linux-kernel - Re: [PATCH 2/5] alpha: Modify the definition logic of WEAK_PER

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250612112215.10868Da1-hca@linux.ibm.com>
Date: Thu, 12 Jun 2025 13:22:15 +0200
From: Heiko Carstens <hca@...ux.ibm.com>
To: Hao Ge <hao.ge@...ux.dev>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
        David Hildenbrand <david@...hat.com>,
        Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
        "Liam R. Howlett" <Liam.Howlett@...cle.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Mike Rapoport <rppt@...nel.org>,
        Richard Henderson <richard.henderson@...aro.org>,
        Matt Turner <mattst88@...il.com>, Dennis Zhou <dennis@...nel.org>,
        Tejun Heo <tj@...nel.org>, Christoph Lameter <cl@...ux.com>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Alexander Gordeev <agordeev@...ux.ibm.com>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Sven Schnelle <svens@...ux.ibm.com>,
        Kent Overstreet <kent.overstreet@...ux.dev>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, linux-alpha@...r.kernel.org,
        linux-s390@...r.kernel.org, Hao Ge <gehao@...inos.cn>
Subject: Re: [PATCH 2/5] alpha: Modify the definition logic of WEAK_PER_CPU

On Thu, Jun 12, 2025 at 04:27:27PM +0800, Hao Ge wrote:
> From: Hao Ge <gehao@...inos.cn>
> 
> As stated in the first patch of this patch series,
> we make ARCH_NEEDS_WEAK_PER_CPU a Kconfig option,
> and replace all instances of ARCH_NEEDS_WEAK_PER_CPU
> in the kernel code with MODULE_NEEDS_WEAK_PER_CPU,
> gated by #ifdef CONFIG_ARCH_NEEDS_WEAK_PER_CPU.
> 
> We'll make corresponding changes for the alpha
> architecture.
> 
> Suggested-by: Suren Baghdasaryan <surenb@...gle.com>
> Signed-off-by: Hao Ge <gehao@...inos.cn>
> ---
>  arch/alpha/Kconfig              | 1 +
>  arch/alpha/include/asm/percpu.h | 4 ++--
>  2 files changed, 3 insertions(+), 2 deletions(-)

...

> +	select ARCH_NEEDS_WEAK_PER_CPU
>  	select ARCH_NO_PREEMPT
>  	select ARCH_NO_SG_CHAIN
>  	select ARCH_USE_CMPXCHG_LOCKREF
> diff --git a/arch/alpha/include/asm/percpu.h b/arch/alpha/include/asm/percpu.h
> index 6923249f2d49..5d8b75ec3bf2 100644
> --- a/arch/alpha/include/asm/percpu.h
> +++ b/arch/alpha/include/asm/percpu.h
> @@ -10,8 +10,8 @@
>   *
>   * Always use weak definitions for percpu variables in modules.
>   */
> -#if defined(MODULE) && defined(CONFIG_SMP)
> -#define ARCH_NEEDS_WEAK_PER_CPU
> +#if defined(MODULE) && defined(CONFIG_SMP) && defined(CONFIG_ARCH_NEEDS_WEAK_PER_CPU)
> +#define MODULE_NEEDS_WEAK_PER_CPU

CONFIG_ARCH_NEEDS_WEAK_PER_CPU is always set with the above select.
So there is no point in adding this to the check.

Furthermore this removes ARCH_NEEDS_WEAK_PER_CPU and defines
MODULE_NEEDS_WEAK_PER_CPU while the common code conversion happens
only with patch 4. Or in other words: if patches are split like this
things break.

Same is true for patch 3. Just merging patches 2-4 would be the
easiest solution to this problem.