From: Heiko Carstens <hca@linux.ibm.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Mete Durlu <meted@linux.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Juergen Christ <jchrist@linux.ibm.com>,
Ilya Leoshkevich <iii@linux.ibm.com>,
linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org
Subject: Re: [PATCH v2 12/12] s390/percpu: Rework to simplify percpu_entry() and percpu_exit()
Date: Fri, 18 Sep 2026 13:02:03 +0200 [thread overview]
Message-ID: <20260918110203.20386F2b-hca@linux.ibm.com> (raw)
In-Reply-To: <aq0VFSS_81QTKjcj@J2N7QTR9R3>
On Fri, Sep 18, 2026 at 11:40:21AM +0100, Mark Rutland wrote:
> On Fri, Sep 18, 2026 at 10:48:42AM +0200, Heiko Carstens wrote:
> > +#define __PCPU_AGRK(regptr, regpcp, regoff) \
> > + " agrk " regptr "," regpcp "," regoff "\n"
> > +
> > +#define __PCPU_BEGIN(lcreg, lcoff, regpcp, regoff, regptr) \
> > + __PCPU_MVIY_REGS(lcreg, regpcp, regoff) \
> > + __PCPU_LG(regoff, lcoff) \
> > + __PCPU_AGRK(regptr, regpcp, regoff)
>
> Since percpu_exit() relies on regptr being regoff + 1, maybe it's worth
> having a check here to verify that? Perhaps in __PCPU_MVIY_REGS() with
> the uniqueness check.
>
> Hopefully that never goes wrong, but catching a violation at build time
> might save some future pain.
Yes, that makes sense. Especially considering that there was already a
previous bug which could have been caught at build time.
Thanks a lot for taking a look!
next prev parent reply other threads:[~2026-09-18 11:02 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-18 8:48 [PATCH v2 00/12] s390: More this_cpu_*() changes Heiko Carstens
2026-09-18 8:48 ` [PATCH v2 01/12] s390/percpu: Fix comment typo Heiko Carstens
2026-09-18 8:48 ` [PATCH v2 02/12] s390/percpu: Add sanity check to GEN_MVIY macro Heiko Carstens
2026-09-18 8:48 ` [PATCH v2 03/12] s390/lowcore: Remove _AC() from LOWCORE_ALT_ADDRESS Heiko Carstens
2026-09-18 8:48 ` [PATCH v2 04/12] s390/percpu: Let MVIY_PERCPU() calculate alternative displacement Heiko Carstens
2026-09-18 8:48 ` [PATCH v2 05/12] s390/percpu/lowcore: Add and use LC_PERCPU lowcore offset defines Heiko Carstens
2026-09-18 8:48 ` [PATCH v2 06/12] s390/percpu: Rename inline assembly symbolic names Heiko Carstens
2026-09-18 8:48 ` [PATCH v2 07/12] s390/percpu: Use __PCPU_BEGIN() and __PCPU_END() for inline assemblies Heiko Carstens
2026-09-18 8:48 ` [PATCH v2 08/12] s390/percpu: Use percpu code section for this_cpu_cmpxchg128() Heiko Carstens
2026-09-18 8:48 ` [PATCH v2 09/12] s390/percpu: Use percpu code section for this_cpu_xchg() Heiko Carstens
2026-09-18 8:48 ` [PATCH v2 10/12] s390/percpu: Use percpu code section for this_cpu_cmpxchg() Heiko Carstens
2026-09-18 8:48 ` [PATCH v2 11/12] s390: Add CC_HAS_ASM_M_FORMAT_FLAG config option Heiko Carstens
2026-09-18 8:48 ` [PATCH v2 12/12] s390/percpu: Rework to simplify percpu_entry() and percpu_exit() Heiko Carstens
2026-09-18 9:53 ` Heiko Carstens
2026-09-18 10:40 ` Mark Rutland
2026-09-18 11:02 ` Heiko Carstens [this message]
2026-09-18 10:31 ` [PATCH v2 00/12] s390: More this_cpu_*() changes Mark Rutland
2026-09-18 10:59 ` Heiko Carstens
2026-09-18 11:24 ` Mark Rutland
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