arm64 kexec hang
panand at redhat.com
Fri Mar 27 14:11:53 PDT 2015
On Friday 27 March 2015 10:53 PM, Geoff Levand wrote:
> Hi Pratyush,
> On Wed, 2015-03-25 at 15:55 +0530, Pratyush Anand wrote:
>> So with following changes kexec load seems to complete without any
>> error. However, kexec reboot does not work yet, Nothing after bye
>> message :( (1st kernel booted with maxcpus=1)
> 'Bye!' doesn't mean much, other than the first kernel has
> almost shutdown. I recommend for debugging you either define
> ARM64_DEBUG_PORT for the kexec-tools build, or have a suitable
> earlyprintk= on the kernel command line. See the read_sink()
> routine in kexec-arm64.c.
Well, I was already using earlycon and it did not print anything after
I got OCD-H and is able to track the flow atleast and to see when it dies.
So, it all goes like machine_kexec ->..... -> arm64_kexec_kimage_start
-> purgatory_start -> purgatory -> printf ... -> putchar
Here it dies (goes to el2_sync_invalid) as arm64_sink does not seem to
be correct. arm64_sink is (-1) 0xffffffffffffffff. I also tried by just
returning from printf without doing anything, still it goes to
el2_sync_invalid (may be from some other location).
I will try to see tomorrow why arm64_sink is wrong and why did not it
work if printf was null.
just for info: is_hyp_mode_available is true in my case.
> Either of these will output something like this from the
> purgatory code:
> I'm in purgatory
> purgatory: kernel_entry: 0000000080080000
> purgatory: dtb: 0000000080760000
> Another option is to add my 'debugging: early putc' patch,
> build the kernel with ARM64_DEBUG_PORT defined for your
> board. This will output 'stext' when the second
> stage kernel is entered
> The kexec --lite option will bypass purgatory and should just
> show 'stext'.
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