[PATCH v5 3/5] riscv: Separate memory init from paging init

[Geert Uytterhoeven]

Hi Atish,

On Wed, Mar 10, 2021 at 5:41 PM Geert Uytterhoeven <geert at linux-m68k.org> wrote:
> On Thu, Nov 19, 2020 at 1:40 AM Atish Patra <atish.patra at wdc.com> wrote:
> > Currently, we perform some memory init functions in paging init. But,
> > that will be an issue for NUMA support where DT needs to be flattened
> > before numa initialization and memblock_present can only be called
> > after numa initialization.
> >
> > Move memory initialization related functions to a separate function.
> >
> > Signed-off-by: Atish Patra <atish.patra at wdc.com>
> > Reviewed-by: Greentime Hu <greentime.hu at sifive.com>
> > Reviewed-by: Anup Patel <anup at brainfault.org>
> > Reviewed-by: Palmer Dabbelt <palmerdabbelt at google.com>
>
> This is now commit cbd34f4bb37d62d8 in v5.12-rc1, breaking the boot on
> Vexriscv:
>
> [    0.000000] earlycon: sbi0 at I/O port 0x0 (options '')
> [    0.000000] printk: bootconsole [sbi0] enabled
> [    0.000000] printk: debug: ignoring loglevel setting.
> [    0.000000] Initial ramdisk at: 0x(ptrval) (8388608 bytes)
> [    0.000000] Unable to handle kernel paging request at virtual
> address c8000008

> Note that I have "[PATCH v2 3/4] RISC-V: Fix L1_CACHE_BYTES for RV32"[1]
> applied, to avoid another crash (7c4fc8e3e982 = v5.11 + [1] +
> cherry-picked commits from the riscv-for-linus-5.12-mw0 pull request).
>
> If I revert the L1_CACHE_BYTES change, the boot continues, but I'm back
> to the old issue fixed by [1]:
>
> [   22.126687] Freeing initrd memory: 8192K
> [   22.321811] workingset: timestamp_bits=30 max_order=15 bucket_order=0
> [   29.001509] Block layer SCSI generic (bsg) driver version 0.4
> loaded (major 253)
> [   29.021555] io scheduler mq-deadline registered
> [   29.033692] io scheduler kyber registered
> [   29.141294] Unable to handle kernel paging request at virtual
> address 69726573

> Will have a deeper look later...

I found the core issue, and sent a fix: "[PATCH] RISC-V: Fix
out-of-bounds accesses in init_resources()"
https://lore.kernel.org/linux-riscv/20210312154634.3541844-1-geert@linux-m68k.org/

It works now with either value of L1_CACHE_SHIFT, so patch "[PATCH v2
3/4] RISC-V: Fix L1_CACHE_BYTES for RV32" is no longer needed.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds