From: Guo Ren <ren_guo@c-sky.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
tglx@linutronix.de, daniel.lezcano@linaro.org,
jason@lakedaemon.net, arnd@arndb.de,
c-sky_gcc_upstream@c-sky.com, gnu-csky@mentor.com,
thomas.petazzoni@bootlin.com, wbx@uclibc-ng.org,
green.hu@gmail.com
Subject: Re: [PATCH V2 16/19] csky: SMP support
Date: Fri, 6 Jul 2018 19:32:01 +0800 [thread overview]
Message-ID: <20180706113200.GA27148@guoren> (raw)
In-Reply-To: <20180706052432.q74gql32dtj5gj3b@salmiak>
On Fri, Jul 06, 2018 at 06:24:33AM +0100, Mark Rutland wrote:
> > + if (cpu >= NR_CPUS)
> > + goto error;
> > +
> > + if (of_property_read_string(node, "status", &status))
> > + status = "enable";
> > +
> > + if (strcmp(status, "disable") == 0)
> > + goto error;
>
> Please use of_device_is_available(node);
Ok.
> "enable" is not a sensible value for
> the status property, and "disable" (rather than "disabled") is simply unusual.
>
> Neither "enable" nor "disable" are correct values for the status property.
cpus {
#address-cells = <1>;
#size-cells = <0>;
cpu@0 {
device_type = "cpu";
reg = <0>;
status = "on";
};
cpu@1 {
device_type = "cpu";
reg = <1>;
status = "off";
};
};
> What is the value in the reg property, exactly?
See above, I'll remove the reg property and it's no use.
> Is there a unique ID in
> hardware for each CPU in the system?
There is no unique ID in current CPU: ck860.
>
> It would be good to document this, e.g. as arm does in
> Documentation/devicetree/bindings/arm/cpus.txt
Ok.
> > +
> > + return cpu;
> > +error:
> > + return -ENODEV;
> > +}
> > +
> > +void __init setup_smp(void)
> > +{
> > + struct device_node *node = NULL;
> > + int cpu;
> > +
> > + while ((node = of_find_node_by_type(node, "cpu"))) {
> > + cpu = csky_of_cpu(node);
> > + if (cpu >= 0) {
> > + set_cpu_possible(cpu, true);
> > + set_cpu_present(cpu, true);
> > + }
> > + }
> > +}
>
> What happens if/when the value in the reg property is larger than NR_CPUS?
Bug. I'll add NR_CPUS limit.
> > +int __cpu_up(unsigned int cpu, struct task_struct *tidle)
> > +{
> > + unsigned int tmp;
> > +
> > + secondary_stack = (unsigned int)tidle->stack + THREAD_SIZE;
> > +
> > + secondary_hint = mfcr("cr31");
> > +
> > + secondary_ccr = mfcr("cr18");
> > +
> > + pr_info("%s: CPU%u\n", __func__, cpu);
> > +
> > + tmp = mfcr("cr<29, 0>");
> > + tmp |= 1 << cpu;
> > + mtcr("cr<29, 0>", tmp);
> > +
> > + while (!cpu_online(cpu));
> > +
> > + secondary_stack = 0;
> > +
> > + return 0;
> > +}
>
> I don't see a start address being setup here, so I assume that CPUs branch to a
> fixed address out-of-reset. Does that mean that the kernel has to be loaded at
> a particular physical address on a given platform?
No, not a fixed address. I put it arch/csky/kernel/traps.c:79-83
trap_init()
#ifdef CONFIG_SMP
mtcr("cr<28, 0>", virt_to_phys(vec_base));
VEC_INIT(VEC_RESET, (void *)virt_to_phys(_start_smp_secondary));
#endi
Guo Ren
next prev parent reply other threads:[~2018-07-06 11:32 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-01 17:30 [PATCH V2 00/19] C-SKY(csky) Linux Kernel Port Guo Ren
2018-07-01 17:30 ` [PATCH V2 01/19] csky: Build infrastructure Guo Ren
2018-07-01 21:01 ` Randy Dunlap
2018-07-02 1:13 ` Guo Ren
2018-07-03 3:33 ` Rob Herring
2018-07-03 9:14 ` Guo Ren
2018-07-03 16:03 ` Arnd Bergmann
2018-07-04 11:40 ` Guo Ren
2018-07-01 17:30 ` [PATCH V2 02/19] csky: defconfig Guo Ren
2018-07-03 3:16 ` Rob Herring
2018-07-03 8:31 ` Guo Ren
2018-07-01 17:30 ` [PATCH V2 03/19] csky: Kernel booting Guo Ren
2018-07-01 17:30 ` [PATCH V2 04/19] csky: Exception handling Guo Ren
2018-07-01 17:30 ` [PATCH V2 05/19] csky: System Call Guo Ren
2018-07-03 19:53 ` Arnd Bergmann
2018-07-04 11:49 ` Guo Ren
2018-07-04 21:04 ` Arnd Bergmann
2018-07-05 5:38 ` Guo Ren
2018-07-01 17:30 ` [PATCH V2 06/19] csky: Cache and TLB routines Guo Ren
2018-07-05 17:40 ` Peter Zijlstra
2018-07-07 11:51 ` Guo Ren
2018-07-01 17:30 ` [PATCH V2 07/19] csky: MMU and page table management Guo Ren
2018-07-02 13:29 ` Christoph Hellwig
2018-07-03 2:53 ` Guo Ren
2018-07-01 17:30 ` [PATCH V2 08/19] csky: Process management and Signal Guo Ren
2018-07-01 17:30 ` [PATCH V2 09/19] csky: VDSO and rt_sigreturn Guo Ren
2018-07-01 17:30 ` [PATCH V2 10/19] csky: IRQ handling Guo Ren
2018-07-01 17:30 ` [PATCH V2 11/19] csky: Atomic operations Guo Ren
2018-07-05 17:50 ` Peter Zijlstra
2018-07-06 11:01 ` Guo Ren
2018-07-06 11:56 ` Peter Zijlstra
2018-07-06 12:17 ` Peter Zijlstra
2018-07-07 8:08 ` Guo Ren
2018-07-07 20:10 ` Andrea Parri
2018-07-08 1:05 ` Guo Ren
2018-07-07 7:42 ` Guo Ren
2018-07-07 19:54 ` Andrea Parri
2018-07-08 0:39 ` Guo Ren
2018-07-05 17:59 ` Peter Zijlstra
2018-07-06 11:44 ` Guo Ren
2018-07-06 12:03 ` Peter Zijlstra
2018-07-06 13:01 ` Peter Zijlstra
2018-07-06 14:06 ` Guo Ren
2018-07-05 18:00 ` Peter Zijlstra
2018-07-06 11:48 ` Guo Ren
2018-07-06 12:05 ` Peter Zijlstra
2018-07-06 13:46 ` Guo Ren
2018-07-01 17:30 ` [PATCH V2 12/19] csky: ELF and module probe Guo Ren
2018-07-01 17:30 ` [PATCH V2 13/19] csky: Library functions Guo Ren
2018-07-03 20:04 ` Arnd Bergmann
2018-07-04 10:51 ` Guo Ren
2018-07-01 17:30 ` [PATCH V2 14/19] csky: User access Guo Ren
2018-07-01 17:30 ` [PATCH V2 15/19] csky: Debug and Ptrace GDB Guo Ren
2018-07-01 17:30 ` [PATCH V2 16/19] csky: SMP support Guo Ren
2018-07-05 18:05 ` Peter Zijlstra
2018-07-06 6:07 ` Guo Ren
2018-07-06 9:39 ` Peter Zijlstra
2018-07-06 13:22 ` Guo Ren
2018-07-06 5:24 ` Mark Rutland
2018-07-06 11:32 ` Guo Ren [this message]
2018-07-06 11:43 ` Mark Rutland
2018-07-06 12:26 ` Guo Ren
2018-07-06 16:21 ` Mark Rutland
2018-07-07 6:16 ` Guo Ren
2018-07-01 17:30 ` [PATCH V2 17/19] csky: Misc headers Guo Ren
2018-07-01 17:30 ` [PATCH V2 18/19] clocksource: add C-SKY clocksource drivers Guo Ren
2018-07-01 17:34 ` Guo Ren
2018-07-03 9:39 ` Thomas Gleixner
2018-07-04 10:49 ` Guo Ren
2018-07-04 14:35 ` Thomas Gleixner
2018-07-05 5:03 ` Guo Ren
2018-07-04 17:05 ` Daniel Lezcano
2018-07-05 3:30 ` Guo Ren
2018-07-05 9:23 ` Daniel Lezcano
2018-07-06 5:57 ` Guo Ren
2018-07-01 17:30 ` [PATCH V2 19/19] irqchip: add C-SKY irqchip drivers Guo Ren
2018-07-03 3:27 ` Rob Herring
2018-07-03 7:38 ` Guo Ren
2018-07-03 9:28 ` Thomas Gleixner
2018-07-04 5:08 ` Guo Ren
2018-07-04 6:43 ` Thomas Gleixner
2018-07-04 11:58 ` Guo Ren
2018-07-11 9:51 ` [PATCH V2 00/19] C-SKY(csky) Linux Kernel Port David Howells
2018-07-12 12:51 ` Guo Ren
2018-07-12 16:04 ` Sandra Loosemore
2018-07-13 1:30 ` Guo Ren
2018-07-13 10:23 ` David Howells
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180706113200.GA27148@guoren \
--to=ren_guo@c-sky.com \
--cc=arnd@arndb.de \
--cc=c-sky_gcc_upstream@c-sky.com \
--cc=daniel.lezcano@linaro.org \
--cc=gnu-csky@mentor.com \
--cc=green.hu@gmail.com \
--cc=jason@lakedaemon.net \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=tglx@linutronix.de \
--cc=thomas.petazzoni@bootlin.com \
--cc=wbx@uclibc-ng.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).