Re: [PATCH v9 05/21] ARM64 / ACPI: Get RSDP and ACPI boot-time tables

[Hanjun Guo]

On 2015å03æ10æ 19:19, Leif Lindholm wrote:
> On Tue, Mar 10, 2015 at 04:01:16PM +0800, Hanjun Guo wrote:
> > > > index 0000000..f052e7a
> > > > --- /dev/null
> > > > +++ b/arch/arm64/kernel/acpi.c
> > > > @@ -0,0 +1,101 @@
> > > > +/*
> > > > + *  ARM64 Specific Low-Level ACPI Boot Support
> > > > + *
> > > > + *  Copyright (C) 2013-2014, Linaro Ltd.
> > > > + *	Author: Al Stone <al.stone@xxxxxxxxxx>
> > > > + *	Author: Graeme Gregory <graeme.gregory@xxxxxxxxxx>
> > > > + *	Author: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> > > > + *	Author: Tomasz Nowicki <tomasz.nowicki@xxxxxxxxxx>
> > > > + *	Author: Naresh Bhat <naresh.bhat@xxxxxxxxxx>
> > > > + *
> > > > + *  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.
> > > > + */
> > > > +
> > > > +#define pr_fmt(fmt) "ACPI: " fmt
> > > > +
> > > > +#include <linux/acpi.h>
> > > > +#include <linux/bootmem.h>
> > > > +#include <linux/cpumask.h>
> > > > +#include <linux/init.h>
> > > > +#include <linux/irq.h>
> > > > +#include <linux/irqdomain.h>
> > > > +#include <linux/memblock.h>
> > > > +#include <linux/smp.h>
> > > > +
> > > > +int acpi_noirq;			/* skip ACPI IRQ initialization */
> > > > +int acpi_disabled;
> > > > +EXPORT_SYMBOL(acpi_disabled);
> > > > +
> > > > +int acpi_pci_disabled;		/* skip ACPI PCI scan and IRQ initialization */
> > > > +EXPORT_SYMBOL(acpi_pci_disabled);
> > > > +
> > > > +/*
> > > > + * __acpi_map_table() will be called before page_init(), so early_ioremap()
> > > > + * or early_memremap() should be called here to for ACPI table mapping.
> > > > + */
> > > > +char *__init __acpi_map_table(unsigned long phys, unsigned long size)
> > > > +{
> > > > +	if (!phys || !size)
> > >
> > > Is there a reason to rule out physical address 0x0 ?
> >
> > No particular reasons, unless some arch/firmware limits, I'm
> > not sure if we need this check (x86 needs it), I'm CC Leif
> > to confirm.
>
> Nothing in UEFI explicitly bans using physical address 0 for anything,
> and nothing in the architecture reserves it. So I don't think this
> check is necessary.

Thanks for the confirmation, will remove the !phys check.

Hanjun
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