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[PATCH V3 1/2] ACPI / EC: Fix broken big-endian 64bit platforms using 'global_lock'

Started byViresh Kumar <viresh.kumar@linaro.org>
First post2015-09-15 10:40 +0200
Last post2015-09-16 04:00 +0200
Articles 4 — 2 participants

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  [PATCH V3 1/2] ACPI / EC: Fix broken big-endian 64bit platforms using 'global_lock' Viresh Kumar <viresh.kumar@linaro.org> - 2015-09-15 10:40 +0200
    Re: [PATCH V3 1/2] ACPI / EC: Fix broken big-endian 64bit platforms using 'global_lock' "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-09-16 03:30 +0200
      Re: [PATCH V3 1/2] ACPI / EC: Fix broken big-endian 64bit platforms using 'global_lock' "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-09-16 03:40 +0200
        Re: [PATCH V3 1/2] ACPI / EC: Fix broken big-endian 64bit platforms  using 'global_lock' Viresh Kumar <viresh.kumar@linaro.org> - 2015-09-16 04:00 +0200

#1224766 — [PATCH V3 1/2] ACPI / EC: Fix broken big-endian 64bit platforms using 'global_lock'

FromViresh Kumar <viresh.kumar@linaro.org>
Date2015-09-15 10:40 +0200
Subject[PATCH V3 1/2] ACPI / EC: Fix broken big-endian 64bit platforms using 'global_lock'
Message-ID<q8TWq-7VB-31@gated-at.bofh.it>
global_lock is defined as an unsigned long and accessing only its lower
32 bits from sysfs is incorrect, as we need to consider other 32 bits
for big endian 64 bit systems.

Fix that by making global_lock an u32 instead.

Cc: <stable@vger.kernel.org>  # v4.1+
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

---
Its marked just for # v4.1+, because arm64 has the first 64 big-endian
platform with ACPI. And ACPI support for that is mainlined recently
only (Arnd Bergmann).

Another thing worth noticing is that, global_lock is getting an unsigned
long long value assigned to it in ec_parse_device() and this is what
Arnd had to say about that:

"I think that's fine, it does this because the _GLP variable in ACPI is
defined as an u64. And that's what happens on 32-bit architectures
anyway."

This patch should go via GregKH, as the second patch has dependency on
it.

V2->V3:
- Moved this out in a separate patch, so that it can be backported.
---
 drivers/acpi/ec_sys.c   | 2 +-
 drivers/acpi/internal.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/ec_sys.c b/drivers/acpi/ec_sys.c
index b4c216bab22b..bea8e425a8de 100644
--- a/drivers/acpi/ec_sys.c
+++ b/drivers/acpi/ec_sys.c
@@ -128,7 +128,7 @@ static int acpi_ec_add_debugfs(struct acpi_ec *ec, unsigned int ec_device_count)
 	if (!debugfs_create_x32("gpe", 0444, dev_dir, (u32 *)&first_ec->gpe))
 		goto error;
 	if (!debugfs_create_bool("use_global_lock", 0444, dev_dir,
-				 (u32 *)&first_ec->global_lock))
+				 &first_ec->global_lock))
 		goto error;
 
 	if (write_support)
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 9e426210c2a8..9db196de003c 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -138,7 +138,7 @@ struct acpi_ec {
 	unsigned long gpe;
 	unsigned long command_addr;
 	unsigned long data_addr;
-	unsigned long global_lock;
+	u32 global_lock;
 	unsigned long flags;
 	unsigned long reference_count;
 	struct mutex mutex;
-- 
2.4.0

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#1225655

From"Rafael J. Wysocki" <rjw@rjwysocki.net>
Date2015-09-16 03:30 +0200
Message-ID<q99HQ-6jL-5@gated-at.bofh.it>
In reply to#1224766
On Tuesday, September 15, 2015 02:04:58 PM Viresh Kumar wrote:
> global_lock is defined as an unsigned long and accessing only its lower
> 32 bits from sysfs is incorrect, as we need to consider other 32 bits
> for big endian 64 bit systems.
> 
> Fix that by making global_lock an u32 instead.
> 
> Cc: <stable@vger.kernel.org>  # v4.1+
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> 
> ---
> Its marked just for # v4.1+, because arm64 has the first 64 big-endian
> platform with ACPI. And ACPI support for that is mainlined recently
> only (Arnd Bergmann).

OK

So are you aware of any ARM platform implementing the ACPI EC?

I am not.  Moreover, I'm not aware of any plans in that area.

> Another thing worth noticing is that, global_lock is getting an unsigned
> long long value assigned to it in ec_parse_device() and this is what
> Arnd had to say about that:
> 
> "I think that's fine, it does this because the _GLP variable in ACPI is
> defined as an u64. And that's what happens on 32-bit architectures
> anyway."
> 
> This patch should go via GregKH, as the second patch has dependency on
> it.
> 
> V2->V3:
> - Moved this out in a separate patch, so that it can be backported.

Lv, can you have a look at this, please?

> ---
>  drivers/acpi/ec_sys.c   | 2 +-
>  drivers/acpi/internal.h | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/acpi/ec_sys.c b/drivers/acpi/ec_sys.c
> index b4c216bab22b..bea8e425a8de 100644
> --- a/drivers/acpi/ec_sys.c
> +++ b/drivers/acpi/ec_sys.c
> @@ -128,7 +128,7 @@ static int acpi_ec_add_debugfs(struct acpi_ec *ec, unsigned int ec_device_count)
>  	if (!debugfs_create_x32("gpe", 0444, dev_dir, (u32 *)&first_ec->gpe))
>  		goto error;
>  	if (!debugfs_create_bool("use_global_lock", 0444, dev_dir,
> -				 (u32 *)&first_ec->global_lock))
> +				 &first_ec->global_lock))
>  		goto error;
>  
>  	if (write_support)
> diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
> index 9e426210c2a8..9db196de003c 100644
> --- a/drivers/acpi/internal.h
> +++ b/drivers/acpi/internal.h
> @@ -138,7 +138,7 @@ struct acpi_ec {
>  	unsigned long gpe;
>  	unsigned long command_addr;
>  	unsigned long data_addr;
> -	unsigned long global_lock;
> +	u32 global_lock;
>  	unsigned long flags;
>  	unsigned long reference_count;
>  	struct mutex mutex;
> 

Thanks,
Rafael

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#1225660

From"Rafael J. Wysocki" <rjw@rjwysocki.net>
Date2015-09-16 03:40 +0200
Message-ID<q99Rw-6uQ-9@gated-at.bofh.it>
In reply to#1225655
On Wednesday, September 16, 2015 03:57:05 AM Rafael J. Wysocki wrote:
> On Tuesday, September 15, 2015 02:04:58 PM Viresh Kumar wrote:
> > global_lock is defined as an unsigned long and accessing only its lower
> > 32 bits from sysfs is incorrect, as we need to consider other 32 bits
> > for big endian 64 bit systems.
> > 
> > Fix that by making global_lock an u32 instead.
> > 
> > Cc: <stable@vger.kernel.org>  # v4.1+
> > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> > 
> > ---
> > Its marked just for # v4.1+, because arm64 has the first 64 big-endian
> > platform with ACPI. And ACPI support for that is mainlined recently
> > only (Arnd Bergmann).
> 
> OK
> 
> So are you aware of any ARM platform implementing the ACPI EC?
> 
> I am not.  Moreover, I'm not aware of any plans in that area.

In any case, please just split the EC-related changes off from your second
patch and send them separately.

Thanks,
Rafael

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#1225662 — Re: [PATCH V3 1/2] ACPI / EC: Fix broken big-endian 64bit platforms using 'global_lock'

FromViresh Kumar <viresh.kumar@linaro.org>
Date2015-09-16 04:00 +0200
SubjectRe: [PATCH V3 1/2] ACPI / EC: Fix broken big-endian 64bit platforms using 'global_lock'
Message-ID<q9aaS-6Rm-1@gated-at.bofh.it>
In reply to#1225660
On 16-09-15, 04:06, Rafael J. Wysocki wrote:
> In any case, please just split the EC-related changes off from your second
> patch and send them separately.

That !! change isn't required anymore, will be dropping it completely.

-- 
viresh
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