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From: "Arnd Bergmann" <arnd@arndb.de>
To: "Tiwei Bie" <tiwei.bie@linux.dev>,
	"Richard Weinberger" <richard@nod.at>,
	"Anton Ivanov" <anton.ivanov@cambridgegreys.com>,
	"Johannes Berg" <johannes@sipsolutions.net>
Cc: linux-um@lists.infradead.org, linux-kernel@vger.kernel.org,
	benjamin@sipsolutions.net, "Tiwei Bie" <tiwei.btw@antgroup.com>,
	Linux-Arch <linux-arch@vger.kernel.org>
Subject: Re: [PATCH v3 6/7] asm-generic: percpu: Add assembly guard
Date: Mon, 15 Sep 2025 09:40:35 +0200	[thread overview]
Message-ID: <a10395f7-6666-4bdb-9aa0-bdd873029cc9@app.fastmail.com> (raw)
In-Reply-To: <20250914155658.1028790-7-tiwei.bie@linux.dev>

On Sun, Sep 14, 2025, at 17:56, Tiwei Bie wrote:
> From: Tiwei Bie <tiwei.btw@antgroup.com>
>
> Currently, asm/percpu.h is directly or indirectly included by
> some assembly files on x86. Some of them (e.g., checksum_32.S)
> are also used on um. But x86 and um provide different versions
> of asm/percpu.h -- um uses asm-generic/percpu.h directly.
>
> When SMP is enabled, asm-generic/percpu.h will introduce C code
> that cannot be assembled. Since asm-generic/percpu.h currently
> is not designed for use in assembly, and these assembly files
> do not actually need asm/percpu.h on um, let's add the assembly
> guard in asm-generic/percpu.h to fix this issue.
>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: linux-arch@vger.kernel.org
> Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>

Have you tried if you can remove the percpu.h dependency from
the files that currently include it? In many cases it should
be enough to use percpu-defs.h.

If that doesn't work, I have no objections to this patch either.

Acked-by: Arnd Bergmann <arnd@arndb.de>


  reply	other threads:[~2025-09-15  7:41 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-14 15:56 [PATCH v3 0/7] um: Add SMP support Tiwei Bie
2025-09-14 15:56 ` [PATCH v3 1/7] um: Turn signals_* into thread-local variables Tiwei Bie
2025-09-14 15:56 ` [PATCH v3 2/7] um: Determine sleep based on need_resched() Tiwei Bie
2025-09-14 15:56 ` [PATCH v3 3/7] um: Define timers on a per-CPU basis Tiwei Bie
2025-09-14 15:56 ` [PATCH v3 4/7] um: Add initial SMP support Tiwei Bie
2025-09-14 15:56 ` [PATCH v3 5/7] um: vdso: Remove getcpu support on x86 Tiwei Bie
2025-09-14 15:56 ` [PATCH v3 6/7] asm-generic: percpu: Add assembly guard Tiwei Bie
2025-09-15  7:40   ` Arnd Bergmann [this message]
2025-09-15 15:29     ` Tiwei Bie
2025-09-14 15:56 ` [PATCH v3 7/7] um: Enable SMP support on x86 Tiwei Bie

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