From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Arnd Bergmann <arnd@arndb.de>
Cc: afzal mohammed <afzal.mohd.ma@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: ARM: static kernel in vmalloc space
Date: Fri, 15 May 2020 00:40:14 +0100 [thread overview]
Message-ID: <20200514234013.GQ1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <CAK8P3a2KR+O5Ua5hsNgzLQV5-V1pat6JH_WM10Es-oUhXO2OgA@mail.gmail.com>
On Thu, May 14, 2020 at 11:12:01PM +0200, Arnd Bergmann wrote:
> On Thu, May 14, 2020 at 6:25 PM Russell King - ARM Linux admin
> <linux@armlinux.org.uk> wrote:
> > On Thu, May 14, 2020 at 02:41:11PM +0200, Arnd Bergmann wrote:
> > > On Thu, May 14, 2020 at 1:18 PM afzal mohammed <afzal.mohd.ma@gmail.com> wrote:
>
> > > It's clearly possible to do something very similar for older chips
> > > (v6 or v7 without LPAE, possibly even v5), it just gets harder
> > > while providing less benefit.
> >
> > Forget about doing this for anything without a PIPT cache - or you're
> > going to end up having to flush the data cache each time you enter or
> > exit the kernel.
>
> Right, let's forget I said anything about v5 or earlier ;-)
>
> I expected the non-aliasing VIPT caches to work the same as PIPT, can
> you clarify if there is something to be aware of for those? I see that some
> ARMv8 chips and most ARMv6 chips (not OMAP2 and Realview) are
> of that kind, and at we clearly don't want to break running on ARMv8 at
> least.
There are some aliasing VIPT implementations on ARMv6, but I don't
remember how common.
> Anyway my point was that it's best to only do it for LPAE anyway, everything
> else being a distraction, as the only non-LPAE SoCs I could find with
> support for over 2GB are some of the higher-end i.MX6 versions and the
> original highbank.
Yep.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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WARNING: multiple messages have this Message-ID (diff)
From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Arnd Bergmann <arnd@arndb.de>
Cc: afzal mohammed <afzal.mohd.ma@gmail.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: ARM: static kernel in vmalloc space
Date: Fri, 15 May 2020 00:40:14 +0100 [thread overview]
Message-ID: <20200514234013.GQ1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <CAK8P3a2KR+O5Ua5hsNgzLQV5-V1pat6JH_WM10Es-oUhXO2OgA@mail.gmail.com>
On Thu, May 14, 2020 at 11:12:01PM +0200, Arnd Bergmann wrote:
> On Thu, May 14, 2020 at 6:25 PM Russell King - ARM Linux admin
> <linux@armlinux.org.uk> wrote:
> > On Thu, May 14, 2020 at 02:41:11PM +0200, Arnd Bergmann wrote:
> > > On Thu, May 14, 2020 at 1:18 PM afzal mohammed <afzal.mohd.ma@gmail.com> wrote:
>
> > > It's clearly possible to do something very similar for older chips
> > > (v6 or v7 without LPAE, possibly even v5), it just gets harder
> > > while providing less benefit.
> >
> > Forget about doing this for anything without a PIPT cache - or you're
> > going to end up having to flush the data cache each time you enter or
> > exit the kernel.
>
> Right, let's forget I said anything about v5 or earlier ;-)
>
> I expected the non-aliasing VIPT caches to work the same as PIPT, can
> you clarify if there is something to be aware of for those? I see that some
> ARMv8 chips and most ARMv6 chips (not OMAP2 and Realview) are
> of that kind, and at we clearly don't want to break running on ARMv8 at
> least.
There are some aliasing VIPT implementations on ARMv6, but I don't
remember how common.
> Anyway my point was that it's best to only do it for LPAE anyway, everything
> else being a distraction, as the only non-LPAE SoCs I could find with
> support for over 2GB are some of the higher-end i.MX6 versions and the
> original highbank.
Yep.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 10.2Mbps down 587kbps up
next prev parent reply other threads:[~2020-05-14 23:40 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-31 9:32 [PATCH 0/3] Highmem support for 32-bit RISC-V Eric Lin
2020-03-31 9:32 ` Eric Lin
2020-03-31 9:32 ` [PATCH 1/3] riscv/mm: Add pkmap region and CONFIG_HIGHMEM Eric Lin
2020-03-31 9:32 ` Eric Lin
2020-03-31 9:32 ` [PATCH 2/3] riscv/mm: Implement kmap() and kmap_atomic() Eric Lin
2020-03-31 9:32 ` Eric Lin
2020-03-31 9:32 ` [PATCH 3/3] riscv/mm: Add pkmap in print_vm_layout() Eric Lin
2020-03-31 9:32 ` Eric Lin
2020-04-02 9:31 ` [PATCH 0/3] Highmem support for 32-bit RISC-V Arnd Bergmann
2020-04-02 9:31 ` Arnd Bergmann
2020-04-08 3:51 ` Alan Kao
2020-04-08 3:51 ` Alan Kao
2020-04-08 14:40 ` Arnd Bergmann
2020-04-08 14:40 ` Arnd Bergmann
2020-04-14 15:17 ` afzal mohammed
2020-04-14 15:17 ` afzal mohammed
2020-04-14 19:29 ` Arnd Bergmann
2020-04-14 19:29 ` Arnd Bergmann
2020-04-15 13:54 ` afzal mohammed
2020-04-15 13:54 ` afzal mohammed
2020-05-03 14:50 ` afzal mohammed
2020-05-03 14:50 ` afzal mohammed
2020-05-03 20:20 ` Arnd Bergmann
2020-05-03 20:20 ` Arnd Bergmann
2020-05-04 9:10 ` afzal mohammed
2020-05-04 9:10 ` afzal mohammed
2020-05-04 9:10 ` afzal mohammed
2020-05-04 11:27 ` Arnd Bergmann
2020-05-04 11:27 ` Arnd Bergmann
2020-05-04 11:27 ` Arnd Bergmann
2020-05-11 14:21 ` ARM: static kernel in vmalloc space (was Re: [PATCH 0/3] Highmem support for 32-bit RISC-V) afzal mohammed
2020-05-11 14:21 ` afzal mohammed
2020-05-11 15:29 ` Arnd Bergmann
2020-05-11 15:29 ` Arnd Bergmann
2020-05-12 10:47 ` ARM: static kernel in vmalloc space afzal mohammed
2020-05-12 10:47 ` afzal mohammed
2020-05-12 19:49 ` Arnd Bergmann
2020-05-12 19:49 ` Arnd Bergmann
2020-05-14 11:17 ` afzal mohammed
2020-05-14 11:17 ` afzal mohammed
2020-05-14 12:41 ` Arnd Bergmann
2020-05-14 12:41 ` Arnd Bergmann
2020-05-14 13:35 ` afzal mohammed
2020-05-14 13:35 ` afzal mohammed
2020-05-14 14:44 ` afzal mohammed
2020-05-14 14:44 ` afzal mohammed
2020-05-14 15:32 ` Arnd Bergmann
2020-05-14 15:32 ` Arnd Bergmann
2020-05-16 6:06 ` afzal mohammed
2020-05-16 6:06 ` afzal mohammed
2020-05-16 7:35 ` Arnd Bergmann
2020-05-16 7:35 ` Arnd Bergmann
2020-06-07 12:59 ` ARM: vmsplit 4g/4g afzal mohammed
2020-06-07 16:11 ` Russell King - ARM Linux admin
2020-06-07 16:11 ` Russell King - ARM Linux admin
2020-06-08 11:09 ` afzal mohammed
2020-06-08 11:09 ` afzal mohammed
2020-06-10 10:10 ` Linus Walleij
2020-06-10 10:10 ` Linus Walleij
2020-06-12 10:25 ` afzal mohammed
2020-06-12 10:25 ` afzal mohammed
2020-06-15 9:11 ` Linus Walleij
2020-06-15 9:11 ` Linus Walleij
2020-06-15 10:01 ` afzal mohammed
2020-06-15 10:01 ` afzal mohammed
2020-06-07 19:26 ` Arnd Bergmann
2020-06-07 19:26 ` Arnd Bergmann
2020-06-08 11:18 ` afzal mohammed
2020-06-08 11:18 ` afzal mohammed
2020-06-08 14:43 ` Arnd Bergmann
2020-06-08 14:43 ` Arnd Bergmann
2020-06-08 15:17 ` afzal mohammed
2020-06-08 15:17 ` afzal mohammed
2020-06-09 12:15 ` afzal mohammed
2020-06-09 12:15 ` afzal mohammed
2020-06-09 14:22 ` Arnd Bergmann
2020-06-09 14:22 ` Arnd Bergmann
2020-05-14 16:25 ` ARM: static kernel in vmalloc space Russell King - ARM Linux admin
2020-05-14 16:25 ` Russell King - ARM Linux admin
2020-05-14 21:12 ` Arnd Bergmann
2020-05-14 21:12 ` Arnd Bergmann
2020-05-14 23:40 ` Russell King - ARM Linux admin [this message]
2020-05-14 23:40 ` Russell King - ARM Linux admin
2020-05-15 15:41 ` Arnd Bergmann
2020-05-15 15:41 ` Arnd Bergmann
2020-07-30 9:33 ` Linus Walleij
2020-07-30 9:33 ` Linus Walleij
2020-07-30 10:17 ` Arnd Bergmann
2020-07-30 10:17 ` Arnd Bergmann
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