From mboxrd@z Thu Jan  1 00:00:00 1970
From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Subject: Re: [PATCH v10 18/21] ARM64 / ACPI: Select
 ACPI_REDUCED_HARDWARE_ONLY if ACPI is enabled on ARM64
Date: Tue, 17 Mar 2015 12:50:05 +0000
Message-ID: <20150317125005.GC14984@red-moon>
References: <1426077587-1561-1-git-send-email-hanjun.guo@linaro.org>
 <1426077587-1561-19-git-send-email-hanjun.guo@linaro.org>
 <20150312182151.GA3867@red-moon>
 <5502596D.6020901@huawei.com>
 <20150313110421.GA5229@red-moon>
 <5506BF89.9040703@linaro.org>
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To: Hanjun Guo <hanjun.guo@linaro.org>
Cc: "guohanjun@huawei.com" <guohanjun@huawei.com>, Catalin Marinas <Catalin.Marinas@arm.com>, "Rafael J. Wysocki" <rjw@rjwysocki.net>, Will Deacon <Will.Deacon@arm.com>, Olof Johansson <olof@lixom.net>, "grant.likely@linaro.org" <grant.likely@linaro.org>, Arnd Bergmann <arnd@arndb.de>, Mark Rutland <Mark.Rutland@arm.com>, "graeme.gregory@linaro.org" <graeme.gregory@linaro.org>, Sudeep Holla <Sudeep.Holla@arm.com>, "jcm@redhat.com" <jcm@redhat.com>, Marc Zyngier <Marc.Zyngier@arm.com>, Mark Brown <broonie@kernel.org>, Robert Richter <rric@kernel.org>, Timur Tabi <timur@codeaurora.org>, Ashwin Chaugule <ashwinc@codeaurora.org>, "suravee.suthikulpanit@amd.com" <suravee.suthikulpanit@amd.com>, "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, "linux-kernel@vger.kernel.org" <linux-kern>

On Mon, Mar 16, 2015 at 11:33:29AM +0000, Hanjun Guo wrote:

[...]

> > Patch rewritten, here below, please have a look, test it and rework
> > bits as needed, I added comments where I thought they were needed but
> > please add to that if you feel it is worth it.
> >
> > It should be easy to split, let me know if you want an incremental
> > version.
> 
> This one is much better, pretty fine to me, thanks!
> 
> I assume that this patch is cleanup patch on top of ARM64 ACPI
> core patches, right?

Well, it is a clean-up patch on top of your series, I can split it
in the respective patches and send you the patches in your series
updated with this code.

Thanks,
Lorenzo

> 
> Thanks
> Hanjun
> 
> >
> > Thanks !
> > Lorenzo
> >
> > ---
> >   arch/arm64/kernel/acpi.c | 103 +++++++++++++++++++++++++++++++----------------
> >   1 file changed, 69 insertions(+), 34 deletions(-)
> >
> > diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> > index 5819ef7..e5ee4d4 100644
> > --- a/arch/arm64/kernel/acpi.c
> > +++ b/arch/arm64/kernel/acpi.c
> > @@ -291,43 +291,60 @@ void acpi_unregister_gsi(u32 gsi)
> >   }
> >   EXPORT_SYMBOL_GPL(acpi_unregister_gsi);
> >
> > -static int __init acpi_parse_fadt(struct acpi_table_header *table)
> > +/*
> > + * acpi_fadt_sanity_check() - Check FADT presence and carry out sanity
> > + *			      checks on it
> > + *
> > + * Return 0 on success,  <0 on failure
> > + */
> > +static int __init acpi_fadt_sanity_check(void)
> >   {
> > -	struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table;
> > +	struct acpi_table_header *table;
> > +	struct acpi_table_fadt *fadt;
> > +	acpi_status status;
> > +	acpi_size tbl_size;
> > +	int ret = 0;
> > +
> > +	/*
> > +	 * FADT is required on arm64; retrieve it to check its presence
> > +	 * and carry out revision and ACPI HW reduced compliancy tests
> > +	 */
> > +	status = acpi_get_table_with_size(ACPI_SIG_FADT, 0, &table, &tbl_size);
> > +	if (ACPI_FAILURE(status)) {
> > +		const char *msg = acpi_format_exception(status);
> > +
> > +		pr_err("Failed to get FADT table, %s\n", msg);
> > +		return -ENODEV;
> > +	}
> > +
> > +	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.
> > +	 * boot protocol configuration data.
> >   	 */
> > -	if (table->revision > 5 ||
> > -	    (table->revision == 5 && fadt->minor_revision >= 1)) {
> > -		if (!acpi_gbl_reduced_hardware) {
> > -			pr_err("Not hardware reduced ACPI mode, will not be supported\n");
> > -			goto disable_acpi;
> > -		}
> > -
> > -		/*
> > -		 * ACPI 5.1 only has two explicit methods to boot up SMP,
> > -		 * PSCI and Parking protocol, but the Parking protocol is
> > -		 * only specified for ARMv7 now, so make PSCI as the only
> > -		 * way for the SMP boot protocol before some updates for
> > -		 * the Parking protocol spec.
> > -		 */
> > -		if (acpi_psci_present())
> > -			return 0;
> > -
> > -		pr_warn("No PSCI support, will not bring up secondary CPUs\n");
> > -		return -EOPNOTSUPP;
> > +	if (table->revision < 5 ||
> > +	   (table->revision == 5 && fadt->minor_revision < 1)) {
> > +		pr_err("Unsupported FADT revision %d.%d, should be 5.1+\n",
> > +		       table->revision, fadt->minor_revision);
> > +		ret = -EINVAL;
> > +		goto out;
> >   	}
> >
> > -	pr_warn("Unsupported FADT revision %d.%d, should be 5.1+, will disable ACPI\n",
> > -		table->revision, fadt->minor_revision);
> > +	if (!(fadt->flags & ACPI_FADT_HW_REDUCED)) {
> > +		pr_err("FADT not ACPI hardware reduced compliant\n");
> > +		ret = -EINVAL;
> > +	}
> >
> > -disable_acpi:
> > -	disable_acpi();
> > -	return -EINVAL;
> > +out:
> > +	/*
> > +	 * acpi_get_table_with_size() creates FADT table mapping that
> > +	 * should be released after parsing and before resuming boot
> > +	 */
> > +	early_acpi_os_unmap_memory((char *)table, tbl_size);
> > +	return ret;
> >   }
> >
> >   /*
> > @@ -335,12 +352,17 @@ disable_acpi:
> >    *	1. find RSDP and get its address, and then find XSDT
> >    *	2. extract all tables and checksums them all
> >    *	3. check ACPI FADT revision
> > + *	4. check ACPI FADT HW reduced flag
> >    *
> >    * We can parse ACPI boot-time tables such as MADT after
> >    * this function is called.
> > + *
> > + * ACPI is enabled on return if ACPI tables initialized and sanity checks
> > + * passed, disabled otherwise
> >    */
> >   void __init acpi_boot_table_init(void)
> >   {
> > +
> >   	/*
> >   	 * Enable ACPI instead of device tree unless
> >   	 * - ACPI has been disabled explicitly (acpi=off), or
> > @@ -351,19 +373,32 @@ void __init acpi_boot_table_init(void)
> >   	    (!param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
> >   		return;
> >
> > +	/*
> > +	 * ACPI is disabled at this point. Enable it in order to parse
> > +	 * the ACPI tables and carry out sanity checks
> > +	 */
> >   	enable_acpi();
> >
> >   	/* Initialize the ACPI boot-time table parser. */
> >   	if (acpi_table_init()) {
> > -		disable_acpi();
> > -		return;
> > +		pr_err("Failed to init ACPI tables\n");
> > +		goto init_failed;
> >   	}
> >
> > -	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");
> > -	}
> > +	/*
> > +	 * Check FADT presence and carry out FADT sanity checks
> > +	 */
> > +	if (acpi_fadt_sanity_check() < 0)
> > +		goto init_failed;
> > +
> > +	/*
> > +	 * ACPI tables initialized and FADT sanity checks passed, leave
> > +	 * ACPI enabled and carry on booting
> > +	 */
> > +	return;
> > +
> > +init_failed:
> > +	disable_acpi();
> >   }
> >
> >   void __init acpi_gic_init(void)
> >
> 

From mboxrd@z Thu Jan  1 00:00:00 1970
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	Tue, 17 Mar 2015 08:50:04 -0400
Date: Tue, 17 Mar 2015 12:50:05 +0000
From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Hanjun Guo <hanjun.guo@linaro.org>
Cc: "guohanjun@huawei.com" <guohanjun@huawei.com>,
        Catalin Marinas <Catalin.Marinas@arm.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Will Deacon <Will.Deacon@arm.com>, Olof Johansson <olof@lixom.net>,
        "grant.likely@linaro.org" <grant.likely@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>, Mark Rutland <Mark.Rutland@arm.com>,
        "graeme.gregory@linaro.org" <graeme.gregory@linaro.org>,
        Sudeep Holla <Sudeep.Holla@arm.com>, "jcm@redhat.com" <jcm@redhat.com>,
        Marc Zyngier <Marc.Zyngier@arm.com>, Mark Brown <broonie@kernel.org>,
        Robert Richter <rric@kernel.org>, Timur Tabi <timur@codeaurora.org>,
        Ashwin Chaugule <ashwinc@codeaurora.org>,
        "suravee.suthikulpanit@amd.com" <suravee.suthikulpanit@amd.com>,
        "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linaro-acpi@lists.linaro.org" <linaro-acpi@lists.linaro.org>,
        Al Stone <al.stone@linaro.org>
Subject: Re: [PATCH v10 18/21] ARM64 / ACPI: Select
 ACPI_REDUCED_HARDWARE_ONLY if ACPI is enabled on ARM64
Message-ID: <20150317125005.GC14984@red-moon>
References: <1426077587-1561-1-git-send-email-hanjun.guo@linaro.org>
 <1426077587-1561-19-git-send-email-hanjun.guo@linaro.org>
 <20150312182151.GA3867@red-moon>
 <5502596D.6020901@huawei.com>
 <20150313110421.GA5229@red-moon>
 <5506BF89.9040703@linaro.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <5506BF89.9040703@linaro.org>
User-Agent: Mutt/1.5.21 (2010-09-15)
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List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Mon, Mar 16, 2015 at 11:33:29AM +0000, Hanjun Guo wrote:

[...]

> > Patch rewritten, here below, please have a look, test it and rework
> > bits as needed, I added comments where I thought they were needed but
> > please add to that if you feel it is worth it.
> >
> > It should be easy to split, let me know if you want an incremental
> > version.
> 
> This one is much better, pretty fine to me, thanks!
> 
> I assume that this patch is cleanup patch on top of ARM64 ACPI
> core patches, right?

Well, it is a clean-up patch on top of your series, I can split it
in the respective patches and send you the patches in your series
updated with this code.

Thanks,
Lorenzo

> 
> Thanks
> Hanjun
> 
> >
> > Thanks !
> > Lorenzo
> >
> > ---
> >   arch/arm64/kernel/acpi.c | 103 +++++++++++++++++++++++++++++++----------------
> >   1 file changed, 69 insertions(+), 34 deletions(-)
> >
> > diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> > index 5819ef7..e5ee4d4 100644
> > --- a/arch/arm64/kernel/acpi.c
> > +++ b/arch/arm64/kernel/acpi.c
> > @@ -291,43 +291,60 @@ void acpi_unregister_gsi(u32 gsi)
> >   }
> >   EXPORT_SYMBOL_GPL(acpi_unregister_gsi);
> >
> > -static int __init acpi_parse_fadt(struct acpi_table_header *table)
> > +/*
> > + * acpi_fadt_sanity_check() - Check FADT presence and carry out sanity
> > + *			      checks on it
> > + *
> > + * Return 0 on success,  <0 on failure
> > + */
> > +static int __init acpi_fadt_sanity_check(void)
> >   {
> > -	struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table;
> > +	struct acpi_table_header *table;
> > +	struct acpi_table_fadt *fadt;
> > +	acpi_status status;
> > +	acpi_size tbl_size;
> > +	int ret = 0;
> > +
> > +	/*
> > +	 * FADT is required on arm64; retrieve it to check its presence
> > +	 * and carry out revision and ACPI HW reduced compliancy tests
> > +	 */
> > +	status = acpi_get_table_with_size(ACPI_SIG_FADT, 0, &table, &tbl_size);
> > +	if (ACPI_FAILURE(status)) {
> > +		const char *msg = acpi_format_exception(status);
> > +
> > +		pr_err("Failed to get FADT table, %s\n", msg);
> > +		return -ENODEV;
> > +	}
> > +
> > +	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.
> > +	 * boot protocol configuration data.
> >   	 */
> > -	if (table->revision > 5 ||
> > -	    (table->revision == 5 && fadt->minor_revision >= 1)) {
> > -		if (!acpi_gbl_reduced_hardware) {
> > -			pr_err("Not hardware reduced ACPI mode, will not be supported\n");
> > -			goto disable_acpi;
> > -		}
> > -
> > -		/*
> > -		 * ACPI 5.1 only has two explicit methods to boot up SMP,
> > -		 * PSCI and Parking protocol, but the Parking protocol is
> > -		 * only specified for ARMv7 now, so make PSCI as the only
> > -		 * way for the SMP boot protocol before some updates for
> > -		 * the Parking protocol spec.
> > -		 */
> > -		if (acpi_psci_present())
> > -			return 0;
> > -
> > -		pr_warn("No PSCI support, will not bring up secondary CPUs\n");
> > -		return -EOPNOTSUPP;
> > +	if (table->revision < 5 ||
> > +	   (table->revision == 5 && fadt->minor_revision < 1)) {
> > +		pr_err("Unsupported FADT revision %d.%d, should be 5.1+\n",
> > +		       table->revision, fadt->minor_revision);
> > +		ret = -EINVAL;
> > +		goto out;
> >   	}
> >
> > -	pr_warn("Unsupported FADT revision %d.%d, should be 5.1+, will disable ACPI\n",
> > -		table->revision, fadt->minor_revision);
> > +	if (!(fadt->flags & ACPI_FADT_HW_REDUCED)) {
> > +		pr_err("FADT not ACPI hardware reduced compliant\n");
> > +		ret = -EINVAL;
> > +	}
> >
> > -disable_acpi:
> > -	disable_acpi();
> > -	return -EINVAL;
> > +out:
> > +	/*
> > +	 * acpi_get_table_with_size() creates FADT table mapping that
> > +	 * should be released after parsing and before resuming boot
> > +	 */
> > +	early_acpi_os_unmap_memory((char *)table, tbl_size);
> > +	return ret;
> >   }
> >
> >   /*
> > @@ -335,12 +352,17 @@ disable_acpi:
> >    *	1. find RSDP and get its address, and then find XSDT
> >    *	2. extract all tables and checksums them all
> >    *	3. check ACPI FADT revision
> > + *	4. check ACPI FADT HW reduced flag
> >    *
> >    * We can parse ACPI boot-time tables such as MADT after
> >    * this function is called.
> > + *
> > + * ACPI is enabled on return if ACPI tables initialized and sanity checks
> > + * passed, disabled otherwise
> >    */
> >   void __init acpi_boot_table_init(void)
> >   {
> > +
> >   	/*
> >   	 * Enable ACPI instead of device tree unless
> >   	 * - ACPI has been disabled explicitly (acpi=off), or
> > @@ -351,19 +373,32 @@ void __init acpi_boot_table_init(void)
> >   	    (!param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
> >   		return;
> >
> > +	/*
> > +	 * ACPI is disabled at this point. Enable it in order to parse
> > +	 * the ACPI tables and carry out sanity checks
> > +	 */
> >   	enable_acpi();
> >
> >   	/* Initialize the ACPI boot-time table parser. */
> >   	if (acpi_table_init()) {
> > -		disable_acpi();
> > -		return;
> > +		pr_err("Failed to init ACPI tables\n");
> > +		goto init_failed;
> >   	}
> >
> > -	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");
> > -	}
> > +	/*
> > +	 * Check FADT presence and carry out FADT sanity checks
> > +	 */
> > +	if (acpi_fadt_sanity_check() < 0)
> > +		goto init_failed;
> > +
> > +	/*
> > +	 * ACPI tables initialized and FADT sanity checks passed, leave
> > +	 * ACPI enabled and carry on booting
> > +	 */
> > +	return;
> > +
> > +init_failed:
> > +	disable_acpi();
> >   }
> >
> >   void __init acpi_gic_init(void)
> >
> 

From mboxrd@z Thu Jan  1 00:00:00 1970
From: lorenzo.pieralisi@arm.com (Lorenzo Pieralisi)
Date: Tue, 17 Mar 2015 12:50:05 +0000
Subject: [PATCH v10 18/21] ARM64 / ACPI: Select
 ACPI_REDUCED_HARDWARE_ONLY if ACPI is enabled on ARM64
In-Reply-To: <5506BF89.9040703@linaro.org>
References: <1426077587-1561-1-git-send-email-hanjun.guo@linaro.org>
 <1426077587-1561-19-git-send-email-hanjun.guo@linaro.org>
 <20150312182151.GA3867@red-moon> <5502596D.6020901@huawei.com>
 <20150313110421.GA5229@red-moon> <5506BF89.9040703@linaro.org>
Message-ID: <20150317125005.GC14984@red-moon>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, Mar 16, 2015 at 11:33:29AM +0000, Hanjun Guo wrote:

[...]

> > Patch rewritten, here below, please have a look, test it and rework
> > bits as needed, I added comments where I thought they were needed but
> > please add to that if you feel it is worth it.
> >
> > It should be easy to split, let me know if you want an incremental
> > version.
> 
> This one is much better, pretty fine to me, thanks!
> 
> I assume that this patch is cleanup patch on top of ARM64 ACPI
> core patches, right?

Well, it is a clean-up patch on top of your series, I can split it
in the respective patches and send you the patches in your series
updated with this code.

Thanks,
Lorenzo

> 
> Thanks
> Hanjun
> 
> >
> > Thanks !
> > Lorenzo
> >
> > ---
> >   arch/arm64/kernel/acpi.c | 103 +++++++++++++++++++++++++++++++----------------
> >   1 file changed, 69 insertions(+), 34 deletions(-)
> >
> > diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> > index 5819ef7..e5ee4d4 100644
> > --- a/arch/arm64/kernel/acpi.c
> > +++ b/arch/arm64/kernel/acpi.c
> > @@ -291,43 +291,60 @@ void acpi_unregister_gsi(u32 gsi)
> >   }
> >   EXPORT_SYMBOL_GPL(acpi_unregister_gsi);
> >
> > -static int __init acpi_parse_fadt(struct acpi_table_header *table)
> > +/*
> > + * acpi_fadt_sanity_check() - Check FADT presence and carry out sanity
> > + *			      checks on it
> > + *
> > + * Return 0 on success,  <0 on failure
> > + */
> > +static int __init acpi_fadt_sanity_check(void)
> >   {
> > -	struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table;
> > +	struct acpi_table_header *table;
> > +	struct acpi_table_fadt *fadt;
> > +	acpi_status status;
> > +	acpi_size tbl_size;
> > +	int ret = 0;
> > +
> > +	/*
> > +	 * FADT is required on arm64; retrieve it to check its presence
> > +	 * and carry out revision and ACPI HW reduced compliancy tests
> > +	 */
> > +	status = acpi_get_table_with_size(ACPI_SIG_FADT, 0, &table, &tbl_size);
> > +	if (ACPI_FAILURE(status)) {
> > +		const char *msg = acpi_format_exception(status);
> > +
> > +		pr_err("Failed to get FADT table, %s\n", msg);
> > +		return -ENODEV;
> > +	}
> > +
> > +	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.
> > +	 * boot protocol configuration data.
> >   	 */
> > -	if (table->revision > 5 ||
> > -	    (table->revision == 5 && fadt->minor_revision >= 1)) {
> > -		if (!acpi_gbl_reduced_hardware) {
> > -			pr_err("Not hardware reduced ACPI mode, will not be supported\n");
> > -			goto disable_acpi;
> > -		}
> > -
> > -		/*
> > -		 * ACPI 5.1 only has two explicit methods to boot up SMP,
> > -		 * PSCI and Parking protocol, but the Parking protocol is
> > -		 * only specified for ARMv7 now, so make PSCI as the only
> > -		 * way for the SMP boot protocol before some updates for
> > -		 * the Parking protocol spec.
> > -		 */
> > -		if (acpi_psci_present())
> > -			return 0;
> > -
> > -		pr_warn("No PSCI support, will not bring up secondary CPUs\n");
> > -		return -EOPNOTSUPP;
> > +	if (table->revision < 5 ||
> > +	   (table->revision == 5 && fadt->minor_revision < 1)) {
> > +		pr_err("Unsupported FADT revision %d.%d, should be 5.1+\n",
> > +		       table->revision, fadt->minor_revision);
> > +		ret = -EINVAL;
> > +		goto out;
> >   	}
> >
> > -	pr_warn("Unsupported FADT revision %d.%d, should be 5.1+, will disable ACPI\n",
> > -		table->revision, fadt->minor_revision);
> > +	if (!(fadt->flags & ACPI_FADT_HW_REDUCED)) {
> > +		pr_err("FADT not ACPI hardware reduced compliant\n");
> > +		ret = -EINVAL;
> > +	}
> >
> > -disable_acpi:
> > -	disable_acpi();
> > -	return -EINVAL;
> > +out:
> > +	/*
> > +	 * acpi_get_table_with_size() creates FADT table mapping that
> > +	 * should be released after parsing and before resuming boot
> > +	 */
> > +	early_acpi_os_unmap_memory((char *)table, tbl_size);
> > +	return ret;
> >   }
> >
> >   /*
> > @@ -335,12 +352,17 @@ disable_acpi:
> >    *	1. find RSDP and get its address, and then find XSDT
> >    *	2. extract all tables and checksums them all
> >    *	3. check ACPI FADT revision
> > + *	4. check ACPI FADT HW reduced flag
> >    *
> >    * We can parse ACPI boot-time tables such as MADT after
> >    * this function is called.
> > + *
> > + * ACPI is enabled on return if ACPI tables initialized and sanity checks
> > + * passed, disabled otherwise
> >    */
> >   void __init acpi_boot_table_init(void)
> >   {
> > +
> >   	/*
> >   	 * Enable ACPI instead of device tree unless
> >   	 * - ACPI has been disabled explicitly (acpi=off), or
> > @@ -351,19 +373,32 @@ void __init acpi_boot_table_init(void)
> >   	    (!param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
> >   		return;
> >
> > +	/*
> > +	 * ACPI is disabled at this point. Enable it in order to parse
> > +	 * the ACPI tables and carry out sanity checks
> > +	 */
> >   	enable_acpi();
> >
> >   	/* Initialize the ACPI boot-time table parser. */
> >   	if (acpi_table_init()) {
> > -		disable_acpi();
> > -		return;
> > +		pr_err("Failed to init ACPI tables\n");
> > +		goto init_failed;
> >   	}
> >
> > -	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");
> > -	}
> > +	/*
> > +	 * Check FADT presence and carry out FADT sanity checks
> > +	 */
> > +	if (acpi_fadt_sanity_check() < 0)
> > +		goto init_failed;
> > +
> > +	/*
> > +	 * ACPI tables initialized and FADT sanity checks passed, leave
> > +	 * ACPI enabled and carry on booting
> > +	 */
> > +	return;
> > +
> > +init_failed:
> > +	disable_acpi();
> >   }
> >
> >   void __init acpi_gic_init(void)
> >
>