linux-kernel - Re: [PATCH v4 1/2] arm: introduce psci_smp

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20130402110255.GA26949@mudshark.cambridge.arm.com>
Date:	Tue, 2 Apr 2013 12:02:55 +0100
From:	Will Deacon <will.deacon@....com>
To:	Stefano Stabellini <stefano.stabellini@...citrix.com>
Cc:	"xen-devel@...ts.xensource.com" <xen-devel@...ts.xensource.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"arnd@...db.de" <arnd@...db.de>,
	Marc Zyngier <Marc.Zyngier@....com>,
	"linux@....linux.org.uk" <linux@....linux.org.uk>,
	"nico@...aro.org" <nico@...aro.org>
Subject: Re: [PATCH v4 1/2] arm: introduce psci_smp_ops

Hi Stefano,

On Fri, Mar 29, 2013 at 04:42:49PM +0000, Stefano Stabellini wrote:
> Rename virt_smp_ops to psci_smp_ops and move them to arch/arm/kernel/psci_smp.c.
> Remove mach-virt/platsmp.c, now unused.
> Compile psci_smp if CONFIG_ARM_PSCI and CONFIG_SMP.
> 
> Add a cpu_die smp_op based on psci_ops.cpu_off.
> 
> Initialize PSCI before setting smp_ops in setup_arch.
> Use psci_smp_ops if the platform doesn't provide its own smp_ops.
> 
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@...citrix.com>
> CC: will.deacon@....com
> CC: arnd@...db.de
> CC: marc.zyngier@....com
> CC: linux@....linux.org.uk
> CC: nico@...aro.org
> ---
>  arch/arm/include/asm/psci.h  |    9 +++++
>  arch/arm/kernel/Makefile     |    5 ++-
>  arch/arm/kernel/psci.c       |    3 +-
>  arch/arm/kernel/psci_smp.c   |   67 ++++++++++++++++++++++++++++++++++++++++++
>  arch/arm/kernel/setup.c      |    7 ++++-
>  arch/arm/mach-virt/Makefile  |    1 -
>  arch/arm/mach-virt/platsmp.c |   58 ------------------------------------
>  arch/arm/mach-virt/virt.c    |    3 --
>  8 files changed, 87 insertions(+), 66 deletions(-)
>  create mode 100644 arch/arm/kernel/psci_smp.c
>  delete mode 100644 arch/arm/mach-virt/platsmp.c
> 
> diff --git a/arch/arm/include/asm/psci.h b/arch/arm/include/asm/psci.h
> index ce0dbe7..4134dda 100644
> --- a/arch/arm/include/asm/psci.h
> +++ b/arch/arm/include/asm/psci.h
> @@ -32,5 +32,14 @@ struct psci_operations {
>  };
>  
>  extern struct psci_operations psci_ops;
> +extern struct smp_operations psci_smp_ops;
>  
> +#ifdef CONFIG_ARM_PSCI
> +int psci_init(void);
> +bool psci_smp_available(void);
> +#else
> +static inline int psci_init(void) { return -ENODEV; }
> +static inline bool psci_smp_available(void) { return false; }

You can probably make psci_init return void now that it's no longer an
initcall (you're not checking it's return value anyway).

> diff --git a/arch/arm/kernel/psci_smp.c b/arch/arm/kernel/psci_smp.c
> new file mode 100644
> index 0000000..66b0f77
> --- /dev/null
> +++ b/arch/arm/kernel/psci_smp.c
> @@ -0,0 +1,67 @@
> +/*
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * Copyright (C) 2012 ARM Limited
> + *
> + * Author: Will Deacon <will.deacon@....com>
> + */
> +
> +#include <linux/init.h>
> +#include <linux/irqchip/arm-gic.h>
> +#include <linux/smp.h>
> +#include <linux/of.h>
> +
> +#include <asm/psci.h>
> +#include <asm/smp_plat.h>
> +
> +extern void secondary_startup(void);
> +
> +static int __cpuinit psci_boot_secondary(unsigned int cpu,
> +					 struct task_struct *idle)
> +{
> +	if (psci_ops.cpu_on)
> +		return psci_ops.cpu_on(cpu_logical_map(cpu),
> +				       __pa(secondary_startup));
> +	return -ENODEV;
> +}

Since this code is now likely to be shared, it could be worth a comment
before each function to describe the expected semantics (e.g. mpidr is used
as the CPUID, additional power state information is zero).

Cheers,

Will
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/