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xtensa: mmu: MMU re-initialization API

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With power managment is enabled, depending on the SoC power state
used when idle, the MMU may lose context and may need to be re-initialized.
When re-initializing the MMU, we must not re-create the page table
because it may overwrite changes done during the execution, but we still
need to set the asid and page table for the current context.

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
This commit is contained in:
Flavio Ceolin 2024-04-10 19:39:11 +00:00 • committed by David Leach
commit f74a84b251
2 changed files with 28 additions and 0 deletions
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18
arch/xtensa/core/ptables.c
View file

@ -320,6 +320,24 @@ void xtensa_mmu_init(void)
arch_xtensa_mmu_post_init(_current_cpu->id == 0);
}
void xtensa_mmu_reinit(void)
{
/* First initialize the hardware */
xtensa_init_paging(xtensa_kernel_ptables);
#ifdef CONFIG_USERSPACE
struct k_thread *thread = _current_cpu->current;
struct arch_mem_domain *domain =
&(thread->mem_domain_info.mem_domain->arch);
/* Set the page table for current context */
xtensa_set_paging(domain->asid, domain->ptables);
#endif /* CONFIG_USERSPACE */
arch_xtensa_mmu_post_init(_current_cpu->id == 0);
}
#ifdef CONFIG_ARCH_HAS_RESERVED_PAGE_FRAMES
/* Zephyr's linker scripts for Xtensa usually puts
* something before z_mapped_start (aka .text),

10
include/zephyr/arch/xtensa/xtensa_mmu.h
View file

@ -123,6 +123,16 @@ extern int xtensa_soc_mmu_ranges_num;
*/
void xtensa_mmu_init(void);
/**
* @brief Re-initialize hardware MMU.
*
* This configures the MMU hardware when the cpu lost context and has
* re-started.
*
* It assumes that the page table is already created and accessible in memory.
*/
void xtensa_mmu_reinit(void);
/**
* @brief Tell other processors to flush TLBs.
*