linux-kernel - Re: [PATCH] RISC-V: Show CPU ID and Hart ID separately in /proc/cpuinfo

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Message-ID: <CAAhSdy3Ayy50XnAZk6Fu2Rk6pmMT2YN6KoN9voBg+RW1dUqajg@mail.gmail.com>
Date:   Thu, 13 Sep 2018 09:09:21 +0530
From:   Anup Patel <anup@...infault.org>
To:     Atish Patra <atish.patra@....com>
Cc:     Palmer Dabbelt <palmer@...ive.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Christoph Hellwig <hch@...radead.org>,
        linux-riscv@...ts.infradead.org,
        "linux-kernel@...r.kernel.org List" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] RISC-V: Show CPU ID and Hart ID separately in /proc/cpuinfo

On Wed, Sep 12, 2018 at 10:17 PM Atish Patra <atish.patra@....com> wrote:
>
> On 9/12/18 7:38 AM, Anup Patel wrote:
> > Currently, /proc/cpuinfo show logical CPU ID as Hart ID which
> > is in-correct. This patch shows CPU ID and Hart ID separately
> > in /proc/cpuinfo using cpuid_to_hardid_map().
> >
> > With this patch, contents of /proc/cpuinfo looks as follows:
> > cpu   : 0
> > hart  : 1
> > isa   : rv64imafdcsu
> > mmu   : sv48
> >
> > cpu   : 1
> > hart  : 0
> > isa   : rv64imafdcsu
> > mmu   : sv48
> >
> > cpu   : 2
> > hart  : 3
> > isa   : rv64imafdcsu
> > mmu   : sv48
> >
> > cpu   : 3
> > hart  : 2
> > isa   : rv64imafdcsu
> > mmu   : sv48
> >
> > Signed-off-by: Anup Patel <anup@...infault.org>
> > ---
> >   arch/riscv/kernel/cpu.c | 3 ++-
> >   1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
> > index f0f0ec2737b7..7c1342e242e6 100644
> > --- a/arch/riscv/kernel/cpu.c
> > +++ b/arch/riscv/kernel/cpu.c
> > @@ -87,7 +87,8 @@ static int c_show(struct seq_file *m, void *v)
> >                                                  NULL);
> >       const char *compat, *isa, *mmu;
> >
> > -     seq_printf(m, "hart\t: %lu\n", cpu_id);
> > +     seq_printf(m, "cpu\t: %lu\n", cpu_id);
> > +     seq_printf(m, "hart\t: %lu\n", cpuid_to_hardid_map(cpu_id));
> >       if (!of_property_read_string(node, "riscv,isa", &isa)
> >           && isa[0] == 'r'
> >           && isa[1] == 'v')
> >
>
> The extra hart information will not be parsed by lscpu which will make
> the cpu information inconsistent between lscpu & /proc/cpuinfo.
>
> Should we patch lscpu as well to show correct hart id as well ?

Yes, we should certainly patch lscpu to parse CPU ID and
HART ID differently.

Regards,
Anup