Hi Alexandru,
On 10/27/20 6:19 PM, Alexandru Elisei wrote:
> Being able to cause a stage 1 data abort might be useful for future tests.
> Add a function that unmaps a page from the translation tables.
>
> Signed-off-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
> ---
> lib/arm/asm/mmu-api.h | 1 +
> lib/arm/mmu.c | 32 ++++++++++++++++++++++++++++++++
> 2 files changed, 33 insertions(+)
>
> diff --git a/lib/arm/asm/mmu-api.h b/lib/arm/asm/mmu-api.h
> index 2bbe1faea900..305f77c6501f 100644
> --- a/lib/arm/asm/mmu-api.h
> +++ b/lib/arm/asm/mmu-api.h
> @@ -23,4 +23,5 @@ extern void mmu_set_range_ptes(pgd_t *pgtable, uintptr_t virt_offset,
> phys_addr_t phys_start, phys_addr_t phys_end,
> pgprot_t prot);
> extern void mmu_clear_user(pgd_t *pgtable, unsigned long vaddr);
> +extern void mmu_unmap_page(pgd_t *pgtable, unsigned long vaddr);
> #endif
> diff --git a/lib/arm/mmu.c b/lib/arm/mmu.c
> index 540a1e842d5b..72ac0be8d146 100644
> --- a/lib/arm/mmu.c
> +++ b/lib/arm/mmu.c
> @@ -232,3 +232,35 @@ void mmu_clear_user(pgd_t *pgtable, unsigned long vaddr)
> out_flush_tlb:
> flush_tlb_page(vaddr);
> }
> +
> +void mmu_unmap_page(pgd_t *pgtable, unsigned long vaddr)
> +{
> + pgd_t *pgd;
> + pmd_t *pmd;
> + pte_t *pte;
> +
> + if (!mmu_enabled())
> + return;
> +
> + pgd = pgd_offset(pgtable, vaddr);
> + if (!pgd_valid(*pgd))
> + return;
> +
> + pmd = pmd_offset(pgd, vaddr);
> + if (!pmd_valid(*pmd))
> + return;
> +
> + if (pmd_huge(*pmd)) {
> + WRITE_ONCE(*pmd, 0);
> + goto out_flush_tlb;
> + } else {
is the else needed?
> + pte = pte_offset(pmd, vaddr);
> + if (!pte_valid(*pte))
> + return;
> + WRITE_ONCE(*pte, 0);
> + goto out_flush_tlb;
> + }
> +
> +out_flush_tlb:
> + flush_tlb_page(vaddr);
> +}
>
This code is very similar to mmu_clear_user() besides the bit to invalidate
Just wondering if we couldn't use the same code and pass a bit offset.
It seems the offsets in PMD and PTE are same for USER bit and valid bit.
But maybe this is far-fetched and not worth the sharing.
I see Drew is not in CC, + Drew
Besides
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
Thanks
Eric
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