[U-Boot] [PATCH v2 0/9] SMP support for RISC-V

[Anup Patel]

> -----Original Message-----
> From: Atish Patra <atish.patra at wdc.com>
> Sent: Thursday, March 7, 2019 5:20 AM
> To: Anup Patel <anup at brainfault.org>; Auer, Lukas
> <lukas.auer at aisec.fraunhofer.de>
> Cc: schwab at suse.de; paul.walmsley at sifive.com; agraf at suse.de; u-
> boot at lists.denx.de; baruch at tkos.co.il; daniel.schwierzeck at gmail.com;
> bmeng.cn at gmail.com; rick at andestech.com; sr at denx.de;
> palmer at sifive.com; Anup Patel <Anup.Patel at wdc.com>
> Subject: Re: [PATCH v2 0/9] SMP support for RISC-V
> 
> On 3/6/19 4:32 AM, Anup Patel wrote:
> > On Wed, Mar 6, 2019 at 5:45 PM Auer, Lukas
> > <lukas.auer at aisec.fraunhofer.de> wrote:
> >>
> >> On Wed, 2019-03-06 at 13:01 +0100, Andreas Schwab wrote:
> >>> On Mär 06 2019, Anup Patel <anup at brainfault.org> wrote:
> >>>
> >>>> On Wed, Mar 6, 2019 at 5:17 PM Andreas Schwab <schwab at suse.de>
> >>>> wrote:
> >>>>> On Mär 06 2019, Anup Patel <Anup.Patel at wdc.com> wrote:
> >>>>>
> >>>>>>> -----Original Message-----
> >>>>>>> From: Andreas Schwab <schwab at suse.de>
> >>>>>>> Sent: Wednesday, March 6, 2019 4:27 PM
> >>>>>>> To: Anup Patel <Anup.Patel at wdc.com>
> >>>>>>> Cc: Auer, Lukas <lukas.auer at aisec.fraunhofer.de>;
> >>>>>>> u-boot at lists.denx.de; paul.walmsley at sifive.com; agraf at suse.de;
> >>>>>>> anup at brainfault.org; baruch at tkos.co.il;
> >>>>>>> daniel.schwierzeck at gmail.com; bmeng.cn at gmail.com;
> >>>>>>> rick at andestech.com; sr at denx.de; palmer at sifive.com; Atish Patra
> >>>>>>> <Atish.Patra at wdc.com>
> >>>>>>> Subject: Re: [PATCH v2 0/9] SMP support for RISC-V
> >>>>>>>
> >>>>>>> Apparently sometimes u-boot tries to boot the kernel on heart
> >>>>>>> 0 (the E51
> >>>>>>> core), which will then fail to start userspace, since that
> >>>>>>> cannot cope with the missing fpu.
> >>>>>>
> >>>>>> That's not possible
> >>>>>
> >>>>> Yes, it is.
> >>>>>
> >>>>>
> >>>>> OpenSBI v0.3 (Mar  6 2019 10:55:01)
> >>>>>     ____                    _____ ____ _____
> >>>>>    / __ \                  / ____|  _ \_   _|
> >>>>>   | |  | |_ __   ___ _ __ | (___ | |_) || |
> >>>>>   | |  | | '_ \ / _ \ '_ \ \___ \|  _ < | |
> >>>>>   | |__| | |_) |  __/ | | |____) | |_) || |_
> >>>>>    \____/| .__/ \___|_| |_|_____/|____/_____|
> >>>>>          | |
> >>>>>          |_|
> >>>>>
> >>>>> Platform Name          : SiFive Freedom U540
> >>>>> Platform HART Features : RV64ACDFIMSU
> >>>>> Platform Max HARTs     : 5
> >>>>> Current Hart           : 2
> >>>>> Firmware Base          : 0x80000000
> >>>>> Firmware Size          : 88 KB
> >>>>> Runtime SBI Version    : 0.1
> >>>>>
> >>>>> PMP0: 0x0000000080000000-0x000000008001ffff (A)
> >>>>> PMP1: 0x0000000000000000-0x0000007fffffffff (A,R,W,X)
> >>>>>
> >>>>>
> >>>>> U-Boot 2019.04-rc3-00010-g3ea5582c09 (Mar 06 2019 - 10:06:10
> >>>>> +0100)
> >>>>>
> >>>>> CPU:   rv64imac
> >>>>> Model: sifive,hifive-unleashed-a00
> >>>>> DRAM:  8 GiB
> >>>>
> >>>> How does this prove that U-Boot is booting on HART 0?
> >>>
> >>> See the CPU isa.
> >>>
> >>
> >> Interesting.. U-Boot assumes that it can run on any core it is
> >> started on. In this case, OpenSBI must have booted its payload on hart 0.
> >
> > This is certainly not reproducible on cold-boot at my end but this
> > does mean OpenSBI has booted HART0 and let it jump to U-Boot.
> >
> > Now OpenSBI (by default) on SiFive FU540 does not allow HART0 to go
> > forward due to lack of S-mode. I think this is definitely the
> > warm-boot issue where OpenSBI sees corrupted memory contents.
> >
> 
> I am able to test both warm-boot and cold-boot several times(>10) without
> any issue with following pending PR in openSBI.
> 
> https://github.com/riscv/opensbi/pull/84

Thanks Atish, your changes have been merged in OpenSBI.

> 
> @Andreas @Anup: Can you please apply the above PR on top of master and
> verify at your end as well?
> 
> All the harts booted in Linux every time as well.

I tried warm-boot 10 times from U-Boot prompt and I did not see any issue
at all.

I also tried warm-boot 10 times from Linux prompt and I did not see any
Issue at all.

In both above cases, it came back to U-Boot prompt after warm-boot.

Also, tried cold-boot couple of times. I works perfectly fine as well.

Like I mentioned, there is no functional issue with this series. The
warm-boot issues were fixed in OpenSBI.

@Andreas, please try at your end.

Regards,
Anup