Linux-RISC-V Archive on lore.kernel.org
 help / color / Atom feed
From: Atish Patra <atishp@atishpatra.org>
To: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>,
	Vincent Chen <vincent.chen@sifive.com>,
	Anup Patel <Anup.Patel@wdc.com>,
	"linux-kernel@vger.kernel.org List"
	<linux-kernel@vger.kernel.org>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Atish Patra <Atish.Patra@wdc.com>, Zong Li <zong.li@sifive.com>,
	sudeep.holla@arm.com, Greentime Hu <greentime.hu@sifive.com>,
	linux-riscv <linux-riscv@lists.infradead.org>
Subject: Re: [PATCH 1/4] RISC-V: Setup exception vector early
Date: Fri, 24 Jul 2020 22:26:10 -0700
Message-ID: <CAOnJCUL7=i3XXMDJ5vgnNo==3zOANxGEe3ufznAhn7LE7vVAZQ@mail.gmail.com> (raw)
In-Reply-To: <mhng-8ce8d920-4b65-432c-8b51-8d81f55936c0@palmerdabbelt-glaptop1>

On Fri, Jul 24, 2020 at 10:12 PM Palmer Dabbelt <palmer@dabbelt.com> wrote:
>
> On Wed, 15 Jul 2020 16:30:06 PDT (-0700), Atish Patra wrote:
> > The trap vector is set only in trap_init which may be too late in some
> > cases. Early ioremap/efi spits many warning messages which may be useful.
> >
> > Setup the trap vector early so that any warning/bug can be handled before
> > generic code invokes trap_init.
> >
> > Signed-off-by: Atish Patra <atish.patra@wdc.com>
> > ---
> >  arch/riscv/kernel/head.S    | 10 ++++++++--
> >  arch/riscv/kernel/smpboot.c |  1 -
> >  arch/riscv/kernel/traps.c   |  8 +-------
> >  3 files changed, 9 insertions(+), 10 deletions(-)
> >
> > diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
> > index 7ed1b22950fd..d0c5c316e9bb 100644
> > --- a/arch/riscv/kernel/head.S
> > +++ b/arch/riscv/kernel/head.S
> > @@ -77,10 +77,16 @@ relocate:
> >       csrw CSR_SATP, a0
> >  .align 2
> >  1:
> > -     /* Set trap vector to spin forever to help debug */
> > -     la a0, .Lsecondary_park
> > +     /* Set trap vector to exception handler */
> > +     la a0, handle_exception
> >       csrw CSR_TVEC, a0
> >
> > +     /*
> > +      * Set sup0 scratch register to 0, indicating to exception vector that
> > +      * we are presently executing in kernel.
> > +      */
> > +     csrw CSR_SCRATCH, zero
> > +
> >       /* Reload the global pointer */
> >  .option push
> >  .option norelax
> > diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> > index 4e9922790f6e..5a9c127a380e 100644
> > --- a/arch/riscv/kernel/smpboot.c
> > +++ b/arch/riscv/kernel/smpboot.c
> > @@ -154,7 +154,6 @@ asmlinkage __visible void smp_callin(void)
> >       mmgrab(mm);
> >       current->active_mm = mm;
> >
> > -     trap_init();
> >       notify_cpu_starting(smp_processor_id());
> >       update_siblings_masks(smp_processor_id());
> >       set_cpu_online(smp_processor_id(), 1);
> > diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
> > index 7d95cce5e47c..ad14f4466d92 100644
> > --- a/arch/riscv/kernel/traps.c
> > +++ b/arch/riscv/kernel/traps.c
> > @@ -174,13 +174,7 @@ int is_valid_bugaddr(unsigned long pc)
> >  }
> >  #endif /* CONFIG_GENERIC_BUG */
> >
> > +/* stvec & scratch is already set from head.S */
> >  void trap_init(void)
> >  {
> > -     /*
> > -      * Set sup0 scratch register to 0, indicating to exception vector
> > -      * that we are presently executing in the kernel
> > -      */
> > -     csr_write(CSR_SCRATCH, 0);
> > -     /* Set the exception vector address */
> > -     csr_write(CSR_TVEC, &handle_exception);
> >  }
>
> While I think these are all actual fixes, it's pretty late in the cycle here so
> I'm going to a bit on the careful side and only take the patches that actually
> manifest as bugs in the current port.  Assuming this doesn't manifest until
> early_ioremap is enabled (and we don't do that yet), I've put it on for-next.
>

Yeah. early_ioremap is part of the UEFI series. So this can go into for-next.
Thanks.

> LMK if I'm wrong about this, or the following ones.
>
> Thanks!
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv



-- 
Regards,
Atish

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

  reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-15 23:30 [PATCH 0/4] Few mm & exception handling fixes Atish Patra
2020-07-15 23:30 ` [PATCH 1/4] RISC-V: Setup exception vector early Atish Patra
2020-07-25  5:12   ` Palmer Dabbelt
2020-07-25  5:26     ` Atish Patra [this message]
2020-07-15 23:30 ` [PATCH 2/4] RISC-V: Set maximum number of mapped pages correctly Atish Patra
2020-07-25  5:12   ` Palmer Dabbelt
2020-07-15 23:30 ` [PATCH 3/4] RISC-V: Do not rely on initrd_start/end computed during early dt parsing Atish Patra
2020-07-25  5:12   ` Palmer Dabbelt
2020-07-25  5:44     ` Atish Patra
2020-07-15 23:30 ` [PATCH 4/4] riscv: Parse all memory blocks to remove unusable memory Atish Patra
2020-07-25  5:12   ` Palmer Dabbelt

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAOnJCUL7=i3XXMDJ5vgnNo==3zOANxGEe3ufznAhn7LE7vVAZQ@mail.gmail.com' \
    --to=atishp@atishpatra.org \
    --cc=Anup.Patel@wdc.com \
    --cc=Atish.Patra@wdc.com \
    --cc=aou@eecs.berkeley.edu \
    --cc=greentime.hu@sifive.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=palmer@dabbelt.com \
    --cc=paul.walmsley@sifive.com \
    --cc=sudeep.holla@arm.com \
    --cc=vincent.chen@sifive.com \
    --cc=zong.li@sifive.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-RISC-V Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-riscv/0 linux-riscv/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-riscv linux-riscv/ https://lore.kernel.org/linux-riscv \
		linux-riscv@lists.infradead.org
	public-inbox-index linux-riscv

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.infradead.lists.linux-riscv


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git