kaspar/RIOT
1
0
Fork 0
mirror of https://github.com/RIOT-OS/RIOT.git synced 2025-12-14 17:13:50 +01:00
Code Releases Activity

cpu/arm7_common: align stacks correctly

Browse Source 
`thread_stack_init()` didn't correctly set up the stack alignment.
This fixes the issue and brings the function closer to the Cortex M
version, laying the groundwork for future code duplication.

This fixes https://github.com/RIOT-OS/RIOT/issues/11885
This commit is contained in:
Marian Buschsieweke 2022-09-24 18:02:36 +02:00
parent 913bf3748c
commit f57a15131e
No known key found for this signature in database
GPG Key ID: CB8E3238CE715A94
1 changed files with 28 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
cpu/arm7_common/arm_cpu.c
View File

@ -16,6 +16,7 @@
* @}
*/
#include <stdint.h>
#include <stdio.h>
#include "arm_cpu.h"
#include "irq.h"
@ -42,37 +43,54 @@ __attribute__((used, section(".svc_stack"), aligned(4))) uint8_t svc_stack[ISR_S
*--------------------------------------------------------------------------*/
char *thread_stack_init(thread_task_func_t task_func, void *arg, void *stack_start, int stack_size)
{
unsigned int *stk;
int i;
stk = (unsigned int *)((uintptr_t)stack_start + stack_size);
stk--;
uint32_t *stk;
uintptr_t sp;
stk = (uint32_t *)((uintptr_t)stack_start + stack_size);
/* adjust to 32 bit boundary by clearing the last two bits in the address */
stk = (uint32_t *)(((uintptr_t)stk) & ~((uintptr_t)0x3));
/* stack start marker */
stk--;
*stk = STACK_MARKER;
/* make sure the stack is double word aligned (8 bytes) */
/* This is required in order to conform with Procedure Call Standard for the
* ARM® Architecture (AAPCS) */
/* https://web.archive.org/web/20150316114702/http://infocenter.arm.com/help/topic/com.arm.doc.ihi0042e/IHI0042E_aapcs.pdf
*/
if (((uint32_t) stk & 0x7) != 0) {
/* add a single word padding */
--stk;
*stk = ~((uint32_t)STACK_MARKER);
}
sp = (uintptr_t)stk;
/* set the return address (LR) */
stk--;
*stk = (unsigned int) sched_task_exit;
*stk = (uintptr_t)sched_task_exit;
/* set the stack pointer (SP) */
stk--;
*stk = (unsigned int)((unsigned int)stack_start + stack_size) - 4;
*stk = sp;
/* build base stack */
for (i = REGISTER_CNT; i > 0 ; i--) {
for (int i = REGISTER_CNT; i > 0 ; i--) {
stk--;
*stk = i;
}
/* set argument to task_func */
stk--;
*stk = ((unsigned int) arg);
*stk = (uintptr_t)arg;
/* set the entry point */
stk--;
*stk = ((unsigned int) task_func);
*stk = (uintptr_t)task_func;
/* set the saved program status register */
stk--;
*stk = (unsigned int) NEW_TASK_CPSR;
*stk = (uint32_t)NEW_TASK_CPSR;
return (char *)stk;
}