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From: Paul Sherman <shermanpauldylan@gmail.com>
To: Paul Walmsley <pjw@kernel.org>
Cc: palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr,
	hchauhan@ventanamicro.com, apatel@ventanamicro.com,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] riscv: sbi: fix errno mapping for SBI_ERR_ALREADY_* error codes
Date: Wed, 29 Jul 2026 17:01:25 -0700	[thread overview]
Message-ID: <amqUVf8KLUivRUMW@got-milk> (raw)
In-Reply-To: <8760a4fc-fde1-85be-174d-dc6dc6012265@kernel.org>

Hi,

On Wed, Jul 29, 2026 at 12:43:30PM -0600, Paul Walmsley wrote:

> It looks like -EALREADY is defined as "connection already in progress," 
> which doesn't quite map to the meaning of these errors, here.
> 
> https://en.cppreference.com/cpp/error/errno_macros

You're right that the POSIX description is networking-specific. My
reasoning was that it was the closest existing errno expressing "the
requested operation was unnecessary because the target was already in
the requested state." If you think another errno is a better fit I'm
happy to respin with that mapping.

> Does this patch fix anything or change any behavior?

Yes, concretely. Today SBI_ERR_ALREADY_STARTED falls through to
-ENOTSUPP, so callers cannot distinguish "already running" from an
unsupported SBI implementation. The companion patch updates
cpu_ops_sbi.c to recognize the translated errno and treat the
"already started" response as success, which fixes the boot-hart
bringup path on many-hart multi-node platforms like SG2042 where
firmware releases all harts simultaneously before SBI HSM state
is established.

> I don't think the comment is a good idea; it creates one more artifact 
> that can get out of sync with the code.  We'd just expect people to read 
> the code, I think.

Agreed, dropping it in v2.

Thanks,
Paul

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http://lists.infradead.org/mailman/listinfo/linux-riscv

WARNING: multiple messages have this Message-ID (diff)
From: Paul Sherman <shermanpauldylan@gmail.com>
To: Paul Walmsley <pjw@kernel.org>
Cc: palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr,
	hchauhan@ventanamicro.com, apatel@ventanamicro.com,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] riscv: sbi: fix errno mapping for SBI_ERR_ALREADY_* error codes
Date: Wed, 29 Jul 2026 17:01:25 -0700	[thread overview]
Message-ID: <amqUVf8KLUivRUMW@got-milk> (raw)
In-Reply-To: <8760a4fc-fde1-85be-174d-dc6dc6012265@kernel.org>

Hi,

On Wed, Jul 29, 2026 at 12:43:30PM -0600, Paul Walmsley wrote:

> It looks like -EALREADY is defined as "connection already in progress," 
> which doesn't quite map to the meaning of these errors, here.
> 
> https://en.cppreference.com/cpp/error/errno_macros

You're right that the POSIX description is networking-specific. My
reasoning was that it was the closest existing errno expressing "the
requested operation was unnecessary because the target was already in
the requested state." If you think another errno is a better fit I'm
happy to respin with that mapping.

> Does this patch fix anything or change any behavior?

Yes, concretely. Today SBI_ERR_ALREADY_STARTED falls through to
-ENOTSUPP, so callers cannot distinguish "already running" from an
unsupported SBI implementation. The companion patch updates
cpu_ops_sbi.c to recognize the translated errno and treat the
"already started" response as success, which fixes the boot-hart
bringup path on many-hart multi-node platforms like SG2042 where
firmware releases all harts simultaneously before SBI HSM state
is established.

> I don't think the comment is a good idea; it creates one more artifact 
> that can get out of sync with the code.  We'd just expect people to read 
> the code, I think.

Agreed, dropping it in v2.

Thanks,
Paul

  reply	other threads:[~2026-07-30  0:01 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-27 22:15 [PATCH] riscv: sbi: fix errno mapping for SBI_ERR_ALREADY_* error codes Paul Sherman
2026-07-27 22:15 ` Paul Sherman
2026-07-29 18:43 ` Paul Walmsley
2026-07-29 18:43   ` Paul Walmsley
2026-07-30  0:01   ` Paul Sherman [this message]
2026-07-30  0:01     ` Paul Sherman

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