Hi, Kazu.
On Thu, Mar 24, 2022 at 3:01 PM HAGIO KAZUHITO(萩尾 一仁) <k-hagio-ab@xxxxxxx> wrote:
-----Original Message-----
> 1.) When I tested live system with "crash vmlinux /proc/kcore" in kernel v5.7,
> I met the following crash issue:
> ........................................
> crash: seek error: kernel virtual address: ffff75e9fffff000 type: "pud page"
> ........................................
>
> 2.) The root cause is the PTOV does not work correctly for some kernel,
> and then arm64_vtop_4level_4k() does not work correctly too.
>
> Why PTOV does not work?
>
> Because the physvirt_offset does not get the correct value.
>
> 3.) This patch uses symbol_value_from_proc_kallsyms() to get the
> virtual address of "physvirt_offset", and then uses
> READMEM(,..,KCORE_USE_VADDR) to get the correct value of
> "physvirt_offset".
>
> And also updates the ms->phys_offset which is initialized with
> a wrong value in kernel version [5.4, 5.10).
>
> Also add more comments for arm64_calc_physvirt_offset().
>
> Signed-off-by: Huang Shijie <shijie@xxxxxxxxxxxxxxxxxxxxxx>
> ---
> v1 --> v2:
> v1 tried to get the correct value for phys_offset,
> and then get the physvirt_offset correctly.
>
> v2 tried to get the physvirt_offset correctly,
> and them update phys_offset correctly.
>
> Tested this patch with kernel 5.7.
Thank you for the change. The code looks good to me.
Acked-by: Kazuhito Hagio <k-hagio-ab@xxxxxxx>
Lianbo, can we add the following with this? it's missing in help -m.
Sure. This looks good, I will add the fix when merging, maybe today.
BTW: I am testing them today.
Thanks.
Lianbo
@@ -1065,6 +1065,7 @@ arm64_dump_machdep_table(ulong arg)
fprintf(fp, " kimage_voffset: %016lx\n", ms->kimage_voffset);
}
fprintf(fp, " phys_offset: %lx\n", ms->phys_offset);
+ fprintf(fp, " physvirt_offset: %lx\n", ms->physvirt_offset);
fprintf(fp, "__exception_text_start: %lx\n", ms->__exception_text_start);
fprintf(fp, " __exception_text_end: %lx\n", ms->__exception_text_end);
fprintf(fp, " __irqentry_text_start: %lx\n", ms->__irqentry_text_start);
Thanks,
Kazu
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