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x86: additional debug output for page faults

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Page faults will additionally dump out some interesting
page directory and page table flags for the faulting
memory address.

Intended to help determine whether the page tables have been
configured incorrectly as we enable memory protection features.

This only happens if CONFIG_EXCEPTION_DEBUG is turned on.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2017-08-01 13:04:43 -07:00 • committed by Anas Nashif
commit 9ffaaae5ad
3 changed files with 61 additions and 0 deletions
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20
arch/x86/core/x86_mmu.c
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@ -65,6 +65,26 @@ static inline u32_t check_pte_flags(union x86_mmu_pte pte,
}
void _x86_mmu_get_flags(void *addr, u32_t *pde_flags, u32_t *pte_flags)
{
int pde_index, pte_index;
union x86_mmu_pde *pde;
union x86_mmu_pte *pte;
struct x86_mmu_page_table *pt;
pde_index = MMU_PDE_NUM(addr);
pte_index = MMU_PAGE_NUM(addr);
pde = &X86_MMU_PD->entry[pde_index];
pt = (struct x86_mmu_page_table *)(pde->pt.page_table << 12);
pte = &pt->entry[pte_index];
*pde_flags = pde->pt.value & ~MMU_PDE_PAGE_TABLE_MASK;
*pte_flags = pte->value & ~MMU_PTE_PAGE_MASK;
}
/**
* @brief check page table entry flags
*