From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: Pavel Tatashin <pasha.tatashin@soleen.com>,
James Morris <jmorris@namei.org>,
Sasha Levin <sashal@kernel.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
kexec mailing list <kexec@lists.infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
Catalin Marinas <catalin.marinas@arm.com>,
will@kernel.org,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Marc Zyngier <marc.zyngier@arm.com>,
James Morse <james.morse@arm.com>,
Vladimir Murzin <vladimir.murzin@arm.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
Bhupesh Sharma <bhsharma@redhat.com>,
linux-mm <linux-mm@kvack.org>,
Mark Rutland <mark.rutland@arm.com>,
steve.capper@arm.com, rfontana@redhat.com,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v7 00/25] arm64: MMU enabled kexec relocation
Date: Thu, 17 Oct 2019 10:26:33 -0400 [thread overview]
Message-ID: <CA+CK2bC2KwWufE1DWa4szn_hQ1dbjDVHgYUu7=J4O_kvKXTrHg@mail.gmail.com> (raw)
In-Reply-To: <20191016200034.1342308-1-pasha.tatashin@soleen.com>
> https://lore.kernel.org/lkml/45a2f0b8-5bac-8b5d-d595-f92e9acb27ad@arm.com
> > + /* Map relocation function va == pa */
> > + rc = trans_pgd_map_page(&info, trans_ttbr0, __va(kern_reloc),
> > + kern_reloc, PAGE_KERNEL_EXEC);
> > + if (rc)
> > + return rc;
> James wrote:
> You can't do this with the page table helpers. We support platforms
> with no memory in range of TTBR0's VA space. See dd006da21646f
>
> You will need some idmapped memory to turn the MMU off on a system
> that booted at EL1. This will need to be in a set of page tables
> that the helpers can't easily touch - so it should only be a single
> page. (like the arch code's existing idmap - although that may
> have been overwritten).
>
> (I have a machine where this is a problem, if I get the time I will
> have a stab at making hibernate's safe page idmaped).
> ---
>
> As I understand, there are platforms where TTBR0 cannot include all
> physical memory for idmap. However, kexec must have at least one page
> idmapped (kimage->control_code_page) to be able to relocate kernel
> while MMU is enabled:
>
> I am still trying to fully understand the problem:
> CONFIG_ARM64_VA_BITS must be smaller than 48 and physical memory must
> start at a high address for this problem to occur.
>
> Why can't we simply decrease T0SZ to cover all physical memory?
Is there a way to reproduce this platform with qemu?
Pasha
prev parent reply other threads:[~2019-10-17 14:26 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-16 20:00 Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 01/25] kexec: quiet down kexec reboot Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 02/25] kexec: add machine_kexec_post_load() Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 03/25] arm64: kexec: remove unnecessary debug prints Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 04/25] arm64: kexec: make dtb_mem always enabled Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 05/25] arm64: hibernate: pass the allocated pgdp to ttbr0 Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 06/25] arm64: hibernate: use get_safe_page directly Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 07/25] arm64: hibernate: remove gotos as they are not needed Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 08/25] arm64: hibernate: rename dst to page in create_safe_exec_page Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 09/25] arm64: hibernate: add PUD_SECT_RDONLY Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 10/25] arm64: hibernate: add trans_pgd public functions Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 11/25] arm64: hibernate: move page handling function to new trans_pgd.c Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 12/25] arm64: trans_pgd: make trans_pgd_map_page generic Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 13/25] arm64: trans_pgd: pass allocator trans_pgd_create_copy Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 14/25] arm64: trans_pgd: pass NULL instead of init_mm to *_populate functions Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 15/25] arm64: kexec: move relocation function setup Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 16/25] arm64: kexec: call kexec_image_info only once Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 17/25] arm64: kexec: cpu_soft_restart change argument types Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 18/25] arm64: kexec: arm64_relocate_new_kernel clean-ups Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 19/25] arm64: kexec: arm64_relocate_new_kernel don't use x0 as temp Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 20/25] arm64: kexec: add expandable argument to relocation function Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 21/25] arm64: kexec: offset for " Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 22/25] arm64: kexec: kexec EL2 vectors Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 23/25] arm64: kexec: configure trans_pgd page table for kexec Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 24/25] arm64: kexec: enable MMU during kexec relocation Pavel Tatashin
2019-10-16 20:00 ` [PATCH v7 25/25] arm64: kexec: remove head from relocation argument Pavel Tatashin
2019-10-17 14:26 ` Pavel Tatashin [this message]
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