Re: [Xen-devel] [PATCH v4 05/21] arm/acpi: Add basic ACPI initialization

[Shannon Zhao <zhaoshenglong@xxxxxxxxxx>]

On 2016/1/27 22:54, Stefano Stabellini wrote:
> On Sat, 23 Jan 2016, Shannon Zhao wrote:
>> > From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>> > 
>> > acpi_boot_table_init() will be called in start_xen to get the RSDP and
>> > all the table pointers. With this patch, we can get ACPI boot-time
>> > tables from firmware on ARM64.
>> > 
>> > Signed-off-by: Naresh Bhat <naresh.bhat@xxxxxxxxxx>
>> > Signed-off-by: Parth Dixit <parth.dixit@xxxxxxxxxx>
>> > Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>> > ---
>> >  xen/arch/arm/acpi/Makefile |  1 +
>> >  xen/arch/arm/acpi/boot.c   | 58 
>> > ++++++++++++++++++++++++++++++++++++++++++++++
>> >  xen/arch/arm/setup.c       |  4 ++++
>> >  3 files changed, 63 insertions(+)
>> >  create mode 100644 xen/arch/arm/acpi/boot.c
>> > 
>> > diff --git a/xen/arch/arm/acpi/Makefile b/xen/arch/arm/acpi/Makefile
>> > index b5be22d..196c40a 100644
>> > --- a/xen/arch/arm/acpi/Makefile
>> > +++ b/xen/arch/arm/acpi/Makefile
>> > @@ -1 +1,2 @@
>> >  obj-y += lib.o
>> > +obj-y += boot.o
>> > diff --git a/xen/arch/arm/acpi/boot.c b/xen/arch/arm/acpi/boot.c
>> > new file mode 100644
>> > index 0000000..1570f7e
>> > --- /dev/null
>> > +++ b/xen/arch/arm/acpi/boot.c
>> > @@ -0,0 +1,58 @@
>> > +/*
>> > + *  ARM Specific Low-Level ACPI Boot Support
>> > + *
>> > + *  Copyright (C) 2001, 2002 Paul Diefenbaugh 
>> > <paul.s.diefenbaugh@xxxxxxxxx>
>> > + *  Copyright (C) 2001 Jun Nakajima <jun.nakajima@xxxxxxxxx>
>> > + *  Copyright (C) 2014, Naresh Bhat <naresh.bhat@xxxxxxxxxx>
>> > + *  Copyright (C) 2015, Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>> > + *
>> > + * 
>> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> > + *
>> > + *  This program is free software; you can redistribute it and/or modify
>> > + *  it under the terms of the GNU General Public License as published by
>> > + *  the Free Software Foundation; either version 2 of the License, or
>> > + *  (at your option) any later version.
>> > + *
>> > + *  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.
>> > + *
>> > + *  You should have received a copy of the GNU General Public License
>> > + *  along with this program; if not, write to the Free Software
>> > + *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  
>> > USA
>> > + *
>> > + * 
>> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> > + */
>> > +
>> > +#include <xen/init.h>
>> > +#include <xen/acpi.h>
>> > +
>> > +#include <asm/acpi.h>
>> > +
>> > +/*
>> > + * acpi_boot_table_init() called from setup_arch(), always.
>> > + *      1. find RSDP and get its address, and then find XSDT
>> > + *      2. extract all tables and checksums them all
>> > + *
>> > + * return value: (currently ignored)
>> > + *        0: success
>> > + *        !0: failure
>> > + *
>> > + * We can parse ACPI boot-time tables such as FADT, MADT after
>> > + * this function is called.
>> > + */
>> > +int __init acpi_boot_table_init(void)
>> > +{
>> > +    int error;
>> > +
>> > +    /* Initialize the ACPI boot-time table parser. */
>> > +    error = acpi_table_init();
>> > +    if ( error )
>> > +    {
>> > +        disable_acpi();
>> > +        return error;
>> > +    }
>> > +
>> > +    return 0;
>> > +}
>> > diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
>> > index 0ba601e..c15a09d 100644
>> > --- a/xen/arch/arm/setup.c
>> > +++ b/xen/arch/arm/setup.c
>> > @@ -36,6 +36,7 @@
>> >  #include <xen/pfn.h>
>> >  #include <xen/vmap.h>
>> >  #include <xen/libfdt/libfdt.h>
>> > +#include <xen/acpi.h>
>> >  #include <asm/page.h>
>> >  #include <asm/current.h>
>> >  #include <asm/setup.h>
>> > @@ -749,6 +750,9 @@ void __init start_xen(unsigned long boot_phys_offset,
>> >  
>> >      setup_mm(fdt_paddr, fdt_size);
>> >  
>> > +    /* Parse the ACPI tables for possible boot-time configuration */
>> > +    acpi_boot_table_init();
> As I asked before, why do you need to call acpi_boot_table_init() before
> vm_init?  If you called acpi_boot_table_init() after vm_init(), you
> could implement __acpi_map_table with vmap, which would be better.
> 
Yes, if we call acpi_boot_table_init() before vm_init, it needs to move
end_boot_allocator after acpi_boot_table_init because it will assert in
acpi_os_zalloc_memory.
TBH, I'm not sure where acpi_boot_table_init should be called. The
current way refers to x86.

Thanks,
-- 
Shannon


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