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From: Heiko Carstens <hca@linux.ibm.com>
To: 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>,
	Mark Rutland <mark.rutland@arm.com>,
	Juergen Christ <jchrist@linux.ibm.com>,
	Ilya Leoshkevich <iii@linux.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org
Subject: [PATCH 00/12] s390: More this_cpu_*() changes
Date: Thu, 17 Sep 2026 21:22:25 +0200	[thread overview]
Message-ID: <20260917192237.638324-1-hca@linux.ibm.com> (raw)

Most of this is only about cleaning up the percpu code after preemptible
this_cpu_*() operations have been implemented. The first ten patches are
all more or less trivial cleanup patches trying to make the code shorter
and more readable.

The only non-trivial patch is the last one, which converts s390's
this_cpu_*() operations to use a similar scheme like Mark Rutland
provided it for arm64 [1]. This allows to simplify the irq entry and exit
path, however at the cost of slightly worse code for this_cpu_*()
operations.

The simplified irq entry and exit code seems to be worth it. Usable
performance numbers are not available yet, however I don't expect big
difference to before.

[1] https://lore.kernel.org/all/20260904161758.376504-1-mark.rutland@arm.com/

Thanks,
Heiko

Heiko Carstens (12):
  s390/percpu: Fix comment typo
  s390/percpu: Add sanity check to GEN_MVIY macro
  s390/lowcore: Remove _AC() from LOWCORE_ALT_ADDRESS
  s390/percpu: Let MVIY_PERCPU() calculate alternative displacement
  s390/percpu/lowcore: Add and use LC_PERCPU lowcore offset defines
  s390/percpu: Rename inline assembly symbolic names
  s390/percpu: Use __PCPU_BEGIN() and __PCPU_END() for inline assemblies
  s390/percpu: Use percpu code section for this_cpu_cmpxchg128()
  s390/percpu: Use percpu code section for this_cpu_xchg()
  s390/percpu: Use percpu code section for this_cpu_cmpxchg()
  s390: Add CC_HAS_ASM_M_FORMAT_FLAG config option
  s390/percpu: Rework to simplify percpu_entry() and percpu_exit()

 arch/s390/Kconfig                    |   6 +
 arch/s390/include/asm/entry-percpu.h |  74 ++----
 arch/s390/include/asm/lowcore.h      |   5 +-
 arch/s390/include/asm/percpu.h       | 381 +++++++++++++++++----------
 arch/s390/include/asm/ptrace.h       |   1 -
 arch/s390/kernel/irq.c               |  10 +-
 arch/s390/kernel/nmi.c               |   4 +-
 arch/s390/kernel/traps.c             |   4 +-
 8 files changed, 279 insertions(+), 206 deletions(-)

-- 
2.53.0


             reply	other threads:[~2026-09-17 19:22 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-17 19:22 Heiko Carstens [this message]
2026-09-17 19:22 ` [PATCH 01/12] s390/percpu: Fix comment typo Heiko Carstens
2026-09-17 19:22 ` [PATCH 02/12] s390/percpu: Add sanity check to GEN_MVIY macro Heiko Carstens
2026-09-17 19:22 ` [PATCH 03/12] s390/lowcore: Remove _AC() from LOWCORE_ALT_ADDRESS Heiko Carstens
2026-09-17 19:22 ` [PATCH 04/12] s390/percpu: Let MVIY_PERCPU() calculate alternative displacement Heiko Carstens
2026-09-17 19:22 ` [PATCH 05/12] s390/percpu/lowcore: Add and use LC_PERCPU lowcore offset defines Heiko Carstens
2026-09-17 19:22 ` [PATCH 06/12] s390/percpu: Rename inline assembly symbolic names Heiko Carstens
2026-09-17 19:22 ` [PATCH 07/12] s390/percpu: Use __PCPU_BEGIN() and __PCPU_END() for inline assemblies Heiko Carstens
2026-09-17 19:22 ` [PATCH 08/12] s390/percpu: Use percpu code section for this_cpu_cmpxchg128() Heiko Carstens
2026-09-17 19:22 ` [PATCH 09/12] s390/percpu: Use percpu code section for this_cpu_xchg() Heiko Carstens
2026-09-17 19:22 ` [PATCH 10/12] s390/percpu: Use percpu code section for this_cpu_cmpxchg() Heiko Carstens
2026-09-17 19:22 ` [PATCH 11/12] s390: Add CC_HAS_ASM_M_FORMAT_FLAG config option Heiko Carstens
2026-09-17 19:22 ` [PATCH 12/12] s390/percpu: Rework to simplify percpu_entry() and percpu_exit() Heiko Carstens

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