[Crash-utility] [PATCH] arm64 : assign page_offset and kvbase based on VA_BITS passed

[lijiang]

> Date: Thu, 23 Sep 2021 01:46:31 +0530
> From: Ankur Bansal <er.ankurbansal at gmail.com>
> To: crash-utility at redhat.com
> Cc: Ankur Bansal <er.ankurbansal at gmail.com>
> Subject: [Crash-utility] [PATCH] arm64 : assign page_offset and kvbase
>         based   on VA_BITS passed
> Message-ID:
>         <1632341791-10205-1-git-send-email-er.ankurbansal at gmail.com>
> Content-Type: text/plain; charset="US-ASCII"
>
> assign page_offset and kvbase based on VA_BITS passed
>

Thank you for the patch, Ankur.
Can you help to describe the reason in detail? And what happened?

Thanks.
Lianbo

> Change-Id: I525f3c7fd91e1f06e909c2f4c1749c44c068baea
> Signed-off-by: Ankur Bansal <er.ankurbansal at gmail.com>
> ---
>  arm64.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/arm64.c b/arm64.c
> index 7069312..2dc77f7 100644
> --- a/arm64.c
> +++ b/arm64.c
> @@ -220,10 +220,17 @@ arm64_init(int when)
>
>                 /* vabits_actual introduced after mm flip, so it should be flipped layout */
>                 if (ms->VA_BITS_ACTUAL) {
> -                       ms->page_offset = ARM64_FLIP_PAGE_OFFSET;
> -                       /* useless on arm64 */
> -                       machdep->identity_map_base = ARM64_FLIP_PAGE_OFFSET;
> -                       machdep->kvbase = ARM64_FLIP_PAGE_OFFSET;
> +                       if ((pc->flags2 & SNAP)) {
> +                               ms->page_offset = ARM64_FLIP_PAGE_OFFSET;
> +                               /* useless on arm64 */
> +                               machdep->identity_map_base = ARM64_FLIP_PAGE_OFFSET;
> +                               machdep->kvbase = ARM64_FLIP_PAGE_OFFSET;
> +                       }
> +                       else{
> +                               ms->page_offset = ARM64_FLIP_PAGE_OFFSET_ACTUAL;
> +                               machdep->identity_map_base = ARM64_FLIP_PAGE_OFFSET_ACTUAL;
> +                               machdep->kvbase = ARM64_FLIP_PAGE_OFFSET_ACTUAL;
> +                       }
>                         ms->userspace_top = ARM64_USERSPACE_TOP_ACTUAL;
>                 } else {
>                         ms->page_offset = ARM64_PAGE_OFFSET;
> --
> 2.7.4