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All tasks, even user mode tasks, must start in supervisor mode until they get past the start-up trampoline

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This commit is contained in:
Gregory Nutt 2014-09-11 18:42:52 -06:00
parent 4821587509
commit 62e608be8c
1 changed files with 5 additions and 22 deletions
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27
arch/arm/src/armv7-a/arm_initialstate.c
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@ -110,30 +110,14 @@ void up_initial_state(struct tcb_s *tcb)
}
#endif
/* Set supervisor- or user-mode, depending on how NuttX is configured and
* what kind of thread is being started. Disable FIQs in any event
*/
#ifdef CONFIG_BUILD_KERNEL
if ((tcb->flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_KERNEL)
{
/* It is a kernel thread.. set supervisor mode */
cpsr = PSR_MODE_SVC;
}
else
{
/* It is a normal task or a pthread. Set user mode */
cpsr = PSR_MODE_USR;
}
#else
/* If the kernel build is not selected, then all threads run in
* supervisor-mode.
/* Set supervisor-mode and disable FIQs, regardless of how NuttX is
* configured and of what kind of thread is being started. That is
* because all threads, even user-mode threads will start in kernel
* trampoline at task_start() or pthread_start(). The thread's
* privileges will be dropped before transitioning to user code.
*/
cpsr = PSR_MODE_SVC;
#endif
/* Enable or disable interrupts, based on user configuration */
@ -154,4 +138,3 @@ void up_initial_state(struct tcb_s *tcb)
xcp->regs[REG_CPSR] = cpsr;
}