[Crash-utility] [PATCH v2] arm64: handle 1GB block for VM_L4_4K

[lijiang]

On Wed, Apr 6, 2022 at 11:48 PM <crash-utility-request at redhat.com> wrote:

> Date: Wed,  6 Apr 2022 22:38:40 +0800
> From: Rongwei Wang <rongwei.wang at linux.alibaba.com>
> To: crash-utility at redhat.com, k-hagio-ab at nec.com,
>         shijie at os.amperecomputing.com, piliu at redhat.com
> Subject: [Crash-utility] [PATCH v2] arm64: handle 1GB block for
>         VM_L4_4K
> Message-ID: <20220406143840.76523-1-rongwei.wang at linux.alibaba.com>
> Content-Type: text/plain; charset="US-ASCII"; x-default=true
>
> When arm64 is configured with PAGE_SIZE=4k and 4 level
> translation, the pagetable of all pages may be created with
> block mapping or contiguous mapping as much as possible, likes
> disable CONFIG_RODATA_FULL_DEFAULT_ENABLED. But now, vtop
> command can not handle 1GB block (PUD mapping) well, and just
> shows a seek error:
>
> crash> vtop ffff00184a800000
> VIRTUAL           PHYSICAL
> ffff00184a800000  188a800000
>
> PAGE DIRECTORY: ffff8000110aa000
>    PGD: ffff8000110aa000 => 203fff9003
>    PUD: ffff001fffff9308 => 68001880000705
>    PMD: ffff0018400002a0 => ffff8000103b4fd0
> vtop: seek error: kernel virtual address: ffff7fffd03b4000  type: "page
> table"
>
> This patch fixes it, and shows as following:
>
> crash> vtop ffff00184a800000
> VIRTUAL           PHYSICAL
> ffff00184a800000  188a800000
>
> PAGE DIRECTORY: ffff8000110aa000
>    PGD: ffff8000110aa000 => 203fff9003
>    PUD: ffff001fffff9308 => 68001880000705
>   PAGE: 1880000000  (1GB)
>
>      PTE         PHYSICAL   FLAGS
> 68001880000705  1880000000  (VALID|SHARED|AF|PXN|UXN)
>
>       PAGE         PHYSICAL      MAPPING       INDEX CNT FLAGS
> fffffe00610a0000 188a800000                0        0  0 77fffe0000000000
>
> Acked-by: Kazuhito Hagio <k-hagio-ab at nec.com>
> Signed-off-by: Rongwei Wang <rongwei.wang at linux.alibaba.com>
> ---
>  arm64.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/arm64.c b/arm64.c
> index 2177c52..65f6cdf 100644
> --- a/arm64.c
> +++ b/arm64.c
> @@ -1999,6 +1999,16 @@ arm64_vtop_4level_4k(ulong pgd, ulong vaddr,
> physaddr_t *paddr, int verbose)
>         if (!pud_val)
>                 goto no_page;
>
> +       if ((pud_val & PUD_TYPE_MASK) == PUD_TYPE_SECT) {
> +               ulong sectionbase = (pud_val & SECTION_PAGE_MASK_1GB) &
> PHYS_MASK;
> +               if (verbose) {
> +                       fprintf(fp, "  PAGE: %lx  (1GB)\n\n", sectionbase);
> +                       arm64_translate_pte(pud_val, 0, 0);
> +               }
> +               *paddr = sectionbase + (vaddr & ~SECTION_PAGE_MASK_1GB);
> +               return TRUE;
> +       }
> +
>         pmd_base = (ulong *)PTOV(pud_val & PHYS_MASK &
> (s32)machdep->pagemask);
>         FILL_PMD(pmd_base, KVADDR, PTRS_PER_PMD_L4_4K * sizeof(ulong));
>         pmd_ptr = pmd_base + (((vaddr) >> PMD_SHIFT_L4_4K) &
> (PTRS_PER_PMD_L4_4K - 1));
> --


Thank you for the fix.
The v2 looks good to me. Applied.

Thanks.
Lianbo


> 2.27.0
>
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