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arch: xtensa: Carve space for saved HiFi regs

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As the BSA can not be used when lazy HiFi context switching is
used, a more permanent and predictable location in which to store
the registers is required. To this end ...
  1. reserve some space in the arch-specific portion of the k_thread
     structure for those registers.
  2. clear that region when the thread is created.

Signed-off-by: Peter Mitsis <peter.mitsis@intel.com>
This commit is contained in:
Peter Mitsis 2025-06-10 12:44:23 -07:00 committed by Chris Friedt
parent cd351208d5
commit 6505cf2e54
2 changed files with 13 additions and 0 deletions
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4
arch/xtensa/core/thread.c
View File

@ -120,6 +120,10 @@ void arch_new_thread(struct k_thread *thread, k_thread_stack_t *stack,
{
thread->switch_handle = init_stack(thread, (int *)stack_ptr, entry,
p1, p2, p3);
#ifdef CONFIG_XTENSA_LAZY_HIFI_SHARING
memset(thread->arch.hifi_regs, 0, sizeof(thread->arch.hifi_regs));
#endif /* CONFIG_XTENSA_LAZY_HIFI_SHARING */
#ifdef CONFIG_KERNEL_COHERENCE
__ASSERT((((size_t)stack) % XCHAL_DCACHE_LINESIZE) == 0, "");
__ASSERT((((size_t)stack_ptr) % XCHAL_DCACHE_LINESIZE) == 0, "");

9
include/zephyr/arch/xtensa/thread.h
View File

@ -14,6 +14,10 @@
#include <zephyr/arch/xtensa/mpu.h>
#endif
#ifdef CONFIG_XTENSA_LAZY_HIFI_SHARING
#include <xtensa/config/tie.h>
#endif
/* Xtensa doesn't use these structs, but Zephyr core requires they be
* defined so they can be included in struct _thread_base. Dummy
* field exists for sizeof compatibility with C++.
@ -48,6 +52,11 @@ struct _thread_arch {
*/
uint32_t return_ps;
#endif
#ifdef CONFIG_XTENSA_LAZY_HIFI_SHARING
/* A non-BSA region is required for lazy save/restore */
uint8_t hifi_regs[XCHAL_CP1_SA_SIZE] __aligned(XCHAL_CP1_SA_ALIGN);
#endif
};
typedef struct _thread_arch _thread_arch_t;