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core: align stack on a 32bit boundary

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Fixes #1267.
This commit is contained in:
René Kijewski 2014-06-03 21:53:15 +02:00
parent fc4cf69376
commit 862000b715
3 changed files with 40 additions and 30 deletions
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10
core/include/attributes.h
View File

@ -19,6 +19,8 @@
#ifndef ATTRIBUTES_H_
#define ATTRIBUTES_H_
#include <stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
@ -72,6 +74,14 @@
#define UNREACHABLE() do { /* nothing */ } while (1)
#endif
/**
* @def ALIGN_OF(T)
* @brief Calculate the minimal alignment for type T.
* @param[in] T Type to examine
* @returns The minimal alignment of T.
*/
#define ALIGN_OF(T) (offsetof(struct { char c; T t; }, t))
#ifdef __cplusplus
}
#endif

2
core/include/thread.h
View File

@ -156,7 +156,7 @@ static inline kernel_pid_t thread_getpid(void)
*
* @return the amount of unused space of the thread's stack
*/
int thread_measure_stack_free(char *stack);
uintptr_t thread_measure_stack_free(char *stack);
#endif
#ifdef __cplusplus

58
core/thread.c
View File

@ -90,62 +90,62 @@ int thread_wakeup(kernel_pid_t pid)
}
#ifdef DEVELHELP
int thread_measure_stack_free(char *stack)
uintptr_t thread_measure_stack_free(char *stack)
{
unsigned int *stackp = (unsigned int *)stack;
uintptr_t *stackp = (uintptr_t *)stack;
/* assume that the comparison fails before or after end of stack */
/* assume that the stack grows "downwards" */
while (*stackp == (unsigned int)stackp) {
while (*stackp == (uintptr_t) stackp) {
stackp++;
}
int space_free = (unsigned int)stackp - (unsigned int)stack;
uintptr_t space_free = (uintptr_t) stackp - (uintptr_t) stack;
return space_free;
}
#endif
kernel_pid_t thread_create(char *stack, int stacksize, char priority, int flags, void *(*function)(void *arg), void *arg, const char *name)
{
/* allocate our thread control block at the top of our stackspace */
#ifdef DEVELHELP
int total_stacksize = stacksize;
#endif
stacksize -= sizeof(tcb_t);
/* align tcb address on 32bit boundary */
unsigned int tcb_address = (unsigned int) stack + stacksize;
if (tcb_address & 1) {
tcb_address--;
stacksize--;
}
if (tcb_address & 2) {
tcb_address -= 2;
stacksize -= 2;
}
tcb_t *cb = (tcb_t *) tcb_address;
if (priority >= SCHED_PRIO_LEVELS) {
return -EINVAL;
}
#ifdef DEVELHELP
int total_stacksize = stacksize;
#endif
/* align the stack on a 16/32bit boundary */
uintptr_t misalignment = (uintptr_t) stack % ALIGN_OF(void *);
if (misalignment) {
misalignment = ALIGN_OF(void *) - misalignment;
stack += misalignment;
stacksize -= misalignment;
}
/* make room for the thread control block */
stacksize -= sizeof(tcb_t);
/* round down the stacksize to a multiple of tcb_t alignments (usually 16/32bit) */
stacksize -= stacksize % ALIGN_OF(tcb_t);
/* allocate our thread control block at the top of our stackspace */
tcb_t *cb = (tcb_t *) (stack + stacksize);
#ifdef DEVELHELP
if (flags & CREATE_STACKTEST) {
/* assign each int of the stack the value of it's address */
unsigned int *stackmax = (unsigned int *)((char *)stack + stacksize);
unsigned int *stackp = (unsigned int *)stack;
uintptr_t *stackmax = (uintptr_t *) (stack + stacksize);
uintptr_t *stackp = (uintptr_t *) stack;
while (stackp < stackmax) {
*stackp = (unsigned int)stackp;
*stackp = (uintptr_t) stackp;
stackp++;
}
}
else {
/* create stack guard */
*stack = (unsigned int)stack;
*stack = (uintptr_t) stack;
}
#endif