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

Commit Message

Hanjun Guo Feb. 25, 2015, 8:39 a.m. UTC

From: Al Stone <[e-mail]>

As we want to get ACPI tables to parse and then use the information
for system initialization, we should get the RSDP (Root System
Description Pointer) first, it then locates Extended Root Description
Table (XSDT) which contains all the 64-bit physical address that
pointer to other boot-time tables.

Introduce acpi.c and its related head file in this patch to provide
fundamental needs of extern variables and functions for ACPI core,
and then get boot-time tables as needed.
  - asm/acenv.h for arch specific ACPICA environments and
    implementation, It is needed unconditionally by ACPI core;
  - asm/acpi.h for arch specific variables and functions needed by
    ACPI driver core;
  - acpi.c for ARM64 related ACPI implementation for ACPI driver
    core;

acpi_boot_table_init() is introduced to get RSDP and boot-time tables,
it will be called in setup_arch() before paging_init(), so we should
use eary_memremap() mechanism here to get the RSDP and all the table
pointers.

FADT Major.Minor version was introduced in ACPI 5.1, it is the same
as ACPI version.

In ACPI 5.1, some major gaps are fixed for ARM, such as updates in
MADT table for GIC and SMP init, without those updates, we can not
get the MPIDR for SMP init, and GICv2/3 related init information, so
we can't boot arm64 ACPI properly with table versions predating 5.1.

If firmware provides ACPI tables with ACPI version less than 5.1,
OS has no way to retrieve the configuration data that is necessary
to init SMP boot protocol and the GIC properly, so disable ACPI if
we get an FADT table with version less that 5.1 when acpi_boot_table_init()
called.

CC: Catalin Marinas <[e-mail]>
CC: Will Deacon <[e-mail]>
CC: Lorenzo Pieralisi <[e-mail]>
Tested-by: Suravee Suthikulpanit <[e-mail]>
Tested-by: Yijing Wang <[e-mail]>
Tested-by: Mark Langsdorf <[e-mail]>
Tested-by: Jon Masters <[e-mail]>
Tested-by: Timur Tabi <[e-mail]>
Tested-by: Robert Richter <[e-mail]>
Acked-by: Robert Richter <[e-mail]>
Signed-off-by: Al Stone <[e-mail]>
Signed-off-by: Graeme Gregory <[e-mail]>
Signed-off-by: Tomasz Nowicki <[e-mail]>
Signed-off-by: Hanjun Guo <[e-mail]>
---
 arch/arm64/include/asm/acenv.h |  18 ++++++++
 arch/arm64/include/asm/acpi.h  |  45 ++++++++++++++++++
 arch/arm64/kernel/Makefile     |   1 +
 arch/arm64/kernel/acpi.c       | 101 +++++++++++++++++++++++++++++++++++++++++
 arch/arm64/kernel/setup.c      |   5 ++
 5 files changed, 170 insertions(+)
 create mode 100644 arch/arm64/include/asm/acenv.h
 create mode 100644 arch/arm64/include/asm/acpi.h
 create mode 100644 arch/arm64/kernel/acpi.c

Comments

Olof Johansson March 5, 2015, 6:10 p.m. UTC | #1

On Wed, Feb 25, 2015 at 04:39:45PM +0800, Hanjun Guo wrote:
> From: Al Stone <[e-mail]>
> 
> As we want to get ACPI tables to parse and then use the information
> for system initialization, we should get the RSDP (Root System
> Description Pointer) first, it then locates Extended Root Description
> Table (XSDT) which contains all the 64-bit physical address that
> pointer to other boot-time tables.
> 
> Introduce acpi.c and its related head file in this patch to provide
> fundamental needs of extern variables and functions for ACPI core,
> and then get boot-time tables as needed.
>   - asm/acenv.h for arch specific ACPICA environments and
>     implementation, It is needed unconditionally by ACPI core;
>   - asm/acpi.h for arch specific variables and functions needed by
>     ACPI driver core;
>   - acpi.c for ARM64 related ACPI implementation for ACPI driver
>     core;
> 
> acpi_boot_table_init() is introduced to get RSDP and boot-time tables,
> it will be called in setup_arch() before paging_init(), so we should
> use eary_memremap() mechanism here to get the RSDP and all the table
> pointers.
> 
> FADT Major.Minor version was introduced in ACPI 5.1, it is the same
> as ACPI version.
> 
> In ACPI 5.1, some major gaps are fixed for ARM, such as updates in
> MADT table for GIC and SMP init, without those updates, we can not
> get the MPIDR for SMP init, and GICv2/3 related init information, so
> we can't boot arm64 ACPI properly with table versions predating 5.1.
> 
> If firmware provides ACPI tables with ACPI version less than 5.1,
> OS has no way to retrieve the configuration data that is necessary
> to init SMP boot protocol and the GIC properly, so disable ACPI if
> we get an FADT table with version less that 5.1 when acpi_boot_table_init()
> called.
> 
> CC: Catalin Marinas <[e-mail]>
> CC: Will Deacon <[e-mail]>
> CC: Lorenzo Pieralisi <[e-mail]>
> Tested-by: Suravee Suthikulpanit <[e-mail]>
> Tested-by: Yijing Wang <[e-mail]>
> Tested-by: Mark Langsdorf <[e-mail]>
> Tested-by: Jon Masters <[e-mail]>
> Tested-by: Timur Tabi <[e-mail]>
> Tested-by: Robert Richter <[e-mail]>
> Acked-by: Robert Richter <[e-mail]>
> Signed-off-by: Al Stone <[e-mail]>
> Signed-off-by: Graeme Gregory <[e-mail]>
> Signed-off-by: Tomasz Nowicki <[e-mail]>
> Signed-off-by: Hanjun Guo <[e-mail]>

As long as it goes in together with later patches that adjust what's
enabled by default:

Acked-by: Olof Johansson <[e-mail]>


-Olof

Lorenzo Pieralisi March 5, 2015, 6:51 p.m. UTC | #2

On Wed, Feb 25, 2015 at 08:39:45AM +0000, Hanjun Guo wrote:
> From: Al Stone <[e-mail]>
> 
> As we want to get ACPI tables to parse and then use the information
> for system initialization, we should get the RSDP (Root System
> Description Pointer) first, it then locates Extended Root Description
> Table (XSDT) which contains all the 64-bit physical address that
> pointer to other boot-time tables.
> 
> Introduce acpi.c and its related head file in this patch to provide
> fundamental needs of extern variables and functions for ACPI core,
> and then get boot-time tables as needed.
>   - asm/acenv.h for arch specific ACPICA environments and
>     implementation, It is needed unconditionally by ACPI core;

I am not sure we will ever need it since the global lock is not
needed on HW reduced ACPI (ie ACPI on arm64), and instructions to
flush the caches are not needed either on arm64.

Anyway, I will have a look if it is worth writing optimized div/shift,
to give it a purpose to exist.

[...]

> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
> new file mode 100644
> index 0000000..8b837ab
> --- /dev/null
> +++ b/arch/arm64/include/asm/acpi.h
> @@ -0,0 +1,45 @@
> +/*
> + *  Copyright (C) 2013-2014, Linaro Ltd.
> + *	Author: Al Stone <[e-mail]>
> + *	Author: Graeme Gregory <[e-mail]>
> + *	Author: Hanjun Guo <[e-mail]>
> + *
> + *  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;
> + */
> +
> +#ifndef _ASM_ACPI_H
> +#define _ASM_ACPI_H
> +
> +/* Basic configuration for ACPI */
> +#ifdef	CONFIG_ACPI
> +#define acpi_strict 1	/* No out-of-spec workarounds on ARM64 */
> +extern int acpi_disabled;
> +extern int acpi_noirq;
> +extern int acpi_pci_disabled;
> +
> +static inline void disable_acpi(void)
> +{
> +	acpi_disabled = 1;
> +	acpi_pci_disabled = 1;
> +	acpi_noirq = 1;
> +}
> +
> +/*
> + * It's used from ACPI core in kdump to boot UP system with SMP kernel,
> + * with this check the ACPI core will not override the CPU index
> + * obtained from GICC with 0 and not print some error message as well.
> + * Since MADT must provide at least one GICC structure for GIC
> + * initialization, CPU will be always available in MADT on ARM64.
> + */
> +static inline bool acpi_has_cpu_in_madt(void)
> +{
> +	return true;
> +}

I am still trying to make sense of what's this is used for, to me
it looks like a legacy hack in acpi_processor.c. It is a shame that we need
to define functions to paper over legacy hacks that make no sense
whatsoever on arm64.

> +static inline void arch_fix_phys_package_id(int num, u32 slot) { }

This is only used on ia64 to pass the _SUN value to arch code to fix up
the socket id. See above.

You could define last two functions in generic code, and let the
arch code that needs them override them.

Whether we do it in this series or later, this stuff needs cleaning up.

> +
> +#endif /* CONFIG_ACPI */
> +
> +#endif /*_ASM_ACPI_H*/
> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
> index bef04af..218eb7e 100644
> --- a/arch/arm64/kernel/Makefile
> +++ b/arch/arm64/kernel/Makefile
> @@ -34,6 +34,7 @@ arm64-obj-$(CONFIG_KGDB)		+= kgdb.o
>  arm64-obj-$(CONFIG_EFI)			+= efi.o efi-stub.o efi-entry.o
>  arm64-obj-$(CONFIG_PCI)			+= pci.o
>  arm64-obj-$(CONFIG_ARMV8_DEPRECATED)	+= armv8_deprecated.o
> +arm64-obj-$(CONFIG_ACPI)		+= acpi.o
>  
>  obj-y					+= $(arm64-obj-y) vdso/
>  obj-m					+= $(arm64-obj-m)
> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> new file mode 100644
> 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 <[e-mail]>
> + *	Author: Graeme Gregory <[e-mail]>
> + *	Author: Hanjun Guo <[e-mail]>
> + *	Author: Tomasz Nowicki <[e-mail]>
> + *	Author: Naresh Bhat <[e-mail]>
> + *
> + *  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 ?

Thanks,
Lorenzo

> +		return NULL;
> +
> +	return early_memremap(phys, size);
> +}
> +
> +void __init __acpi_unmap_table(char *map, unsigned long size)
> +{
> +	if (!map || !size)
> +		return;
> +
> +	early_memunmap(map, size);
> +}
> +
> +static int __init acpi_parse_fadt(struct acpi_table_header *table)
> +{
> +	struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table;
> +
> +	/*
> +	 * Revision in table header is the FADT Major revision, and there
> +	 * is a minor revision of FADT which was introduced by ACPI 5.1,
> +	 * we only deal with ACPI 5.1 or newer revision to get GIC and SMP
> +	 * boot protocol configuration data, or we will disable ACPI.
> +	 */
> +	if (table->revision > 5 ||
> +	    (table->revision == 5 && fadt->minor_revision >= 1))
> +		return 0;
> +
> +	pr_warn("Unsupported FADT revision %d.%d, should be 5.1+, will disable ACPI\n",
> +		table->revision, fadt->minor_revision);
> +	disable_acpi();
> +
> +	return -EINVAL;
> +}
> +
> +/*
> + * 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
> + *	3. check ACPI FADT revision
> + *
> + * We can parse ACPI boot-time tables such as MADT after
> + * this function is called.
> + */
> +void __init acpi_boot_table_init(void)
> +{
> +	/* If acpi_disabled, bail out */
> +	if (acpi_disabled)
> +		return;
> +
> +	/* Initialize the ACPI boot-time table parser. */
> +	if (acpi_table_init()) {
> +		disable_acpi();
> +		return;
> +	}
> +
> +	if (acpi_table_parse(ACPI_SIG_FADT, acpi_parse_fadt)) {
> +		/* disable ACPI if no FADT is found */
> +		disable_acpi();
> +		pr_err("Can't find FADT\n");
> +	}
> +}
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index e8420f6..4f1a014 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -17,6 +17,7 @@
>   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>   */
>  
> +#include <linux/acpi.h>
>  #include <linux/export.h>
>  #include <linux/kernel.h>
>  #include <linux/stddef.h>
> @@ -46,6 +47,7 @@
>  #include <linux/efi.h>
>  #include <linux/personality.h>
>  
> +#include <asm/acpi.h>
>  #include <asm/fixmap.h>
>  #include <asm/cpu.h>
>  #include <asm/cputype.h>
> @@ -380,6 +382,9 @@ void __init setup_arch(char **cmdline_p)
>  	efi_init();
>  	arm64_memblock_init();
>  
> +	/* Parse the ACPI tables for possible boot-time configuration */
> +	acpi_boot_table_init();
> +
>  	paging_init();
>  	request_standard_resources();
>  
> -- 
> 1.9.1
> 
>

Grant Likely March 6, 2015, 8:28 p.m. UTC | #3

On Wed, 25 Feb 2015 16:39:45 +0800
, Hanjun Guo <[e-mail]>
 wrote:
> From: Al Stone <[e-mail]>
> 
> As we want to get ACPI tables to parse and then use the information
> for system initialization, we should get the RSDP (Root System
> Description Pointer) first, it then locates Extended Root Description
> Table (XSDT) which contains all the 64-bit physical address that
> pointer to other boot-time tables.
> 
> Introduce acpi.c and its related head file in this patch to provide
> fundamental needs of extern variables and functions for ACPI core,
> and then get boot-time tables as needed.
>   - asm/acenv.h for arch specific ACPICA environments and
>     implementation, It is needed unconditionally by ACPI core;
>   - asm/acpi.h for arch specific variables and functions needed by
>     ACPI driver core;
>   - acpi.c for ARM64 related ACPI implementation for ACPI driver
>     core;
> 
> acpi_boot_table_init() is introduced to get RSDP and boot-time tables,
> it will be called in setup_arch() before paging_init(), so we should
> use eary_memremap() mechanism here to get the RSDP and all the table
> pointers.
> 
> FADT Major.Minor version was introduced in ACPI 5.1, it is the same
> as ACPI version.
> 
> In ACPI 5.1, some major gaps are fixed for ARM, such as updates in
> MADT table for GIC and SMP init, without those updates, we can not
> get the MPIDR for SMP init, and GICv2/3 related init information, so
> we can't boot arm64 ACPI properly with table versions predating 5.1.
> 
> If firmware provides ACPI tables with ACPI version less than 5.1,
> OS has no way to retrieve the configuration data that is necessary
> to init SMP boot protocol and the GIC properly, so disable ACPI if
> we get an FADT table with version less that 5.1 when acpi_boot_table_init()
> called.
> 
> CC: Catalin Marinas <[e-mail]>
> CC: Will Deacon <[e-mail]>
> CC: Lorenzo Pieralisi <[e-mail]>
> Tested-by: Suravee Suthikulpanit <[e-mail]>
> Tested-by: Yijing Wang <[e-mail]>
> Tested-by: Mark Langsdorf <[e-mail]>
> Tested-by: Jon Masters <[e-mail]>
> Tested-by: Timur Tabi <[e-mail]>
> Tested-by: Robert Richter <[e-mail]>
> Acked-by: Robert Richter <[e-mail]>
> Signed-off-by: Al Stone <[e-mail]>
> Signed-off-by: Graeme Gregory <[e-mail]>
> Signed-off-by: Tomasz Nowicki <[e-mail]>
> Signed-off-by: Hanjun Guo <[e-mail]>

Acked-by: Grant Likely <[e-mail]>

> ---
>  arch/arm64/include/asm/acenv.h |  18 ++++++++
>  arch/arm64/include/asm/acpi.h  |  45 ++++++++++++++++++
>  arch/arm64/kernel/Makefile     |   1 +
>  arch/arm64/kernel/acpi.c       | 101 +++++++++++++++++++++++++++++++++++++++++
>  arch/arm64/kernel/setup.c      |   5 ++
>  5 files changed, 170 insertions(+)
>  create mode 100644 arch/arm64/include/asm/acenv.h
>  create mode 100644 arch/arm64/include/asm/acpi.h
>  create mode 100644 arch/arm64/kernel/acpi.c
> 
> diff --git a/arch/arm64/include/asm/acenv.h b/arch/arm64/include/asm/acenv.h
> new file mode 100644
> index 0000000..b49166f
> --- /dev/null
> +++ b/arch/arm64/include/asm/acenv.h
> @@ -0,0 +1,18 @@
> +/*
> + * ARM64 specific ACPICA environments and implementation
> + *
> + * Copyright (C) 2014, Linaro Ltd.
> + *   Author: Hanjun Guo <[e-mail]>
> + *   Author: Graeme Gregory <[e-mail]>
> + *
> + * 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.
> + */
> +
> +#ifndef _ASM_ACENV_H
> +#define _ASM_ACENV_H
> +
> +/* It is required unconditionally by ACPI core, update it when needed. */
> +
> +#endif /* _ASM_ACENV_H */
> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
> new file mode 100644
> index 0000000..8b837ab
> --- /dev/null
> +++ b/arch/arm64/include/asm/acpi.h
> @@ -0,0 +1,45 @@
> +/*
> + *  Copyright (C) 2013-2014, Linaro Ltd.
> + *	Author: Al Stone <[e-mail]>
> + *	Author: Graeme Gregory <[e-mail]>
> + *	Author: Hanjun Guo <[e-mail]>
> + *
> + *  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;
> + */
> +
> +#ifndef _ASM_ACPI_H
> +#define _ASM_ACPI_H
> +
> +/* Basic configuration for ACPI */
> +#ifdef	CONFIG_ACPI
> +#define acpi_strict 1	/* No out-of-spec workarounds on ARM64 */
> +extern int acpi_disabled;
> +extern int acpi_noirq;
> +extern int acpi_pci_disabled;
> +
> +static inline void disable_acpi(void)
> +{
> +	acpi_disabled = 1;
> +	acpi_pci_disabled = 1;
> +	acpi_noirq = 1;
> +}
> +
> +/*
> + * It's used from ACPI core in kdump to boot UP system with SMP kernel,
> + * with this check the ACPI core will not override the CPU index
> + * obtained from GICC with 0 and not print some error message as well.
> + * Since MADT must provide at least one GICC structure for GIC
> + * initialization, CPU will be always available in MADT on ARM64.
> + */
> +static inline bool acpi_has_cpu_in_madt(void)
> +{
> +	return true;
> +}
> +
> +static inline void arch_fix_phys_package_id(int num, u32 slot) { }
> +
> +#endif /* CONFIG_ACPI */
> +
> +#endif /*_ASM_ACPI_H*/
> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
> index bef04af..218eb7e 100644
> --- a/arch/arm64/kernel/Makefile
> +++ b/arch/arm64/kernel/Makefile
> @@ -34,6 +34,7 @@ arm64-obj-$(CONFIG_KGDB)		+= kgdb.o
>  arm64-obj-$(CONFIG_EFI)			+= efi.o efi-stub.o efi-entry.o
>  arm64-obj-$(CONFIG_PCI)			+= pci.o
>  arm64-obj-$(CONFIG_ARMV8_DEPRECATED)	+= armv8_deprecated.o
> +arm64-obj-$(CONFIG_ACPI)		+= acpi.o
>  
>  obj-y					+= $(arm64-obj-y) vdso/
>  obj-m					+= $(arm64-obj-m)
> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> new file mode 100644
> 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 <[e-mail]>
> + *	Author: Graeme Gregory <[e-mail]>
> + *	Author: Hanjun Guo <[e-mail]>
> + *	Author: Tomasz Nowicki <[e-mail]>
> + *	Author: Naresh Bhat <[e-mail]>
> + *
> + *  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)
> +		return NULL;
> +
> +	return early_memremap(phys, size);
> +}
> +
> +void __init __acpi_unmap_table(char *map, unsigned long size)
> +{
> +	if (!map || !size)
> +		return;
> +
> +	early_memunmap(map, size);
> +}
> +
> +static int __init acpi_parse_fadt(struct acpi_table_header *table)
> +{
> +	struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table;
> +
> +	/*
> +	 * Revision in table header is the FADT Major revision, and there
> +	 * is a minor revision of FADT which was introduced by ACPI 5.1,
> +	 * we only deal with ACPI 5.1 or newer revision to get GIC and SMP
> +	 * boot protocol configuration data, or we will disable ACPI.
> +	 */
> +	if (table->revision > 5 ||
> +	    (table->revision == 5 && fadt->minor_revision >= 1))
> +		return 0;
> +
> +	pr_warn("Unsupported FADT revision %d.%d, should be 5.1+, will disable ACPI\n",
> +		table->revision, fadt->minor_revision);
> +	disable_acpi();
> +
> +	return -EINVAL;
> +}
> +
> +/*
> + * 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
> + *	3. check ACPI FADT revision
> + *
> + * We can parse ACPI boot-time tables such as MADT after
> + * this function is called.
> + */
> +void __init acpi_boot_table_init(void)
> +{
> +	/* If acpi_disabled, bail out */
> +	if (acpi_disabled)
> +		return;
> +
> +	/* Initialize the ACPI boot-time table parser. */
> +	if (acpi_table_init()) {
> +		disable_acpi();
> +		return;
> +	}
> +
> +	if (acpi_table_parse(ACPI_SIG_FADT, acpi_parse_fadt)) {
> +		/* disable ACPI if no FADT is found */
> +		disable_acpi();
> +		pr_err("Can't find FADT\n");
> +	}
> +}
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index e8420f6..4f1a014 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -17,6 +17,7 @@
>   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>   */
>  
> +#include <linux/acpi.h>
>  #include <linux/export.h>
>  #include <linux/kernel.h>
>  #include <linux/stddef.h>
> @@ -46,6 +47,7 @@
>  #include <linux/efi.h>
>  #include <linux/personality.h>
>  
> +#include <asm/acpi.h>
>  #include <asm/fixmap.h>
>  #include <asm/cpu.h>
>  #include <asm/cputype.h>
> @@ -380,6 +382,9 @@ void __init setup_arch(char **cmdline_p)
>  	efi_init();
>  	arm64_memblock_init();
>  
> +	/* Parse the ACPI tables for possible boot-time configuration */
> +	acpi_boot_table_init();
> +
>  	paging_init();
>  	request_standard_resources();
>  
> -- 
> 1.9.1
>

Hanjun Guo March 10, 2015, 8:01 a.m. UTC | #4

On 2015?03?06? 02:51, Lorenzo Pieralisi wrote:
> On Wed, Feb 25, 2015 at 08:39:45AM +0000, Hanjun Guo wrote:
>> From: Al Stone <[e-mail]>
>>
>> As we want to get ACPI tables to parse and then use the information
>> for system initialization, we should get the RSDP (Root System
>> Description Pointer) first, it then locates Extended Root Description
>> Table (XSDT) which contains all the 64-bit physical address that
>> pointer to other boot-time tables.
>>
>> Introduce acpi.c and its related head file in this patch to provide
>> fundamental needs of extern variables and functions for ACPI core,
>> and then get boot-time tables as needed.
>>    - asm/acenv.h for arch specific ACPICA environments and
>>      implementation, It is needed unconditionally by ACPI core;
>
> I am not sure we will ever need it since the global lock is not
> needed on HW reduced ACPI (ie ACPI on arm64), and instructions to
> flush the caches are not needed either on arm64.
>
> Anyway, I will have a look if it is worth writing optimized div/shift,
> to give it a purpose to exist.
>
> [...]
>
>> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
>> new file mode 100644
>> index 0000000..8b837ab
>> --- /dev/null
>> +++ b/arch/arm64/include/asm/acpi.h
>> @@ -0,0 +1,45 @@
>> +/*
>> + *  Copyright (C) 2013-2014, Linaro Ltd.
>> + *	Author: Al Stone <[e-mail]>
>> + *	Author: Graeme Gregory <[e-mail]>
>> + *	Author: Hanjun Guo <[e-mail]>
>> + *
>> + *  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;
>> + */
>> +
>> +#ifndef _ASM_ACPI_H
>> +#define _ASM_ACPI_H
>> +
>> +/* Basic configuration for ACPI */
>> +#ifdef	CONFIG_ACPI
>> +#define acpi_strict 1	/* No out-of-spec workarounds on ARM64 */
>> +extern int acpi_disabled;
>> +extern int acpi_noirq;
>> +extern int acpi_pci_disabled;
>> +
>> +static inline void disable_acpi(void)
>> +{
>> +	acpi_disabled = 1;
>> +	acpi_pci_disabled = 1;
>> +	acpi_noirq = 1;
>> +}
>> +
>> +/*
>> + * It's used from ACPI core in kdump to boot UP system with SMP kernel,
>> + * with this check the ACPI core will not override the CPU index
>> + * obtained from GICC with 0 and not print some error message as well.
>> + * Since MADT must provide at least one GICC structure for GIC
>> + * initialization, CPU will be always available in MADT on ARM64.
>> + */
>> +static inline bool acpi_has_cpu_in_madt(void)
>> +{
>> +	return true;
>> +}
>
> I am still trying to make sense of what's this is used for, to me
> it looks like a legacy hack in acpi_processor.c. It is a shame that we need
> to define functions to paper over legacy hacks that make no sense
> whatsoever on arm64.

I'm sorry that I'm confused, why call this as a "hack"? If I remember
correctly, this is a bugfix for x86 from Redhat folks to test kdump
on UP system but without CPU entries in MADT table [1], and we make it
arch independent to introduce acpi_has_cpu_in_madt().

[1]: commit c401eb8ee37, ACPI / processor: Check if LAPIC is present
during initialization

>
>> +static inline void arch_fix_phys_package_id(int num, u32 slot) { }
>
> This is only used on ia64 to pass the _SUN value to arch code to fix up
> the socket id. See above.
>
> You could define last two functions in generic code, and let the
> arch code that needs them override them.
>
> Whether we do it in this series or later, this stuff needs cleaning up.
>
>> +
>> +#endif /* CONFIG_ACPI */
>> +
>> +#endif /*_ASM_ACPI_H*/
>> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
>> index bef04af..218eb7e 100644
>> --- a/arch/arm64/kernel/Makefile
>> +++ b/arch/arm64/kernel/Makefile
>> @@ -34,6 +34,7 @@ arm64-obj-$(CONFIG_KGDB)		+= kgdb.o
>>   arm64-obj-$(CONFIG_EFI)			+= efi.o efi-stub.o efi-entry.o
>>   arm64-obj-$(CONFIG_PCI)			+= pci.o
>>   arm64-obj-$(CONFIG_ARMV8_DEPRECATED)	+= armv8_deprecated.o
>> +arm64-obj-$(CONFIG_ACPI)		+= acpi.o
>>
>>   obj-y					+= $(arm64-obj-y) vdso/
>>   obj-m					+= $(arm64-obj-m)
>> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
>> new file mode 100644
>> 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 <[e-mail]>
>> + *	Author: Graeme Gregory <[e-mail]>
>> + *	Author: Hanjun Guo <[e-mail]>
>> + *	Author: Tomasz Nowicki <[e-mail]>
>> + *	Author: Naresh Bhat <[e-mail]>
>> + *
>> + *  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.

Thanks
Hanjun

Lorenzo Pieralisi March 10, 2015, 9:32 a.m. UTC | #5

On Tue, Mar 10, 2015 at 08:01:16AM +0000, Hanjun Guo wrote:

[...]

> >> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
> >> new file mode 100644
> >> index 0000000..8b837ab
> >> --- /dev/null
> >> +++ b/arch/arm64/include/asm/acpi.h
> >> @@ -0,0 +1,45 @@
> >> +/*
> >> + *  Copyright (C) 2013-2014, Linaro Ltd.
> >> + *	Author: Al Stone <[e-mail]>
> >> + *	Author: Graeme Gregory <[e-mail]>
> >> + *	Author: Hanjun Guo <[e-mail]>
> >> + *
> >> + *  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;
> >> + */
> >> +
> >> +#ifndef _ASM_ACPI_H
> >> +#define _ASM_ACPI_H
> >> +
> >> +/* Basic configuration for ACPI */
> >> +#ifdef	CONFIG_ACPI
> >> +#define acpi_strict 1	/* No out-of-spec workarounds on ARM64 */
> >> +extern int acpi_disabled;
> >> +extern int acpi_noirq;
> >> +extern int acpi_pci_disabled;
> >> +
> >> +static inline void disable_acpi(void)
> >> +{
> >> +	acpi_disabled = 1;
> >> +	acpi_pci_disabled = 1;
> >> +	acpi_noirq = 1;
> >> +}
> >> +
> >> +/*
> >> + * It's used from ACPI core in kdump to boot UP system with SMP kernel,
> >> + * with this check the ACPI core will not override the CPU index
> >> + * obtained from GICC with 0 and not print some error message as well.
> >> + * Since MADT must provide at least one GICC structure for GIC
> >> + * initialization, CPU will be always available in MADT on ARM64.
> >> + */
> >> +static inline bool acpi_has_cpu_in_madt(void)
> >> +{
> >> +	return true;
> >> +}
> >
> > I am still trying to make sense of what's this is used for, to me
> > it looks like a legacy hack in acpi_processor.c. It is a shame that we need
> > to define functions to paper over legacy hacks that make no sense
> > whatsoever on arm64.
> 
> I'm sorry that I'm confused, why call this as a "hack"? If I remember
> correctly, this is a bugfix for x86 from Redhat folks to test kdump
> on UP system but without CPU entries in MADT table [1], and we make it
> arch independent to introduce acpi_has_cpu_in_madt().

I gathered that, do not tell me it is nice please. ACPI core code
is chock full of things like this that force you to define functions
in arch arm64 since they are called from "generic" code, and I do not
like that, at all.

It can be cleaned up later.

> [1]: commit c401eb8ee37, ACPI / processor: Check if LAPIC is present
> during initialization
> 
> >
> >> +static inline void arch_fix_phys_package_id(int num, u32 slot) { }
> >
> > This is only used on ia64 to pass the _SUN value to arch code to fix up
> > the socket id. See above.
> >
> > You could define last two functions in generic code, and let the
> > arch code that needs them override them.
> >
> > Whether we do it in this series or later, this stuff needs cleaning up.
> >
> >> +
> >> +#endif /* CONFIG_ACPI */
> >> +
> >> +#endif /*_ASM_ACPI_H*/
> >> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
> >> index bef04af..218eb7e 100644
> >> --- a/arch/arm64/kernel/Makefile
> >> +++ b/arch/arm64/kernel/Makefile
> >> @@ -34,6 +34,7 @@ arm64-obj-$(CONFIG_KGDB)		+= kgdb.o
> >>   arm64-obj-$(CONFIG_EFI)			+= efi.o efi-stub.o efi-entry.o
> >>   arm64-obj-$(CONFIG_PCI)			+= pci.o
> >>   arm64-obj-$(CONFIG_ARMV8_DEPRECATED)	+= armv8_deprecated.o
> >> +arm64-obj-$(CONFIG_ACPI)		+= acpi.o
> >>
> >>   obj-y					+= $(arm64-obj-y) vdso/
> >>   obj-m					+= $(arm64-obj-m)
> >> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> >> new file mode 100644
> >> 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 <[e-mail]>
> >> + *	Author: Graeme Gregory <[e-mail]>
> >> + *	Author: Hanjun Guo <[e-mail]>
> >> + *	Author: Tomasz Nowicki <[e-mail]>
> >> + *	Author: Naresh Bhat <[e-mail]>
> >> + *
> >> + *  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.

If there is no particular reason the check should not be there, "x86
needs it" is not a good reason, there is arch specific code for that
in x86 directories.

Ok, let's wait for Leif to confirm that.

Thanks,
Lorenzo

Leif Lindholm March 10, 2015, 11:19 a.m. UTC | #6

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 <[e-mail]>
> >>+ *	Author: Graeme Gregory <[e-mail]>
> >>+ *	Author: Hanjun Guo <[e-mail]>
> >>+ *	Author: Tomasz Nowicki <[e-mail]>
> >>+ *	Author: Naresh Bhat <[e-mail]>
> >>+ *
> >>+ *  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.

/
    Leif

Hanjun Guo March 10, 2015, 11:36 a.m. UTC | #7

On 2015?03?10? 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 <[e-mail]>
>>>> + *	Author: Graeme Gregory <[e-mail]>
>>>> + *	Author: Hanjun Guo <[e-mail]>
>>>> + *	Author: Tomasz Nowicki <[e-mail]>
>>>> + *	Author: Naresh Bhat <[e-mail]>
>>>> + *
>>>> + *  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

Patch

diff --git a/arch/arm64/include/asm/acenv.h b/arch/arm64/include/asm/acenv.h
new file mode 100644
index 0000000..b49166f
--- /dev/null
+++ b/arch/arm64/include/asm/acenv.h
@@ -0,0 +1,18 @@ 
+/*
+ * ARM64 specific ACPICA environments and implementation
+ *
+ * Copyright (C) 2014, Linaro Ltd.
+ *   Author: Hanjun Guo <[e-mail]>
+ *   Author: Graeme Gregory <[e-mail]>
+ *
+ * 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.
+ */
+
+#ifndef _ASM_ACENV_H
+#define _ASM_ACENV_H
+
+/* It is required unconditionally by ACPI core, update it when needed. */
+
+#endif /* _ASM_ACENV_H */
diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
new file mode 100644
index 0000000..8b837ab
--- /dev/null
+++ b/arch/arm64/include/asm/acpi.h
@@ -0,0 +1,45 @@ 
+/*
+ *  Copyright (C) 2013-2014, Linaro Ltd.
+ *	Author: Al Stone <[e-mail]>
+ *	Author: Graeme Gregory <[e-mail]>
+ *	Author: Hanjun Guo <[e-mail]>
+ *
+ *  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;
+ */
+
+#ifndef _ASM_ACPI_H
+#define _ASM_ACPI_H
+
+/* Basic configuration for ACPI */
+#ifdef	CONFIG_ACPI
+#define acpi_strict 1	/* No out-of-spec workarounds on ARM64 */
+extern int acpi_disabled;
+extern int acpi_noirq;
+extern int acpi_pci_disabled;
+
+static inline void disable_acpi(void)
+{
+	acpi_disabled = 1;
+	acpi_pci_disabled = 1;
+	acpi_noirq = 1;
+}
+
+/*
+ * It's used from ACPI core in kdump to boot UP system with SMP kernel,
+ * with this check the ACPI core will not override the CPU index
+ * obtained from GICC with 0 and not print some error message as well.
+ * Since MADT must provide at least one GICC structure for GIC
+ * initialization, CPU will be always available in MADT on ARM64.
+ */
+static inline bool acpi_has_cpu_in_madt(void)
+{
+	return true;
+}
+
+static inline void arch_fix_phys_package_id(int num, u32 slot) { }
+
+#endif /* CONFIG_ACPI */
+
+#endif /*_ASM_ACPI_H*/
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index bef04af..218eb7e 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -34,6 +34,7 @@  arm64-obj-$(CONFIG_KGDB)		+= kgdb.o
 arm64-obj-$(CONFIG_EFI)			+= efi.o efi-stub.o efi-entry.o
 arm64-obj-$(CONFIG_PCI)			+= pci.o
 arm64-obj-$(CONFIG_ARMV8_DEPRECATED)	+= armv8_deprecated.o
+arm64-obj-$(CONFIG_ACPI)		+= acpi.o
 
 obj-y					+= $(arm64-obj-y) vdso/
 obj-m					+= $(arm64-obj-m)
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
new file mode 100644
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 <[e-mail]>
+ *	Author: Graeme Gregory <[e-mail]>
+ *	Author: Hanjun Guo <[e-mail]>
+ *	Author: Tomasz Nowicki <[e-mail]>
+ *	Author: Naresh Bhat <[e-mail]>
+ *
+ *  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)
+		return NULL;
+
+	return early_memremap(phys, size);
+}
+
+void __init __acpi_unmap_table(char *map, unsigned long size)
+{
+	if (!map || !size)
+		return;
+
+	early_memunmap(map, size);
+}
+
+static int __init acpi_parse_fadt(struct acpi_table_header *table)
+{
+	struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table;
+
+	/*
+	 * Revision in table header is the FADT Major revision, and there
+	 * is a minor revision of FADT which was introduced by ACPI 5.1,
+	 * we only deal with ACPI 5.1 or newer revision to get GIC and SMP
+	 * boot protocol configuration data, or we will disable ACPI.
+	 */
+	if (table->revision > 5 ||
+	    (table->revision == 5 && fadt->minor_revision >= 1))
+		return 0;
+
+	pr_warn("Unsupported FADT revision %d.%d, should be 5.1+, will disable ACPI\n",
+		table->revision, fadt->minor_revision);
+	disable_acpi();
+
+	return -EINVAL;
+}
+
+/*
+ * 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
+ *	3. check ACPI FADT revision
+ *
+ * We can parse ACPI boot-time tables such as MADT after
+ * this function is called.
+ */
+void __init acpi_boot_table_init(void)
+{
+	/* If acpi_disabled, bail out */
+	if (acpi_disabled)
+		return;
+
+	/* Initialize the ACPI boot-time table parser. */
+	if (acpi_table_init()) {
+		disable_acpi();
+		return;
+	}
+
+	if (acpi_table_parse(ACPI_SIG_FADT, acpi_parse_fadt)) {
+		/* disable ACPI if no FADT is found */
+		disable_acpi();
+		pr_err("Can't find FADT\n");
+	}
+}
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index e8420f6..4f1a014 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -17,6 +17,7 @@ 
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <linux/acpi.h>
 #include <linux/export.h>
 #include <linux/kernel.h>
 #include <linux/stddef.h>
@@ -46,6 +47,7 @@ 
 #include <linux/efi.h>
 #include <linux/personality.h>
 
+#include <asm/acpi.h>
 #include <asm/fixmap.h>
 #include <asm/cpu.h>
 #include <asm/cputype.h>
@@ -380,6 +382,9 @@  void __init setup_arch(char **cmdline_p)
 	efi_init();
 	arm64_memblock_init();
 
+	/* Parse the ACPI tables for possible boot-time configuration */
+	acpi_boot_table_init();
+
 	paging_init();
 	request_standard_resources();