Re: RISC-V: patched kexec-tools on github for review/testing

[Yixun Lan <yixun.lan@gmail.com>]

Hi Alexandre, Nick:

On Wed, Oct 6, 2021 at 11:15 AM Alexandre Ghiti
<alexandre.ghiti@canonical.com> wrote:
>
> Hi Nick,
>
> On Tue, Oct 5, 2021 at 4:07 PM Alexandre Ghiti
> <alexandre.ghiti@canonical.com> wrote:
> >
> > On Tue, Oct 5, 2021 at 2:15 PM Nick Kossifidis <mick@ics.forth.gr> wrote:
> > >
> > > Hello all,
> > >
> > > I've uploaded my kexec-tools patches for riscv on github for
> > > testing/review before sending them upstream.
> > > https://github.com/riscv-collab/kexec-tools/tree/riscv
> > >
> > > Both kexec and kdump were tested on latest rv64 qemu, using for-next
> > > branch with this patch applied:
> > > https://patchwork.kernel.org/project/linux-riscv/patch/20211002122026.1451269-1-mick@ics.forth.gr/
> > >
> >
> > I'll test that asap and review your patch too.
> >
> > Thanks for your time Nick!
> >
> > Alex
> >
>
> 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@ubuntu:~$ 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've finally spent some time debugging this, and found the fix:

--- a/kexec/arch/riscv/kexec-riscv.c
+++ b/kexec/arch/riscv/kexec-riscv.c
@@ -120,7 +120,7 @@ int load_extra_segments(struct kexec_info *info,
uint64_t kernel_base,
                               initrd_base + initrd_size);

                dbgprintf("Base addr for initrd image: 0x%lX\n", initrd_base);
-               min_usable = initrd_base;
+               max_usable = initrd_base;
        }

the initrd image has been put at end of memory space( from high
address down to low address),
for example, my case here:
  the crash memory: 0x90000000 - 0xA0000000
  and the initrd base: 0x9F78F000

so, the max_usable address need to update
>
> 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
>
> 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@ubuntu:~$ 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.
>
> > > Regards,
> > > Nick
> > >
> > > _______________________________________________
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>
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