Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20210914121036.3975026-1-ardb@kernel.org> <20210914121036.3975026-2-ardb@kernel.org>
 <CAHk-=whkCzP-wyZ08r9RDJRx9cbANVHy-jy=vJAGTkSbXm50iA@mail.gmail.com>
In-Reply-To: <CAHk-=whkCzP-wyZ08r9RDJRx9cbANVHy-jy=vJAGTkSbXm50iA@mail.gmail.com>
From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Tue, 14 Sep 2021 17:42:40 +0200
Message-ID: <CAMj1kXHK74XKWWs4C9zckOZsJP4cD+=B8gMx8QoohYVN61CJ-g@mail.gmail.com>
Subject: Re: [RFC PATCH 1/8] arm64: add CPU field to struct thread_info
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Keith Packard <keithpac@amazon.com>,
        Russell King <linux@armlinux.org.uk>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Paul Mackerras <paulus@samba.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Kees Cook <keescook@chromium.org>,
        Andy Lutomirski <luto@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        linux-riscv <linux-riscv@lists.infradead.org>,
        linux-s390 <linux-s390@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Tue, 14 Sept 2021 at 17:41, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> On Tue, Sep 14, 2021 at 5:10 AM Ard Biesheuvel <ardb@kernel.org> wrote:
> >
> > The CPU field will be moved back into thread_info even when
> > THREAD_INFO_IN_TASK is enabled, so add it back to arm64's definition of
> > struct thread_info.
>
> The series looks sane to me, but it strikes me that it's inconsistent
> - here for arm64, you make it unconditional, but for the other
> architectures you end up putting it inside a #ifdef CONFIG_SMP.
>
> Was there some reason for this odd behavior?
>

Yes. CONFIG_SMP is a 'def_bool y' on arm64.