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git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3073 42af7a65-404d-4744-a932-0658087f49c3
This commit is contained in:
patacongo 2010-11-05 00:29:37 +00:00
parent fd96300d6e
commit 45091e25c4
3 changed files with 37 additions and 3 deletions
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1
arch/avr/include/avr32/irq.h
View File

@ -98,7 +98,6 @@
#define INTCONTEXT_REGS 8 /* r8-r12, lr, pc, sr */
#define XCPTCONTEXT_REGS 17 /* Plus r0-r7, sp */
/****************************************************************************
* Public Types
****************************************************************************/

22
arch/avr/src/avr32/up_fullcontextrestore.S
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@ -53,6 +53,28 @@
/****************************************************************************
* Name: up_fullcontextrestore
*
* Descripion:
* Restore the full-running contex of a thread.
*
* NOTE: Thus function must handle one very strange case. That is when
* this function is called with up_sigdeliver(). That case is strange in
* two ways:
*
* 1. It is not a context switch between threads. Rather, up_fullcontextrestore
* must behave more it more like a longjmp within the same task, using the
* same stack.
* 2. In this case, this function is called with r12 pointing to a register
* save area on the stack to be destroyed. This is dangerous for two
* reasons: (a) there is a period of time where the stack contents still
* contain valid data, but are outside of range protected by the stack
* pointer (hence, interrupts must be disabled), and (b) there is the
* very real possibility that the new stack pointer might overlap with
* the register save area and stack usage in this function might corrupt
* the register save data before the state is restored.
*
* Input Parameters:
* r12 = A pointer to the register save area of the thread to be restored.
*
* C Prototype:
* void up_fullcontextrestore(uint32_t *regs);
*

17
arch/avr/src/avr32/up_sigdeliver.c
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@ -82,7 +82,7 @@
void up_sigdeliver(void)
{
_TCB *rtcb = (_TCB*)g_readytorun.head;
uint32_t regs[XCPTCONTEXT_REGS];
uint32_t regs[XCPTCONTEXT_REGS+3]; /* Why +3? See below */
sig_deliver_t sigdeliver;
/* Save the errno. This must be preserved throughout the signal handling
@ -128,7 +128,20 @@ void up_sigdeliver(void)
(void)irqsave();
rtcb->pterrno = saved_errno;
/* Then restore the correct state for this thread of execution. */
/* Then restore the correct state for this thread of execution. This is an
* unusual case that must be handled by up_fullcontextresore. This case is
* unusal in two ways:
*
* 1. It is not a context switch between threads. Rather, up_fullcontextrestore
* must behave more it more like a longjmp within the same task, using
* he same stack.
* 2. In this case, up_fullcontextrestore is called with r12 pointing to
* a register save area on the stack to be destroyed. This is
* dangerous because there is the very real possibility that the new
* stack pointer might overlap with the register save area and hat stack
* usage in up_fullcontextrestore might corrupt the register save data
* before the state is restored.
*/
up_ledoff(LED_SIGNAL);
up_fullcontextrestore(regs);