From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Arnd Bergmann <arnd@kernel.org>
Cc: v.narang@samsung.com, a.sahrawat@samsung.com,
Andrew Morton <akpm@linux-foundation.org>,
Marc Zyngier <maz@kernel.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Vincent Whitchurch <vincent.whitchurch@axis.com>,
Nick Desaulniers <ndesaulniers@google.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Valentin Schneider <valentin.schneider@arm.com>,
Dmitry Safonov <0x7f454c46@gmail.com>,
Maninder Singh <maninder1.s@samsung.com>,
Thomas Gleixner <tglx@linutronix.de>,
Nathan Huckleberry <nhuck@google.com>,
Will Deacon <will@kernel.org>, Jian Cai <caij2003@gmail.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 2/3] arm: introduce IRQ stacks
Date: Wed, 21 Oct 2020 13:45:42 +0100 [thread overview]
Message-ID: <20201021124542.GL1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <CAK8P3a3eZjBVSuhv=Cx4aYC+E9tex+BbJH1b6YyMMief-mO7kQ@mail.gmail.com>
On Wed, Oct 21, 2020 at 02:42:48PM +0200, Arnd Bergmann wrote:
> (also resending this reply from @kernel.org)
>
> On Fri, Oct 16, 2020 at 12:19 PM Arnd Bergmann <arnd@arndb.de> wrote:
> > On Thu, Oct 8, 2020 at 9:20 AM Maninder Singh <maninder1.s@samsung.com> wrote:
> > >
> > > This patch adds code for switching to IRQ stack.
> > > IRQ stack and Kernel SVC stack have below design.
> > >
> > > IRQ STACK:-
> > > ------------ IRQ stack top
> > > | |
> > > ------------
> > > . .
> > > . .
> > > . .
> > > ------------
> > > | sp | <- irq_stack_base + 0x8
> > > ------------
> > > | fp | <- irq_stack_base + 0x4
> > > ------------
> > > |tinfo_ptr | /* pointer to thread info */
> > > irq_stack_ptr --> ------------ IRQ stack base
> > >
> > > Kernel SVC stack:-
> > > ------------ Kernel stack top
> > > | |
> > > ------------
> > > . .
> > > . .
> > > . .
> > > ------------
> > > | |
> > > | |
> > > ------------
> > > |tinfo_ptr | /* pointer to thread info */
> > > ------------ Kernel stack base
> >
> > The extra indirection doesn't look great, and I don't see any of the
> > other architectures need that. Since we can access percpu data
> > without going through thread_info, maybe doing the same as
> > x86 would work here:
> >
> > - define 'current' as 'this_cpu_read_stable(current_task);'
> > - convert to CONFIG_THREAD_INFO_IN_TASK
That means we need to also code that up in assembly - remember, we
need to access thread_info from assembly code.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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next prev parent reply other threads:[~2020-10-21 12:47 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20201008071628epcas5p24d196a6023a47a3b0bfa7b7f231ec811@epcas5p2.samsung.com>
2020-10-08 7:15 ` [PATCH 0/3] IRQ stack support for ARM Maninder Singh
[not found] ` <CGME20201008071633epcas5p20f5c533ac67ab235997e7e4a8ad3022b@epcas5p2.samsung.com>
2020-10-08 7:15 ` [PATCH 1/3] arm: introduce self pointer in thread info Maninder Singh
[not found] ` <CGME20201008071639epcas5p465f13d992a25936ba63436baf1fb6f83@epcas5p4.samsung.com>
2020-10-08 7:15 ` [PATCH 2/3] arm: introduce IRQ stacks Maninder Singh
[not found] ` <CAK8P3a2RYeNiTy9QmwFVKtFifXxWc9XfAT6ThPoSH9wGYsKGpA@mail.gmail.com>
2020-10-21 12:42 ` Arnd Bergmann
2020-10-21 12:45 ` Russell King - ARM Linux admin [this message]
2020-10-21 12:55 ` Arnd Bergmann
2020-10-21 12:57 ` Russell King - ARM Linux admin
2020-10-21 15:59 ` Arnd Bergmann
2020-11-09 14:45 ` Tony Lindgren
2020-11-09 19:10 ` Arnd Bergmann
2020-11-10 9:19 ` Tony Lindgren
2020-11-10 10:04 ` Arnd Bergmann
2020-11-10 12:04 ` Tony Lindgren
2020-11-10 13:35 ` Arnd Bergmann
2020-11-11 6:56 ` Tony Lindgren
[not found] ` <CGME20201008071639epcas5p465f13d992a25936ba63436baf1fb6f83@epcms5p7>
2020-10-21 13:46 ` Vaneet Narang
[not found] ` <CGME20201008071644epcas5p1f5c220b5f58fd4251695af147325b7c4@epcas5p1.samsung.com>
2020-10-08 7:15 ` [PATCH 3/3] arm: Modify stack trace and dump for use with irq stack Maninder Singh
2020-10-08 7:53 ` [PATCH 0/3] IRQ stack support for ARM Sebastian Andrzej Siewior
2020-10-08 8:30 ` Russell King - ARM Linux admin
2020-10-15 20:59 ` Nick Desaulniers
2020-10-15 21:16 ` Florian Fainelli
[not found] ` <CAK8P3a0h=D8_Kn_fpHbsik_jf4to2jayxj7K7B7=HaNFzKqNnw@mail.gmail.com>
2020-10-21 11:58 ` Arnd Bergmann
2020-10-21 12:34 ` Russell King - ARM Linux admin
2020-10-21 12:46 ` Arnd Bergmann
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