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From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: pasha.tatashin@soleen.com, jmorris@namei.org, sashal@kernel.org,
	ebiederm@xmission.com, kexec@lists.infradead.org,
	linux-kernel@vger.kernel.org, corbet@lwn.net,
	catalin.marinas@arm.com, will@kernel.org,
	linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: [RFC v1 0/4] arm64: MMU enabled kexec kernel relocation
Date: Tue, 16 Jul 2019 12:56:37 -0400
Message-ID: <20190716165641.6990-1-pasha.tatashin@soleen.com> (raw)

Added identity mapped page table, and keep MMU enabled while
kernel is being relocated from sparse pages to the final
destination during kexec.

More description about the problem I am trying to solve here, can be
found here:
https://lore.kernel.org/lkml/20190709182014.16052-1-pasha.tatashin@soleen.com/

This patch series works in terms, that I can kexec-reboot both in QEMU
and on a physical machine. However, I do not see performance improvement
during relocation. The performance is just as slow as before with disabled
caches.

Am I missing something? Perhaps, there is some flag that I should also
enable in page table? Please provide me with any suggestions.

Pavel Tatashin (4):
  arm64, mm: identity mapped page table
  arm64, kexec: interface preparation for mmu enabled kexec
  arm64, kexec: add kexec's own identity page table
  arm64: Keep MMU on while kernel is being relocated

 arch/arm64/include/asm/ident_map.h  |  26 ++++++
 arch/arm64/include/asm/kexec.h      |   5 +-
 arch/arm64/kernel/cpu-reset.S       |   8 --
 arch/arm64/kernel/cpu-reset.h       |   7 +-
 arch/arm64/kernel/machine_kexec.c   | 128 +++++++++++++++++++++-------
 arch/arm64/kernel/relocate_kernel.S |  36 +++++---
 arch/arm64/mm/Makefile              |   1 +
 arch/arm64/mm/ident_map.c           |  99 +++++++++++++++++++++
 8 files changed, 255 insertions(+), 55 deletions(-)
 create mode 100644 arch/arm64/include/asm/ident_map.h
 create mode 100644 arch/arm64/mm/ident_map.c

-- 
2.22.0


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Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-16 16:56 Pavel Tatashin [this message]
2019-07-16 16:56 ` [RFC v1 1/4] arm64, mm: identity mapped page table Pavel Tatashin
2019-07-16 16:56 ` [RFC v1 2/4] arm64, kexec: interface preparation for mmu enabled kexec Pavel Tatashin
2019-07-16 16:56 ` [RFC v1 3/4] arm64, kexec: add kexec's own identity page table Pavel Tatashin
2019-07-16 16:56 ` [RFC v1 4/4] arm64: Keep MMU on while kernel is being relocated Pavel Tatashin
2019-07-16 19:14 ` [RFC v1 0/4] arm64: MMU enabled kexec kernel relocation Bhupesh Sharma
2019-07-16 19:26   ` Pavel Tatashin
2019-07-17 17:51 ` James Morse
2019-07-17 19:13   ` Pavel Tatashin
2019-07-26 14:00     ` James Morse

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