Date:   Sat, 2 Jul 2022 11:35:12 +0000
From:   Yixun Lan <yixun.lan@...il.com>
To:     Nick Kossifidis <mick@....forth.gr>
Cc:     Alexandre Ghiti <alexandre.ghiti@...onical.com>,
        ebiederm@...ssion.com, kexec@...ts.infradead.org,
        linux-riscv <linux-riscv@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org List" <linux-kernel@...r.kernel.org>,
        Alexandre ghiti <alex@...ti.fr>,
        Mike Rapoport <rppt@...nel.org>, geert+renesas@...der.be,
        Stephano Cetola <scetola@...uxfoundation.org>,
        Philipp Tomsich <philipp.tomsich@...ll.eu>,
        Palmer Dabbelt <palmer@...belt.com>,
        Anup Patel <anup.patel@....com>,
        Atish Patra <atish.patra@....com>
Subject: Re: RISC-V: patched kexec-tools on github for review/testing

hi Nick

On Thu, Nov 25, 2021 at 11:45 PM Nick Kossifidis <mick@....forth.gr> wrote:
>
> Στις 2021-10-15 10:07, Alexandre Ghiti έγραψε:
> > On Sat, Oct 9, 2021 at 3:25 PM Nick Kossifidis <mick@....forth.gr>
> > wrote:
> >>
> >> Στις 2021-10-06 14:10, Alexandre Ghiti έγραψε:
> >> >
> >> > So I followed the instructions here:
> >> > https://documentation.suse.com/fr-fr/sles/12-SP3/html/SLES-all/cha-tuning-kexec.html#cha-tuning-kexec-basic-usage,
> >> > below the output on an Unmatched board using a vmlinux stored on a sd
> >> > card:
> >> >
> >> > ubuntu@...ntu:~$ sudo sbin/kexec -l vmlinux --append="$(cat
> >> > /proc/cmdline)" --initrd=/boot/initrd.img
> >> > Warning: No cmdline provided, using append string as cmdline
> >> > Warning: No dtb provided, using /sys/firmware/fdt
> >> > [ 1813.472671] INFO: task kworker/1:0:988 blocked for more than 120
> >> > seconds.
> >> > [ 1813.478751]       Not tainted 5.15.0-rc1+ #15
> >> > [ 1813.483110] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
> >> > disables this message.
> >> > Could not find a free area of memory of 0x3000 bytes...
> >> > locate_hole failed
> >> >
> >> > I used the Ubuntu kernel, so this is pretty large:
> >> > -rwxrwxr-x 1 ubuntu ubuntu 277M Oct  5 15:47 vmlinux
> >> > -rw-r--r-- 1 root root 98M Sep 21 03:25 /boot/initrd.img
> >> >
> >>
> >> ACK, I haven't tested initrd much TBH, I usually don't use an initrd,
> >> and when I do it's a small busybox-based rootfs.
> >>
> >> > Then if I don't load the initrd (I sometimes have the same warning as
> >> > above) I can at least kexec the new kernel but it fails to boot:
> >> >
> >> > ubuntu@...ntu:~$ sudo ./sbin/kexec -e
> >> > Warning: No cmdline or append string provided
> >> > Warning: No dtb provided, using /sys/firmware/fdt
> >> > [...]
> >> > [    0.000000] SBI v0.2 HSM extension detected
> >> > [    0.000000] CPU with hartid=0 is not available
> >> > [    0.000000] ------------[ cut here ]------------
> >> > [    0.000000] kernel BUG at arch/riscv/kernel/smpboot.c:107!
> >> > [    0.000000] Kernel BUG [#1]
> >> > [    0.000000] Modules linked in:
> >> > [    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.15.0-rc1+ #15
> >> > [    0.000000] Hardware name: SiFive HiFive Unmatched A00 (DT)
> >> > [    0.000000] epc : setup_smp+0xcc/0x142
> >> > [    0.000000]  ra : setup_smp+0xc4/0x142
> >> > [    0.000000] epc : ffffffff80a04080 ra : ffffffff80a04078 sp :
> >> > ffffffff81803ec0
> >> > [    0.000000]  gp : ffffffff81a23220 tp : ffffffff81810500 t0 :
> >> > ffffffff81a3551f
> >> > [    0.000000]  t1 : ffffffffffffffff t2 : 0000000000000000 s0 :
> >> > ffffffff81803f00
> >> > [    0.000000]  s1 : 0000000000000000 a0 : 0000000000000000 a1 :
> >> > 0000000000000000
> >> > [    0.000000]  a2 : 0000000000000000 a3 : 0000000000000001 a4 :
> >> > 0000000000000000
> >> > [    0.000000]  a5 : ffffffff80c64500 a6 : 0000000000000004 a7 :
> >> > 000000000000ff00
> >> > [    0.000000]  s2 : 0000000000000005 s3 : 0000000000000000 s4 :
> >> > ffffffff8118f9a8
> >> > [    0.000000]  s5 : 0000000000000007 s6 : ffffffff80c0b790 s7 :
> >> > 0000000080000200
> >> > [    0.000000]  s8 : 0000000000000fff s9 : 0000000081000200 s10:
> >> > 0000000000000018
> >> > [    0.000000]  s11: 000000000000000b t3 : 0000000000ff0000 t4 :
> >> > ffffffffffffffff
> >> > [    0.000000]  t5 : ffffffff80c0b7a0 t6 : ffffffff81803bd8
> >> > [    0.000000] status: 0000000200000100 badaddr: 0000000000000000
> >> > cause: 0000000000000003
> >> > [    0.000000] [<ffffffff80a04080>] setup_smp+0xcc/0x142
> >> > [    0.000000] [<ffffffff80a03d88>] setup_arch+0x56a/0x590
> >> > [    0.000000] [<ffffffff80a00aa2>] start_kernel+0xaa/0xa5c
> >> > [    0.000000] random: get_random_bytes called from
> >> > oops_exit+0x44/0x70 with crng_init=0
> >> > [    0.000000] ---[ end trace 0000000000000000 ]---
> >> > [    0.000000] Kernel panic - not syncing: Attempted to kill the idle
> >> > task!
> >> > [    0.000000] ---[ end Kernel panic - not syncing: Attempted to kill
> >> > the idle task! ]---
> >> >
> >> > This reliably fails here.
> >> >
> >>
> >> This looks weird, I'll check it out (we have an unmatched here so I'll
> >> try to get my hands on it sometime next week).
> >>
> >> Did you try kdump ? Do you get the same error ?
> >
> > kdump works fine, it fails to find the rootfs but I think my setup is
> > faulty here.
> > I took a quick look at kexec_relocate.S, and the use of va_pa_offset
> > is also wrong here, we should use va_kernel_pa_offset as it is used to
> > modify a text address But fixing that did not work either.
> >
> > Alex
> >
>
> Sorry for the delay, I finally got some time to work on this. As it
> turns out I'm passing cpu id instead of hart id to the next kernel (that
> comment on smp.h claiming that raw_smp_processor_id returns the hart id
> didn't help much) and interestingly enough cpu id and hart id match on
> qemu and also sometimes match on the unmatched / unleashed board. Also
> on unmatched / unleashed, hart id 0 is used by the non-linux hart so if
> we pass the cpu id of the boot cpu that's always going to be 0 it'll be
> invalid, but that's not always the case, especially for kdump. I'm also
> getting an error when trying to mount the rootfs on kdump on the
> unmatched board, because swiotlb can't allocate bounce buffers and the
> pcie driver doesn't work, so no nvme access. I'm looking for a way to
> make this work without messing things up, in any case I'll send some
> patches over the weekend. For the initrd issue I need to patch
> kexec-tools.
>
> Regards,
> Nick
>

ping, any update for this? any new patch for kexec-tools?

I'd also like to try kexec on unmatched board, and encounter the same error
as Alexandre Ghiti reported, generally I'm using almost same cmdline

Yixun Lan

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