From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: James Morse <james.morse@arm.com>
Cc: 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 Deacon <will@kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Marc Zyngier <maz@kernel.org>,
Vladimir Murzin <vladimir.murzin@arm.com>,
Matthias Brugger <matthias.bgg@gmail.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>,
Selin Dag <selindag@gmail.com>
Subject: Re: [PATCH v9 08/18] arm64: kexec: move relocation function setup
Date: Fri, 22 Jan 2021 20:01:21 -0500 [thread overview]
Message-ID: <CA+CK2bAsC-ZBPh-CPhmdjdwtLshHcPOsnEu_NzJ38pvPh0YPPQ@mail.gmail.com> (raw)
In-Reply-To: <ea2b39d7-d496-d9ac-23c9-c279ec29f5d5@arm.com>
On Wed, Apr 29, 2020 at 1:01 PM James Morse <james.morse@arm.com> wrote:
>
> Hi Pavel,
>
> On 26/03/2020 03:24, Pavel Tatashin wrote:
> > Currently, kernel relocation function is configured in machine_kexec()
> > at the time of kexec reboot by using control_code_page.
> >
> > This operation, however, is more logical to be done during kexec_load,
> > and thus remove from reboot time. Move, setup of this function to
> > newly added machine_kexec_post_load().
>
> This would avoid the need to special-case the cache maintenance, so its a good cleanup...
Yes, the computation should be moved from kexec-reboot to kexec-load
when possible.
>
>
> > Because once MMU is enabled, kexec control page will contain more than
> > relocation kernel, but also vector table, add pointer to the actual
> > function within this page arch.kern_reloc. Currently, it equals to the
> > beginning of page, we will add offsets later, when vector table is
> > added.
>
> If the vector table always comes second, wouldn't this be extra work to hold the value 0?
> You can control the layout of this relocation code, as it has to be written in assembly.
> I don't get why this would be necessary.
>
>
> > diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
> > index ae1bad0156cd..ec71a153cc2d 100644
> > --- a/arch/arm64/kernel/machine_kexec.c
> > +++ b/arch/arm64/kernel/machine_kexec.c
> > @@ -58,6 +59,17 @@ void machine_kexec_cleanup(struct kimage *kimage)
> > /* Empty routine needed to avoid build errors. */
> > }
> >
> > +int machine_kexec_post_load(struct kimage *kimage)
> > +{
> > + void *reloc_code = page_to_virt(kimage->control_code_page);
> > +
> > + memcpy(reloc_code, arm64_relocate_new_kernel,
> > + arm64_relocate_new_kernel_size);
> > + kimage->arch.kern_reloc = __pa(reloc_code);
>
> Could we move the two cache maintenance calls for this area in here too. Keeping it next
> to the modification makes it clearer why it is required.
Yes, I moved it.
>
> In this case we can use flush_icache_range() instead of its __variant because this now
> happens much earlier.
True.
>
>
> > + return 0;
> > +}
>
> Regardless,
> Reviewed-by: James Morse <james.morse@arm.com>
Thank you for your review.
Pasha
>
>
> Thanks,
>
> James
next prev parent reply other threads:[~2021-01-23 1:03 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-26 3:24 [PATCH v9 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
2020-03-26 3:24 ` [PATCH v9 01/18] arm64: kexec: make dtb_mem always enabled Pavel Tatashin
2020-04-29 17:00 ` James Morse
2021-01-23 0:17 ` Pavel Tatashin
2020-03-26 3:24 ` [PATCH v9 02/18] arm64: hibernate: move page handling function to new trans_pgd.c Pavel Tatashin
2020-04-29 17:00 ` James Morse
2021-01-23 0:18 ` Pavel Tatashin
2020-03-26 3:24 ` [PATCH v9 03/18] arm64: trans_pgd: make trans_pgd_map_page generic Pavel Tatashin
2020-04-29 17:01 ` James Morse
2021-01-22 21:52 ` Pavel Tatashin
2020-03-26 3:24 ` [PATCH v9 04/18] arm64: trans_pgd: pass allocator trans_pgd_create_copy Pavel Tatashin
2020-04-29 17:01 ` James Morse
2021-01-23 0:20 ` Pavel Tatashin
2020-03-26 3:24 ` [PATCH v9 05/18] arm64: trans_pgd: pass NULL instead of init_mm to *_populate functions Pavel Tatashin
2020-04-29 17:01 ` James Morse
2021-01-23 0:22 ` Pavel Tatashin
2020-03-26 3:24 ` [PATCH v9 06/18] arm64: mm: Always update TCR_EL1 from __cpu_set_tcr_t0sz() Pavel Tatashin
2020-03-26 3:24 ` [PATCH v9 07/18] arm64: trans_pgd: hibernate: idmap the single page that holds the copy page routines Pavel Tatashin
2020-04-29 17:01 ` James Morse
2021-01-23 0:35 ` Pavel Tatashin
2020-03-26 3:24 ` [PATCH v9 08/18] arm64: kexec: move relocation function setup Pavel Tatashin
2020-04-29 17:01 ` James Morse
2021-01-23 1:01 ` Pavel Tatashin [this message]
2020-03-26 3:24 ` [PATCH v9 09/18] arm64: kexec: call kexec_image_info only once Pavel Tatashin
2020-04-29 17:01 ` James Morse
2020-03-26 3:24 ` [PATCH v9 10/18] arm64: kexec: cpu_soft_restart change argument types Pavel Tatashin
2020-04-29 17:01 ` James Morse
2021-01-23 1:14 ` Pavel Tatashin
2020-03-26 3:24 ` [PATCH v9 11/18] arm64: kexec: arm64_relocate_new_kernel clean-ups Pavel Tatashin
2020-05-07 16:22 ` James Morse
2020-03-26 3:24 ` [PATCH v9 12/18] arm64: kexec: arm64_relocate_new_kernel don't use x0 as temp Pavel Tatashin
2020-05-07 16:22 ` James Morse
2020-03-26 3:24 ` [PATCH v9 13/18] arm64: kexec: add expandable argument to relocation function Pavel Tatashin
2020-05-07 16:22 ` James Morse
2021-01-23 2:49 ` Pavel Tatashin
2020-03-26 3:24 ` [PATCH v9 14/18] arm64: kexec: offset for " Pavel Tatashin
2020-05-07 16:22 ` James Morse
2020-03-26 3:24 ` [PATCH v9 15/18] arm64: kexec: kexec EL2 vectors Pavel Tatashin
2020-04-29 17:35 ` Marc Zyngier
2021-01-25 19:07 ` Pavel Tatashin
2020-05-07 16:21 ` James Morse
2020-03-26 3:24 ` [PATCH v9 16/18] arm64: kexec: configure trans_pgd page table for kexec Pavel Tatashin
2020-05-07 16:22 ` James Morse
2020-03-26 3:24 ` [PATCH v9 17/18] arm64: kexec: enable MMU during kexec relocation Pavel Tatashin
2020-03-26 3:24 ` [PATCH v9 18/18] arm64: kexec: remove head from relocation argument Pavel Tatashin
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