On 09/02/2020 05:12 PM, Aneesh Kumar K.V wrote:
> This will help in adding proper locks in a later patch
>
> Signed-off-by: Aneesh Kumar K.V
> ---
> mm/debug_vm_pgtable.c | 51 ---
> 1 file changed, 28 insertions(+), 23 deletions(-)
>
> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
> index de333871f407..f59cf6a9b05e 100644
> --- a/mm/debug_vm_pgtable.c
> +++ b/mm/debug_vm_pgtable.c
> @@ -986,7 +986,7 @@ static int __init debug_vm_pgtable(void)
> p4dp = p4d_alloc(mm, pgdp, vaddr);
> pudp = pud_alloc(mm, p4dp, vaddr);
> pmdp = pmd_alloc(mm, pudp, vaddr);
> - ptep = pte_alloc_map_lock(mm, pmdp, vaddr, );
> + ptep = pte_alloc_map(mm, pmdp, vaddr);
>
> /*
>* Save all the page table page addresses as the page table
> @@ -1006,33 +1006,12 @@ static int __init debug_vm_pgtable(void)
> p4d_basic_tests(p4d_aligned, prot);
> pgd_basic_tests(pgd_aligned, prot);
>
> - pte_clear_tests(mm, ptep, vaddr);
> - pmd_clear_tests(mm, pmdp);
> - pud_clear_tests(mm, pudp);
> - p4d_clear_tests(mm, p4dp);
> - pgd_clear_tests(mm, pgdp);
> -
> - pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
> - pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot);
> - pud_advanced_tests(mm, vma, pudp, pud_aligned, vaddr, prot);
> - hugetlb_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
> -
> pmd_leaf_tests(pmd_aligned, prot);
> pud_leaf_tests(pud_aligned, prot);
>
> - pmd_huge_tests(pmdp, pmd_aligned, prot);
> - pud_huge_tests(pudp, pud_aligned, prot);
> -
> pte_savedwrite_tests(pte_aligned, protnone);
> pmd_savedwrite_tests(pmd_aligned, protnone);
>
> - pte_unmap_unlock(ptep, ptl);
> -
> - pmd_populate_tests(mm, pmdp, saved_ptep);
> - pud_populate_tests(mm, pudp, saved_pmdp);
> - p4d_populate_tests(mm, p4dp, saved_pudp);
> - pgd_populate_tests(mm, pgdp, saved_p4dp);
> -
> pte_special_tests(pte_aligned, prot);
> pte_protnone_tests(pte_aligned, protnone);
> pmd_protnone_tests(pmd_aligned, protnone);
> @@ -1050,11 +1029,37 @@ static int __init debug_vm_pgtable(void)
> pmd_swap_tests(pmd_aligned, prot);
>
> swap_migration_tests();
> - hugetlb_basic_tests(pte_aligned, prot);
>
> pmd_thp_tests(pmd_aligned, prot);
> pud_thp_tests(pud_aligned, prot);
>
> + hugetlb_basic_tests(pte_aligned, prot);
> +
> + pte_clear_tests(mm, ptep, vaddr);
> + pmd_clear_tests(mm, pmdp);
> + pud_clear_tests(mm, pudp);
> + p4d_clear_tests(mm, p4dp);
> + pgd_clear_tests(mm, pgdp);
> +
> + ptl = pte_lockptr(mm, pmdp);
> + spin_lock(ptl);
> +
> + pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
> + pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot);
> + pud_advanced_tests(mm, vma, pudp, pud_aligned, vaddr, prot);
> + hugetlb_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
> +
> +
> + pmd_huge_tests(pmdp, pmd_aligned, prot);
> + pud_huge_tests(pudp, pud_aligned, prot);
> +
> + pte_unmap_unlock(ptep, ptl);
> +
> + pmd_populate_tests(mm, pmdp, saved_ptep);
> + pud_populate_tests(mm, pudp, saved_pmdp);
> + p4d_populate_tests(mm, p4dp, saved_pudp);
> + pgd_populate_tests(mm, pgdp, saved_p4dp);
> +
> p4d_free(mm, saved_p4dp);
> pud_free(mm, saved_pudp);
> pmd_free(mm, saved_pmdp);
>
Patches applied till here [i.e PATCH_1..PATCH_8] does not boot on arm64
platform, which might create a potential git bisect problem later on.
static void __init pte_advanced_tests(struct mm_struct *mm,
struct vm_area_struct *vma, pte_t *ptep,
unsigned long pfn, unsigned long vaddr,
pgprot_t prot)
{
pte_t pte = pfn_pte(pfn, prot);
/*
* Architectures optimize set_pte_at by avoiding TLB flush.
* This requires set_pte_at to be not used to update an
* existing pte entry. Clear pte before we do set_pte_at
*/
pr_debug("Validating PTE advanced\n");
pte = pfn_pte(pfn, prot);
set_pte_at(mm, vaddr, ptep, pte); --> Crashed here.
[ 19.031831] Unable to handle kernel paging request at virtual address
fdfffde00028
[ 19.033181] Mem abort info:
[ 19.033627] ESR = 0x9606
[ 19.034129] EC = 0x25: DABT (current EL), IL = 32 bits
[ 19.035002] SET = 0, FnV = 0
[ 19.035523] EA = 0, S1PTW = 0
[ 19.036054] Data abort info:
[ 19.036538] ISV = 0, ISS = 0x0006
[ 19.037170] CM = 0, WnR = 0
[ 19.037662] swapper pgtable: 4k pages, 48-bit VAs, pgdp=8158b000
[ 19.038749] [fdfffde00028] pgd=81d69003, p4d=81d69003,
pud=81d6a003, pmd=
[ 19.040560] Internal error: Oops: 9606 [#1] PREEMPT SMP
[ 19.041467]
