[v8,09/21] ARM64 / ACPI: Disable ACPI if FADT revision is less than 5.1

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.

CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Tested-by: Yijing Wang <wangyijing@huawei.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Jon Masters <jcm@redhat.com>
Tested-by: Timur Tabi <timur@codeaurora.org>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
---
 arch/arm64/kernel/acpi.c | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

On 2015年02月04日 01:20, Catalin Marinas wrote:
> On Mon, Feb 02, 2015 at 12:45:37PM +0000, Hanjun Guo wrote:
>> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
>> index afe10b4..b9f64ec 100644
>> --- a/arch/arm64/kernel/acpi.c
>> +++ b/arch/arm64/kernel/acpi.c
>> @@ -13,6 +13,8 @@
>>    *  published by the Free Software Foundation.
>>    */
>>
>> +#define pr_fmt(fmt) "ACPI: " fmt
>> +
>>   #include <linux/acpi.h>
>>   #include <linux/bootmem.h>
>>   #include <linux/cpumask.h>
>> @@ -49,10 +51,32 @@ void __init __acpi_unmap_table(char *map, unsigned long size)
>>   	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.
>> @@ -64,8 +88,16 @@ void __init acpi_boot_table_init(void)
>>   		return;
>>
>>   	/* Initialize the ACPI boot-time table parser. */
>> -	if (acpi_table_init())
>> +	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");
>> +	}
>>   }
>
> It looks fine to call disable_acpi() here but a bit weird to call it
> again in acpi_parse_fadt(). I guess that's because acpi_table_parse()
> ignores the return value of the handler() call. I think it's better to
> fix the core code (can be an additional patch on top of this series).

I checked all the code calling acpi_table_parse() and I found that it
will be no functional change if we return the value of handler(), but
I need Rafael's confirm on it.

Thanks
Hanjun
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On 2015年02月04日 21:06, Lorenzo Pieralisi wrote:
> On Wed, Feb 04, 2015 at 09:38:25AM +0000, Hanjun Guo wrote:
>> On 2015年02月04日 01:20, Catalin Marinas wrote:
>>> On Mon, Feb 02, 2015 at 12:45:37PM +0000, Hanjun Guo wrote:
>>>> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
>>>> index afe10b4..b9f64ec 100644
>>>> --- a/arch/arm64/kernel/acpi.c
>>>> +++ b/arch/arm64/kernel/acpi.c
>>>> @@ -13,6 +13,8 @@
>>>>     *  published by the Free Software Foundation.
>>>>     */
>>>>
>>>> +#define pr_fmt(fmt) "ACPI: " fmt
>>>> +
>>>>    #include <linux/acpi.h>
>>>>    #include <linux/bootmem.h>
>>>>    #include <linux/cpumask.h>
>>>> @@ -49,10 +51,32 @@ void __init __acpi_unmap_table(char *map, unsigned long size)
>>>>    	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.
>>>> @@ -64,8 +88,16 @@ void __init acpi_boot_table_init(void)
>>>>    		return;
>>>>
>>>>    	/* Initialize the ACPI boot-time table parser. */
>>>> -	if (acpi_table_init())
>>>> +	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");
>>>> +	}
>>>>    }
>>>
>>> It looks fine to call disable_acpi() here but a bit weird to call it
>>> again in acpi_parse_fadt(). I guess that's because acpi_table_parse()
>>> ignores the return value of the handler() call. I think it's better to
>>> fix the core code (can be an additional patch on top of this series).
>>
>> I checked all the code calling acpi_table_parse() and I found that it
>> will be no functional change if we return the value of handler(), but
>> I need Rafael's confirm on it.
>
> Are you sure ? All calls to acpi_table_parse() that checks the return
> value are affected. I guess that depends on what an error return from
> the handler means, from acpi_table_parse():
>
> * Return 0 if table found, -errno if not.

Yes, you are right. What I mean for the "no functional change" because
of most handler passed to acpi_table_parse() just return 0, I didn't
describe it clearly, my bad.

In ARM64 case, I find that we can not disable ACPI even if we return
error for the handler, for example, we return -EOPNOTSUPP when there is
no PSCI support, we can go on with cpu0 boot only.

>
> So, if table is found but parsing fails that acpi_table_parse()
> signature should be changed if the handler barfs with an error and
> it is propagated. Still, I share Catalin's comment.

Sorry, I don't understand the last sentence, do you mean you agree
with Catalin to return the result of handler()?

Thanks
Hanjun
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