----- Original Message -----
> I have recently sent a kernel patch upstream to add 'TCR_EL1.T1SZ' to
> vmcoreinfo for arm64 (see [0]), instead of VA_BITS_ACTUAL.
> 
> 'crash' can read the 'TCR_EL1.T1SZ' value from vmcoreinfo
> [which indicates the size offset of the memory region addressed by
> TTBR1_EL1] and hence can be used for determining the vabits_actual
> value.

Thanks Bhupesh -- your patch has been queued for crash-7.2.8:

  
https://github.com/crash-utility/crash/commit/bfd9a651f9426d86250295ac875d7e33d8de2a97

Dave


> 
> [0].http://lists.infradead.org/pipermail/kexec/2019-November/023962.html
> 
> Cc: Dave Anderson <[email protected]>
> Cc: AKASHI Takahiro <[email protected]>
> Cc: Prabhakar Kushwaha <[email protected]>
> Cc: [email protected]
> Signed-off-by: Bhupesh Sharma <[email protected]>
> ---
>  arm64.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/arm64.c b/arm64.c
> index af7147d24e20..083491331985 100644
> --- a/arm64.c
> +++ b/arm64.c
> @@ -3856,8 +3856,17 @@ arm64_calc_VA_BITS(void)
>               } else if (ACTIVE())
>                       error(FATAL, "cannot determine VA_BITS_ACTUAL: please 
> use
>                       /proc/kcore\n");
>               else {
> -                     if ((string = 
> pc->read_vmcoreinfo("NUMBER(VA_BITS_ACTUAL)"))) {
> -                             value = atol(string);
> +                     if ((string = 
> pc->read_vmcoreinfo("NUMBER(tcr_el1_t1sz)"))) {
> +                             /* See ARMv8 ARM for the description of
> +                              * TCR_EL1.T1SZ and how it can be used
> +                              * to calculate the vabits_actual
> +                              * supported by underlying kernel.
> +                              *
> +                              * Basically:
> +                              * vabits_actual = 64 - T1SZ;
> +                              */
> +                             value = 64 - strtoll(string, NULL, 0);
> +                             fprintf(fp,  "vmcoreinfo : vabits_actual: 
> %ld\n", value);
>                               free(string);
>                               machdep->machspec->VA_BITS_ACTUAL = value;
>                               machdep->machspec->VA_BITS = value;
> --
> 2.7.4
> 
> 


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