 0);
(void)VALGRIND_STACK_REGISTER(_end_context.uc_stack.ss_sp,
(char *)_end_context.uc_stack.ss_sp + _end_context.uc_stack.ss_size);
VALGRIND_DEBUG("VALGRIND_STACK_REGISTER(%p, %p)\n",
(void*)_end_context.uc_stack.ss_sp,
(void*)((char *)_end_context.uc_stack.ss_sp + _end_context.uc_stack.ss_size));
DEBUG_CPU("RIOT native cpu initialized.\n");
}
/* ========================================= */
static inline void *align_stack(uintptr_t start, int *stacksize) static inline void *align_stack(uintptr_t start, int *stacksize)
{ {
const size_t alignment = sizeof(uintptr_t); const size_t alignment = sizeof(uintptr_t);
@ -83,17 +238,18 @@ char *thread_stack_init(thread_task_func_t task_func, void *arg, void *stack_sta
ucontext_t *p; ucontext_t *p;
stack_start = align_stack((uintptr_t)stack_start, &stacksize); stack_start = align_stack((uintptr_t)stack_start, &stacksize);
DEBUG_CPU("... ISR: switching to user thread, calling setcontext(PID %" PRIkernel_pid ")\n\n", thread_getpid());
(void) VALGRIND_STACK_REGISTER(stack_start, (char *)stack_start + stacksize); (void) VALGRIND_STACK_REGISTER(stack_start, (char *)stack_start + stacksize);
VALGRIND_DEBUG("VALGRIND_STACK_REGISTER(%p, %p)\n", VALGRIND_DEBUG("VALGRIND_STACK_REGISTER(%p, %p)\n",
stack_start, (void*)((char *)stack_start + stacksize)); stack_start, (void*)((char *)stack_start + stacksize));
DEBUG("thread_stack_init\n"); DEBUG_CPU("thread_stack_init\n");
/* Use intermediate cast to uintptr_t to silence -Wcast-align. The stack /* Use intermediate cast to uintptr_t to silence -Wcast-align. The stack
* is aligned to word size above. */ * is aligned to word size above. */
p = (ucontext_t *)(uintptr_t)((uint8_t *)stack_start + (stacksize - sizeof(ucontext_t))); p = (ucontext_t *)(uintptr_t)((uint8_t *)stack_start + (stacksize - sizeof(ucontext_t)));
/* Stack guards might be in the way. */
memset(p, 0, sizeof(ucontext_t));
stacksize -= sizeof(ucontext_t); stacksize -= sizeof(ucontext_t);
if (getcontext(p) == -1) { if (getcontext(p) == -1) {
@ -103,135 +259,13 @@ char *thread_stack_init(thread_task_func_t task_func, void *arg, void *stack_sta
p->uc_stack.ss_sp = stack_start; p->uc_stack.ss_sp = stack_start;
p->uc_stack.ss_size = stacksize; p->uc_stack.ss_size = stacksize;
p->uc_stack.ss_flags = 0; p->uc_stack.ss_flags = 0;
p->uc_link = &end_context; p->uc_link = &_end_context;
if (sigemptyset(&(p->uc_sigmask)) == -1) { if (sigemptyset(&(p->uc_sigmask)) == -1) {
err(EXIT_FAILURE, "thread_stack_init: sigemptyset"); err(EXIT_FAILURE, "thread_stack_init: sigemptyset");
} }
makecontext(p, (void (*)(void)) task_func, 1, arg); makecontext(p, (void (*)(void))task_func, 1, arg);
return (char *) p; return (char *) p;
} }
void isr_cpu_switch_context_exit(void)
{
ucontext_t *ctx;
DEBUG_CPU("_isr_schedule_and_switch\n");
if (((sched_context_switch_request == 1) || (thread_get_active() == NULL))
&& IS_USED(MODULE_CORE_THREAD)) {
sched_run();
}
DEBUG("isr_cpu_switch_context_exit: calling setcontext(%" PRIkernel_pid ")\n\n", thread_getpid());
/* Use intermediate cast to uintptr_t to silence -Wcast-align.
* stacks are manually word aligned in thread_static_init() */
ctx = (ucontext_t *)(uintptr_t)(thread_get_active()->sp);
native_interrupts_enabled = 1;
_native_mod_ctx_leave_sigh(ctx);
if (setcontext(ctx) == -1) {
err(EXIT_FAILURE, "isr_cpu_switch_context_exit: setcontext");
}
errx(EXIT_FAILURE, "2 this should have never been reached!!");
}
void cpu_switch_context_exit(void)
{
#ifdef NATIVE_AUTO_EXIT
if (sched_num_threads <= 1) {
extern unsigned _native_retval;
DEBUG_CPU("cpu_switch_context_exit: last task has ended. exiting.\n");
real_exit(_native_retval);
}
#endif
if (_native_in_isr == 0) {
irq_disable();
_native_in_isr = 1;
native_isr_context.uc_stack.ss_sp = __isr_stack;
native_isr_context.uc_stack.ss_size = __isr_stack_size;
native_isr_context.uc_stack.ss_flags = 0;
makecontext(&native_isr_context, isr_cpu_switch_context_exit, 0);
if (setcontext(&native_isr_context) == -1) {
err(EXIT_FAILURE, "cpu_switch_context_exit: setcontext");
}
errx(EXIT_FAILURE, "1 this should have never been reached!!");
}
else {
isr_cpu_switch_context_exit();
}
errx(EXIT_FAILURE, "3 this should have never been reached!!");
}
void isr_thread_yield(void)
{
DEBUG_CPU("... ISR: switched to ISR context, scheduling\n");
if (_native_sigpend > 0) {
native_irq_handler();
DEBUG_CPU("... ISR: pending signals, handling signals\n\n");
}
if (!IS_USED(MODULE_CORE_THREAD)) {
return;
}
sched_run();
/* Use intermediate cast to uintptr_t to silence -Wcast-align.
* stacks are manually word aligned in thread_static_init() */
ucontext_t *ctx = (ucontext_t *)(uintptr_t)(thread_get_active()->sp);
DEBUG("isr_thread_yield: switching to(%" PRIkernel_pid ")\n\n",
thread_getpid());
native_interrupts_enabled = 1;
_native_mod_ctx_leave_sigh(ctx);
if (setcontext(ctx) == -1) {
err(EXIT_FAILURE, "isr_thread_yield: setcontext");
}
}
void thread_yield_higher(void)
{
sched_context_switch_request = 1;
if (_native_in_isr == 0 && native_interrupts_enabled) {
/* Use intermediate cast to uintptr_t to silence -Wcast-align.
* stacks are manually word aligned in thread_static_init() */
ucontext_t *ctx = (ucontext_t *)(uintptr_t)(thread_get_active()->sp);
DEBUG_CPU("yielding higher priority thread, switching to ISR context ...\n");
_native_in_isr = 1;
irq_disable();
native_isr_context.uc_stack.ss_sp = __isr_stack;
native_isr_context.uc_stack.ss_size = __isr_stack_size;
native_isr_context.uc_stack.ss_flags = 0;
makecontext(&native_isr_context, isr_thread_yield, 0);
if (swapcontext(ctx, &native_isr_context) == -1) {
err(EXIT_FAILURE, "thread_yield_higher: swapcontext");
}
irq_enable();
}
}
void native_cpu_init(void)
{
if (getcontext(&end_context) == -1) {
err(EXIT_FAILURE, "native_cpu_init: getcontext");
}
end_context.uc_stack.ss_sp = malloc(SIGSTKSZ);
expect(end_context.uc_stack.ss_sp != NULL);
end_context.uc_stack.ss_size = SIGSTKSZ;
end_context.uc_stack.ss_flags = 0;
makecontext(&end_context, sched_task_exit, 0);
(void)VALGRIND_STACK_REGISTER(end_context.uc_stack.ss_sp,
(char *)end_context.uc_stack.ss_sp + end_context.uc_stack.ss_size);
VALGRIND_DEBUG("VALGRIND_STACK_REGISTER(%p, %p)\n",
(void*)end_context.uc_stack.ss_sp,
(void*)((char *)end_context.uc_stack.ss_sp + end_context.uc_stack.ss_size));
DEBUG("RIOT native cpu initialized.\n");
}