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kernel: Fix bug in spawning of legacy tasks using floating point

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A thread defined via a legacy MDEF that belongs to the FPU or
SSE task group must set the thread option bits for FP or SSE
register use prior to being spawned.

If this is not done, and the kernel is configured for SSE support,
the kernel will auto-enable the thread's use of floating point
so that the thread saves SSE register context info even if it
belongs to just the FPU task group, which could cause the thread
to overflow its stack.

Note that this change only increases footprint for x86-based
applications that enable floating point register sharing.

Change-Id: Idfe4d20bcd7bc42b4cee6ac40ad7987e2a45ccf6
Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
This commit is contained in:
Allan Stephens 2016-11-09 07:30:14 -06:00 • committed by Benjamin Walsh
commit 40325d2d28
1 changed files with 20 additions and 0 deletions
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20
kernel/unified/thread.c
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@ -42,6 +42,25 @@ extern struct _static_thread_data _static_thread_data_list_end[];
thread_data < _static_thread_data_list_end; \
thread_data++)
#ifdef CONFIG_FP_SHARING
static inline void _task_group_adjust(struct _static_thread_data *thread_data)
{
/*
* set thread options corresponding to legacy FPU and SSE task groups
* so thread spawns properly; EXE and SYS task groups need no adjustment
*/
if (thread_data->init_groups & K_TASK_GROUP_FPU) {
thread_data->init_options |= K_FP_REGS;
}
#ifdef CONFIG_SSE
if (thread_data->init_groups & K_TASK_GROUP_SSE) {
thread_data->init_options |= K_SSE_REGS;
}
#endif /* CONFIG_SSE */
}
#else
#define _task_group_adjust(thread_data) do { } while (0)
#endif /* CONFIG_FP_SHARING */
/* Legacy API */
@ -359,6 +378,7 @@ void _init_static_threads(void)
unsigned int key;
_FOREACH_STATIC_THREAD(thread_data) {
_task_group_adjust(thread_data);
_new_thread(
thread_data->init_stack,
thread_data->init_stack_size,