From: Nam Cao <namcao@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Sebastian Andrzej Siewior" <bigeasy@linutronix.de>,
"Clément Léger" <cleger@rivosinc.com>,
"Maciej W. Rozycki" <macro@orcam.me.uk>,
"Palmer Dabbelt" <palmer@dabbelt.com>,
"Paul Walmsley" <paul.walmsley@sifive.com>,
aou@eecs.berkeley.edu, "Alexandre Ghiti" <alex@ghiti.fr>,
clrkwllms@kernel.org, rostedt@goodmis.org,
linux-rt-devel@lists.linux.dev, linux-riscv@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] riscv: Enable interrupt during exception handling
Date: Tue, 24 Jun 2025 17:33:14 +0200 [thread overview]
Message-ID: <20250624153314.2Mwvvjmy@linutronix.de> (raw)
In-Reply-To: <20250624143458.GW1613200@noisy.programming.kicks-ass.net>
On Tue, Jun 24, 2025 at 04:34:58PM +0200, Peter Zijlstra wrote:
> On Tue, Jun 24, 2025 at 04:23:50PM +0200, Sebastian Andrzej Siewior wrote:
> > On 2025-06-24 16:18:01 [+0200], Peter Zijlstra wrote:
> > > I'm confused, sending signals is for exception from userspace. That has
> > > nothing to do with exceptions from kernelspace being NMI like.
> >
> > Yes. See the original submission
> > https://lore.kernel.org/linux-riscv/20250620114346.1740512-1-namcao@linutronix.de/
>
> I'm still confused, that code is trying to enable IRQs in the
> from-kernel part. That's insane.
>
> Can some Risc-V person explain why a from-kernel exception would ever
> result in a signal?!?!
Exceptions from kernel do not raise signals. Enabling irqs there is not
necessary, I can remove that part.
But for my curiousity, do you mind elaborating why it is insane to enable
irqs in from-kernel exception handling?
For "NMI-like" exceptions, (I think) I get it, the context would be messed
up. But what about the others, e.g. kernel page faults?
Best regards,
Nam
next prev parent reply other threads:[~2025-06-24 15:33 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-20 11:43 Nam Cao
2025-06-23 22:17 ` Palmer Dabbelt
2025-06-24 2:09 ` Maciej W. Rozycki
2025-06-24 11:37 ` Clément Léger
2025-06-24 13:17 ` Nam Cao
2025-06-24 13:48 ` Clément Léger
2025-06-24 14:08 ` Peter Zijlstra
2025-06-24 14:11 ` Sebastian Andrzej Siewior
2025-06-24 14:18 ` Peter Zijlstra
2025-06-24 14:23 ` Sebastian Andrzej Siewior
2025-06-24 14:34 ` Peter Zijlstra
2025-06-24 15:33 ` Nam Cao [this message]
2025-06-24 18:51 ` Peter Zijlstra
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