Hi Kazu,
On Wed, Dec 4, 2019 at 11:20 PM Kazuhito Hagio <k-hagio@xxxxxxxxxxxxx> wrote:
>
> > -----Original Message-----
> > This patch marks '--mem-usage' option as unsupported for arm64
> > architecture.
> >
> > With the newer arm64 kernels supporting 48-bit/52-bit VA address spaces
> > and keeping a single binary for supporting the same, the address of
> > kernel symbols like _stext which could be earlier used to determine
> > VA_BITS value, can no longer to determine whether VA_BITS is set to 48
> > or 52 in the kernel space.
>
> The --mem-usage option works with older arm64 kernels, so we should not
> mark it unsupported for all arm64 kernels.
>
> (If we use ELF note vmcoreinfo in kcore, is it possible to support the
> option? Let's think about it later..)
Ok, I am in the process of discussing this with arm64 maintainers in
detail as _stext symbol address can no longer be used to separate
48-bit v/s 52-bit kernel VA space configurations.
Also other user-space utilities like 'kexec-tools' also face a similar
problem with the 52-bit change (as the vmcore-dmesg stops working).
I am currently caught up with another high priority issue. Will come
back with more thoughts on this in a couple of days.
Thanks,
Bhupesh
> > Hence for now, it makes sense to mark '--mem-usage' option as
> > unsupported for arm64 architecture until we have more clarity from arm64
> > kernel maintainers on how to manage the same in future
> > kernel/makedumpfile versions.
> >
> > Cc: John Donnelly <john.p.donnelly@xxxxxxxxxx>
> > Cc: Kazuhito Hagio <k-hagio@xxxxxxxxxxxxx>
> > Cc: kexec@xxxxxxxxxxxxxxxxxxx
> > Signed-off-by: Bhupesh Sharma <bhsharma@xxxxxxxxxx>
> > ---
> > makedumpfile.c | 5 +++++
> > 1 file changed, 5 insertions(+)
> >
> > diff --git a/makedumpfile.c b/makedumpfile.c
> > index baf559e4d74e..ae60466a1e9c 100644
> > --- a/makedumpfile.c
> > +++ b/makedumpfile.c
> > @@ -11564,6 +11564,11 @@ main(int argc, char *argv[])
> > MSG("\n");
> > MSG("The dmesg log is saved to %s.\n", info->name_dumpfile);
> > } else if (info->flag_mem_usage) {
> > +#ifdef __aarch64__
> > + MSG("mem-usage not supported for arm64 architecure.\n");
> > + goto out;
> > +#endif
> > +
> > if (!check_param_for_creating_dumpfile(argc, argv)) {
> > MSG("Commandline parameter is invalid.\n");
> > MSG("Try `makedumpfile --help' for more information.\n");
> > --
> > 2.7.4
> >
>
>
>
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